The American Journal of Sports Medicine

In pediatric patients, anterior cruciate ligament (ACL) reconstruction is controversial; however, delaying surgery until skeletal maturity is complete may increase the risk of secondary meniscal and articular cartilage injury.

To assess the risk of meniscal and chondral injuries with delay of ACL reconstruction.

Cohort study; Level of evidence, 3.

Records were reviewed in patients younger than 17 years (median age, 14 years) who had ACL reconstruction. Patients were consecutively enrolled and assigned to 1 of 3 surgical groups based on timing of surgery: acute (<6 weeks after surgery), subacute (6-12 weeks), or chronic (>3 months). The type and grade of meniscal injuries was documented according to the International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine (ISAKOS) meniscal classification criteria. International Cartilage Repair Society (ICRS) criteria were used to document location and grade of chondral injuries. Associations between patient characteristics and meniscal injury were tested using rank sum and chi-square tests. Regression analyses were conducted to model incidence and severity of lateral and medial meniscal tears. There were 130 patients who had 135 ACL reconstructions between the years of 2000 and 2012.

Sixty-two ACL injuries were treated acutely, 37 were subacute, and 36 were chronic. Meniscal injuries (n = 112) included 70 lateral and 42 medial tears. Time to surgery had bivariate association with lateral and medial meniscal tears (P = .016 and .007, respectively). Independent risk factors for incidence of lateral meniscal tears were younger age (P = .028) and return to sports activities before surgery (P = .007). Patients with 1 episode of instability had 3-fold higher odds of higher grade lateral meniscal tear (95% CI, 1.30-7.60). Compared with acute reconstruction, subacute and chronic reconstruction patients had 1.45 and 2.82 times higher odds, respectively, of lateral meniscal tear severity (P = .12). Independent risk factors for incidence of medial meniscal tears were female sex (P = .03), older age (P = .01), and any episode of instability (P = .01). Adjusted odds ratio for medial meniscal tear was 4.7 for an instability episode (vs no episode; P = .01). Adjusted odds ratio for increased severity of medial meniscal tears included any instability episode, 5.6 (P < .01); playing sports before reconstruction, 15.2 (P < .01); and time to surgery greater than 3 months, 4.3 (P = .046). Seventeen patients had 23 chondral injuries. The risk factors for chondral injury included increased time to surgery (P = .005) and any instability episode (P = .001). For increased grade of chondral injury, risk factors were time to surgery (P ≤ .001) and any instability episode (P = .003).

Delayed ACL reconstruction increased the risks of secondary meniscal and chondral injuries in this population of pediatric patients.

The timing of treatment for pediatric anterior cruciate ligament (ACL) injuries remains controversial. The risks of delaying reconstruction and the differences between age groups are poorly defined.

To investigate factors that contribute to the prevalence and severity of concomitant chondral and meniscal injuries among patients aged 14 to 19 years versus those aged ≤14 years at the time of ACL reconstruction. The hypothesis was that concomitant injuries would be more prevalent in older versus younger subjects. Also, a delay in surgery would be predictive of the presence and severity of concomitant knee injuries requiring additional operative procedures.

Cohort study; Level of evidence, 3.

All subjects who underwent primary ACL reconstruction at a single tertiary pediatric hospital between 2005 and 2012 were retrospectively reviewed. The location, severity, and treatment of all concomitant knee injuries were recorded. Chi-square tests were used to compare the prevalence of chondral and meniscal injuries in the older (age, 14-19 years; n = 165) versus younger (age, ≤14 years; n = 66) cohorts. A multivariable logistic regression analysis was used to identify factors related to the presence of a concomitant injury that required additional treatment. Kaplan-Meier analyses were used to explore the relation between time to surgery and meniscal injury severity.

There was a significant relationship between time to surgery and the development of an irreparable meniscal injury (P < .05 for all) in both the younger and older groups. Time to surgery correlated with severity of chondral injury in the younger cohort (P = .0343) but not in the older cohort (P = .8877). In the younger cohort, only a delay in surgery >3 months (odds ratio [OR] = 4.8; 95% CI, 1.7-14.4; P = .0027) was significantly predictive of the presence of an injury that required additional operative procedures. In the older patients, a return to activity before surgery (OR = 3.8; 95% CI, 1.52-11.9; P = .0034) and obesity (OR = 2.5; 95% CI, 1.1-7.4; P = .0381) were significantly predictive of an injury that required additional operative procedures.

Compared with younger subjects, the prevalence of concomitant knee injuries as well as the need for additional operative procedures was greater among older subjects. A delay to surgery correlated with increased severity of injury among both older and younger populations. A delay in surgery >3 months was the strongest predictor of the development of a concomitant injury in the younger cohort. A return to activity and obesity were significantly related to the presence of a concomitant knee injury in the older cohort.

The treatment of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial. Current evidence supports the view that surgical techniques restore knee stability and prevent progressive articular damage. However, most of the studies on this topic are small case series or they have short- or medium-term follow-up times.

To determine the long-term functional outcomes and secondary complications of transphyseal intra-articular ACL reconstruction with hamstring graft in skeletally immature patients.

Case series; Level of evidence, 4.

Transphyseal ACL reconstruction with autograft hamstrings was performed in 27 skeletally immature patients. The average age at surgery was 13 years (range, 12-16 years), and the average follow-up time was 10.6 years (range, 10-13 years). Clinical outcomes were assessed with preoperative and final follow-up Tegner, International Knee Documentation Committee (IKDC) subjective, and Lysholm scores. Surgery details, return to sports, and ACL reconstruction failures were collected. The anteroposterior knee laxity was assessed by arthrometry, and the presence of deformities and lower limb length discrepancies were evaluated by radiographs. The presence of degenerative signs on anteroposterior and lateral knee radiographs at final follow-up was also evaluated.

Transphyseal ACL reconstruction was performed with vertically oriented tunnels, 7 to 10 mm in diameter, using semitendinosus-gracilis autograft. The average preoperative Tegner, IKDC, and Lysholm scores were 7, 55, and 40, respectively. Significant differences in these scores were observed at the time of the final assessment (Tegner, 6 [P = .026]; IKDC, 94 [P < .001]; Lysholm, 92 [P < .001]). Two patients reported instability during sports activity. Three patients had a rupture of the ACL graft. No leg length discrepancy, axis malalignment, or degenerative changes were observed.

The transphyseal ACL reconstruction in skeletally immature patients is a safe option, with high functional and satisfaction results, without significant growth plate damage in this series of patients.

Identifying predictors of contralateral anterior cruciate ligament (ACL) reconstruction is important to focus preventive strategies and related research on high-risk groups.

To investigate predictors of contralateral ACL reconstruction in patients who have already undergone a primary ipsilateral reconstruction.

Cohort study; Level of evidence, 2.

