The American Journal of Sports Medicine

Background: Recovery duration may be too short during the congested fixtures of professional soccer players with regard to maintaining physical performance and a low injury rate.

Purpose: To analyze the effects of 2 matches per week on physical performance and injury rate in male elite soccer players.

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

Methods: Match results, match-related physical performance, and injuries were monitored during 2 seasons (2007–2008 and 2008–2009) for 32 professional soccer players in a top-level team participating in the UEFA (Union of European Football Associations) Champions League. Total distance, high-intensity distance, sprint distance, and number of sprints were collected for 52 home matches. Injuries and player participation in matches and training were recorded throughout the full season.

Results: Physical performance, as characterized by total distance covered, high-intensity distance, sprint distance, and number of sprints, was not significantly affected by the number of matches per week (1 versus 2), whereas the injury rate was significantly higher when players played 2 matches per week versus 1 match per week (25.6 versus 4.1 injuries per 1000 hours of exposure; P < .001).

Conclusion: The recovery time between 2 matches, 72 to 96 hours, appears sufficient to maintain the level of physical performance tested but is not long enough to maintain a low injury rate. The present data highlight the need for player rotation and for improved recovery strategies to maintain a low injury rate among athletes during periods with congested match fixtures.

Background: Shoe manufacturers market motion control, stability, and cushioned shoes for plantar shapes defined as low, normal, and high, respectively. This assignment procedure is presumed to reduce injuries by compensating for differences in running mechanics.

Hypothesis: Assigning running shoes based on plantar shape will not reduce injury risk in Marine Corps basic training.

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

Methods: After foot examinations, Marine Corps recruits in an experimental group (E: 408 men, 314 women) were provided motion control, stability, or cushioned shoes for plantar shapes indicative of low, medium, or high arches, respectively. A control group (C: 432 men, 257 women) received a stability shoe regardless of plantar shape. Injuries during the 12 weeks of training were determined from outpatient visits obtained from the Defense Medical Surveillance System. Other known injury risk factors (eg, fitness, smoking, prior physical activity) were obtained from a questionnaire, existing databases, or the training units.

Results: Cox regression indicated little difference in injury risk between the E and C groups among men (hazard ratio [E/C] = 1.01; 95% confidence interval, 0.82-1.24) or women (hazard ratio [E/C] = 0.88; 95% confidence interval, 0.70-1.10).

Conclusion: This prospective study demonstrated that assigning shoes based on the shape of the plantar foot surface had little influence on injuries even after considering other injury risk factors.

Background: Recently, variations of the remnant bundle preservation technique, including selective bundle reconstruction and preservation of the anterior cruciate ligament tibial remnant, have produced good outcomes. The authors chose to investigate whether remnant bundle preservation in anterior cruciate ligament reconstruction would affect the remodeling process without inducing complications.

Hypothesis: An anterior cruciate ligament reconstruction graft can be augmented with a tensioned remnant of the native anterior cruciate ligament fibers without increasing the tendency of cyclops lesions. The magnetic resonance imaging signal intensity in an anterior cruciate ligament graft using the remnant bundle preservation technique would be lower than that using the standard technique.

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

Methods: Forty-one patients who underwent an anterior cruciate ligament reconstruction using the remnant bundle preservation technique with quadrupled hamstring tendon autograft were evaluated by magnetic resonance imaging at a mean of 6.3 ± 0.7 months after surgery. The control group included 41 consecutive patients who underwent a single-bundle anterior cruciate ligament reconstruction by the standard technique. The 2 groups did not differ significantly in gender, age distribution, mean time until postoperative magnetic resonance imaging, or other patient characteristics. The magnetic resonance imaging evaluation focused on 5 measurements as follows: (1) dimensions of the anterior cruciate ligament graft, (2) signal intensity of the anterior cruciate ligament graft using the signal/noise quotient (SNQ) from a region of interest analysis, (3) magnetic resonance imaging signal intensity and continuity of the preserved remnant bundle, (4) orientation of the anterior cruciate ligament, and (5) tibial tunnel placement.

