The American Journal of Sports Medicine

Background: Results of a previous randomized controlled trial have shown comparable effectiveness of a standardized eccentric loading training and of repetitive low-energy shock-wave treatment (SWT) in patients suffering from chronic midportion Achilles tendinopathy. No randomized controlled trials have tested whether a combined approach might lead to even better results.

Purpose: To compare the effectiveness of 2 management strategies—group 1: eccentric loading and group 2: eccentric loading plus repetitive low-energy shock-wave therapy.

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

Methods: Sixty-eight patients with a chronic recalcitrant (>6 months) noninsertional Achilles tendinopathy were enrolled in a randomized controlled study. All patients had received unsuccessful management for >3 months, including at least (1) peritendinous local injections, (2) nonsteroidal anti-inflammatory drugs, and (3) physiotherapy. A computerized random-number generator was used to draw up an allocation schedule. Analysis was on an intention-to-treat basis.

Results: At 4 months from baseline, the VISA-A score increased in both groups, from 50 to 73 points in group 1 (eccentric loading) and from 51 to 87 points in group 2 (eccentric loading plus shock-wave treatment). Pain rating decreased in both groups, from 7 to 4 points in group 1 and from 7 to 2 points in group 2. Nineteen of 34 patients in group 1 (56%) and 28 of 34 patients in group 2 (82%) reported a Likert scale of 1 or 2 points (“completely recovered” or “much improved”). For all outcome measures, groups 1 and 2 differed significantly in favor of the combined approach at the 4-month follow-up. At 1 year from baseline, there was no difference any longer, with 15 failed patients of group 1 opting for having the combined therapy as cross-over and with 6 failed patients of group 2 having undergone surgery.

Conclusion: At 4-month follow-up, eccentric loading alone was less effective when compared with a combination of eccentric loading and repetitive low-energy shock-wave treatment.

Background: Few long-term studies exist that evaluate how the loss of normal knee range of motion affects results after anterior cruciate ligament reconstruction.

Hypothesis: Patients with normal knee motion will have higher subjective scores than patients with less than normal motion. Study Design: Cohort study; Level of evidence, 2.

Methods: Patients were prospectively evaluated at > 10 years after anterior cruciate ligament reconstruction according to International Knee Documentation Committee criteria. Normal knee motion was within 2° of extension (including hyperextension) and 5° of flexion compared with the uninvolved knee. Regression analysis was performed to determine what factors affected subjective scores.

Results: Objective follow-up was obtained on 502 patients at a mean of 14.1 years postoperatively. Regression analysis showed that the most statistically significant factor related to lower subjective scores was lack of normal knee extension; loss of normal flexion was also significant. Patients who had meniscectomy or articular cartilage damage had statistically significantly lower subjective scores if they also had less than normal motion. Ninety-eight percent of patients with intact menisci, normal articular cartilage, and normal knee motion had normal radiographs; 29% of patients with normal motion had less than normal radiographs versus 71% of patients who had less than normal motion. The overall International Knee Documentation Committee objective grade was normal in 48%, nearly normal in 42%, abnormal in 9%, and severely abnormal in 0.5%.

Conclusion: The loss of 3° to 5° of knee extension, to include loss of hyperextension, adversely affected the subjective and objective results after surgery, especially when coupled with meniscectomy and articular cartilage damage.

Background: Varus thrust of the knee is a dynamic increase of an often preexisting varus angle and it is suspected to be a major reason for failure of anterior cruciate ligament reconstructions. However, it is not known if a direct relationship exists between varus thrust and forces in the anterior cruciate ligament.

Hypothesis: Forces in the anterior cruciate ligament increase with increasing varus alignment, and consequently an anterior cruciate ligament deficiency in a varus-aligned leg leads to more lateral tibiofemoral joint opening.

Study Design: Controlled laboratory study.

