The American Journal of Sports Medicine

Background: Soccer injuries are common, and athletes returning to play after injury are especially at risk. Few studies have investigated how to prevent reinjury.

Hypothesis: The rate of reinjury is reduced using a coach-controlled rehabilitation program.

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

Methods: Twenty-four male amateur soccer teams were randomized into an intervention (n = 282) and control group (n = 300). The intervention was implemented by team coaches and consisted of information about risk factors for reinjury, rehabilitation principles, and a 10-step progressive rehabilitation program including return to play criteria. During the 2003 season, coaches reported individual exposure and all time loss injuries were evaluated by a doctor and a physiotherapist. Four teams (n = 100) withdrew from the study after randomization, leaving 10 teams with 241 players for analysis in both groups.

Results: There were 90 injured players (132 injuries) in the intervention group, and 10 of these (11%) suffered 14 reinjuries during the season. In the control group, 23 of 79 injured players (29%) had 40 recurrences (134 injuries). A Cox regression analysis showed a 66% reinjury risk reduction in the intervention group for all injury locations (hazard ratio [HR] 0.34, 95% confidence interval [CI] 0.16-0.72, P = .0047) and 75% for lower limb injuries (HR 0.25, 95% CI 0.11-0.57, P < .001). The preventive effect was greatest within the first week of return to play. Injured players in the intervention group complied with the intervention for 90 of 132 injuries (68%).

Conclusion: The reinjury rate in amateur male soccer players was reduced after a controlled rehabilitation program implemented by coaches.

Background: Previous studies have shown that increasing tibial slope can shift the resting position of the tibia anteriorly. As a result, sagittal osteotomies that alter slope have recently been proposed for treatment of posterior cruciate ligament (PCL) injuries.

Hypotheses: Increasing tibial slope with an osteotomy shifts the resting position anteriorly in a PCL-deficient knee, thereby partially reducing the posterior tibial “sag” associated with PCL injury. This shift in resting position from the increased slope causes a decrease in posterior tibial translation compared with the PCL-deficient knee in response to posterior tibial and axial compressive loads.

Study Design: Controlled laboratory study.

Methods: Three knee conditions were tested with a robotic universal force-moment sensor testing system: intact, PCL-deficient, and PCL-deficient with increased tibial slope. Tibial slope was increased via a 5-mm anterior opening wedge osteotomy. Three external loading conditions were applied to each knee condition at 0°, 30°, 60°, 90°, and 120° of knee flexion: (1) 134-N anterior-posterior (A-P) tibial load, (2) 200-N axial compressive load, and (3) combined 134-N A-P and 200-N axial loads. For each loading condition, kinematics of the intact knee were recorded for the remaining 5 degrees of freedom (ie, A-P, medial-lateral, and proximal-distal translations, internal-external and varus-valgus rotations).

Results: Posterior cruciate ligament deficiency resulted in a posterior shift of the tibial resting position to 8.4 ± 2.6 mm at 90° compared with the intact knee. After osteotomy, tibial slope increased from 9.2° ± 1.0° in the intact knee to 13.8° ± 0.9°. This increase in slope reduced the posterior sag of the PCL-deficient knee, shifting the resting position anteriorly to 4.0 ± 2.0 mm at 90°. Under a 200-N axial compressive load with the osteotomy, an additional increase in anterior tibial translation to 2.7 ± 1.7 mm at 30° was observed. Under a 134-N A-P load, the osteotomy did not significantly affect total A-P translation when compared with the PCL-deficient knee. However, because of the anterior shift in resting position, there was a relative decrease in posterior tibial translation and increase in anterior tibial translation.

Conclusion: Increasing tibial slope in a PCL-deficient knee reduces tibial sag by shifting the resting position of the tibia anteriorly. This sag is even further reduced when the knee is subjected to axial compressive loads.

Clinical Relevance: These data suggest that increasing tibial slope may be beneficial for patients with PCL-deficient knees.