Results: The remnant bundle preservation group had a significantly larger mean anterior cruciate ligament graft (293.4 mm²) than did the standard group (219.6 mm²) (P < .0001). However, the SNQ values of the anterior cruciate ligament graft in the remnant bundle preservation group were not significantly lower than those in the standard group in any of the 3 zones. In the remnant bundle preservation group, magnetic resonance imaging signals obtained from preserved remnant bundles in 35 patients (85%) showed 14 knees with a grade I signal (homogeneous low intensity) and 21 knees with a grade II signal (a portion of the preserved bundle was edematous). The continuity of remnant bundles in 37 patients (90%) as determined by magnetic resonance imaging was partial in 20 patients and complete in 17. The 2 groups did not differ significantly in the number of cyclops lesions detected by postoperative magnetic resonance imaging.

Conclusion: After anterior cruciate ligament reconstruction, magnetic resonance imaging showed significantly larger anterior cruciate ligament grafts in the remnant bundle preservation group than in the standard procedure group, and these preserved remnant bundles showed progressive remodeling in the anterior cruciate ligament graft with no increase in the incidence of cyclops lesions. To determine a clinical advantage for the remnant preservation technique, magnetic resonance imaging results such as these must be correlated with clinical findings.

Background: Increased knee pain at the time of anterior cruciate ligament reconstruction may potentially predict more difficult rehabilitation, prolonged recovery, and/or be predictive of increased knee pain at 2 years.

Hypothesis: A bone bruise and/or other preoperative factors are associated with more knee pain/symptoms at the time of index anterior cruciate ligament reconstruction, and the presence of a bone bruise would be associated with specific demographic and injury-related factors.

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

Methods: In 2007, the Multicenter Orthopaedic Outcomes Network (MOON) database began to prospectively collect surgeon-reported magnetic resonance imaging bone bruise status. A multivariable analysis was performed to (1) determine if a bone bruise, among other preoperative factors, is associated with more knee symptoms/pain and (2) examine the association of factors related to bone bruise. To evaluate the association of a bone bruise with knee pain/symptoms, linear multiple regression models were fit using the continuous scores of the Knee injury and Osteoarthritis Outcome Score (KOOS) symptoms and pain subscales and the Short Form 36 (SF-36) bodily pain subscale as dependent variables. To examine the association between a bone bruise and risk factors, a logistic regression model was used, in which the dependent variable was the presence or absence of a bone bruise.

Results: Baseline data for 525 patients were used for analysis, and a bone bruise was present in 419 (80%). The cohort comprises 58% male patients, with a median age of 23 years. The median Marx activity level was 13. Factors associated with more pain were higher body mass index (P < .0001), female sex (P = .001), lateral collateral ligament injury (P = .012), and older age (P = .038). Factors associated with more symptoms were a concomitant lateral collateral ligament injury (P = .014), higher body mass index (P < .0001), and female sex (P < .0001). Bone bruise is not associated with symptoms/pain at the time of index anterior cruciate ligament reconstruction. None of the factors included in the SF-36 bodily pain model were found to be significant. After controlling for other baseline factors, the following factors were associated with a bone bruise: younger age (P = .034) and not jumping at the time of injury (P = .006).

Conclusion: After anterior cruciate ligament injury, risk factors associated with a bone bruise are younger age and not jumping at the time of injury. Bone bruise is not associated with symptoms/pain at the time of index anterior cruciate ligament reconstruction.

Background: Biomechanical differences between anatomical double-bundle and central single-bundle anterior cruciate ligament reconstruction using the same graft tissue have not been defined.

Purpose: The purpose of this study was to compare these reconstructions in their ability to restore native knee kinematics during a reproducible Lachman and pivot-shift examination.

Study Design: Controlled laboratory study.

Methods: Using a computer-assisted navigation system, 10 paired knees were subjected to biomechanical testing with a standardized Lachman and mechanized pivot-shift examination. The navigation system recorded the 3D motion path of a tracked point at the center of the tibia, center of the medial tibial plateau, and center of the lateral tibial plateau with each maneuver. The testing protocol consisted of evaluation in the intact state, after complete anterior cruciate ligament transection, after medial and lateral meniscectomy, and after anterior cruciate ligament reconstruction with (1) a single-bundle center-center or (2) anatomical double-bundle technique. Repeated-measures analysis of variance with a post hoc Tukey test was used to compare the measured translations with each test condition.

Results: A significant difference in anterior translation was seen with Lachman examination between the anterior cruciate ligament– and medial and lateral meniscus–deficient condition compared with both the double-bundle and single-bundle center-center anterior cruciate ligament reconstruction (P < .001); no significant difference was observed between reconstructions. The double-bundle construct was significantly better in limiting anterior translation of the lateral compartment compared with the single-bundle reconstruction during a pivot-shift maneuver (2.0 ± 5.7 mm vs 7.8 ± 1.8 mm, P < .001) and was not significantly different than the intact anterior cruciate ligament condition (2.7 mm ± 4.7 mm, P > .05).