Methods: Six human cadaver legs were axially loaded with 3 different weightbearing lines—a neutral weightbearing line, a weightbearing line that passes through the middle of the medial tibial plateau (50% varus), and a line passing the edge of the medial tibial plateau (100% varus)—that were used to create a varus moment. The resulting lateral tibiofemoral joint opening and corresponding anterior cruciate ligament tension were measured. The tests were repeated with and without the anterior cruciate ligament in place.

Results: In the neutral aligned legs, there was no apparent lateral joint opening, and no anterior cruciate ligament tension change was noted. The lateral joint opening increased when the weightbearing line increased from 0% to 50% to 100%. The lateral joint opening was significantly higher in 10° of knee flexion compared with knee extension. In the 100% varus weightbearing line, the anterior cruciate ligament tension was significantly higher (53.9 N) compared with neutral (31 N) or the 50% weightbearing line (37.9 N). A thrust could only be observed in the 100% weightbearing line tests. In the absence of an anterior cruciate ligament, there was more lateral joint opening, although this was only significant in the 100% weightbearing line.

Conclusion: There is a direct relationship between varus alignment and anterior cruciate ligament tension. In the absence of an anterior cruciate ligament, the amount of lateral opening tends to increase. With increasing lateral opening, a thrust can sometimes be experimentally observed.

Clinical Relevance: A varus alignment in an anterior cruciate ligament—deficient knee does not necessarily lead to a varus thrust and therefore does not always need operative varus alignment correction. However, in an unstable anterior cruciate ligament—deficient knee with a varus thrust, it might be safer to perform a high valgus tibial osteotomy to minimize the risk of an anterior cruciate ligament reconstruction failure.

Background: Modification of the Bröstrom repair with suture anchors has been used to address chronic lateral ankle instability. However, there are few studies in the literature reporting the functional outcomes after this particular procedure in the high-demand athlete.

Hypothesis: Anatomical reconstruction of the lateral ankle ligaments for chronic instability will return the high-demand athlete functionally to his or her previous level of activity.

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

Methods: Sixty-two patients who had grade III ankle sprain that failed at least a 6-month course of supervised conservative management with a preinjury Tegner score of ≥ 6 underwent a variant of the Gould-modified Broström procedure with suture anchors for lateral ankle instability. Each patient was given the Tegner and Karlsson questionnaire at the 6-month, 1-year, and 2-year time points. Range of motion of the operative ankle was also assessed. The mean age was 19.6 years (range, 16-26 years), and 10 patients were lost to follow-up.

Results: The mean follow-up was 29 months (minimum, 24 months) in the remaining 52 patients (84%). Mean Tegner scores at the 1- and 2-year time points were 8.2 (range, 5-9) and 8.6 (range, 5-9), respectively. The mean Karlsson scores were 92 ± 5.2 and 95 ± 3.1 at the 1- and 2-year time points, respectively. Range of motion was equal to the contralateral ankle in all but 3 patients at the 2-year follow up. A 6% major complication rate included 3 reruptures.

Conclusion: Anatomical ligament reconstruction for chronic lateral ankle instability using a variant of the Gould-modified Broström procedure with suture anchors was effective in returning high-demand athletes to their preinjury functional level.

Background: Anterior cruciate ligament (ACL) injury prevention programs show promising results with changing movement; however, little information exists regarding whether a program designed for an individual’s movements may be effective or how baseline movements may affect outcomes.

Hypothesis: A program designed to change specific movements would be more effective than a “one-size-fits-all” program. Greatest improvement would be observed among individuals with the most baseline error. Subjects of different ages and sexes respond similarly.

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

Methods: One hundred seventy-three youth soccer players from 27 teams were randomly assigned to a generalized or stratified program. Subjects were videotaped during jump-landing trials before and after the program and were assessed using the Landing Error Scoring System (LESS), which is a valid clinical movement analysis tool. A high LESS score indicates more errors. Generalized players performed the same exercises, while the stratified players performed exercises to correct their initial movement errors. Change scores were compared between groups of varying baseline errors, ages, sexes, and programs.