Background: Knee-specific quality-of-life instruments are commonly used outcome measures. However, they have not been compared for their ability to detect symptoms and disabilities important to patients.

Study Design: Cohort study (diagnosis); Level of evidence, 1.

Methods: Subjective portions of 11 knee-specific instruments were consolidated. The frequency and importance of each item were assessed. One hundred fifty-three patients with anterior cruciate ligament ruptures, isolated meniscal tears, or osteoarthritis were polled. Instruments were ranked according to the number of items with high mean importance, high frequency importance product, and low mean importance, and according to the number endorsed by at least 51% of patients.

Results: For anterior cruciate ligament tears, the Mohtadi quality-of-life instrument scored highest in 3 categories. For meniscal tears, the Western Ontario Meniscal Evaluation Tool scored highly in all 4 categories. For osteoarthritis, the Western Ontario and McMaster Universities Osteoarthritis Index scored highly in 4 categories. Of the general knee instruments, the International Knee Documentation Committee Standard Evaluation Form and the Knee Injury and Osteoarthritis Outcome Score scored favorably.

Conclusion: The Mohtadi quality-of-life instrument, Western Ontario Meniscal Evaluation Tool, and Western Ontario and McMaster Universities Osteoarthritis Index—disease-specific instruments—contain many items important to patients. Of general knee instruments studied, the International Knee Documentation Committee Standard Evaluation Form and the Knee Injury and Osteoarthritis Outcome Score contain the most items important to patients.

Clinical Relevance: This study guides clinicians and researchers in selecting instruments that ensure that the patient's perspective is considered for outcome studies involving 3 common knee disorders.

Background: Although recent studies have shown intermediate-term success of both meniscal allograft transplantation (MAT) and autologous chondrocyte implantation (ACI) performed separately, there have been no peer-reviewed studies focused prospectively on the combined procedure. By potentially reestablishing a compartment contact area closer to normal, MAT may allow a more optimal environment for ACI by reducing stress (stress = force/unit area). On the other hand, the literature suggests that MAT alone in the presence of extensive chondrosis performs poorly. Restoring the articular cartilage may allow the MAT to perform more similarly to series with nearly normal articular cartilage.

Hypothesis: Performed concomitantly, ACI and MAT will result in significant improvements in knee function as measured by functional scoring scales and visual analog pain scales.

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

Methods: Preoperative and postoperative comparisons of Browne modified Cincinnati functional levels, Lysholm, visual analog rest and maximum pain, and satisfaction scores were recorded. Thirty-six total procedures were performed between 1999 and 2004.

Results: Of the 36 patients entering the series, 29 had >2-year evaluation and scores. Four patients were recorded as failures before the 2-year follow-up and required revision surgery. Three patients were lost to follow-up. A total of 21 medial and 8 lateral MAT/femoral condyle ACIs were performed. Sixteen of 29 patients had concomitant procedures performed, including tibial tuberosity osteotomy, anterior cruciate ligament reconstruction, and high tibial osteotomy. Patients demonstrated statistically significant improvement in the standardized outcome surveys, visual analog pain, and satisfaction scores. The Browne Cincinnati (Patient and Clinician, respectively) showed an improvement from 3.9 (standard deviation [SD], 1.5) and 4.0 (SD, 1.4) preoperatively to 6.3 (SD, 1.9) postoperatively for both. The Lysholm also showed an improvement from 57.7 (SD, 16.2) preoperatively to 77.7 (SD, 19.3) postoperatively. There were no significant differences noted in any of the subgroups (medial vs lateral, isolated vs concomitant, or unipolar vs bipolar).

Conclusion: At a minimum of 2-year follow-up, MAT in combination with ACI demonstrates improvement in both symptoms and knee function. However, the improvements are less than literature-reported outcomes of either procedure performed in isolation.

Background: The optimal device for the fixation of osteochondritis dissecans fragments of the knee remains controversial and lacks long-term results.

Purpose: To review a group of young adults with osteochondritis dissecans of the knee treated with arthroscopic fixation of the fragment using bioabsorbable pins and nails and to examine the medium-term outcome of the fixation via magnetic resonance imaging and clinical evaluation.

