The American Journal of Sports Medicine

Background: Patients with focal cartilage defects in the knee may suffer from both pain and functional impairment. Treatment options are often insufficient. It is not known, however, to what extent their complaints affect quality of life, compared with other knee disorders. Knee Injury and Osteoarthritis Outcome Score (KOOS) is a validated global knee score suitable for comparison of patients with knee complaints attributable to different causes.

Hypothesis: Complaints because of localized cartilage defects in the knee reduce quality of life measured by KOOS to a different extent than those due to anterior cruciate ligament deficiency and osteoarthritis, when comparing patients within the working population scheduled for surgery.

Study Design: Cross-sectional study; Level of evidence, 3.

Methods: Previously registered KOOS baseline data on patients enrolled in different knee treatment studies were included in the present study; the patients were 18 to 67 years of age (working population) at data registration. The different patient categories were (1) patients with knee osteoarthritis enrolled for knee arthroplasty, (2) patients with knee osteoarthritis enrolled for osteotomies around the knee, (3) patients with focal cartilage lesions enrolled for cartilage repair, and (4) patients with anterior cruciate ligament—deficient knees enrolled for anterior cruciate ligament reconstruction. The KOOS subscale quality of life was the main parameter for comparison of complaints.

Results: At preoperative baseline, patients with focal cartilage defects in the knee scored 27.5 on the KOOS subscale quality of life, not significantly different from the 28.8 and 27.2 in the patients with osteoarthritis enrolled for knee osteotomies and arthroplasties, respectively. For all the subscales of KOOS, the cartilage patients scored significantly lower than the patients with anterior cruciate ligament deficiency.

Conclusion: Patients with focal cartilage lesions have major problems with pain and functional impairment. Their complaints are worse than those of patients with anterior cruciate ligament—deficient knees, and quality of life is affected to the same extent as in patients scheduled for knee replacement.

Background: Autologous chondrocyte implantation for full-thickness lesions of the distal femur has demonstrated good short- to midterm clinical improvement. However, long-term durability (>5 years) of autologous chondrocyte implantation has not been evaluated in US patients to date.

Hypothesis: Patients who improve from baseline to early follow-up will sustain improvement at later follow-up.

Study Design: Case series, Level of evidence, 4.

Methods: Cartilage Repair Registry patients with full-thickness distal femur lesions who were treated with autologous chondrocyte implantation before December 31, 1996 and had modified overall Cincinnati scores at baseline and 1- to 5-year follow-up scores were re-evaluated at 6- to 10-year follow-up. Autologous chondrocyte implantation durability was determined by comparing early (1-5 years) to long-term (6-10 years) outcomes. Adverse events and treatment failures were recorded.

Results: Seventy-two patients met eligibility criteria (at baseline: mean age, 37 years; mean lesion size, 5.2 cm2; and overall condition score, 3.4 points [poor]). Eighty-seven percent of patients (47 of 54) who improved at the earlier follow-up period sustained a mean improvement in overall condition score of 3.8 points from baseline to the later follow-up period (P < .001). From baseline to 10-year follow-up (mean follow-up, 9.2 years), 69% improved, 17% failed, and 12.5% reported no change from baseline. Most failures (75% [9 of 12]) occurred at a mean follow-up of 2.5 years. Thirty patients (42%) had 42 operations after autologous chondrocyte implantation; 24 operations (57%) occurred in patients who met the study definition of failure.

Conclusion: Treatment with autologous chondrocyte implantation for large, symptomatic, full-thickness lesions of the distal femur can result in early improvement that is sustained at longer follow-up (up to 10 years) in the majority of patients.

Background: Although graft extrusion is of concern after meniscal allograft transplantation (MAT), the correlation between extrusion and clinicoradiological outcomes remains unclear. Hypothesis: Patients with graft extrusion after MAT have worse clinical outcomes and greater arthritic change than those without graft extrusion. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-three patients underwent MAT between 1999 and 2004. Grafts were classified as either nonextruded (<3 mm) or extruded (≥3 mm) according to 1-year postoperative magnetic resonance imaging (MRI) findings. The mean patient age at the time of surgery was 33.5 years (range, 17-43 years), and the mean follow-up period was 5.1 years (range, 3.5-8.3 years). The Lysholm score was used to evaluate knee function. In addition, preoperative and postoperative (final follow-up) measurements were taken to determine the absolute and relative (affected side/normal side) joint space width (JSW) on a standing 45° flexion posteroanterior view. Results: Magnetic resonance imaging at 1 year showed the mean graft subluxation was 3.03 ± 0.872 mm across all patients. Twenty-six knees (60%) were classified as nonextruded and 17 (40%) as extruded. No statistical difference was found between these 2 groups regarding Lysholm score improvement after MAT. Overall, absolute and relative JSWs were slightly narrower postoperatively compared with preoperatively across all patients (mean absolute difference, 0.283 mm; mean relative difference; 4.79%; P < .001). However, extruded and nonextruded knees were similar in terms of absolute (P = .764) and relative (P = .482) JSW after MAT. The amount of extrusion did not correlate with Lysholm score or the relative difference between preoperative and postoperative JSW across all patients or in either group. Conclusion: Joint space width was slightly narrower after MAT. Extrusion had no effect on 5-year clinical or radiological outcomes.