Results: Subjects with the highest baseline LESS score improved the most (95% CI, —3.4 to —2.0). High school subjects (95% CI, —1.7 to —0.98) improved their technique more than pre—high school subjects (95% CI, —1.0 to —0.4). There was no difference between the programs or sexes.

Conclusions: Players with the greatest amount of movement errors experienced the most improvement. A program’s effectiveness may be enhanced if this population is targeted.

Background: Repair of a distal biceps tendon rupture is a challenging procedure and, to date, there is no consensus as to which technique should be used because of the specific complications reported for each.

Purpose: A new endoscopic technique is described that uses a suture anchor to repair distal biceps tendon ruptures.

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

Methods: The results of a cohort of 23 patients (25 elbows) are reported with a median follow-up of 26 months. All patients were male and their median age was 44 years (range, 30-58). Ten of the patients (12 ruptures) were professional athletes or had a high level of physical activity. All repairs were performed via a 3-cm incision made in the “safe area” of the anterior crease of the forearm. The whole procedure was performed within the tendon sheath. The tendon was reinserted using a single anchor.

Results: Of the 23 patients, 22 were satisfied and 20 patients returned to their preinjury sports and jobs. There was a mean loss of 8.6° of pronation and 5° of supination. A single severe neurologic complication, which required a second surgical procedure, was reported. There were also 2 ectopic ossifications without clinical consequences and a transitory radial nerve paralysis.

Conclusions: This study clearly demonstrated that endoscopic repair of the ruptured distal biceps tendon is safe, effective, and reproducible. It provides good functional outcome and early recovery with few complications. Postoperative median nerve palsy due to edema is a possible concern for patients involved in athletic activity and with a history of nerve entrapment; thus this technique should be used with caution in this group of patients.

Background: The double-bundle technique has recently gained much interest in ligament reconstruction. In addition to potential kinematic advantages, perhaps double tunnels have the potential for faster and more secure tendon-to-bone healing.

Hypothesis: Placement of tendons in 2 osseous tunnels, as opposed to 1, will enhance tendon fixation as determined biomechanically and histologically.

Study Design: Controlled laboratory study.

Methods: Fourteen sheep were used, and an extra-articular tendon graft reconstruction was performed on both knees of each sheep. In 1 randomly selected knee, the long digital extensor tendon was released from the femur and placed into a single tunnel in the proximal tibia. In the contralateral knee, the tendon was split and placed into 2 tibial tunnels. Ten sheep were analyzed by mechanical testing, and the remaining 4 were subjected to histologic evaluation at 6 weeks after surgery. Paired t tests were used for statistical analysis.

Results: Mechanical testing demonstrated that the peak load (981.8 ± 143.2 N, mean ± SD) and stiffness (570.9 ± 114.6 N/mm) at 6 weeks after surgery in the double-tunnel group were significantly greater than for the single-tunnel group (714.8 ± 94.2 N and 432.2 ± 56.7 N/mm, respectively; load, P = .007; stiffness, P = .03). Histologic analysis suggested similar tendon-to-bone healing for both groups.

Conclusion: This study demonstrated enhanced biomechanical fixation of the tendon to the surrounding bone in the double-tunnel compared with the single-tunnel technique in this ovine model.

Clinical Relevance: The double-tunnel technique may provide better fixation and healing in human ligament reconstruction.

Background: High rotational traction between football shoes and the playing surface may be a potential mechanism of injury for the lower extremity.

Hypothesis: Rotational traction at the shoe-surface interface depends on shoe design and surface type.

Study Design: Controlled laboratory study.

Methods: A mobile testing apparatus with a compliant ankle was used to apply rotations and measure the torque at the shoe-surface interface. The mechanical surrogate was used to compare 5 football cleat patterns (total of 10 shoe models) and 4 football surfaces (FieldTurf, AstroPlay, and 2 natural grass systems) on site at actual surface installations.