Discussion: Although double-bundle and single-bundle, center-center anterior cruciate ligament reconstructions appear equally effective in controlling anterior translation during a Lachman examination, analysis of pivot-shift kinematics reveals significant differences between these surgical reconstructions. An altered rotational axis resulted in significantly greater translation of the lateral compartment in the single-bundle compared with double-bundle reconstruction.

Clinical Relevance: A double-bundle anterior cruciate ligament reconstruction may be a favorable construct for restoration of knee kinematics in the at-risk knee with associated meniscal injuries and/or significant pivot shift on preoperative examination.

Background: Traumatic anterior-inferior shoulder joint dislocations are common injuries among the young athletic population. The aim of this study was to assess which factors, including concomitant injury (rotator cuff tears, superior labral anterior posterior [SLAP] lesions), patient age, and fixation methods, led to redislocation after arthroscopic stabilization.

Hypothesis: There are several risk factors for the outcome after arthroscopic anterior-inferior glenohumeral stabilization.

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

Methods: Between 1996 and 2000, 221 patients were treated with arthroscopic stabilization for anterior-inferior shoulder dislocation. Of these 221 consecutive patients, 190 (140 male, 50 female) with an average age of 28.0 years (range, 14.4-59.2 years) were available for follow-up (average follow-up, 37.4 ± 15.8 months). Fixation methods were FASTak (n = 138), Suretac (n = 28), or Panalok (n = 24) anchors. Concomitant SLAP lesions were seen in 38 of 190 cases (20%).

Results: Redislocation rates varied between anchor systems (FASTak, 6.5%; Suretac, 25%; Panalok, 16.8%). Superior labral anterior posterior lesions, when treated, did not influence clinical outcomes or redislocation rate. A concomitant rotator cuff tear did not influence redislocation rate. Postoperative outcomes (Rowe score, Constant score, American Shoulder and Elbow Surgeons [ASES] shoulder index, 12-item questionnaire) in patients with a partial tear were also not altered. On the other hand, the redislocation rate correlated with patient age and number of prior dislocations. Return to sports at preinjury level was possible in 80% of cases.

Conclusion: Arthroscopic repair of anterior-inferior instability using the 5:30-o’clock portal is dependent on anchor type and can show good to excellent results. Because of several coinjuries in anterior-inferior instability, an arthroscopic approach may be required to identify and treat such lesions.

Background: Symptomatic early-onset chondromalacia often develops after a meniscectomy in the affected knee compartment. The role of meniscal transplantation in reducing pain and improving function in patients with prior ipsilateral meniscectomy is still being defined.

Hypothesis: Patients with symptomatic early-onset chondromalacia of the knee after ipsilateral meniscectomy will have improved clinical outcomes after meniscal transplantation.

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

Methods: All patients who underwent meniscal allograft transplantation between July 2003 and December 2006 were prospectively followed. The indications for surgery were unicompartmental knee pain and postactivity effusions after total or near-total meniscectomy in patients with closed physes. High-field magnetic resonance imaging (1.5-T or 3-T magnets) was used to assess the articular cartilage of the affected compartment. The meniscal transplantations were performed with an arthroscopically assisted technique. Modified Cincinnati knee and International Knee Documentation Committee (IKDC) subjective and IKDC objective outcome scores were obtained on all patients preoperatively and postoperatively to evaluate patients’ outcomes.

Results: Forty patients with an average age of 25 years and a body mass index of 25.4 were included. After an average final follow-up of 2.5 years, IKDC subjective scores increased significantly from 54.5 to 72.0 (P < .001). Modified Cincinnati knee scores increased from 55.2 to 75.3 (P < .001). The preoperative IKDC objective scores measuring effusion improved significantly from 6 A (normal), 29 B (nearly normal), and 5 C (abnormal), when compared with the postoperative scores of 33 A (normal) and 1 B (nearly normal) (P < .01). Five patients sustained tears of their meniscal transplants and underwent partial meniscectomies of the transplant graft.

Conclusion: The results confirm that meniscal transplantation significantly reduces pain, decreases activity-related effusions, and improves function in patients with prior meniscectomy; however, the long-term chondroprotective effects remain unknown.

Introduction: Posterior thigh muscle injuries in athletes are common, and prediction of recovery time would be of value.