Background: Platelet-rich plasma (PRP) has shown to be a general stimulation for repair.

Purpose: To determine the effectiveness of PRP compared with corticosteroid injections in patients with chronic lateral epicondylitis.

Study Design: Randomized controlled trial; Level of evidence, 1.

Patients: The trial was conducted in 2 teaching hospitals in the Netherlands. One hundred patients with chronic lateral epicondylitis were randomly assigned in the PRP group (n = 51) or the corticosteroid group (n = 49). A central computer system carried out randomization and allocation to the trial group. Patients were randomized to receive either a corticosteroid injection or an autologous platelet concentrate injection through a peppering technique. The primary analysis included visual analog scores and DASH Outcome Measure scores (DASH: Disabilities of the Arm, Shoulder, and Hand).

Results: Successful treatment was defined as more than a 25% reduction in visual analog score or DASH score without a reintervention after 1 year. The results showed that, according to the visual analog scores, 24 of the 49 patients (49%) in the corticosteroid group and 37 of the 51 patients (73%) in the PRP group were successful, which was significantly different (P < .001). Furthermore, according to the DASH scores, 25 of the 49 patients (51%) in the corticosteroid group and 37 of the 51 patients (73%) in the PRP group were successful, which was also significantly different (P = .005). The corticosteroid group was better initially and then declined, whereas the PRP group progressively improved.

Conclusion: Treatment of patients with chronic lateral epicondylitis with PRP reduces pain and significantly increases function, exceeding the effect of corticosteroid injection. Future decisions for application of the PRP for lateral epicondylitis should be confirmed by further follow-up from this trial and should take into account possible costs and harms as well as benefits.

Background: The efficacy of single-bundle versus double-bundle ACL reconstruction in improving knee stability has been widely discussed. The biomechanics of all-inside double-bundle ACL reconstructions have not been evaluated.

Hypothesis: An anatomic all-inside double-bundle ACL reconstruction will more effectively restore native knee kinematics in vitro, especially rotational stability, when compared with an all-inside single-bundle ACL reconstruction.

Study Design: Controlled laboratory study.

Methods: Seven pairs of fresh-frozen cadaveric human knees were used. Knees were tested using 88 N of force for anterior and posterior drawers, 5 N·m internal and external rotation moments, 10 N·m valgus and varus moments, and coupled 5 N·m internal rotation and 10 N·m valgus moments to simulate a pivot shift at 0°, 20°, 30°, 60°, and 90° of knee flexion. Motion of the knee in response to external loading was measured with a Polhemus electromagnetic tracking system. Knees were first tested in the intact state, with either the anteromedial or posterolateral bundle cut, and then with both bundles cut. Subsequently, 7 single-bundle and 7 double-bundle all-inside ACL reconstructions were performed.

Results: Both single- and double-bundle all-inside ACL reconstructions restored knee kinematics for posterior drawer, varus/valgus rotation, and internal/external rotation motions. After single-bundle all-inside ACL reconstruction, anterior translation during the simulated pivot-shift test was significantly higher compared with the intact state at 20°, 30°, and 60° of flexion. There was no significant difference between the double-bundle all-inside ACL reconstruction and the intact knee during a simulated pivot shift.

Conclusion: We found that an all-inside double-bundle ACL reconstruction demonstrated significant improvement in restoring normal rotational knee motion during simulated pivot-shift testing compared with single-bundle ACL reconstructions in vitro, with no significant differences in other knee loading conditions.

Clinical Relevance: All-inside double-bundle ACL reconstruction may provide advantages over single-bundle ACL reconstruction for rotational knee stability.

Background: The popularity of running is still growing. As participation increases, running-related injuries also increase. Until now, little is known about the predictors for injuries in novice runners.

Hypothesis: Predictors for running-related injuries (RRIs) will differ between male and female novice runners.

Study Design: Cohort study; Level of evidence, 2.

Methods: Participants were 532 novice runners (226 men, 306 women) preparing for a recreational 4-mile (6.7-km) running event. After completing a baseline questionnaire and undergoing an orthopaedic examination, they were followed during the training period of 13 weeks. An RRI was defined as any self-reported running-related musculoskeletal pain of the lower extremity or back causing a restriction of running for at least 1 week.

Results: Twenty-one percent of the novice runners had at least one RRI during follow-up. The multivariate adjusted Cox regression model for male participants showed that body mass index (BMI) (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.05-1.26), previous injury in the past year (HR, 2.7; 95% CI, 1.36-5.55), and previous participation in sports without axial load (HR, 2.05; 95% CI, 1.03-4.11) were associated with RRI. In female participants, only navicular drop (HR, 0.85; 95% CI, 0.75-0.97) remained a significant predictor for RRI in the multivariate Cox regression modeling. Type A behavior and range of motion (ROM) of the hip and ankle did not affect risk. Conclusion: Male and female novice runners have different risk profiles. Higher BMI, previous injury, and previous sports participation without axial loading are important predictors for RRI in male participants. Further research is needed to detect more predictors for female novice runners.