Results: Both artificial surfaces yielded significantly higher peak torque and rotational stiffness than the natural grass surfaces. The only cleat pattern that produced a peak torque significantly different than all others was the turf-style cleat, and it yielded the lowest torque. The model of shoe had a significant effect on rotational stiffness.

Conclusion: The infill artificial surfaces in this study exhibited greater rotational traction characteristics than natural grass. The cleat pattern did not predetermine a shoe’s peak torque or rotational stiffness. A potential shoe design factor that may influence rotational stiffness is the material(s) used to construct the shoe’s upper.

Clinical Relevance: The study provides data on the rotational traction of shoe-surface interfaces currently employed in football. As football shoe and surface designs continue to be updated, new evaluations of their performance must be assessed under simulated loading conditions to ensure that player performance needs are met while minimizing injury risk.

Background: Surgical reconstruction of the ulnar collateral ligament has evolved since Frank Jobe’s original description. The “docking technique” is a popular modification that allows for securing the graft within a single humeral tunnel. More recently, interference screw fixation has been introduced as a means of improving the ultimate strength, stiffness, and kinematics of these constructs.

Purpose: This study was conducted to compare the biomechanical performance of the docking technique with and without interference screw fixation in the humerus.

Study Design: Controlled laboratory study.

Methods: Nine matched pairs of human cadaveric elbows (age 49.9 ± 8.0 years) were reconstructed with a tendon graft using the docking technique (group 1) or the docking technique with the addition of a 4.75-mm bioabsorbable humeral interference screw (group 2). Before the reconstruction, joint laxity was measured on each specimen with the ulnar collateral ligament intact and then after transection of the ligament. Laxity measurements were repeated after the reconstruction. Failure testing was then performed at 70° of elbow flexion. The specimens were preloaded with a 1-N·m moment and then loaded to failure at a displacement rate of 14 mm/s to approximate 50% strain per second.

Results: Within group 1, the elbow laxity of the reconstructed state was significantly greater than the intact state at all tested flexion angles (P < .021). Within group 2, no statistically significant difference existed in elbow laxity between the intact state and the reconstructed state. When comparing laxities between groups, group 1 tended to be more lax at all tested flexion angles but was only significantly greater at 105° of flexion. The most common mode of failure for both groups involved the sutures pulling out of the tendon. No significant difference was found for ultimate moment of failure between the 2 groups. However, the moment associated with 3 mm of gap formation for group 2 (12.8 ± 4.2 N·m) was statistically greater than that of group 1 (7.5 ± 1.2 N·m) (P = .001). The stiffness of group 2 (14.7 ± 6.4 N/mm) was significantly greater than group 1 (9.9 ± 3.1 N/mm) (P = .044).

Conclusion: The biomechanical performance of the docking technique with and without a humeral interference screw is similar.

Clinical Relevance: The stiffness of the construct, along with the difference in moment that allows a 3-mm gap formation, suggests that the addition of a humeral interference screw is potentially beneficial. Further research in a healing model will help clarify this benefit.

Background: In vitro data suggest that injury to the posterior cruciate ligament stresses the posterolateral structures of the knee, placing them at greater risk of secondary injury. However, it is not known how isolated posterior cruciate ligament deficiency affects these soft tissue stabilizers of the knee joint in vivo.

Hypothesis: Posterior cruciate ligament deficiency will alter the apparent length patterns of the lateral collateral ligament (LCL) and popliteus.

Study Design: Controlled laboratory study.

Methods: The apparent length changes in the lateral collateral ligament and popliteus muscle-tendon unit during weightbearing knee flexion were studied in 14 patients with isolated, unilateral posterior cruciate ligament deficiency using magnetic resonance imaging, dual-orthogonal fluoroscopy, and 3-dimensional modeling. Data of the injured and uninjured contralateral sides were compared.

Results: Posterior cruciate ligament deficiency caused significant increases in the apparent length of both posterolateral structures (P < .05). The differences between injured and uninjured contralateral side were greatest at 120° of knee flexion in the lateral collateral ligament (48.2 ± 6.1 mm and 51.6 ± 6.1 mm, respectively) and at 30° of knee flexion in the popliteus (101.2 ± 9.3 mm and 110.4 ± 10.2 mm, respectively).