Hypothesis: Knee active range of motion deficit 48 hours after a unilateral posterior thigh muscle injury correlates with time to full recovery.

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

Methods: One hundred sixty-five track and field athletes with acute, first-time, unilateral posterior thigh muscle injuries were prospectively evaluated regarding knee active range of motion deficit. This was compared with the uninjured side 48 hours after injury. A control group was also examined. Ultrasound was used to image the muscle lesion. All athletes were managed nonoperatively with the same rehabilitation protocol. The “full rehabilitation time” (interval from the injury to full athletic activities) was recorded.

Results: Range of motion of the affected leg was decreased in the 165 injured athletes compared with the uninjured side and the control group. Sonography identified abnormalities in 55% (90 of 165) of the injured athletes. The biceps femoris was the most commonly affected muscle (68 of 90 [75%]). The musculotendinous junction (proximal or distal) was involved in 93% (85 of 90) of lesions. Eighty-one percent (133 of 165) of athletes had active range of motion deficit of less than 20°, and had returned to full performance at 2 weeks. In 6 of 165 athletes (3.6%), with active range of motion deficit of more than 30°, recovery time exceeded 6 weeks, with a significant correlation between full rehabilitation time and active range of motion deficit (χ² = 152.560; P = .0001).

Conclusion: Knee active range of motion deficit is an objective and accurate measurement, predicting recovery time in elite athletes.

Background: Abnormal 3-dimensional tibiofemoral joint kinematics have been identified in anterior cruciate ligament-reconstructed knees during functional gait tasks, which is suggested to directly affect risk of knee osteoarthritis. However, the extent to which similar high-risk abnormalities are present during more demanding maneuvers, such as single-legged hopping, is largely unknown.

Hypothesis: When performing a single-legged forward hop landing, the reconstructed knee will demonstrate altered sagittal, frontal, and transverse plane kinematics compared with the contralateral limb.

Study Design: Controlled laboratory study.

Methods: High-speed biplane radiography was used to quantify bilateral 3-dimensional tibiofemoral joint kinematics in 9 subjects with unilaterally reconstructed anterior cruciate ligaments (mean time after surgery, 4 months) during 3 single-legged, forward hop landing trials. Mean subject-based initial foot contact and maximum stance (0-250 ms) values were calculated for each kinematic variable. Two-tailed paired t tests were subsequently applied to examine for the main effect of limb (reconstructed vs contralateral).

Results: The reconstructed knees exhibited significantly greater extension (P = .04), external tibial rotation (P = .006), and medial tibial translation (P = .02) than the contralateral knees at initial contact. Reconstructed knees underwent significantly greater maximum flexion (P = .05), maximum external tibial rotation (P = .01), and maximum anterior tibial translation (P = .02). No significant differences existed between limbs for initial contact (P = .65) or maximum adduction-abduction (P = .55).

Conclusion: Tibiofemoral joint kinematics of the anterior cruciate ligament-reconstructed knee are significantly different from those of the uninjured contralateral limb during a single-legged hop landing. This altered kinematic profile, in conjunction with the large impact loads associated with hopping, may further contribute to the risk of posttraumatic knee osteoarthritis.

Clinical Relevance: Returning to sports involving dynamic single-legged landings at 4 months after anterior cruciate ligament reconstruction surgery may contribute to accelerated knee joint degeneration.

Background: Yearly changes in active joint stiffness may help explain when neuromuscular sex differences emerge in adolescent athletes that may relate to increased anterior cruciate ligament injury risk in females.

Hypothesis: Pubertal males would demonstrate increases in knee stiffness while pubertal females would not. Second, postpubertal female athletes would have significantly lower knee joint stiffness than postpubertal male athletes.

Study Design: Cohort Study; Level of Evidence 2 and Cross-Sectional Study; Level of Evidence 3.

Methods: Two hundred sixty-five females and 50 males participated in 2 testing sessions approximately 1 year apart. The subjects were classified as either pubertal (n = 182, age 12.4 ± 0.9 years) or postpubertal (n = 133, age 14.5 ± 1.4 years) based on the modified Pubertal Maturational Observational Scale at each visit. Active joint stiffness of the ankle, knee, and hip was estimated during a drop vertical jump. Stiffness was calculated as the slope of the moment-angle curve from a least squares linear regression during the stance phase.