This study was based on data from the Swedish National Knee Ligament Register from January 1, 2005, to December 31, 2013. Patients aged 13 to 59 years who underwent primary ipsilateral (index) ACL reconstruction with hamstring tendon or bone–patellar tendon–bone autografts were included. Follow-up started on date of index ACL reconstruction and ended either with primary contralateral ACL reconstruction, after 5 years of follow-up, or on December 31, 2013, whichever occurred first. The investigated variables were patient sex, age at index reconstruction, activity at the time of index injury, timing of surgery, graft selection, graft harvest site, and meniscal and chondral injury. The study end point was primary contralateral ACL reconstruction. Relative risks (RRs) and 95% CIs were calculated and adjusted for confounding factors using multivariate statistics.

A total of 9061 participants were included (n = 5196 males [57.3%] and 3865 females [42.7%]), of which 270 participants (3.0%) underwent primary contralateral ACL reconstruction during the 5-year follow-up. There was no difference in contralateral reconstruction rates between males and females (3.0% vs 2.9%, P = .695). Age <20 years significantly increased the risk of contralateral reconstruction (males: RR = 2.4 [95% CI, 1.7-3.4] and females: RR = 2.9 [95% CI, 1.9-4.5]; P < .001). Among female patients undergoing reconstruction using autograft hamstring, harvest of a contralateral hamstring tendon significantly increased this risk (RR = 3.4 [95% CI, 1.4-7.9]; P = .006).

In both male and female participants, age <20 years predicted an almost 3 times higher 5-year risk of contralateral ACL reconstruction. Among female participants undergoing reconstruction with autograft hamstring, a contralateral harvest predicted a more than 3 times higher 5-year risk of contralateral ACL reconstruction. Patient sex, activity at the time of index injury, graft selection, meniscal injury, and chondral injury were not predictors of contralateral ACL reconstruction.

Osteochondritis dissecans (OCD) is a vexing condition for patients, parents, and physicians because of the frequent slow healing and nonhealing that leads to prolonged treatment. Several features on plain radiographs have been identified as predictors of healing, but the reliability of their measurement has not been established.

To determine the inter- and intrarater reliability of several radiographic features used in the diagnosis, treatment, and prognosis of OCD femoral condyle lesions.

Cohort study (Diagnosis); Level of evidence, 3.

Pretreatment anteroposterior, lateral, and notch radiographs of 45 knees containing OCD lesions of the medial or lateral femoral condyle were reviewed in blinded fashion by 7 orthopaedic physician raters from different institutions over a secure web portal at 2 time points over a month apart. Classification variables included lesion location, growth plate maturity, parent bone radiodensity, progeny bone fragmentation, progeny bone displacement, progeny bone contour, lesion boundary, and radiodensity of the lesion center and rim. Condylar width and lesion size were measured on all views. Interrater reliability was assessed using free-marginal kappa and intraclass correlations. Intrarater reliability was assessed using the Cohen kappa, linear-weighted kappa, and intraclass correlations based on measurement type.

Raters had excellent reliability for differentiating medial and lateral lesions and growth plate maturity and for measuring condylar width and lesion size. In the subset of knees with visible bone in the lesion, the fragmentation, displacement, boundary, central radiodensity, and contour (concave/nonconcave) of the lesion bone were classified with moderate to substantial reliability. The radiodensity of the lesion rim and surrounding epiphyseal bone were classified with poor to fair reliability.

Many diagnostic features of femoral condyle OCD lesions can be reliably classified on plain radiographs, supporting their future testing in multifactorial classification systems and multicenter research to develop prognostic algorithms. Other radiographic features should be excluded, however, because of poor reliability.

Anterior cruciate ligament (ACL) reconstruction failure occurs in up to 10% of cases. Technical errors are considered the most common cause of graft failure despite the absence of validated studies. Limited data are available regarding the agreement among orthopaedic surgeons regarding the causes of primary ACL reconstruction failure and accuracy of graft tunnel placement.

Experienced knee surgeons have a high level of interobserver reliability in the agreement about the causes of primary ACL reconstruction failure, anatomic graft characteristics, and tunnel placement.

Cohort study (diagnosis); Level of evidence, 3.

Twenty cases of revision ACL reconstruction were randomly selected from the Multicenter ACL Revision Study (MARS) database. Each case included the patient’s history, standardized radiographs, and a concise 30-second arthroscopic video taken at the time of revision demonstrating the graft remnant and location of the tunnel apertures. All 20 cases were reviewed by 10 MARS surgeons not involved with the primary surgery. Each surgeon completed a 2-part questionnaire dealing with each surgeon’s training and practice, as well as the placement of the femoral and tibial tunnels, condition of the primary graft, and the surgeon’s opinion as to the causes of graft failure. Interrater agreement was determined for each question with the kappa coefficient and the prevalence-adjusted, bias-adjusted kappa (PABAK).

The 10 reviewers have been in practice an average of 14 years and have performed at least 25 ACL reconstructions per year, and 9 were fellowship trained in sports medicine. There was wide variability in agreement among knee experts as to the specific causes of ACL graft failure. When participants were specifically asked about technical error as the cause for failure, interobserver agreement was only slight (PABAK = 0.26). There was fair overall agreement on ideal femoral tunnel placement (PABAK = 0.55) but only slight agreement on whether a femoral tunnel was too anterior (PABAK = 0.24) and fair agreement on whether it was too vertical (PABAK = 0.46). There was poor overall agreement for ideal tibial tunnel placement (PABAK = 0.17).

This study suggests that more objective criteria are needed to accurately determine the causes of primary ACL graft failure as well as the ideal femoral and tibial tunnel placement in patients undergoing revision ACL reconstruction.

Coculture of mesenchymal stem cells (MSCs) from the retropatellar fat pad and peripheral blood has been shown to stimulate anterior cruciate ligament (ACL) fibroblast proliferation and collagen production in vitro. Current techniques of bioenhanced ACL repair in animal studies involve adding a biologic scaffold, in this case an extracellular matrix–based scaffold saturated with autologous whole blood, to a simple suture repair of the ligament. Whether the enrichment of whole blood with MSCs would further improve the in vivo results of bioenhanced ACL repair was investigated.

The addition of MSCs derived from adipose tissue or peripheral blood to the blood–extracellular matrix composite, which is used in bioenhanced ACL repair to stimulate healing, would improve the biomechanical properties of a bioenhanced ACL repair after 15 weeks of healing.

Controlled laboratory study.

Twenty-four adolescent Yucatan mini-pigs underwent ACL transection followed by (1) bioenhanced ACL repair, (2) bioenhanced ACL repair with the addition of autologous adipose-derived MSCs, and (3) bioenhanced ACL repair with the addition of autologous peripheral blood derived MSCs. After 15 weeks of healing, the structural properties of the ACL (yield load, failure load, and linear stiffness) were measured. Cell and vascular density were measured in the repaired ACL via histology, and its tissue structure was qualitatively evaluated using the advanced Ligament Maturity Index.

After 15 weeks of healing, there were no significant improvements in the biomechanical or histological properties with the addition of adipose-derived MSCs. The only significant change with the addition of peripheral blood MSCs was an increase in knee anteroposterior laxity when measured at 30° of flexion.

These findings suggest that the addition of adipose or peripheral blood MSCs to whole blood before saturation of an extracellular matrix carrier with the blood did not improve the functional results of bioenhanced ACL repair after 15 weeks of healing in the pig model.