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

Methods: Twenty-eight patients (30 knees) with osteochondritis dissecans of the knee were treated with arthroscopic fixation using bioabsorbable, self-reinforced poly-L-lactide pins and nails. All patients were young adult males with closed physes. The average follow-up time was 5.4 years (range, 3-12). At follow-up, magnetic resonance imaging studies were used to evaluate subchondral bone healing, and the outcome was evaluated by the Kujala score.

Results: The functional results were excellent or good for 73% of the patients in the nail group versus 35% in the pin group. The lesions treated were large, with an average size of 447 mm2, affecting the weightbearing area in the majority of the patients. On magnetic resonance imaging, incomplete bone consolidation was predominant in the pin group.

Conclusions: Arthroscopic fixation with bioabsorbable nails seems to be a suitable method of repair for osteochondritis dissecans of the adult knee and appears to be superior to arthroscopic fixation with bioabsorbable pins.

Background: A type VIII superior labrum anterior posterior lesion represents pathologic posteroinferior extension of a type II superior labrum anterior posterior lesion with injury to the insertion of the posterior band of the inferior glenohumeral ligament. No reports in the literature describe arthroscopic treatment of a type VIII superior labrum anterior posterior lesion and its associated glenohumeral instability.

Hypothesis: Arthroscopic capsulolabral reconstruction is effective in alleviating pain and restoring stability and function in athletes with glenohumeral instability due to the type VIII superior labrum anterior posterior lesion.

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

Methods: From 2003 to 2006, 23 shoulders in 23 athletes were diagnosed with a type VIII superior labrum anterior posterior lesion by physical examination, magnetic resonance arthrography, and arthroscopy. All were treated with an arthroscopic capsulolabral reconstruction. Ten patients were involved in rehabilitation less than 9 months after surgery and were not included in this study. Thirteen remaining shoulders in 13 athletes with a mean age of 27.8 ± 10.9 years were analyzed at a mean follow-up of 24 months. Shoulders were evaluated preoperatively and postoperatively using the American Shoulder and Elbow Surgeons scoring system and standard subjective scales for stability, strength, function, and range of motion.

Results: Athletes most commonly participated in sport at the recreational level (n = 8), followed by collegiate (n = 3) and high school (n = 2). The most common activity was weight lifting (n = 4). Eight athletes (62%) participated in contact sports, most commonly football and wrestling. Two patients (15%) had a partial-thickness articular-sided supraspinatus tendon tear that was debrided at the time of surgery. Mean American Shoulder and Elbow Surgeons score improved from 51.4 to 90.0 (P < .001). There were significant improvements in stability, pain, function, and range of motion based on standardized subjective scales (P < .001). No shoulder required revision surgery for recurrent instability. All patients were able to return to sports, with 9 (69%) able to return to their highest level before surgery.

Conclusion: Arthroscopic capsulolabral reconstruction is an effective and reliable treatment for glenohumeral instability due to a type VIII superior labrum anterior posterior lesion in the contact, noncontact, and throwing athlete. Successful postoperative return to sport is a reasonable expectation.

Background: Few studies have documented the outcomes of thermal capsulorrhaphy for shoulder instability.

Purpose: To examine prospective evaluate outcomes of the first 100 patients with glenohumeral instability treated with thermal capsulorrhaphy.

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

Methods: Between 1997 and 1999, 85 of 100 patients treated with thermal capsulorrhaphy for glenohumeral instability were available for review at 2-year minimum follow-up (average, 4 years). Fifty-one patients suffered from anterior instability; 24 had an associated Bankart lesion. Ten patients demonstrated posterior instability; 1 had an associated reverse Bankart lesion. Seventeen patients had multidirectional instability; 8 had an associated Bankart lesion. Seven patients demonstrated anterior and posterior instability without an inferior component; 2 had an associated Bankart lesion. Failures were defined as shoulders requiring revision stabilization (14) or with recurrent instability (18), recalcitrant pain (3), or stiffness (2).