Background: Knee joint infection is a potentially devastating complication of anterior cruciate ligament (ACL) reconstruction. There is a theoretical increased risk of infection with the use of allograft material.

Hypothesis: An allograft ACL reconstruction predisposes patients to a higher risk of bacterial infection.

Study Design: Cohort Study; Level of evidence, 3.

Methods: All primary ACL reconstructions performed at our institution between January 2002 and December 2006 were reviewed; 3126 total procedures were identified. A retrospective medical record review was performed to determine the incidence of infection, offending organism, time after surgery until presentation, infection treatment, and graft salvage as an outcome of graft choice.

Results: Of the 3126 ACL reconstructions, 1777 autografts and 1349 allografts were performed. Eighteen infections were identified (0.58%). Infections occurred in 6 of the 1349 allografts (0.44%), 7 of the 1430 bone-patellar tendon-bone (BPTB) autografts (0.49%), and 5 of the 347 hamstring autografts (1.44%). Five grafts were removed because of graft incompetence or loosening: 3 hamstring tendon, 1 BPTB, and 1 allograft. The most common organism isolated was Staphylococcus aureus. Hamstring tendon autograft had an increased incidence of infection compared with both BPTB autograft and allograft (P < .05), with a trend toward a more common need for graft removal (P = .09). Allograft reconstructions were equally likely to have graft salvage as autograft reconstructions.

Conclusion: Hamstring tendon autografts have a higher incidence of infection than BPTB autografts or allografts. The use of allograft material in ACL reconstructions does not increase the risk of infection or the need for graft removal with infection.

Background: Immobilization or orthosis is required after conventional Achilles tendon surgery.

Hypothesis: This new Achilles tendon repair approach enables early rehabilitation without any postoperative immobilization or orthosis.

Study Design: Case series; Level of evidence, 4.

Methods: Twenty consecutive patients (14 men and 6 women; mean age, 43.4 years; range, 16-70 years) who had acute subcutaneous Achilles tendon rupture were treated by the new method, with an average follow-up of 2.9 years (range, 2-4.8 years). Among them, 15 injuries were sports-related and 5 were work-related. The authors applied a side-locking loop technique of their own design for the core suture, using braided polyblend suture thread, with peripheral cross-stitches added. The patients started active and passive ankle mobilization from the next day, partial weightbearing walking from 1 week, full-load walking from 4 weeks, and double-legged heel raises from 6 weeks after surgery.

Results: The range of motion recovery equal to the intact side averaged 3.2 weeks. Double-legged heel raises and 20 continuous singlelegged heel raise exercises were possible at an average of 6.3 weeks and 9.9 weeks, respectively. T2-weighted magnetic resonance signal intensity recovered to equal that of the intact portion of the same tendon at 12 weeks. The patients resumed sports activities or heavy labor at an average of 14.4 weeks. The Achilles tendon rupture score averaged 98.3 at 24 weeks. There were no complications.

Conclusion: This new Achilles tendon repair approach enables early mobilization exercise without costly specialized orthosis or immobilization and allows an early return to normal life and sports activities, reducing the physical and economic burden on patients.

Background: A recent study has described radiographic landmarks for femoral insertion of the medial patellofemoral ligament. Clinical relevance and application of these landmarks for surgical reconstruction have yet to be determined. Hypothesis: Radiographic landmarks can be used to accurately determine the femoral insertion of the medial patellofemoral ligament in a percutaneous fluoroscopically guided surgical technique. Study Design: Descriptive laboratory study. Methods: The femoral insertion of the medial patellofemoral ligament was estimated using fluoroscopy in 8 fresh-frozen human cadaveric knees. The knees were dissected and the true anatomical medial patellofemoral ligament femoral insertion was identified. Radiographic markers were placed on both the estimated and anatomical medial patellofemoral ligament and a repeat lateral radiograph was performed. Using imaging software, the distance between the true anatomical insertion and the fluoroscopically determined insertion was calculated. Results: All 8 points determined by fluoroscopically guided pin placement averaged less than 4 mm from the anatomical insertion. The radiographic landmark method consistently placed the origin on average 2.5 mm anterior and 0.6 mm distal to the anatomical insertion. Conclusion: Radiographic landmarks determined by fluoroscopy can be used to accurately reproduce the femoral insertion of the medial patellofemoral ligament in ligament reconstruction. Clinical Relevance: Confirming the use of radiographic landmarks to determine the medial patellofemoral ligament femoral insertion may help to increase accuracy and precision in ligament reconstruction and minimize surgical dissection.