Whole blood represents a practical biologic additive to ligament repair, and any other additive (including stem cells) should be demonstrated to be superior to this baseline before clinical use is considered.

Femoral nerve block (FNB) has become a popular method of postoperative analgesia for anterior cruciate ligament (ACL) reconstruction in pediatric and adolescent patients. Successful rehabilitation after surgery involves return of quadriceps and hamstring strength.

To compare knee strength and function 6 months after ACL reconstruction in pediatric and adolescent patients who received FNB versus patients with no nerve block.

Cohort study; Level of evidence, 3.

Patients 18 years or younger who underwent primary ACL reconstruction between 2000 and 2010 at a single institution were identified. If the patient was skeletally immature, a transphyseal ACL reconstruction was performed. Of these patients, 68% underwent reconstruction with a patellar tendon autograft, and in 32% of patients a hamstring autograft was utilized. There were 124 patients who met the study inclusion criteria, including 62 in the FNB group (31 males, 31 females) and 62 patients in the control group (25 males, 37 females). All study patients participated in a comprehensive rehabilitation program that included isokinetic strength and functional testing at 6 months postoperatively.

Univariate analysis showed a significantly higher deficit at 6 months in the FNB group with respect to fast isokinetic extension strength (17.6% vs 11.2%; P = .01) as well as fast (9.9% vs 5.7%; P = .04) and slow (13.0% vs 8.5%; P = .03) isokinetic flexion strength. There was no difference in slow isokinetic extension strength deficit between the 2 groups (FNB, 22.3% vs control, 18.7%; P = .20). With respect to function, there were no differences in deficit for vertical jump (FNB, 9.4% vs control, 11.3%; P = .30), single hop (7.6% vs 7.5%; P = .96), or triple hop (8.0% vs 6.6%; P = .34) between the 2 groups. A significantly higher percentage of patients in the control group met functional and isokinetic criteria for return to sports at 6 months (90.2% vs 67.7%; odds ratio, 4.37; P = .002).

Pediatric and adolescent patients treated with FNB for postoperative analgesia after ACL reconstruction had significant isokinetic deficits in knee extension and flexion strength at 6 months when compared with patients who did not receive a nerve block. Patients without a block were 4 times more likely to meet criteria for clearance to return to sports at 6 months.

Postoperative knee chondrolysis caused by continuous intra-articular pain pumps infusing bupivacaine with epinephrine is a rare but serious complication.

To determine the association between postoperative intra-articular infusion of bupivacaine with epinephrine and the development of knee chondrolysis in patients who have undergone arthroscopic anterior cruciate ligament reconstruction (ACLR). The authors hypothesized that the development of knee chondrolysis after ACLR is associated with postoperative high-dose intra-articular bupivacaine with epinephrine infusion.

Cohort study; Level of evidence, 3.

In this retrospective cohort study, the charts of all patients treated with arthroscopic ACLR by a single surgeon between January 1, 2004, and December 31, 2006, were reviewed. Patients with severe articular cartilage damage at the time of the index procedure, with known knee joint infection, inflammatory arthritis, multiligament knee injury, bilateral knee injury, or any previous knee surgery, were excluded. Patients were grouped into 2 cohorts: the exposure group (those who had postoperative infusion of bupivacaine with epinephrine via an intra-articular pain pump [IAPP]) and the nonexposure group (those without postoperative infusion).

A total of 105 patients met the inclusion and exclusion criteria. There were 57 male and 48 female patients with a mean age at surgery of 25.5 ± 8.6 years (range, 13-52 years). The exposure group consisted of 46 patients and the control group of 59 patients. Thirteen of 46 patients (28.3%) who received an IAPP developed chondrolysis. There were no cases of chondrolysis in the control group. Of those in the exposure group, 32 patients were exposed to 0.5% bupivacaine with epinephrine and 12 developed chondrolysis (37.5%), while 14 patients were exposed to 0.25% bupivacaine with epinephrine and 1 developed chondrolysis (7.1%). Patients exposed to 0.5% bupivacaine with epinephrine had a significantly higher incidence of chondrolysis compared with those exposed to 0.25% (P = .03). Patients with chondrolysis had severe pain and limitations in daily activity.

The development of knee chondrolysis was associated with the intra-articular infusion of bupivacaine with epinephrine postoperatively. Furthermore, the presented evidence suggests that this occurs in a dose-dependent manner. The risk of knee chondrolysis might be reduced by avoidance of intra-articular infusion of bupivacaine with epinephrine. We recommend against continuous intra-articular infusion of local anesthetic postoperatively.

Fear of reinjury and lack of confidence influence return-to-sport outcomes after anterior cruciate ligament (ACL) reconstruction. The physical, psychosocial, and functional recovery of patients reporting fear of reinjury or lack of confidence as their primary barrier to resuming sports participation is unknown.

To compare physical impairment, functional, and psychosocial measures between subgroups based on return-to-sport status and fear of reinjury/lack of confidence in the return-to-sport stage and to determine the association of physical impairment and psychosocial measures with function for each subgroup at 6 months and 1 year after surgery.

Case-control study; Level of evidence, 3.

Physical impairment (quadriceps index [QI], quadriceps strength/body weight [QSBW], hamstring:quadriceps strength ratio [HQ ratio], pain intensity), self-report of function (International Knee Documentation Committee [IKDC]), and psychosocial (Tampa Scale for Kinesiophobia–shortened form [TSK-11]) measures were collected at 6 months and 1 year after surgery in 73 patients with ACL reconstruction. At 1 year, subjects were divided into “return-to-sport” (YRTS) or “not return-to-sport” (NRTS) subgroups based on their self-reported return to preinjury sport status. Patients in the NRTS subgroup were subcategorized as NRTS-Fear/Confidence if fear of reinjury/lack of confidence was the primary reason for not returning to sports, and all others were categorized as NRTS-Other.

A total of 46 subjects were assigned to YRTS, 13 to NRTS-Other, and 14 to NRTS-Fear/Confidence. Compared with the YRTS subgroup, the NRTS-Fear/Confidence subgroup was older and had lower QSBW, lower IKDC score, and higher TSK-11 score at 6 months and 1 year; however, they had similar pain levels. In the NRTS-Fear/Confidence subgroup, the IKDC score was associated with QSBW and pain at 6 months and QSBW, QI, pain, and TSK-11 scores at 1 year.

Elevated pain-related fear of movement/reinjury, quadriceps weakness, and reduced IKDC score distinguish patients who are unable to return to preinjury sports participation because of fear of reinjury/lack of confidence. Despite low average pain ratings, fear of pain may influence function in this subgroup. Assessment of fear of reinjury, quadriceps strength, and self-reported function at 6 months may help identify patients at risk for not returning to sports at 1 year and should be considered for inclusion in return-to-sport guidelines.

Lateral extra-articular soft tissue reconstructions in the knee may be used as a combined procedure in revision anterior cruciate ligament surgery as well as in primary treatment for patients who demonstrate excessive anterolateral rotatory instability. Only a few studies examining length change patterns and isometry in lateral extra-articular reconstructions have been published.