Results: All athletes showed increased active knee stiffness during the span of a year (P < 0.05). However, this increase was not different when stiffness was normalized to body mass. Only males demonstrated greater magnitudes of ankle and hip active stiffness (P < .05). Peak ankle and hip moments, but not knee moments, in postpubertal males were significantly greater than postpubertal females (P < .05). Females had a higher knee to hip moment ratio than males (P < .05).

Conclusion: Both males and females showed increased active knee stiffness during the span of a year; males demonstrated increased ankle and hip active stiffness as well. Differences in hip joint posture at initial contact (greater flexion in males) and external hip flexion moment (greater flexion magnitude in males) may indicate that males use a different hip recruitment strategy during drop vertical jumps than females.

Background: Most biomechanical studies for evaluation of the structural properties of meniscal repairs have been performed in tensile loading scenarios perpendicular to the circumferential meniscal fibers. However, meniscal repair constructs are also exposed to shear forces parallel to the circumferential meniscal fibers during healing, particularly in the midportion of the meniscus.

Hypothesis: Material properties of meniscal repair devices cannot be extrapolated from tensile to shear load scenarios.

Study Design: Controlled laboratory study.

Methods: In 84 harvested and isolated bovine lateral menisci following removal of adjacent soft tissue, a standardized vertical lesion was set followed by repair using all-inside flexible (FasT-Fix, FasT-Fix AB, RapidLoc) and rigid (Meniscus Screw, Meniscus Arrow) meniscal repair devices. Vertical and horizontal 2.0 Ethibond sutures were used as controls. The repaired meniscal construct was tested in a tensile (parallel to the axis of the tested repair device) and shear load scenario (perpendicular to the axis of the tested repair device) at 5 mm/min and 37°C environmental temperature. Maximum load to failure, stiffness, and failure mode were recorded.

Results: The absolute load to failure values of each repair device in the shear scenario were only marginally different from the tensile load scenario. However, the stiffness of several tested devices was markedly reduced in the shear scenario. In both scenarios, large differences of the load to failure and the stiffness between the implant types up to 5-fold were found (P < .05). The failure mode of several all-inside flexible repair devices was different in the shear versus tensile load scenario, while the failure mode of the rigid systems was similar in both scenarios.

Conclusion: All-inside meniscal repair devices exposed to shear load scenarios have comparable maximum loads to failures as tensile load scenarios. However, the stiffness of the majority of the flexible meniscal repair implants in a shear load scenario is markedly reduced. The applied scenario also affects the failure mode in several flexible meniscal repair devices.

Clinical Relevance: Meniscal repair devices with sufficient stiffness and stability against shear loads may be favored for meniscal repair, especially within the midportion of the meniscus where shear loads occur during healing.

Background: Microfracture and drilling elicit a cartilage repair whose quality depends on subchondral bone repair. Alternatively activated (AA) macrophages express arginase-1, release angiogenic factors, and could be potential mediators of trabecular bone repair.

Hypothesis: Chitosan–glycerol phosphate (GP)/blood implants elicit arginase-1+ macrophages in vivo through neutrophil-dependent mechanisms and improve trabecular bone repair of drilled defects compared with drilling alone.

Study Design: Controlled laboratory study.

Methods: Bilateral trochlear cartilage defects were created in 15 rabbits, microdrilled, and treated or not with chitosan-GP/blood implant to analyze AA macrophages, CD-31+ blood vessels, bone, and cartilage repair after 1, 2, or 8 weeks. Neutrophil and macrophage chemotaxis to rabbit subcutaneous implants of autologous blood and chitosan-GP (±blood) was quantified at 1 or 7 days. In vitro, sera from human chitosan-GP/blood and whole blood clots cultured at 37°C were analyzed by proteomics and neutrophil chemotaxis assays.

Results: Chitosan-GP/blood clots and whole blood clots released a similar profile of chemotactic factors (PDGF-BB, IL-8/CXCL8, MCP-1/CCL2, and no IL-1β or IL-6), although chitosan clot sera attracted more neutrophils in vitro. Subcutaneous chitosan-GP (±blood) implants attracted more neutrophils (P < .001) and AA macrophages than whole blood clots in vivo. In repairing subchondral drill holes, chitosan-GP/blood implant attracted more AA macrophages at 1 and 2 weeks and more blood vessels at 2 weeks compared with drilled controls. Treatment elicited a more complete woven bone repair at 8 weeks than controls (P = .0011) with a more uniform, integrated collagen type II+ cartilage repair tissue.