Background: Tibial eminence fractures are rare injuries in children and adolescents. Displaced fractures require reduction and fixation. Operative stabilization can be accomplished with either open or arthroscopic reduction and fixation. Whereas loss of extension has been reported, there are no reports in the literature that quantify loss of motion or provide guidance for treatment. Purpose: To report a series of patients who developed knee stiffness after operative treatment for displaced tibial eminence fractures. Study Design: Case series; Level of evidence, 4. Methods: Review of medical records and imaging studies of pediatric patients with displaced tibial eminence fractures who developed arthrofibrosis after surgical intervention. Results: Thirty-two patients were identified. Twenty-four required reoperation for loss of flexion (n = 9), loss of extension (n = 4), or both (n = 11). Manipulation under anesthesia resulted in distal femoral fractures and subsequent growth arrest in 3 patients. Twenty-nine patients were able to achieve near full knee motion at final follow-up. Conclusions: Children with tibial spine fractures are at risk for arthrofibrosis. Stabilization of the fracture is important to allow early postoperative rehabilitation. Should stiffness occur, manipulation of the knee should be performed only in conjunction with lysis of adhesions.

Background: Arthroscopic treatment has evolved to become the primary surgical option in the management of anterior shoulder instability as studies show comparable outcomes between open and arthroscopic techniques.

Objective: To evaluate prospectively the results of our institutional database for arthroscopic Bankart repairs at a minimum 2-year follow-up for patients with anterior instability treated with suture anchors.

Study Design: Case series; Level of evidence, 4.

Methods: Eighty-three consecutive patients underwent arthroscopic Bankart repair with suture anchors. The mean age at the time of surgery was 33 years (range, 15-55 years). At an average follow-up of 33 months (range, 24-49 months), 73 patients (61 males, 12 females) were assessed with outcomes scores including the American Shoulder and Elbow Surgeons, L’Insalata, and visual analog scores. The rate of recurrent instability, range of motion, and risk factors for postoperative recurrence were evaluated.

Results: Thirteen patients (18%) suffered a recurrence after surgery. Seven patients (10%) had a subsequent dislocation and 6 (8%) a subluxation event or apprehension. Six of the 13 had a traumatic event that resulted in recurrent episodes of instability. Revision surgery was needed for 2 patients (3%) for instability and 2 for postoperative shoulder stiffness. On average there was no significant loss of external rotation postoperatively (average, 71° pre- and postoperatively). The American Shoulder and Elbow Surgeons and L’Insalata scores improved from 75.4 to 94.9 and 66.5 to 90.9, respectively (P < .0001). The visual analog score improved from 2.4 to 0.4 (P < .001). Patient age under 25, ligamentous laxity, and the presence of a large (>250 mm 3) Hill-Sachs lesion were associated with recurrence (P < .05). Patients under age 20 had a 37.5% recurrence rate.

Conclusion: In the arthroscopic treatment of anterior instability, identification of risk factors for recurrence allows for appropriate patient counseling and consideration of open stabilization. In our series, patients under age 25, with ligamentous laxity, and with a large (>250 mm3) Hill-Sachs lesion were at the greatest risk of recurrence.

Background: Recent studies demonstrate a potentially critical role of matrix metalloproteinases (MMPs) and their inhibitors in the pathophysiology of rotator cuff tears.

Hypothesis: Doxycycline-mediated MMP inhibition after rotator cuff repair will improve tendon-to-bone healing.

Study Design: Controlled laboratory study.

Methods: Rats (n = 183) underwent acute detachment and repair of the supraspinatus tendon and the animals were divided into 4 groups: In controls (n = 66), the supraspinatus was repaired to its anatomical footprint. In experimental groups, an identical surgery was performed with doxycycline (130 mg/kg/d) administered orally at (1) preoperative day 1 (n = 66), (2) postoperative day (POD) 5 (n = 28), or (3) POD 14 (n = 23). Animals were sacrificed at 5 days, 8 days, 2 weeks, and 4 weeks. Tendon-bone interface was evaluated with histomorphometry. Enzyme-linked immunosorbent assay for local MMP-13 activity was performed at 8 days and 4 weeks. Biomechanical testing of the healing enthesis was performed at 8 days, 2 weeks, and 4 weeks. Serum doxycycline levels were measured at sacrifice. Statistical analysis was performed using unpaired t tests and 2-way analysis of variance (P < .05).

Results: Serum doxycycline levels were significantly higher in all treated groups compared with controls (1830 ± 835 vs 3 ± 3 ng/mL, respectively; P < .001). Doxycycline-treated animals demonstrated greater metachromasia and improved collagen organization at the healing enthesis at POD 5 (P < .06), POD 8 (P < .03), and 2 weeks (P < .04). The MMP-13 activity was significantly reduced in doxycycline-treated compared with control animals at POD 8 (6740 ± 2770 vs 10400 ± 2930 relative fluorescent units [RFU], respectively; P < .02) but not at 4 weeks (3600 ± 3280 vs 4530 ± 2720 RFU, respectively). The healing enthesis of animals started on doxycycline preoperatively or at POD 5 had an increased load to failure compared to controls at 2 weeks (13.6 ± 1.8 and 13.2 ± 1.94 N vs 9.1 ± 2.5 N, respectively; P < .01).

Conclusion/Clinical Relevance: Modulation of MMP-13 activity after rotator cuff repair may offer a novel biological pathway to augment tendon-to-bone healing.