To determine a recommended femoral insertion area and graft path for lateral extra-articular reconstructions by measuring length change patterns through a range of knee flexion angles of several combinations of tibial and femoral insertion points on the lateral side of the knee.

Controlled laboratory study.

Eight fresh-frozen cadaveric knees were freed of skin and subcutaneous fat. The knee was then mounted in a kinematics rig that loaded the quadriceps muscles and simulated open-chain knee flexion. The length changes of several combinations of tibiofemoral points were measured at knee flexion angles between 0° and 90° by use of linear variable displacement transducers. The changes in length relative to the 0° measurement were recorded.

The anterior fiber region of the iliotibial tract displayed a significantly different (P < .001) length change pattern compared with the posterior fiber region. The reconstructions that had a femoral insertion site located proximal to the lateral epicondyle and with the grafts passed deep to the lateral collateral ligament displayed similar length change patterns to each other, with small length increases during knee extension. These reconstructions also showed a significantly lower total strain range compared with the reconstruction located anterior to the epicondyle (P < .001).

These findings show that the selection of graft attachment points and graft course affects length change pattern during knee flexion. A graft attached proximal to the lateral femoral epicondyle and running deep to the lateral collateral ligament will provide desirable graft behavior, such that it will not suffer excessive tightening or slackening during knee motion.

These results provide a surgical rationale for lateral extra-articular soft tissue reconstruction in terms of femoral graft fixation site and graft route.

Meniscal root tears present in many forms and can have profound consequences on the health of knee articular cartilage. While the biomechanics, natural history, and treatment of root tears have been increasingly investigated, the spectrum of meniscal root tear patterns observed during arthroscopic examination has yet to be defined and categorized.

To establish a classification system for meniscal root tears by reporting the morphology of meniscal root tears from a consecutive series of arthroscopic surgeries. It was hypothesized that meniscal root tears could be grouped into types by distinct tear patterns and that recognition of tear pattern would affect treatment choice.

Case series; Level of evidence, 4.

All patients who underwent arthroscopic surgery from April 2010 to May 2014 by a single orthopaedic surgeon were included. After arthroscopic examination, data regarding the integrity of the meniscal roots were prospectively recorded in a data registry. Tear morphology and treatment received were subsequently extracted by 2 independent reviewers from operative notes and arthroscopic surgical photos.

A total of 71 meniscal root tears in 67 patients were grouped into tear types with similar tear morphologies. Meniscal root tear patterns were categorized into partial stable root tears (type 1; n = 5); complete radial tears within 9 mm of the bony root attachment (type 2; n = 48), further subclassified into types 2A, 2B, and 2C, located 0 to <3 mm, 3 to <6 mm, and 6 to 9 mm from the root attachment, respectively; bucket-handle tears with a complete root detachment (type 3; n = 4); complex oblique tears with complete root detachments extending into the root attachment (type 4; n = 7); and bony avulsion fractures of the root attachments (type 5; n = 7).

This study demonstrated that it was possible to establish a concise classification system to group patients with meniscal root tears by tear morphology. Treatments received varied across tear types.

Altered local mechanical loading may disrupt normal cartilage homeostasis and play a role in the progression of osteoarthritis. Currently, there are limited data quantifying local cartilage strains in response to dynamic activity in normal or injured knees.

To directly measure local tibiofemoral cartilage strains in response to a dynamic hopping activity in normal healthy knees. We hypothesized that local regions of cartilage will exhibit significant compressive strains in response to hopping, while overall compartmental averages may not.

Controlled laboratory study.

Both knees of 8 healthy subjects underwent magnetic resonance imaging before and immediately after a dynamic hopping activity. Images were segmented and then used to create 3-dimensional surface models of bone and cartilage. These pre- and postactivity models were then registered using an iterative closest point technique to enable site-specific measurements of cartilage strain (defined as the normalized change in cartilage thickness before and after activity) on the femur and tibia.

Significant strains were observed in both the medial and lateral tibial cartilage, with each compartment averaging a decrease of 5%. However, these strains varied with location within each compartment, reaching a maximum compressive strain of 8% on the medial plateau and 7% on the lateral plateau. No significant averaged compartmental strains were observed in the medial or lateral femoral cartilage. However, local regions of the medial and lateral femoral cartilage experienced significant compressive strains, reaching maximums of 6% and 3%, respectively.

Local regions of both the femur and tibia experienced significant cartilage strains as a result of dynamic activity. An understanding of changes in cartilage strain distributions may help to elucidate the biomechanical factors contributing to cartilage degeneration after joint injury.

Site-specific measurements of in vivo cartilage strains are important because altered loading is believed to be a factor contributing to the development and progression of osteoarthritis. Specifically, this methodology and data could be used to evaluate the effects of soft tissue injuries (such as ligament or meniscus tears) on cartilage strains in response to dynamic activities of daily living.

Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the rate of recurrence has been consistently high for a number of years. Long-lasting neuromuscular inhibition has been noted in previously injured athletes, but it is not known if this influences the athlete’s adaptive response to training.

To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display less improvement in eccentric hamstring strength during preseason training compared with athletes without a history of HSIs (control group).

Cohort study; Level of evidence, 2.

A total of 99 elite Australian footballers (17 with a history of unilateral HSIs in the previous 12-month period) participated in this study. Eccentric hamstring strength was assessed at the start and end of preseason training using an instrumented Nordic hamstring device. The change in eccentric strength across the preseason was determined in absolute terms and normalized to the start of preseason strength. The start of preseason strength was used as a covariate to control for differences in starting strength.

The left and right limbs in the control group showed no difference in absolute or relative change (left limb: 60.7 ± 72.9 N and 1.28 ± 0.34 N, respectively; right limb: 48.6 ± 83.8 N and 1.24 ± 0.43 N, respectively). Similarly, the injured and uninjured limbs in the previously injured group showed no difference in either absolute or relative change (injured limb: 13.1 ± 57.7 N and 1.07 ± 0.18 N, respectively; uninjured limb: 14.7 ± 54.0 N and 1.07 ± 0.22 N, respectively). The previously injured group displayed significantly less increase in eccentric hamstring strength across the preseason (absolute change, 13.9 ± 55.0 N; relative change, 1.07 ± 0.20 N) compared with the control group (absolute change, 54.6 ± 78.5 N; relative change, 1.26 ± 0.39 N) for both absolute and relative measures (P < .001), even after controlling for differences in the start of preseason eccentric hamstring strength, which had a significant effect on strength improvement.

Elite Australian footballers with a unilateral history of HSIs displayed less improvement in eccentric hamstring strength across preseason training. The smaller improvements were not restricted to the previously injured limb as the contralateral limb also displayed similarly small improvements in eccentric strength. Whether this is the cause of or the result of an injury remains to be seen, but it has the potential to contribute to the risk of hamstring strain reinjuries.

Avulsion of the proximal hamstring origin is well documented, and surgical treatment is advocated for complete avulsions.

To compare the return to preinjury level of sport and the complexity of surgery in athletes undergoing surgical intervention for complete proximal hamstring avulsions within 6 weeks, 6 months, and after 6 months of injury.

Case series; Level of evidence, 4.