Conclusion and Clinical Relevance: AA macrophages may play a role in the regeneration of subchondral bone, and chitosan-GP can attract and transiently accumulate these cells in the repair tissue. The resulting improved subchondral repair could be advantageous toward enhancing integration of a restored chondral surface to the subchondral bone.

Background: The use of mesenchymal stem cells (MSCs) to treat osteochondral defects caused by sports injuries or disease is of particular interest. However, there is a lack of studies in large-animal models examining the benefits of chondrogenic predifferentiation in vitro for repair of chronic osteochondral defects.

Hypothesis: Chondrogenic in vitro predifferentiation of autologous MSCs embedded in a collagen I hydrogel currently in clinical trial use for matrix-associated autologous chondrocyte transplantation facilitates the regeneration of a chronic osteochondral defect in an ovine stifle joint.

Study Design: Controlled laboratory study.

Methods: The optimal predifferentiation period of ovine MSCs within the type I collagen hydrogel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, osteochondral lesions (diameter 7 mm) were created at the medial femoral condyles of the hind legs in 10 merino sheep. To achieve a chronic defect model, implantation of the ovine MSCs/hydrogel constructs was not performed until 6 weeks after defect creation. The 40 defects were divided into 4 treatment groups: (1) chondrogenically predifferentiated ovine MSC/hydrogel constructs (preMSC-gels), (2) undifferentiated ovine MSC/hydrogel constructs (unMSC-gels), (3) cell-free collagen hydrogels (CF-gels), and (4) untreated controls (UCs). Evaluation followed after 6 months.

Results: With regard to proteoglycan content, cell count, gel contraction, apoptosis, compressive properties, and progress of chondrogenic differentiation, a differentiation period of 14 days in vitro was considered optimal. After 6 months in vivo, the defects treated with preMSC-gels showed significantly better histologic scores with morphologic characteristics of hyaline cartilage such as columnarization and presence of collagen type II.

Conclusion: Matrix-associated autologous chondrocyte transplantation with predifferentiated MSCs may be a promising approach for repair of focal, chronic osteochondral defects.

Clinical Relevance: The results suggest an encouraging method for future treatment of focal osteochondral defects to prevent progression to osteoarthritis.

Background: Better understanding of the incidence, mechanisms, and characteristics of potential injuries in wrestling helps to implement preventive measures to better care for these athletes. Several studies have investigated the incidence and type of injuries in amateur and intercollegiate wrestling; however, there is a lack of studies that review the incidence and nature of injuries in elite wrestlers during Olympic Games or World Championships.

Purpose: The purpose of this study was to assess the injury profile of elite senior wrestlers in Greco-Roman, freestyle, and female wrestling during the 2008 Beijing Olympic Games.

Study Design: Descriptive epidemiologic study.

Methods: Study participants consisted of 343 wrestlers participating in the 2008 Beijing Olympic Games. Standard checkoff forms were used to collect the injury data, including injury type, severity, location, timing, and mechanism.

Results: A total of 343 athletes sustained 32 injuries during 406 matches, which is equivalent to an overall incidence of 9.30 injuries per 100 athletes and 7.88 injuries per 100 matches. Among the 3 styles, freestyle had the highest injury rate (10.1%) and female wrestling the lowest (7.5%). In sum, 84.4% of all injuries were categorized as mild. Although the overall injury rate in male athletes was slightly higher than that among female athletes (9.7% versus 7.5%), this difference was not statistically significant (odds ratio = 1.21, 95% confidence interval = 0.46-3.68; P = .40).

Conclusion: The rate and severity of wrestling injuries during the 2008 Beijing Olympic Games were lower than previous reports. No serious and catastrophic injury was recorded, and most injuries were minor.

Background: A more oblique placement of the anterior cruciate ligament (ACL) graft has been related to better control of rotatory knee stability. Femoral fixation with a transverse system might injure its posterolateral structures.

Hypothesis: A cross-pin system, originally developed for transtibial reconstruction of the ACL, can safely be used when creating a lower femoral tunnel through the anteromedial portal. However, a long femoral tunnel must be created to protect the posterolateral structures of the knee.

Study Design: Controlled laboratory study.

Methods: An ACL was arthroscopically reconstructed with a hamstring graft in 22 fresh cadaveric knees. The femoral tunnel was anatomically drilled in all cases. Knee flexion angle was set at 110°. Femoral fixation was performed with a cross-pin system. A 30-mm-long femoral tunnel was created in 11 knees (group A). In the remaining 11 knees, the femoral tunnel was drilled as long as each lateral condyle permitted (group B). For both groups, the relationships were compared between the cross-pin and the lateral collateral ligament (LCL), popliteus tendon, articular cartilage, and peroneal nerve.