Background: Rotator cuff injury in the setting of type II superior labrum anterior posterior lesions is a common finding. Although predictable surgical outcomes can be expected after type II superior labrum anterior posterior repair, the effect of rotator cuff tears on surgical outcome is unknown.

Hypothesis: Rotator cuff tears will not negatively affect surgical outcome of type II superior labrum anterior posterior repairs.

Study Design: Cohort study; Level of evidence, 3.

Methods: The study group included 93 patients younger than 50 years who underwent arthroscopic type II superior labrum anterior posterior repair and were available for review at a minimum of 2 years after surgery. Group 1 patients were identified as having normal rotator cuffs at the time of repair. Group 2 patients were identified as having rotator cuff injury at the time of repair (either partial-thickness or full-thickness tears). Statistical analysis was performed comparing the postoperative University of California, Los Angeles shoulder scores and overall improvement in University of California, Los Angeles score using the Student t test for significance.

Results: Mean follow-up was 2.54 years; 52.7% of patients had evidence of rotator cuff tears at the time of surgery. The mean postoperative University of California, Los Angeles score for group 1 was 32.9 (improvement of 11.0), and the mean postoperative University of California, Los Angeles score for group 2 was 33.3 (improvement of 12.2). There was not a significant difference in any of the outcome measures between groups.

Conclusion: Predictable short-term surgical results and return to activity can be expected after repair of type II superior labrum anterior posterior lesions in patients younger than 50 years who have coexistent rotator cuff tear. Although cuff lesions did not have a negative effect on the short-term outcome in patients with type II superior labrum anterior posterior lesions, longer-term follow-up is needed to determine natural history of this pathologic condition.

Background: Valgus high tibial osteotomy (HTO) may be associated with changes in the patellar height and posterior tibial slope.

Hypothesis: Patellar height increases and posterior tibial slope decreases after closed-wedge HTO, whereas patellar height decreases and tibial slope increases after open-wedge osteotomy.

Study Design: Cohort study; Level of evidence, 3.

Methods: Lateral radiographs of 100 knees were assessed for patellar height (PH) (Insall-Salvati index [ISI], Caton-De Champ index [CDI], and Blackburne-Peel index [BPI]) as well as posterior tibial slope. Measurements were done before HTO (50 closed wedge [CW], 50 open wedge [OW]), direct postoperatively, and before removal of the hardware.

Results: In the CW group, all 3 PH indices were increased direct postoperatively and at removal of the hardware, with changes in CDI and BPI being significant (P < .05). The effect size (ES) for the direct postoperative PH increase was medium (ES = 0.48) according to CDI. In the OW group, all 3 indices showed a significant (P < .05) PH decrease direct postoperatively and at hardware removal. The ES for the direct postoperative PH decrease was large according to CDI (ES = 0.92) and BPI (ES = 0.80). There were no significant changes between the 2 follow-up measurements (P > .05) with a small ES each. Posterior tibial slope showed a significant (P < .05) decrease of 3.1° ± 3.4° after CW HTO and a significant (P < .05) increase of 2.1° ± 3.6° after OW HTO direct postoperatively. These changes did not change at the second follow-up. In CW HTO, the correlations between frontal plane correction and PH changes were moderate (CDI: r = .57; BPI: r = .64). In OW HTO, these correlations were weak (CDI: r = .44; BPI: r = .46). According to ISI, there was no correlation (CW: r = .11; OW: r = .16). There was no correlation between PH changes and slope changes (CDI) and no correlation between frontal plane HTO correction and slope changes in both CW and OW HTO.

Conclusion: The results confirm our hypothesis for PH and posterior tibial slope changes after valgus HTO. However, there is no strong correlation between PH changes and the degree of frontal plane HTO correction. The incidence of patella infera increases after OW HTO, whereas the incidence of patella alta increases after CW HTO. Therefore, we recommend performing CW HTO or OW HTO with the tuberosity left at the proximal tibia in cases of patellofemoral complaints or patella infera. Neither technique leads to patellar lowering. It should be borne in mind that PH and posterior tibial slope may have been altered before planning total knee replacement after HTO.

Background: The amount of medial compartment opening for medial knee injuries determined by valgus stress radiography has not been well documented. The purpose of this study was to develop clinical guidelines for diagnosing medial knee injuries using valgus stress radiography.

Hypothesis: Measurements of medial compartment gapping can accurately differentiate between normal and injured medial structure knees on valgus stress radiographs.

Study Design: Controlled laboratory study.

Methods: Valgus stress radiographs were obtained on 18 adult lower extremities using 10-N·m and clinician-applied valgus loads at 0° and 20° of flexion to intact knees and after sequential sectioning of the superficial medial collateral ligament proximally and distally, the meniscofemoral and meniscotibial portions of the deep medial collateral ligament, the posterior oblique ligament, and the cruciate ligaments. Three independent observers of different experience levels measured all of the radiographs during 2 separate occasions to determine intraobserver repeatability and interobserver reproducibility.