This was the largest case series from a tertiary referral center reported in the literature. A total of 112 athletes were included, with complete proximal avulsion injuries confirmed on MRI scans; 63 patients (56.3%) were high-level athletes. Patients were divided into subgroups depending on the timing of surgical intervention: “early” was defined within 6 weeks, “delayed” within 6 weeks to 6 months, and “late” after 6 months. All patients were surgically explored and repaired with the aim of comparing the timing between each group and the return to preinjury sport. All patients underwent an individualized rehabilitation protocol. There was no loss to follow-up. The primary outcome measure was the return to preinjury level sports activity.

A total of 108 patients (96.4%) returned to sport. In the early intervention group, the average time of return to play was 16 weeks, 9 weeks faster than the delayed group and 13 weeks faster than the late group. There were 2 partial reruptures in those with delayed intervention—both athletes retired from competitive sport but were recreationally active. Two other athletes recovered well but retired from playing at all levels. Twelve athletes (2 in the early intervention group, 5 in the delayed, 5 in the late) were delayed by local nerve symptoms. Only 2 cases required further exploration.

Early surgical intervention was associated with good clinical outcomes and a quicker return to sport; however, delaying the diagnosis can lead to prolonged morbidity and an increased likelihood of complications.

Patients with chronic exertional compartment syndrome (CECS) have pain during exercise that subsides with rest. Diagnosis is usually confirmed by intramuscular compartment pressure (IMCP) measurement. Controversy exists regarding the accuracy of existing diagnostic criteria.

(1) To compare dynamic IMCP measurement and anthropometric factors between patients with CECS and asymptomatic controls and (2) to establish the diagnostic utility of dynamic IMCP measurement.

Cohort study (diagnosis); Level of evidence, 2.

A total of 40 men aged 21 to 40 years were included in the study: 20 with symptoms of CECS of the anterior compartment and 20 asymptomatic controls. Diagnoses other than CECS were excluded with rigorous inclusion criteria and magnetic resonance imaging. The IMCP was measured continuously before, during, and after participants exercised on a treadmill, wearing identical footwear and carrying a 15-kg load.

Pain experienced by study subjects increased incrementally as the study progressed (P < .001). Pain levels experienced by the case group during each phase of the exercise were significantly different (P = .021). Subjects had higher IMCP immediately upon standing at rest compared with controls (23.8 mm Hg [controls] vs 35.5 mm Hg [subjects]; P = .006). This relationship persisted throughout the exercise protocol, with the greatest difference corresponding to the period of maximal tolerable pain (68.7 mm Hg [controls] vs 114 mm Hg [subjects]; P < .001). Sensitivity and specificity were consistently higher than the existing criteria with improved diagnostic value (sensitivity = 63%, specificity = 95%; likelihood ratio = 12.5 [95% CI, 3.2-49]).

Anterior compartment IMCP is elevated immediately upon standing at rest in subjects with CECS. In patients with symptoms consistent with CECS, diagnostic utility of IMCP measurement is improved when measured continuously during exercise. A cutoff of 105 mm Hg in phase 2 provides better diagnostic accuracy than do the Pedowitz criteria of 30 mm Hg and 20 mm Hg at 1 and 5 minutes after exercise, respectively.

Recently, mesenchymal stem cells (MSCs) have been suggested as a source for cell-based treatment of cartilage lesions based on the ability of these cells to differentiate into chondrocytes.

To characterize MSCs derived from the synovial fluid in ankle joints with osteochondral lesion of the talus (OLT).

Controlled laboratory study.

Synovial fluid was collected from the ankle joints of 28 patients with OLT who underwent arthroscopic marrow stimulation between September 2011 and April 2012. Epitope profiles and multilineage differentiation were assessed to characterize the synovial fluid MSCs. To clarify the origin of synovial fluid MSCs, we assessed gene profiles of MSCs derived from various mesenchymal tissues by reverse transcription–polymerase chain reaction (RT-PCR) analysis.

Synovial fluid MSCs expressed CD90 and CD105, showed low expression of CD14 and CD34, and underwent multilineage differentiation in vitro. The RT-PCR revealed strong expression of CD90, CD44, and CD73, whereas CD45 and CD133 were not detected. The colony number of synovial fluid MSCs from OLT significantly increased in stages C and D, as defined by arthroscopic classification. Gene expression profiles indicated that synovial fluid MSCs derived from the patients with OLT were more similar to MSCs from synovium than to MSCs from bone marrow and adipose tissue.

This study confirmed that human synovial fluid is a good source of MSCs, with the capacity to differentiate toward several cell lineages. Further study with matched controls of synovial fluid MSCs derived from ankle joints without OLT is required for a more accurate evaluation of synovial fluid MSCs.

The findings of this study provide a platform for exploring the potential role of synovial fluid MSCs in OLT and their therapeutic potential in novel joint regeneration strategies.

Hill-Sachs lesions are compression fractures that result from shoulder dislocation. They involve “engaging” the humeral head on the anterior glenoid rim when the arm is abducted and externally rotated. The defect grows as the number of dislocations increases.

Arthroscopic remplissage and anterior Bankart repair do not significantly affect infraspinatus strength while ensuring healing of the capsulotenodesis.

Cohort study; Level of evidence, 3.

Sixty-one patients with traumatic anterior shoulder instability treated by arthroscopic Bankart repair and Hill-Sachs remplissage at least 24 months previously were compared with a control group of 40 healthy participants. Preoperative imaging included magnetic resonance imaging for Bankart lesion identification and computed tomography to quantify the humeral head defect. Active range of motion and clinical scores (Walch-Duplay, Constant-Murley, and Rowe) were assessed. External rotation (ER) and internal rotation (IR) were measured with arm at the side (ER₁ and IR₁) and abducted at 90° (ER₂ and IR₂). Infraspinatus strength was assessed with the scapula free (infraspinatus strength test [IST]) and retracted (infraspinatus scapula retraction test [ISRT]). Infraspinatus tenodesis and posterior capsulodesis healing were evaluated by ultrasound (US).

The follow-up median was 39.5 months (range, 24-56 months). One patient experienced a recurrence of instability at 34 months. In the remplissage patients, ER₁ was significantly lower in the affected compared with the unaffected shoulder (P < .001). Mean IST and ISRT strength values did not show differences between sides. The mean Constant-Murley score rose from 62.9 ± 7.1 to 90 ± 5.2 (P < .0001). The Walch-Duplay and Rowe scores were excellent in 23 (78.6%), good in 6 (17.8%), and poor in 1 patient (both scores). The remplissage group had significantly lower ER₁ (P < .001), ER₂ (P < .001), and IR₂ (P < .01) values compared with the control group. Differences in IST and ISRT between the groups were not significant. Capsulotenodesis healing and filling of the Hill-Sachs defect were confirmed by dynamic US in all subjects.

Arthroscopic remplissage is a reliable approach to Hill-Sachs lesions. The ER and IR restriction does not significantly affect quality of life. Infraspinatus strength recovery is satisfactory even compared with healthy subjects. Ultrasound examination allows accurate evaluation of capsulotenodesis healing.

Intratendinous tears of the rotator cuff are rare, and little has been written about them.