Results: In 5 cases of group A, the cross-pin was placed either through the LCL or between the LCL and popliteus tendon, whereas in group B it was always posterior to the LCL (P = .035). The cross-pin was closer to the articular cartilage in group A than in group B (7.14 mm versus 16.9 mm; P < .001). The minimal distance to the peroneal nerve in all specimens was 23.89 mm.

Conclusion: Hamstring graft fixation with a cross-pin system from the anteromedial portal with a 30-mm femoral tunnel presents a higher risk of injury to the LCL. The femoral tunnel should be drilled as long as possible.

Clinical Relevance: A long femoral tunnel is required for safe transverse femoral fixation in an anatomical ACL reconstruction.

Background: Achilles tendinopathy is a considerable problem for active people. The degenerative processes associated with tendinopathy may be associated with changes in the inherent mechanical properties of the musculotendinous unit.

Purpose: The purpose of this study was to compare Achilles tendon–aponeurosis strain between male athletes with and without Achilles tendinopathy.

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

Methods: Fifteen healthy men (age, 35 ± 9 years; height, 1.78 ± 0.05 m; mass, 79 ± 11 kg) and 14 men with midportion Achilles tendinopathy (age, 40 ± 8 years; height, 1.77 ± 0.06 m; mass, 80 ± 9 kg) who were all running over 20 km per week participated in the study. Each participant was tested in a single session that involved maximal isometric plantar flexion efforts being performed on a calf-raise apparatus while synchronous real-time ultrasonography of the triceps surae aponeurosis was recorded. Achilles tendon–aponeurosis strain (%) was calculated by dividing tendon displacement during plantar flexion by resting tendon length (intrarater reliability: intraclass correlation coefficient = .92).

Results: Participants in the Achilles tendinopathy group (5.2% ± 2.6%) had significantly (P = .039) higher Achilles tendon–aponeurosis strain compared with the control group (3.4% ± 1.8%). In contrast, there were no significant between-group differences for maximal isometric plantar flexion force.

Conclusion: Achilles tendon–aponeurosis strain is higher in male athletes with tendinopathy than those without. The results of this study provide a rationale for current clinical approaches to management of Achilles tendinopathy, whereby repetitive mechanical loading may impart a positive benefit through reduced compliance of the musculotendinous unit.

Background: The perception of improvement by a patient has assumed a central role in functional evaluation after a variety of knee problems. One of the instruments most used in clinical research is the International Knee Documentation Committee (IKDC) Subjective Knee Form because its psychometric properties are considered to be excellent. Nonetheless, this questionnaire was originally developed for use in the English language. Therefore, to use this questionnaire in the Brazilian population, it is essential to translate and validate it.

Purpose: The aim of this study was to translate the IKDC Subjective Knee Form into a Brazilian version and to test its validity and reproducibility.

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

Methods: The translation of the original IKDC Subjective Knee Form into a Brazilian version was accomplished in accordance with the American Orthopaedic Society for Sports Medicine guidelines and was tested in 32 patients with knee pathologic conditions to develop the first Brazilian version. To test validity and reproducibility, 117 patients with several knee complaints completed the Brazilian IKDC Subjective Knee Form, the Short Form 36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Lysholm score. From these patients, 85 were retested within a week to achieve reproducibility. The validation was addressed by correlating the Brazilian IKDC Subjective Knee Form to the other outcome measures. The reproducibility was tested by measuring internal consistency, test-retest reliability, and agreement.

Results: The Brazilian IKDC Subjective Knee Form was highly related to the physical component summary of the SF-36, the Lysholm score, and the WOMAC, and weakly related to the mental component summary of SF-36 (r = .79, .89, .85, and .51, respectively). The internal consistency was strong, with a Cronbach α value of .928 and .935 in the test and retest assessment, respectively. The test-retest reliability proved to be excellent, with a high value of the intraclass correlation coefficient (.988), as well as the agreement, demonstrated by the low differences between the means of the test and retest, and the short limit of agreement, observed in the Altman-Bland and survival-agreement plots.

Conclusion: The results of this study provide evidence that the Brazilian IKDC Subjective Knee Form has psychometric properties similar to the original version. In addition, it was a reliable evaluation instrument for patients with knee-related problems.