Results: Forty-eight of 85 procedures were successful, and 37 of 85 failed. For patients with anterior instability plus a Bankart lesion, 7 of 24 (26%) had failed results. For those with anterior instability without a Bankart lesion, 10 of 27 (33%) had failed results. The failure rates for posterior, multidirectional instability, and anteroposterior were 60% (6/10), 59% (10/17), and 57% (4/7), respectively. Of the 48 successes, mean preoperative American Shoulder and Elbow Surgeons score improved from 71 to 96 postoperatively, and patient satisfaction was 9.1 on a 10-point scale.

Conclusion: Because of the high failure rates, we now augment thermal capsulorrhaphy with capsular plication and/or rotator interval closure in cases of posterior and multidirectional instability and have lengthened the initial immobilization period to improve outcomes. Failure rates for thermal capsulorrhaphy, even with labral repairs, are high especially for shoulders with multidirectional instability and posterior instability. When procedures were successful, however, patients were very satisfied with significant improvements in American Shoulder and Elbow Surgeons scores.

Background: Even though there are several physical tests available for superior labrum anterior posterior lesions, there have been very few reports on their accuracy, and none can be regarded as completely predictive for the presence of a superior labrum anterior posterior lesion in the shoulder joint.

Hypothesis: This new clinical test is a useful and accurate technique for detecting superior labral tears in the shoulder joint.

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

Methods: This test was conducted independently by 2 physicians before any other diagnostic evaluation. In all cases, the glenohumeral joint was investigated first, and the appropriate treatments were performed on the lesion. A protocol was established to evaluate the sensitivity, specificity, and positive and negative predictive values of this new clinical test. The reproducibility of this test was evaluated with a κ coefficient.

Results: Sixty-one patients (61 shoulders) were examined with the passive compression test, and all underwent arthroscopic surgery. In 31 patients with a positive passive compression test result, 27 had a superior labrum anterior posterior lesion, and in 30 patients with a negative passive compression test result, 6 had a superior labrum anterior posterior lesion. The sensitivity of the test was 81.8%, and the specificity was 85.7%. The positive predictive value was 87.1%, and the negative predictive value was 80.0%. The κ coefficient was 0.771 between the 2 independent examiners (P < .01).

Conclusion: The passive compression test is a useful and accurate technique for predicting superior labral tears of the shoulder joint.

Background: Allograft tissue is an acceptable alternative to autograft tissue in anterior cruciate ligament (ACL) reconstruction. However, several infections associated with tissue procurement have led some to consider routine intraoperative cultures of allograft tissue before implantation. A positive culture result presents a treatment dilemma in the asymptomatic patient.

Hypothesis: Treatment of culture swab—positive allograft tissue is unnecessary if there is no evidence of clinical infection.

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

Methods: Retrospective analysis was performed on 247 cultures taken in 321 consecutive ACL reconstructions from a single surgeon. Allograft cultures were taken intraoperatively before antibiotic washing and implantation. All patients received standard prophylactic antibiotics consisting of intravenous vancomycin and perioperative cefazolin, and were routinely monitored in the postoperative period for signs of infection.

Results: Twenty-four of 247 (9.7%) cultures were positive after implantation. Sixteen of these (67%) grew organisms of high pathogenicity, whereas 8 (33%) were of low pathogenicity. Cultures were classified as poor, scant, or rare in all 24 patients. These patients did not receive additional antibiotics, and none went on to develop septic arthritis or wound complications. The 2 cases of septic arthritis had negative intraoperative cultures.

Conclusions: Treatment of low-virulence organisms or minimal growth high-virulence organisms is unnecessary if no evidence of clinical infection exists. The results may call into question the utility of routinely culturing allograft tissue as positive results did not correlate with infectious complications.

Background: Magnetic resonance (MR) imaging has established its usefulness in diagnosing hamstring muscle strain and identifying features correlating with the duration of rehabilitation in athletes; however, data are currently lacking that may predict which imaging parameters may be predictive of a repeat strain.