Conclusion: Deficiency of the posterior cruciate ligament alters the length patterns of posterolateral structures in vivo and might place them at greater risk of secondary injury.

Clinical Relevance: Reestablishment of normal kinematics after posterior cruciate ligament injury is critical for restoring normal function of posterolateral structures of the knee.

Background: It is often difficult to identify the attachment sites of the fibular collateral ligament, popliteus tendon, and popliteofibular ligament for chronic posterolateral knee injuries or during revision surgeries. Descriptions of radiographic landmarks for these attachment sites would assist in the intraoperative identification of their locations and also allow for postoperative assessment of the placement of reconstruction tunnels.

Hypothesis: Identification of qualitative and quantitative radiographic landmarks for the attachments of the main posterolateral knee structures are reproducible among observers of various experience levels and allow for improved intraoperative and postoperative identification of these attachment sites.

Study Design: Descriptive laboratory study.

Methods: Dissections were performed on 11 cadaveric knee specimens. The attachments and locations of the investigated structures were labeled with radiopaque markers. The positions of the attachments relative to other attachment sites, labeled bony landmarks, and superimposed reference lines were quantified on anteroposterior and lateral radiographs. Measurements were performed by 3 independent examiners. Intraobserver and interobserver reliability was determined using intraclass correlation coefficients.

Results: Overall intraclass correlation coefficients for intraobserver reproducibility and interobserver reliability were calculated to be 0.981 and 0.983, respectively. On the anteroposterior view, the perpendicular distances from a line intersecting the femoral condyles to the popliteus tendon, proximal fibular collateral ligament, and lateral gastrocnemius tendon were 14.5, 27.1, and 34.5 mm, respectively. On the lateral view, the femoral attachments of the fibular collateral ligament, popliteus tendon, and lateral gastrocnemius tendon were 4.3, 12.2, and 13.1 mm, respectively, from the lateral epicondyle. In addition, the fibular collateral ligament and popliteus tendon were located within 1 mm of a reference line projected along the posterior femoral cortex distally, and also were located within the posteroinferior quadrant bound by the posterior femoral cortex extension reference line and another reference line perpendicular to it at the posterior margin of Blumensaat’s line.

Conclusion: Comprehensive qualitative and quantitative guidelines for assessing posterolateral knee structures on both anteroposterior and lateral knee radiographs were described.

Clinical Significance: This radiographic information regarding the attachment sites of posterolateral structures can serve as a valuable reference for preoperative, intraoperative, and postoperative assessments of surgical reconstructions.

Background: The surgical treatment methods for recurrent dislocation of peroneal tendons are controversial. A simpler and more effective treatment method is valuable for these patients.

Hypothesis: A new rerouting operation designed by the authors will have satisfactory results and avoid disadvantages of the old rerouting methods.

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

Methods: Seventeen consecutive male patients with unilateral recurrent peroneal tendon dislocations were treated by transposition of the calcaneofibular ligament from the tubercle of calcaneofibular ligament with a 1 × 1 × 1 cm3 bone block and elevation of this tubercle with another 1 × 1 × 1 cm 3 calcaneal bone block, which were fixed by a 3.5-mm cancellous screw with a washer. All patients received clinical and radiographic follow-up for at least 2 years. The preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scales were used for functional results assessment.

Results: All bone transposition sites healed radiographically at 6 weeks after surgery. Four patients had transient numbness over the lateral aspect of the injured foot, and 3 patients had swelling and pain involving the operative sites. All complications resolved by 3 to 5 months after the operation. No recurrent dislocation of the peroneal tendons was noted. The mean AOFAS ankle-hindfoot scale improved significantly, from 73.4 ± 5.5 preoperatively to 100 at 2- to 5-year follow-up (P < .001). Normal ankle stability and no tightening of the lateral side of the injured ankles in the inversion position were noted.