Results: Compared with the intact knee, significant medial joint gapping increases of 1.7 mm and 3.2 mm were produced at 0° and 20° of flexion, respectively, by a clinician-applied load on an isolated grade III superficial medial collateral ligament simulated injury. A complete medial knee injury yielded gapping increases of 6.5 mm and 9.8 mm at 0° and 20°, respectively, for a clinician-applied load. Intraobserver repeatability and interobserver reproducibility intraclass correlation coefficients were .99 and .98, respectively.

Conclusion: Valgus stress radiographs accurately and reliably measure medial compartment gapping but cannot definitively differentiate between meniscofemoral- and meniscotibial-based injuries. A grade III medial collateral ligament injury should be suspected with greater than 3.2 mm of medial compartment gapping compared to the contralateral knee at 20° of flexion, and this injury will also result in gapping in full extension.

Clinical Significance: Valgus stress radiographs provide objective and reproducible measurements of medial compartment gapping, which should prove useful for definitive diagnosis, management, and postoperative follow-up of patients with medial knee injuries.

Background: An anatomical medial knee reconstruction has not been described in the literature.

Hypothesis: Knee stability and ligamentous load distribution would be restored to the native state with an anatomical medial knee reconstruction.

Study Design: Controlled laboratory study.

Methods: Ten nonpaired cadaveric knees were tested in the intact, superficial medial collateral ligament and posterior oblique ligament—sectioned, and anatomically reconstructed states. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of knee flexion with a 10-N·m valgus load, 5-N·m external and internal rotation torques, and 88-N anterior and posterior drawer loads. A 6 degrees of freedom electromagnetic motion tracking system measured angulation and displacement changes of the tibia with respect to the femur. Buckle transducers measured the loads on the intact and reconstructed proximal and distal divisions of the superficial medial collateral ligament and the posterior oblique ligament.

Results: A significant increase was found in valgus angulation and external rotation after sectioning the medial knee structures at all tested knee flexion angles. This was restored after an anatomical medial knee reconstruction. The authors also found a significant increase in internal rotation at 0°, 20°, 30°, and 60° of knee flexion after sectioning the medial knee structures, which was restored after the reconstruction. A significant increase in anterior translation was observed after sectioning the medial knee structures at 20°, 30°, 60°, and 90° of knee flexion. This increase in anterior translation was restored following the reconstruction at 20° and 30° of knee flexion, but was not restored at 60° and 90°. A small, but significant, increase in posterior translation was found after sectioning the medial knee structures at 0° and 30° of knee flexion, but this was not restored after the reconstruction. Overall, there were no clinically important differences in observed load on the ligaments when comparing the intact with the reconstructed states for valgus, external and internal rotation, and anterior and posterior drawer loads.

Conclusion: An anatomical medial knee reconstruction restores near-normal stability to a knee with a complete superficial medial collateral ligament and posterior oblique ligament injury, while avoiding overconstraint of the reconstructed ligament grafts.

Clinical Significance: This anatomical medial knee reconstruction technique provides native stability and ligament load distribution in patients with chronic or severe acute medial knee injuries.

Background: The inconsistency in healing after anterior cruciate ligament (ACL) repair has been attributed to ACL fibroblast cellular metabolism, lack of a sufficient vascular supply, and the inability to form a scar or scaffold after ligament rupture because of the uniqueness of the intra-articular environment.

Hypotheses: (1) Stress deprivation in the surgically transected ACL will increase matrix metalloproteinase (MMP) and alpha smooth muscle actin (α-SMA) expression. (2) Stress deprivation will decrease collagen expression. (3) The transected anteromedial bundle of the ACL will demonstrate a pattern of gene expression similar to the completely transected ACL, while gene expression profiles in the intact posterolateral bundle will be similar to the sham-operated controls.

Study Design: Controlled laboratory study.

Methods: Thirty-six New Zealand White rabbits underwent a partial ACL surgical transection separating the anteromedial (AM) and posterolateral (PL) bundles and transecting the AM bundle. Contralateral ACLs were either sham operated or completely transected. Ligament tissue was harvested at 1, 2, or 6 weeks after surgery, and real-time PCR was performed using primers for collagen I, collagen III, α-SMA, MMP-1, and MMP-13.

Results: At 1 week, a 28- and 29-fold increase in MMP-13 expression was seen in the complete transection and the transected AM bundle specimens when compared with sham-operated controls (P = .049, P = .018), respectively. There was no significant difference in MMP-13 between the sham controls and the intact PL bundle specimens. A 22- and 23-fold increase in α-SMA was seen (P = .03, P = .009) in the complete transection and transected AM bundle specimens, respectively, while no difference was seen between the intact PL bundle and controls. No significant differences were seen in collagen I (Col I) or collagen III (Col III) gene expression at 1 week. At 6 weeks, Col I expression increased 5-fold in complete transection samples (P = 3.9 × 10− 6), 3-fold in transected AM samples (P = 3.3 × 10 −6), and 2-fold in the intact PL bundle samples as compared with controls. α-SMA was increased 7.5-fold and 5-fold in complete transection and transected AM samples, respectively (P = .004, P = 2.2 × 10−6), while no significant change was seen in the intact PL bundle samples compared with controls. Complete transection specimens showed a 3-fold increase in MMP-1 expression. Col III increased 5.4-, 2.6-, and 2.4-fold in the complete transection, transected AM, and intact PL groups, respectively (P = .003, P = .004, P = .04).