Purpose: This study was conducted to identify whether any MR imaging-identifiable parameters are predictive of athletes at risk of sustaining a recurrent hamstring strain in the same playing season.

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

Methods: Forty-one players of the Australian Football League who sustained a hamstring injury underwent MR examination within 3 days of injury between February and August 2002. The imaging parameters measured were the length of injury, cross-sectional area, the specific muscle involved, and the location of the injury within the muscle-tendon unit. Players who suffered a repeat injury during the same season were reimaged, and baseline and repeat injury measurements were compared. Comparison was also made between this group and those who sustained a single strain.

Results: Forty-one players sustained hamstring strains that were positive on MR imaging, with 31 injured once and 10 suffering a second injury. The mean length of hamstring muscle injury for the isolated group was 83.4 mm, compared with 98.7 mm for the reinjury group (P = .35). In the reinjury group, the second strain was also of greater length than the original (mean, 107.5 mm; P = .07). Ninety percent of players sustaining a repeat injury demonstrated an injury length greater than 60 mm, compared with only 58% in the single strain group (P = .01). Only 7% of players (1 of 14) with a strain <60 mm suffered a repeat injury. Of the 27 players sustaining a hamstring strain >60 mm, 33% (9 of 27) suffered a repeat injury. Of all the parameters assessed, only a history of anterior cruciate ligament sprain was a statistically significant predictor for suffering a second strain during the same season of competition.

Conclusion: A history of anterior cruciate ligament injury was the only statistically significant risk factor for a recurrent hamstring strain in our study. Of the imaging parameters, the MR length of a strain had the strongest correlation association with a repeat hamstring strain and therefore may assist in identifying which athletes are more likely to suffer further reinjury.

Background: The biomechanical functions of the anterolateral and posteromedial bundles of the posterior cruciate ligament over the range of flexion of the knee joint remain unclear.

Hypothesis: The posterior cruciate ligament bundles have minimal length at low flexion angles and maximal length at high flexion angles.

Study Design: Descriptive laboratory study.

Methods: Seven knees from normal, healthy subjects were scanned with magnetic resonance, and 3-dimensional models of the femur, tibia, and posterior cruciate ligament attachment sites were created. The lines connecting the centroids of the corresponding bundle attachment sites on the femur and tibia represented the anterolateral and posteromedial bundles of the posterior cruciate ligament. Each knee was imaged during weightbearing flexion (from 0° to maximal flexion) using a dual-orthogonal fluoroscopic system. The length, elevation, deviation, and twist of the posterior cruciate ligament bundles were measured as a function of flexion.

Results: The lengths of the anterolateral and posteromedial bundles increased with flexion from 0° to 120° and decreased beyond 120° of flexion. The posteromedial bundle had a lower elevation angle than the anterolateral bundle beyond 60° of flexion. The anterolateral bundle had a larger deviation angle than the posteromedial bundle beyond 75° of flexion. The femoral attachment of the posterior cruciate ligament twisted externally with increasing flexion and reached a maximum of 86.4° ± 14.7° at 135° of flexion (P < .05).

Conclusion: These data suggest that there is no reciprocal function of the bundles with flexion, which is contrary to previous findings. The orientation of the anterolateral and posteromedial bundles suggests that at high flexion, the anterolateral bundle might play an important role in constraining the mediolateral translation, whereas the posteromedial bundle might play an important role in constraining the anteroposterior translation of the tibia.

Clinical Relevance: These data provide a better understanding of the biomechanical function of the posterior cruciate ligament bundles and may help to improve the design of the 2-bundle reconstruction techniques of the ruptured posterior cruciate ligament.

Background: For anterior cruciate ligament reconstruction with a double-bundle procedure, one of the major concerns is to not predispose either one of the grafts to risk of failure by overloading.

Hypothesis: Knee flexion angles between 15° and 45° for anteromedial graft fixation and 15° for posterolateral graft fixation are safe for both grafts in double-bundle anterior cruciate ligament reconstruction.