To investigate the prevalence and clinical and radiological outcomes of arthroscopically confirmed intratendinous tears treated with transtendon suture bridge repair.

Case series; Level of evidence, 4.

Included in the study were 33 patients (16 male, 17 female; mean age, 53.4 years) with arthroscopically confirmed intratendinous tears treated with transtendon suture bridge repair from March 2006 to July 2012. A history of trauma was found in 10 cases (30.3%). The dominant arm was involved in 26 cases (78.8%). The mean follow-up duration was 56 months. Preoperatively, a thorough physical examination was performed; at final follow-up, shoulder range of motion (ROM) in forward flexion, abduction, external rotation (ER) at the side, and internal rotation (IR) at the back was noted, and clinical outcomes (American Shoulder and Elbow Surgeons [ASES] score; University of California, Los Angeles [UCLA] score; visual analog scale [VAS] for pain; and Simple Shoulder Test [SST]) were recorded and compared with the preoperative data. Postoperative magnetic resonance imaging (MRI) was performed at 6 months to investigate rotator cuff healing status and repair integrity.

The prevalence of arthroscopically confirmed intratendinous tears was 4.7% among all arthroscopically treated partial-thickness rotator cuff tears. Impingement signs were positive in most of the patients (positive Hawkins-Kennedy test result in 78.8%, positive Neer sign in 66.7%, and either positive Hawkins-Kennedy test result or Neer sign in 84.8%). At final follow-up, mean ASES, UCLA, VAS, and SST scores improved significantly from a preoperative mean of 51.4, 18.9, 6.0, and 5.4, respectively, to a postoperative mean of 90.6, 32.9, 1.4, and 10.8, respectively (P < .001). According to the UCLA rating scale, outcomes were excellent in 17, good in 13, and fair in 3 cases. Shoulder ROM in forward flexion, abduction, ER at the side, and IR at the back improved from a preoperative mean of 135°, 129°, 25°, and L2, respectively, to a postoperative mean of 161°, 160°, 29°, and T10, respectively (P < .001 for all except ER). As per the Sugaya classification, on postoperative MRI, type I healing status was found in 10 (30.3%), type II in 18 (54.5%), and type III in 2 (6.1%) cases. None of the patients showed any evidence of retears.

Transtendon suture bridge repair yielded satisfactory clinical and radiological outcomes in patients with intratendinous rotator cuff tears.

Studies evaluating the return to sports and work after shoulder arthroplasty are rare, and there are no studies evaluating return to work after total shoulder arthroplasty (TSA).

Patients undergoing TSA will be able to return to their preoperative sports levels and occupations.

Case series; Level of evidence, 4.

A total of 154 patients with 170 TSAs for primary glenohumeral arthritis were included. Two subgroups were formed: patients who had participated in sports during the 5 years before surgery (group 1; n = 105 [68%]) and patients who had never participated in sports (group 2; n = 49 [32%]). The return-to-work rate in patients who had not retired after surgery were also analyzed, as were responses to a survey.

The mean age at the time of surgery was 71 years (range, 33-88 years) in group 1 and 76 years (range, 54-88 years) in group 2. Mean follow-up time was 6.2 years (range, 2.5-12.6 years). Fifty-seven patients (54%) in group 1 participated in sports right up to the time of surgery. All 57 (100%) returned to sports after surgery. A further 3 patients (3%) from group 1 resumed sporting activity after surgery; swimming was the most popular sport. No patient in group 2 started sports activity after shoulder replacement surgery. Many of the patients, 14% of the entire group, had retired by final follow-up because of TSA. Fourteen percent of patients in group 1 and group 2 were pursuing their work at the time of most recent follow-up. Thirty patients of the entire cohort (19.5%) had to change their occupations because of surgery.

Patients who participated in sports before TSA were successfully able to return to sports activities after surgery. Patients who did not participate in sports just before surgery were unlikely to start sports after surgery. Fourteen percent of the entire cohort was able to return to work after surgery.

Capsular laxity is a main contributing factor in recurrent shoulder instability and is suggested to be correlated with increased capsular volume. Arthroscopic capsular shift combined with Bankart repair can reduce the capsular volume and reinforce the redundant capsule; however, as the capsuloligamentous structure has viscoelastic properties, it is possible for the shifted and tensioned capsule of the glenohumeral joint to slowly stretch out again over time, resulting in an increase in capsular volume.

To analyze changes in capsular volume of the glenohumeral joint over time after arthroscopic Bankart repair and capsular shift, the factors associated with these changes, and their relevance to outcomes.

Case series; Level of evidence, 4.

Included in this study were 105 patients (mean age, 25.8 ± 8.2 years) who underwent arthroscopic Bankart repair and capsular shift for anterior shoulder instability and computed tomography arthrography (CTA) at 3 months and 1 year postoperatively and whose various functional outcomes were evaluated preoperatively and at the last follow-up (>12 months). Among these patients, 27 also had preoperative CTA. These 27 patients were used to make comparisons between preoperative and 3-month postoperative CTA measurements, and all 105 patients were used for all other comparisons. Two raters measured the separate anterior and posterior capsular volume and cross-sectional area at the 5-o’clock position using 3-dimensional (3D) Slicer software. These measurements were subsequently adjusted for each glenoid size. The changes in capsular volume and cross-sectional area at the 5-o’clock position over time, the factors related to higher change in anterior capsular volume, and their correlation with outcomes were evaluated.

Three months postoperatively, the total and anterior capsular volume and anterior cross-sectional area significantly decreased; however, these values increased again at 1 year postoperatively (all P < .01). The inter- and intraobserver reliabilities of the measurements were excellent (interclass correlation coefficient = 0.717-0.945). Female sex, being an elite athlete, and more dislocations before surgery were related to a higher increase in anterior capsular volume at 1 year (all P < .05). Eight patients had redislocation, and 18 exhibited positive apprehension test postoperatively, and these patients showed significantly higher increases in anterior and total capsular volume at 1 year than did those without redislocation or positive apprehension sign (all P < .01). However, with the exception of Rowe score, a higher increase in anterior capsular volume was not related to functional outcome measures.

Surgeons should be aware of the re-increase in anterior capsular volume or restretching trait of the anterior capsule over time, even after successful arthroscopic Bankart repair and capsular shift. In this study, women, elite athletes, and those with frequent dislocations were at high risk of capsular restretching. An increase in capsular volume was related to redislocation and positive apprehension sign as well as with Rowe score.

Articular-sided partial-thickness rotator cuff tears are common injuries in throwing athletes. The superior shoulder capsule beneath the supraspinatus and infraspinatus tendons works as a stabilizer of the glenohumeral joint.

To assess the effect of articular-sided partial-thickness rotator cuff tear and repair on shoulder biomechanics. The hypothesis was that shoulder laxity might be changed because of superior capsular plication in transtendon repair of articular-sided partial-thickness rotator cuff tears.

Controlled laboratory study.