Conclusion: This method is a simple, reliable, and reproducible operation to treat recurrent dislocation of the peroneal tendons. It allows early return to daily, working, and sports activities with satisfactory results.

Background: Windmill pitching produces high forces and torques at the shoulder and elbow, making the biceps labrum complex susceptible to overuse injury. Little is known about the muscle firing patterns during a windmill pitch.

Hypothesis: Biceps muscle activity is greater during a windmill pitch than during an overhand throw.

Study Design: Descriptive laboratory study.

Methods: Seven female windmill pitchers underwent motion analysis and surface electromyography evaluation of their biceps muscles during windmill and overhand throwing. Marker motion analysis, muscle activity, and ball release were captured simultaneously. Surface electromyography trials were collected and related to the athletes’ phases of pitching and throwing, identified based on predefined softball and baseball pitching mechanics.

Results: Throws were of similar velocity (24 m/s, 53 mph, P = .71), but peak biceps brachii muscle activation during the windmill pitch was significantly greater than during the overhand throw when normalized (38% vs 19% manual muscle test, P = .02). The highest muscle activity occurred at the 9-o’clock phase of the windmill pitch, during which the biceps brachii undergoes eccentric contraction. In the overhand throw, the highest level of biceps activity occurred during arm cocking.

Conclusion: In female athletes, biceps brachii activity during the windmill pitch is higher than during an overhand throw and is most active during the 9-o’clock and follow-through phases of the pitch.

Clinical Relevance: Repetitive eccentric biceps contractions may help explain the high incidence of anterior shoulder pain clinically observed in elite windmill pitchers. Injury prevention and treatment mechanisms should focus on the phases with the highest muscle activity.

Background: The kinetic chain of the throwing motion functions to optimize efficiency of proximal segments to decrease force loads seen at smaller, distal segments such as the ulnar collateral ligament. Several studies have shown that shoulder internal rotation forms the physiologic counter to the valgus torque generated during the late cocking phase of throwing. Previous studies have implicated decreased glenohumeral internal rotation as a cause of shoulder internal impingement. To date, an association between pathologic glenohumeral internal rotation deficit and elbow injury has not been exhibited.

Hypothesis: Throwers with ulnar collateral ligament insufficiency will exhibit significantly increased glenohumeral internal rotation deficit.

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

Methods: Twenty-nine baseball players with ulnar collateral ligament insufficiency were demographically matched with 29 control baseball players who had no history of shoulder, elbow, or cervical spine injury. The investigators measured passive glenohumeral internal and external rotation, elbow flexion and extension, and forearm pronation and supination. The Mann-Whitney test was used to analyze continuous variables.

Results: There were no significant differences between the groups in terms of demographics. There was a significant difference in dominant arm internal rotation, with injured players having significantly less (P < .004), and in glenohumeral internal rotation deficit between players with ulnar collateral ligament insufficiency and those who were asymptomatic (28.5° vs 12.7°; P < .001). Also, total range of motion was significantly decreased in the injured group. There were no significant differences in elbow or forearm range of motion between the groups.

Conclusion: Our results indicate that pathologic glenohumeral internal rotation deficit may be associated with elbow valgus instability. This has important clinical implications both in terms of preventing ulnar collateral ligament injury and with regard to rehabilitating throwers after ulnar collateral ligament reconstruction.

Background: The anterior cruciate ligament has been shown to have poor healing ability, and reconstruction is the standard treatment.

Hypothesis: Primary anterior cruciate ligament repair combined with bone marrow stimulation could restore stability and function in athletes with acute anterior cruciate ligament incomplete tears.