Background: Careful review of the literature seldom reveals peel-off–type injuries at the tibial attachment of the posterior cruciate ligament in children.

Purpose: The purpose of this research is to describe the diagnosis and treatment of peel-off injuries at the tibial ligament–osseous junction of the posterior cruciate ligament in children.

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

Methods: Between February 2001 and May 2007, 6 patients with diagnosed peel-off injuries at the tibial attachment of the posterior cruciate ligament were surgically treated. All patients were boys from 12 to 13 years of age (mean, 12.3 years). Plain radiographs were normal, but magnetic resonance imaging and arthroscopic findings revealed complete avulsion of the posterior cruciate ligament at the tibial attachment without an osseous fragment. The authors retrospectively reviewed the clinical presentations, diagnostic tests, surgical procedures, and the results of the treatment. The mean follow-up was 37.3 months (range, 25-53 months).

Results: Five of the 6 patients had returned to their preinjury levels of activities. The mean side-to-side difference in posterior translation as measured with the KT-2000 arthrometer and stress radiographs was 2.3 mm (range, 0.7-5.2 mm) and 2.9 mm (range, 0.3-6.4 mm), respectively. The mean Lysholm score was 95 points (range, 90-100 points). According to the assessment with the International Knee Documentation Committee form, 2 patients were classified as A, 3 as B, and 1 as C.

Conclusion: The authors could diagnose peel-off injuries at the tibial attachment of the posterior cruciate ligament in children by careful examinations and arthroscopic surgeries. Satisfactory outcomes without any complications were obtained through the arthroscopic reattachment and fixation using multiple sutures in the case of the avulsed stump that was not split.

Knee meniscectomy is the most common procedure performed by orthopaedic surgeons. While it is generally believed that loss of meniscal tissue leads to osteoarthritis and poor knee function, many variables may significantly influence this outcome. Through literature search engines including PubMed and Ovid, 4 randomized controlled trials, 2 prospective cohorts, and 23 retrospective cohorts that fit the criteria for level I, II, and III level of evidence were included in this systematic review. For the level III evidence studies, follow-up of 5 years or more was required. Preoperative and intraoperative predictors of poor clinical or radiographic outcomes included total meniscectomy or removal of the peripheral meniscal rim, lateral meniscectomy, degenerative meniscal tears, presence of chondral damage, presence of hand osteoarthritis suggestive of genetic predisposition, and increased body mass index. Variables that were not predictive of outcome or were inconclusive or had mixed results included meniscal tear pattern, age, mechanical alignment, sex of patient, activity level, and meniscal tears associated with anterior cruciate ligament (ACL) reconstruction. While an intact meniscus or meniscal repair was generally favorable in the ACL-reconstructed knees, meniscal repair of degenerative meniscal tissue was not favorable. There is a lack of uniformity in the literature on this subject with a preponderance of lower level evidence. Although randomized controlled trials are considered to be the gold standard in medical research, a multicenter prospective cohort design may be more appropriate in assessing the long-term outcome of meniscal surgery and the role that multiple preoperative and intraoperative variables may play in clinical outcomes. In addition, future studies should include factors not assessed or adequately evaluated by several of the included studies, such as meniscal tear pattern, age, mechanical alignment, sex of the patient, activity level, meniscal tears associated with other injuries such as the ACL, smoking, and the effect of previous surgery.

Osteochondritis dissecans of the capitellum is a well-recognized cause of elbow pain and disability in the adolescent athlete. This condition typically affects young athletes, such as throwers and gymnasts, involved in high-demand, repetitive overhead, or weightbearing activities. The true cause, natural history, and optimal treatment of osteochondritis dissecans of the capitellum remain unknown. Suspicion of this condition warrants investigation with proper radiographs and magnetic resonance imaging. Prompt recognition of this disorder and institution of nonoperative treatment for early, stable lesions can result in healing with later resumption of sporting activities. Patients with unstable lesions or those failing nonoperative therapy require operative intervention with treatment based on lesion size and extent. Historically, surgical treatment included arthrotomy with loose body removal and curettage of the residual osteochondral defect base. The introduction of elbow arthroscopy in the treatment of osteochondritis dissecans of the capitellum permits a thorough lesion assessment and evaluation of the entire elbow joint with the ability to treat the lesion and coexistent pathology in a minimally invasive fashion. Unfortunately, the prognosis for advanced lesions remains more guarded, but short-term results after newer reconstruction techniques are promising.