Nine fresh-frozen cadaveric shoulders were tested by using a custom shoulder-testing system at the simulated late-cocking phase and acceleration phase of throwing motion. Maximum glenohumeral external rotation angle, anterior translation, position of the humeral head apex with respect to the glenoid, internal impingement area, and glenohumeral and subacromial contact pressures were measured. Each specimen underwent 3 stages of testing: stage 1, with the intact shoulder; stage 2, after creation of articular-sided partial-thickness tears of the supraspinatus and infraspinatus tendons; and stage 3, after transtendon repair of the torn tendons by using 2 suture anchors.

Articular-sided partial-thickness tears did not significantly change any of the shoulder biomechanical measurements. In the simulated late-cocking phase, transtendon rotator cuff repair resulted in decreased maximum external rotation angle by 4.2° (P = .03), posterior shift of the humeral head (1.1-mm shift; P = .02), decreased glenohumeral contact pressure by 1.7 MPa (56%; P = .004), and decreased internal impingement area by 26.4 mm² (65%; P < .001) compared with values in the torn shoulder. In the acceleration phase, the humeral head shifted inferiorly (1.2-mm shift; P = .03 vs torn shoulder), and glenohumeral anterior translation (1.5-mm decrease; P = .03 vs torn shoulder) and subacromial contact pressure (32% decrease; P = .004 vs intact shoulder) decreased significantly after transtendon repair.

Transtendon repair of articular-sided partial-thickness supraspinatus and infraspinatus tears decreased glenohumeral and subacromial contact pressures at time zero; these changes might lead to reduced secondary subacromial and internal impingements and consequently progression to full-thickness rotator cuff tear. However, repair of the tendons decreased anterior translation and external rotation and changed the positional relationship between the humeral head and the glenoid.

Careful attention should be paid to shoulder laxity and range of motion when transtendon repair is chosen to treat articular-sided partial-thickness rotator cuff tears, specifically in throwing athletes.

It is not known whether the pattern of ulnar collateral ligament (UCL) tear affects elbow biomechanics.

There will be a significant change in elbow biomechanics with 50% proximal but not 50% distal simulated rupture of the UCL.

Controlled laboratory study.

Pressure sensors in the posteromedial elbow joint of 25 male cadaveric elbows (average age, 54.9 years; range, 26-66 years) were used to measure contact area, pressure, and valgus torque at 90° and 30° of elbow flexion. Thirteen specimens were tested with the UCL intact, then with proximal-to-distal detachment of 50%, and then with proximal-to-distal detachment of 100% of the anterior band of the UCL from the ulnar attachment. This method was repeated in the remaining 12 specimens in a distal-to-proximal direction.

With 50% proximal-to-distal detachment, contact area decreased significantly versus intact at 90° (91.3 ± 23.6 vs 112.2 ± 26.0 mm²; P < .001) and 30° (69.3 ± 14.8 vs 83.1 ± 21.6 mm²; P < .001) of elbow flexion; the center of pressure (COP) moved significantly proximally versus intact at 90° (3.8 ± 2.5 vs 5.4 ± 2.3 mm; P < .001) and 30° (5.9 ± 2.8 vs 7.4±1.9 mm; P < .001). With 50% distal-to-proximal UCL detachment versus intact, no significant change was observed in contact area, movement of the COP, or valgus laxity at either flexion position. With 100% proximal-to-distal and distal-to-proximal detachment, significant change in contact area, movement of the COP, and valgus laxity versus intact was found at 90° and 30° of elbow flexion (P < .05). No significant difference in contact pressure was observed in any test conditions.

Significant change in contact area and proximal movement of the COP with 50% proximal UCL detachment and the lack of significant change with 50% distal UCL detachment suggest that the proximal half of the UCL ulnar footprint has a primary role in maintaining posteromedial elbow biomechanics.

The findings suggest that surgical reconstruction should aim to reestablish at least the proximal 50% of the UCL ulnar footprint.

Allograft tendons are commonly used in surgical ligament reconstruction. While it is commonly accepted that donor age will affect mechanical properties of graft tissue, the apparent age threshold is unknown.

Donor age will significantly influence the structural and mechanical properties of tibialis posterior allograft tendons.

Controlled laboratory study.

A total of 550 allograft posterior tibialis tendons were examined. Linear stiffness, ultimate tensile force, ultimate displacement, tensile modulus, ultimate tensile strength, and ultimate tensile strain were calculated for specimens from donors in each of 6 age groups: 15-29, 30-39, 40-49, 50-59, 60-69, and 70-79 years. Both first- and second-order polynomial regressions were performed to determine the correlation between structural and mechanical properties and age. Welch analyses of variance with Games-Howell post hoc tests were performed to facilitate comparisons among age groups.

All parameters displayed a weak correlation with age, with the highest R ² term being 0.063 for ultimate tensile strength. Linear stiffness, ultimate tensile force, and tensile modulus displayed almost no correlation with age. Ultimate tensile strength increased slightly with age up to 40-49 years and then decreased with further increases in age. Slight decreases in ultimate displacement and ultimate tensile strain were observed with increasing age. Numerous statistically significant differences were observed between age groups for each outcome parameter; however, the magnitudes of the differences between age groups are relatively small (<15%) for all outcome parameters.

Age explained at most 6% of the variation in structural and mechanical properties of tibialis posterior allograft tendons.

Posterior tibialis tendons from all age groups displayed structural properties superior to the native anterior cruciate ligament, with higher stiffness and ultimate force, and less displacement to failure. Although statistically significant differences in structural and mechanical properties were observed between age groups, the magnitudes of the differences are small and most likely not clinically relevant. The age of the donor will not likely affect the suitability of a graft for use in surgical reconstruction.

Anterior cruciate ligament (ACL) reconstruction (ACLR) is common after an ACL tear and is thought to restore functional stability to the knee. A recent investigation demonstrated that individuals who have undergone ACLR exhibited increased lower extremity coupling variability during gait, suggestive of altered dynamic stability. However, little is known about whether they exhibit alterations in lower extremity variability during dynamic sport-specific tasks.

To determine if female soccer players who have had an ACLR demonstrate differences in lower extremity coupling variability as compared with athletes with no history of knee injury during a side-step cutting maneuver.

Controlled laboratory study.

Ten female soccer players who had undergone ACLR served as the experimental group, and 10 female soccer players with no history of knee ligament injury composed the control group (CON). Three-dimensional kinematics and ground-reaction forces were collected while each participant performed a side-step cutting maneuver. Based on known ACL loading patterns, 7 lower extremity intralimb couplings were created. With use of a vector-coding technique, the coordination variability was calculated for each coupling. Independent t tests were used to determine group differences in variability for each coupling (P ≤ .05).

Individuals who had undergone ACLR exhibited increased lower extremity variability during side-step cutting as compared with control subjects in the following couplings: hip rotation/knee abduction-adduction (27.2° ± 11.5° [ACLR] vs 19.7° ± 6.8° [CON]; P = .04), hip flexion-extension/knee abduction-adduction (26.0° ± 13.3° [ACLR] vs 18.6° ± 5.3° [CON]; P = .05), knee abduction-adduction/knee flexion-extension (13.5° ± 5.7° [ACLR] vs 7.3° ± 2.7° [CON]; P < .01), and knee abduction-adduction/knee rotation (26.4° ± 10.8° [ACLR] vs 19.3° ± 4.5° [CON]; P = .03). In addition, there was a trend toward increased variability in the hip rotation/ankle inversion-eversion coupling (22.9° ± 9.3° [ACLR] vs 18.0° ± 6.7° [CON]; P = .09) and knee abduction-adduction/ankle inversion-eversion coupling (25.9° ± 10.0° [ACLR] vs 20.2° ± 9.7° [CON]; P = .10).