Conclusion: Partial or complete surgical transection of the rabbit ACL with resultant loss of mechanical stimuli results in an increase in MMP-13 and α-SMA expression at the early time point (1 week) and an increase in α-SMA, Col I, and Col III expression at the later time point (6 weeks). These data provide support for the hypothesis that there is a time-dependent alteration of anabolic and catabolic matrix gene expression after injury/loss of ligament integrity.

Clinical Relevance: Identification of pathways that respond to mechanical stress in the intact ACL and after surgical transection may permit development of novel therapies to alter healing of the partial ACL injury or to assist in the development of biomechanical active ‘‘smart’’ scaffolds for tissue-engineered ligament replacements.

Background: The main clinical symptom of lumbar spondylolysis is lower back pain. Radiculopathy rarely occurs without vertebral slippage.

Hypothesis: Spondylolysis in young athletes can cause lumbar radiculopathy.

Study Design: Case series; Level of evidence, 4.

Methods: Ten patients (7 males and 3 females) were included in this study. The age of the patients ranged from 12 to 27 years. We employed plain radiography, computed tomography, magnetic resonance imaging, and selective radiculography if needed.

Results: The pathomechanism was classified into nonspondylolytic radiculopathy (3 cases) and spondylolytic radiculopathy (7 cases). In the nonspondylolytic group, 1 patient had a juxta-facet cyst at L4-5 and 2 patients had a herniated nucleus pulposus. In the other group, spondylolytic-related factors caused radiculopathy, and spondylolysis was in the early or progressive stage in all 7 patients. Radiologic findings indicated that radiculopathy was caused by extraosseous hematoma or edema in the vicinity of the fracture site. The radiculopathy disappeared within a month of nonoperative management, and radiologic abnormalities disappeared 3 to 6 months later.

Conclusion: Radiculopathy can occur together with lumbar spondylolysis without slippage in young athletes. We propose extraosseous hematoma or edema at the site of spondylolysis as the unique pathomechanism causing radiculopathy in young athletes. Radiculopathy is rare in athletes with spondylolysis. Magnetic resonance imaging is a useful tool to clarify the pathologic changes that induce the radiculopathy for both spondylolytic and nonspondylolytic factors.

Background: Because a majority of throwing injuries occur near the maximum external rotation (MER) of the throwing shoulder, sports medicine practitioners and researchers have paid special attention to the shoulder kinematics at the MER in throwing. However, little is known about the individual kinematics of the glenohumeral, scapulothoracic, and thoracic joints at the MER.

Purpose: To demonstrate the glenohumeral, scapulothoracic, and thoracic joint movements and their contribution to the MER in throwing for baseball players.

Study Design: Descriptive laboratory study.

Methods: We collected throwing motion data for 20 collegiate baseball players by using 3 high-speed cameras and established 3-dimensional coordinates of each landmark with a direct linear translation method. We then obtained the MER of the shoulder complex, the external rotation angle of the glenohumeral joint, the posterior tipping angle of the scapula, and the thoracic extension angles at the MER in throwing.

Results: The mean (± standard deviation) value of the MER was 144.2° ± 11.0°. The mean (± standard deviation) values of the glenohumeral external rotation, the scapular posterior tipping, and the thoracic extension angles at the MER were 105.7° ± 15.5°, 23.5° ± 13.9°, and 8.9° ± 7.3°, respectively.

Conclusion: Our results indicate that not only the glenohumeral joint movement but also the scapular and thoracic movements make major contributions to the MER angle.

Clinical Relevance: To better understand the pathomechanics of the shoulder complex in throwing, we need to take into account the individual contributions of the glenohumeral, scapulothoracic, and thoracic extension movements to the MER.

Background: The objective of this study was to determine the effects of increased horizontal abduction with maximum external rotation, as occurs during the late cocking phase of throwing motion, on shoulder internal impingement.

Hypothesis: An increase in glenohumeral horizontal abduction will cause overlap of the rotator cuff insertion with respect to the glenoid and increase pressure between the supraspinatus and infraspinatus tendon insertions on the greater tuberosity and the glenoid.

Study Design: Controlled laboratory study.

Methods: Eight cadaveric shoulders were tested with a custom shoulder testing system with the specimens in 60° of glenohumeral abduction and maximum external rotation. The amount of internal impingement was evaluated by assessing the location of the supraspinatus and infraspinatus articular insertions on the greater tuberosity relative to the glenoid using a MicroScribe 3DLX. Pressure in the posterior-superior quadrant of the glenoid was measured using Fuji prescale film. Data were obtained with the humerus in the scapular plane and 15°, 30°, and 45° of horizontal abduction from the scapular plane.