Study Design: Controlled laboratory study.

Methods: Nine human cadaveric knees were tested. The double-bundle anterior cruciate ligament reconstruction was conducted with both grafts fixed at 15° of knee flexion (fixation protocol 15/15) and again with the anteromedial and posterolateral grafts fixed at 45° and 15° of knee flexion (fixation protocol 45/15). For both fixation protocols, the knee kinematics and the in situ forces of the reconstructed anterior cruciate ligament and its individual grafts were measured and collected under an anterior tibial load of 134 N and combined rotatory loads of 10 N·m of valgus and 5 N·m of internal tibial torque. The data from both fixation protocols were compared with those of an intact knee.

Results: In response to the 2 external loading conditions, both fixation protocols (15/15 and 45/15) could restore the knee kinematics to within 2 mm of the intact knee (although statistically significant differences were found between fixation protocol 15/15 and the intact knee) and the overall in situ forces in the grafts similar to the intact anterior cruciate ligament. In response to the 134-N anterior tibial load, the in situ forces in the anteromedial graft for both fixation protocols did not exceed those of the intact anteromedial bundle. But at 30° and 45° of knee flexion, the in situ forces for fixation protocol 15/15 were 20.7% and 22.1% lower, respectively, when compared with the intact anteromedial bundle. Under combined rotatory loads, the anteromedial graft for fixation protocol 15/15 had in situ forces that were 45% lower than the intact anteromedial bundle at 30° of knee flexion. The in situ force in the posterolateral graft for both fixation protocols did not exceed those of the intact posterolateral bundle, nor were they significantly different from the intact posterolateral bundle at any of the flexion angles tested.

Conclusion: Both fixation protocols restored knee kinematics without predisposing either graft to failure. Therefore, knee flexion angles between 15° and 45° for graft fixation were found to be safe for the anteromedial graft, while 15° of knee flexion was safe for the posterolateral graft.

Clinical Relevance: A range of knee flexion angles that is safe for the fixation of both grafts in double-bundle anterior cruciate ligament reconstruction was determined.

Background: The fibular collateral ligament is the primary stabilizer to varus instability of the knee. Untreated fibular collateral ligament injuries can lead to residual knee instability and can increase the risk of concurrent cruciate ligament reconstruction graft failures. Anatomic reconstructions of the fibular collateral ligament have not been biomechanically validated.

Purpose: To describe an anatomic fibular collateral ligament reconstruction using an autogenous semitendinosus graft and to test the hypothesis that using this reconstruction technique to treat an isolated fibular collateral ligament injury will restore the knee to near normal stability.

Study Design: Controlled laboratory study.

Methods: Ten nonpaired, fresh-frozen cadaveric knees were biomechanically subjected to a 10 N·m varus moment and 5 N·m external and internal rotation torques at 0°, 15°, 30°, 60°, and 90° of knee flexion. Testing was performed with an intact and sectioned fibular collateral ligament, and also after an anatomic reconstruction of the fibular collateral ligament with an autogenous semitendinosus graft. Motion changes were assessed with a 6 degree of freedom electromagnetic motion analysis system.

Results: After sectioning, we found significant increases in varus rotation at 0°, 15°, 30°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0°, 15°, 30°, 60°, and 90° of knee flexion. After reconstruction, there were significant decreases in motion in varus rotation at 0°, 15°, 30°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0°, 15°, and 30° of knee flexion. In addition, we observed a full recovery of knee stability in varus rotation at 0°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0° and 30° of knee flexion.

Conclusion: An anatomic fibular collateral ligament reconstruction restores varus, external, and internal rotation to near normal stability in a knee with an isolated fibular collateral ligament injury.

Clinical Significance: An anatomic reconstruction of the fibular collateral ligament with an autogenous semitendinosus graft is a viable option to treat nonrepairable acute or chronic fibular collateral ligament tears in patients with varus instability.

Background: The influence of modern studded and bladed soccer boots and sidestep cutting on noncontact knee loading during match play conditions is not fully understood.