Female soccer players who have undergone ACLR and returned to sports participation exhibit altered lower extremity coupling variability during side-step cutting.

While individuals who have had an ACLR exhibit mechanical knee stability before returning to sports, the observed increased movement variability during side-step cutting is likely reflective of altered neuromuscular control and may contribute to the known increased risk for ACL reinjury and knee osteoarthritis after return to sports participation. Improving the understanding of altered lower extremity coupling variability after ACLR will aid in the development of more effective rehabilitation programs.

Anterior cruciate ligament injuries (ACL) commonly occur during jump landing and cutting tasks. Attempts to land softly and land with greater knee flexion are associated with decreased ACL loading. However, their effects on performance are unclear.

Attempts to land softly will decrease peak posterior ground-reaction force (PPGRF) and knee extension moment at PPGRF compared with a natural landing during stop-jump and side-cutting tasks. Attempts to land with greater knee flexion at initial ground contact will increase knee flexion at PPGRF compared with a natural landing during both tasks. In addition, both landing techniques will increase stance time and lower extremity mechanical work as well as decrease jump height and movement speed compared with a natural landing during both tasks.

Controlled laboratory study.

A total of 18 male and 18 female recreational athletes participated in the study. Three-dimensional kinematic and kinetic data were collected during stop-jump and side-cutting tasks under 3 conditions: natural landing, soft landing, and landing with greater knee flexion at initial ground contact.

Attempts to land softly decreased PPGRF and knee extension moment at PPGRF compared with a natural landing during stop-jump tasks. Attempts to land softly decreased PPGRF compared with a natural landing during side-cutting tasks. Attempts to land with greater knee flexion at initial ground contact increased knee flexion angle at PPGRF compared with a natural landing during both stop-jump and side-cutting tasks. Attempts to land softly and land with greater knee flexion at initial ground contact increased stance time and lower extremity mechanical work, as well as decreased jump height and movement speed during both stop-jump and side-cutting tasks.

Although landing softly and landing with greater knee flexion at initial ground contact may reduce ACL loading during stop-jump and side-cutting tasks, the performance of these tasks decreased, as indicated by increased stance time and mechanical work as well as decreased jump height and movement speed.

Training effects tested in laboratory environments with the focus on reducing ACL loading may be reduced in actual competition environments when the focus is on athlete performance. The effects of training programs for ACL injury prevention on lower extremity biomechanics in athletic tasks may need to be evaluated in laboratories as well as in actual competitions.

All rugby training activities carry an injury risk, but in the training environment these injury risks should be more controllable than during matches.

To (1) describe the incidence, severity, anatomic location, and type of youth rugby training injuries; (2) determine the injury events and type of training activities associated with injuries; and (3) compare 2 levels of play (professional academy vs school) within English youth rugby union.

Cohort study; Level of evidence, 2.

A 2-season (2006-2007 and 2007-2008) study recorded exposure to training activities and time-loss injuries in male youth rugby union players (age range, 16-18 years) from 12 English Premiership academies (250 player-seasons) and 7 schools (222 player-seasons). Players from the Premiership academies, associated with the top-level professional clubs in England, represented the elite level of youth rugby; the school players were from established rugby-playing schools but were overall considered at a lower level of play.

There was a trend for training injury incidence to be lower for the academy group (1.4/1000 player-hours; 95% CI, 1.0-1.7) compared with the school group (2.1/1000 player-hours; 95% CI, 1.4-2.9) (P = .06). Injuries to the ankle/heel and thigh were most common in academy players and injuries to the lumbar spine and ankle/heel region most common in school players. The training activities responsible for injury differed between the 2 groups: technical skills (scrummaging) for school players and contact skills (defense and ruck/maul drills) for academy players.

For injury risk management in youth rugby, coaches of school players should focus on the development of the correct technique during practice of technical skills such as scrummaging, weight training, and skills training, and coaches of academy players should consider the extent to which contact drills are necessary during training.

Anterior cruciate ligament (ACL) injuries are more common in female athletes because of anatomic and biomechanical factors. These injuries can have detrimental ramifications for the athlete and the health care system. Neuromuscular training programs have been designed to modify risk factors and prevent ACL injuries.

This systematic review evaluates studies that assess the effectiveness of neuromuscular training programs in reducing ACL injuries in female athletes and provides an update to 2 previously published reviews.

Systematic review.

Medline, Cochrane, and CINAHL databases were searched for relevant journal articles published from 1995 to 2011. We performed a manual review of relevant articles, authors, and journals, including bibliographies from identified articles. Ten studies were included in this review.

Only 2 studies demonstrated a statistically significant decrease in ACL injuries with neuromuscular training programs. Two additional studies showed a statistically significant decrease in subgroup analyses only. Four studies did show a trend toward reduced ACL injuries with neuromuscular training programs but were unable to achieve statistical significance. Neuromuscular training programs utilizing plyometric exercises and a preseason component were the most beneficial. Two studies actually showed an increase in injuries with intervention programs.

Neuromuscular training programs may be a useful adjunct to training, but current literature precludes our universal recommendation of them.

Rotator cuff tears are common, and rotator cuff repair represents a major health care expense. While patients often benefit from rotator cuff repair, anatomic failure of the repair is not unusual.

To identify the published evidence on the factors associated with retears and with suboptimal clinical outcomes of rotator cuff repairs.

Systematic review and meta-analysis of articles with evidence levels 1-4.

A total of 2383 articles on rotator cuff repairs published between 1980 and 2012 were identified. Only 108 of these articles, reporting on over 8011 shoulders, met the inclusion criteria of reporting quantitative data on both imaging and clinical outcomes after rotator cuff repair. Factors related to the patients, their shoulders, the procedures, and the results were systematically categorized and submitted for meta-analysis.

While the number of relevant articles published per year increased dramatically over the period of the study, the clinical and anatomic results did not show improvement over this period. The weighted mean retear rate was 26.6% at a mean of 23.7 months after surgery. Retears were associated with more fatty infiltration, larger tear size, advanced age, and double-row repairs. Clinical improvement averaged 72% of the maximum possible improvement. Patient-reported outcomes were generally improved whether or not the repair restored the integrity of the rotator cuff. The inconsistent and incomplete data in the published articles limited the meta-analysis of factors affecting the outcome of rotator cuff repair.

In spite of a dramatic increase in the number of publications per year, there is little evidence that the results of rotator cuff repair are improving. The information needed to guide the management of this commonly treated and costly condition is seriously deficient. To accumulate the evidence necessary to inform practice, future clinical studies on the outcome of rotator cuff repair must report important data relating to each patient’s condition, the surgical technique, the outcome in terms of integrity, and the change in patient self-assessed comfort and function.