Results: At 30° and 45° of horizontal abduction, the articular margin of the supraspinatus and infraspinatus tendons was anterior to the posterior edge of the glenoid and less than 2 mm from the glenoid rim in the lateral direction; the contact pressure was also greater than that found in the scapular plane and 15° of horizontal abduction.

Conclusion: Horizontal abduction beyond the coronal plane increased the amount of overlap and contact pressure between the supraspinatus and infraspinatus tendons and glenoid.

Clinical Relevance: Excessive glenohumeral horizontal abduction beyond the coronal plane may cause internal impingement, which may lead to rotator cuff tears and superior labral anterior to posterior (SLAP) lesions.

Background: Success rates in the treatment of atraumatic shoulder instability differ, and in vivo identification of the individual insufficient stabilizers is difficult.

Hypothesis: Atraumatic shoulder instability is an inhomogeneous entity with varying alterations of the active and passive stabilizers. This might be a reason for inferior treatment results.

Study Design: Case control study; Level of evidence, 3.

Methods: Shoulders of 28 healthy volunteers and both shoulders of 14 patients with atraumatic instability and multidirectional laxity were examined in different arm positions using open magnetic resonance imaging. Three-dimensional postprocessing techniques were applied to determine 3D glenoid size and retroversion, radius of the humeral head, and curvature of the glenoid. The results of static stabilizers were compared with those of glenohumeral and scapular positioning in the same patients for identification of the individual insufficient stabilizers.

Results: The atraumatic unstable shoulders showed an increased mean retroversion on both sides, the difference being significant on the affected side (9.4° ± 4.8° vs healthy 3.9° ± 1.3°; P < .05) with a range of 2.6° to 16.6°. The curvature analysis demonstrated a pronounced flatness of the glenoid with a significantly increased mean radius (103.8 mm vs healthy 41.7 mm). The extent of these changes varied widely among patients. Comparison of the static stabilizers with glenohumeral and scapular positioning revealed that isolated changes of the active stabilizers exist in some patients, whereas no isolated changes of passive stabilizers were found.

Conclusion: All active and passive stabilizers need to be analyzed in patients with atraumatic instability because the magnitude of alteration varied widely among individuals. Different combinations of alterations of the stabilizers were found. The presented technique allows for in vivo identification of the specific alterations. This is necessary for a better understanding of individual pathomechanics and for initiating a specific causal treatment.

Background: During the throwing motion, the lower extremity is responsible for creating power that is transmitted through the core to the upper extremity. Research has shown that good hip range of motion and strength in throwing athletes results in greater performance and decreased stress placed on the upper extremity. Although research has investigated bilateral differences in hip characteristics among baseball pitchers, little is known about differences between pitchers and position players.

Hypothesis: Pitchers will have decreased passive hip rotation range of motion and gluteus medius strength compared with position players.

Study Design: Cross-sectional study; Level of evidence, 3.

Methods: Forty professional baseball pitchers and 40 position players with no recent history of lower extremity injury participated. Bilateral hip external and internal rotation range of motion, total arc of motion, and gluteus medius strength were measured with a digital inclinometer and handheld dynamometer.

Results: A Hotelling T2 multivariate analysis of variance showed position players to have significantly more hip internal rotation range of motion (3.1°, P = .01, effect size = .53) and abduction strength (3.5 kg, P =.04, effect size = .53) in the trail leg compared with the pitchers. There were no significant differences for any other hip characteristics between groups (P > .07).

Conclusion: The results of this study indicate that baseball pitchers have significantly smaller amounts of hip internal rotation range of motion and abduction strength of the trail leg compared with position players. However, these differences may not be clinically significant.

Clinical Relevance: Position players may be able to develop more energy in the lower extremity, while pitchers may rely more on energy created in the core and upper extremity, potentially placing pitchers at an increased risk for upper extremity injury. These descriptive hip characteristics may help clinicians detect inadequacies and provide appropriate prevention, diagnostic, and treatment interventions for such athletes.

Osteochondral lesions of the ankle are a more common source of ankle pain than previously recognized. Although the exact pathophysiology of the condition has not been clearly established, it is likely that a variety of etiological factors play a role, with trauma, typically from ankle sprains, being the most common. Technological advancements in ankle arthroscopy and radiologic imaging, most importantly magnetic resonance imaging, have improved diagnostic capabilities for detecting osteochondral lesions of the ankle. Moreover, these technologies have allowed for the development of more sophisticated classification systems that may, in due course, direct specific future treatment strategies. Nonoperative treatment yields best results when employed in select pediatric and adolescent patients with osteochondritis dissecans. However, operative treatment, which is dependent on the size and site of the lesion, as well as the presence or absence of cartilage damage, is frequently warranted in both children and adults with osteochondral lesions. Arthroscopic microdrilling, micropicking, and open procedures, such as osteochondral autograft transfer system and matrix-induced autologous chondrocyte implantation, are frequently employed. The purpose of this article is to review the history, etiology, and classification systems for osteochondral lesions of the ankle, as well as to describe current approaches to diagnosis and management.