Hypothesis: Modern soccer boot type and sidestep cutting compared with straight-ahead running do not significantly influence knee internal tibia axial and valgus moments, anterior joint forces, and flexion angles.

Study Design: Controlled laboratory study.

Methods: Fifteen professional male outfield soccer players undertook trials of straight-ahead running and sidestep cutting at 30° and 60° with a controlled approach velocity on a Fédération Internationale de Football Association (FIFA) approved soccer surface. Two bladed and 2 studded soccer boots from 2 manufacturers were investigated. Three-dimensional inverse dynamics analysis determined externally applied internal/external tibia axial and valgus/varus moments, anterior forces, and flexion angles throughout stance.

Results: The soccer boot type imparted no significant difference on knee loading for each maneuver. Internal tibia and valgus moments were significantly greater for sidestep cutting at 30° and 60° compared with straight-ahead running. Sidestep cutting at 60° compared with straight-ahead running significantly increased anterior joint forces.

Conclusion: Varying soccer boot type had no effect on knee loading for each maneuver, but sidestep cutting significantly increased internal tibia and valgus moments and anterior joint forces.

Clinical Relevance: Sidestep cutting, irrespective of the modern soccer boot type worn, may be implicated in the high incidence of noncontact soccer anterior cruciate ligament injuries by significantly altering knee loading.

Background: Shoulder injuries constitute a considerable risk to professional rugby union players; however, there is a shortage of detailed epidemiologic information about injuries in this population.

Purpose: To describe the incidence, severity, and risk factors associated with shoulder injuries in professional rugby union.

Study Design: Descriptive epidemiology study.

Method: Medical personnel prospectively reported time-loss injuries in professional rugby union in England, and the shoulder injuries were evaluated.

Results: The incidence of shoulder injuries was significantly lower during training (0.10/1000 player—training hours) compared with matches (8.9/1000 player—match hours). The most common match injury was acromioclavicular joint injury (32%); the most severe was shoulder dislocation and instability (mean severity, 81 days absent), which also caused the greatest proportion of absence (42%) and had the highest rate of recurrence (62%). The majority of match shoulder injuries were sustained in the tackle (65%), and outside backs were the most likely to sustain an injury from tackling (2.4/1000 player-tackles). Injuries sustained during training were significantly more severe (61 days) than were those sustained during match play (27 days), and defensive training sessions carried the highest risk of injury (0.45/1000 player-hours; mean severity, 67 days). A mean of 241 player-days per club per season were lost to shoulder injuries.

Conclusion: Results suggest the potential to reduce this injury burden by modifying training activities and implementing “prehabilitation” strategies in an effort to minimize the risk of shoulder dislocation/instability.

Background: Surgical repair is the most favored treatment for a rupture of the distal biceps tendon. A variety of techniques have been described for distal biceps tendon reattachment, including transosseous sutures, suture anchors, interference screws, and an EndoButton-based technique.

Hypothesis: EndoButton and suture anchor have initially stronger fixation strengths than do transosseous sutures, allowing early postoperative rehabilitation.

Study Design: Controlled laboratory study.

Methods: Single loads to failure and mode of failure of 13 different fixation techniques were determined using 130 human cadaveric elbows. Quantitative computer tomography was performed to exclude differences in bone mineral density as an affecting factor. Repeated-measures analysis of variance was used to assess differences in failure load between repair techniques.

Results: The EndoButton-based technique showed a significantly higher failure load (259 ± 28 N) than did all other techniques (P < .05). No significant differences were seen between the transosseous suture technique (210 ± 29 N) and most other techniques (P > .05). Failure loads of the TwinFix-QuickT (57 ± 29 N) and Biocuff screw (105 ± 28 N) were significantly lower than those of all other repairs (P < .05).

Conclusion: Significant differences exist in failure loads and modes of failure for the different repair techniques after rupture of the distal biceps tendon.

Clinical Relevance: The transosseous technique is still a sufficient and cost-saving procedure for repair of the distal biceps tendon. TwinFix-QuickT 5.0 mm and Biocuff screw 5.7 mm had significantly lower failure loads, which might affect early rehabilitation, particularly in patients with poor bone quality.

Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies.

Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate.

Study Design: Descriptive laboratory study.

Methods: From 10 patients undergoing surgery for Achilles tendinopathy, 1 tendinosis biopsy specimen and 1 biopsy specimen of macroscopically healthy tendon tissue adjacent to the lesion were collected. Furthermore, biopsy samples were collected from 3 donors with asymptomatic Achilles tendons. Water content, collagen content, percentage of denatured collagen, amount of lysine hydroxylation, number of enzymatic and nonenzymatic crosslinks, matrix metalloproteinase activity, and matrix metalloproteinase and collagen gene-expression levels were analyzed.

Results: In tendinotic lesions, the water content was highest, and collagen content was subnormal with higher amounts of denatured/damaged collagen. Low pentosidine levels in tendinotic tissue indicated the presence of relatively young collagenous matrix. More hydroxylated lysine residues were present in tendinotic samples, but enzymatic crosslinks revealed no differences between tendinotic, adjacent, and healthy samples. In tendinotic specimens, matrix metalloproteinase activity was higher, matrix metalloproteinase gene-expression profile was altered, and collagen type I and III gene expression were upregulated.

Conclusion: In Achilles tendinosis, the collagen turnover rate is increased, and the natural biochemical composition of the collagenous matrix is compromised.

Clinical Relevance: Although tendon tissue directly adjacent to an Achilles tendinosis lesion looks macroscopically healthy, histological and biochemical degenerative changes in adjacent tissue are evident, which may have implications for surgical interventions.

Background: Overtensioning of medial patellofemoral ligament reconstructions may lead to adverse surgical outcomes.

Hypothesis: Increasing tension on a medial patellofemoral ligament graft will increase patellofemoral contact forces and decrease lateral patellar translation.

Study Design: Controlled laboratory study.

Methods: Patellofemoral contact pressures were measured in 8 fresh-frozen cadaveric knees before and after transection of the medial patellofemoral ligament and after a standardized reconstruction surgery. Contact pressures were measured at 3 knee angles (30°, 60°, and 90°) and under 3 levels of tension applied to the graft (2, 10, and 40 N). For each condition, patellar translation was measured at 30° of knee flexion as a 22-N lateral force was applied.

Results: Graft tension of 2 N restored normal translation, but 10 N and 40 N significantly restricted motion (5.2 mm and 1.9 mm, respectively). Compared with the intact knee, medial patellofemoral contact pressures significantly increased (P < .05) when 40 N of tension was applied to the reconstruction. Medial contact pressures were restored to normal with 2 N of graft tension. Lateral patellar translation was significantly greater (P < .05) after the medial patellofemoral ligament was cut (16.3 mm) compared with intact (7.7 mm).

Conclusion: Low (2-N) tension applied to a medial patellofemoral ligament reconstruction stabilized the patella and did not increase medial patellofemoral contact pressures. Higher loads (10 N and 40 N) progressively restricted lateral patellar translation and inappropriately redistributed patellofemoral contact pressures.

Clinical Relevance: Overtensioning can be avoided by applying low loads to medial patellofemoral ligament reconstructions, which reestablished normal translation and patellofemoral contact pressures.

Morphological and spatial abnormalities of the proximal femur and acetabulum have been recently recognized as causes of femoroacetabular impingement. During joint motion in hips with femoroacetabular impingement, abnormal bony contact occurs, and soft tissue structures (chondral and labral) often fail. Femoroacetabular impingement has been reported to be a contributor to early-onset joint degeneration. Ganz et al have described good midterm success with an open surgical dislocation approach to reconstruct normal joint clearance. The purpose of this report is to discuss relevant literature and describe an arthroscopic approach to treat femoroacetabular impingement. This approach has particular relevance in high-demand patients, particularly in athletes seeking to return to high-level sport.