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

Methods: Among a group of 99 patients with clinically diagnosed anterior cruciate ligament acute lesions, 26 athletes with arthroscopically confirmed incomplete anterior cruciate ligament proximal tears were treated with primary repair combined with bone marrow stimulation of the anterior cruciate ligament femoral attachment site. Postoperatively, all patients underwent a specific rehabilitation program. All patients were prospectively evaluated; outcome measures were assessed using Marx, Noyes, Tegner, Single Assessment Numeric Evaluation, Lysholm, and International Knee Documentation Committee scores. Anterior tibial translation was measured using Rolimeter instrument under anesthesia and at final follow-up.

Results: All athletes were followed up for a mean 25.3 months (range, 17-38 months). Mean age was 26.6 years. Mean preinjury Tegner was 7.1 (SD, 1.1) and final Tegner 6.7 (SD, 1.4); mean preinjury Marx was 11.0 (SD, 3.4) and final Marx 9.6 (SD, 3.1); mean preinjury Noyes was 82.5 (SD, 5.8) and final Noyes 83.3 (SD, 7.2). These scores were not statistically different at P values of .020, .011, and .303, respectively. Final Single Assessment Numeric Evaluation rating was significantly lower than was preinjury Single Assessment Numeric Evaluation rating. This was mainly related to decreased self-confidence in high-risk sports and fear of new injury. Final Single Assessment Numeric Evaluation rating and Tegner scores were significantly higher than were their respective preoperative values. Mean Rolimeter side-to-side difference of anterior knee translation was significantly reduced from 3.5 mm (SD, 0.7) preoperatively to 1.3 mm (SD, 0.8) postoperatively.

Conclusion: In this athletic population, anterior cruciate ligament primary repair in acute incomplete lesion combined with bone marrow stimulation effectively restored knee stability and function.

Background: Recent studies have suggested that excessive hip internal rotation during dynamic tasks may be associated with patellofemoral pain. Although diminished hip-muscle strength and altered femoral morphologic characteristics have been implicated in abnormal hip rotation in persons with patellofemoral pain, no study has confirmed this hypothesis.

Hypothesis: Women with patellofemoral pain would demonstrate increased average hip internal rotation, decreased hip-muscle performance, and abnormal femoral shape compared with controls. Furthermore, measures of hip strength and femoral shape are predictive of average hip internal rotation during running.

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

Methods: Nineteen women with patellofemoral pain and 19 pain-free controls participated. Lower extremity kinematics during running, hip-muscle performance, and femoral morphologic characteristics on magnetic resonance imaging were quantified. Independent t tests were used to assess group differences. Stepwise linear regression was used to determine whether measures of strength and/or structure were predictive of average hip internal rotation during running.

Results: Participants with patellofemoral pain demonstrated significantly greater average hip internal rotation (8.2° ± 6.6° vs 0.3° ± 3.6°; P < .001), reduced hip-muscle strength in 8 of 10 hip strength measurements, and greater femoral inclination (132.8° ± 5.2° vs 128.4° ± 5.0°; P = .011) compared with controls. Stepwise regression revealed that isotonic hip extension endurance was the only predictor of average hip internal rotation (r = —.451; P = .004).

Conclusion: Abnormal hip kinematics in women with patellofemoral pain appears to be the result of diminished hip-muscle performance as opposed to altered femoral structure. The results suggest that assessment of hip-muscle performance should be considered in the evaluation and treatment of patellofemoral joint dysfunction.

Background: Whether knee laxity varies throughout the menstrual cycle remains controversial. As increased laxity may be a risk factor for anterior cruciate ligament (ACL) injury, further research is warranted.

Hypothesis: Variation in estradiol and progesterone levels during the menstrual cycle influences knee laxity and stiffness.

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

Methods: The serum estradiol and progesterone levels of 26 healthy female subjects were recorded in the follicular phase, ovulation, and the luteal phase. Knee joint laxity was assessed using a standard knee arthrometer at the same intervals. Stiffness changes in the load-displacement curve were determined. Hormone levels across the cycle were compared between responders and nonresponders, defined by whether changes in knee laxity at 89 N occurred.

Results: Greater laxity at 89 N during ovulation was observed (ovulation: 5.13 ± 1.70 mm vs luteal: 4.55 ± 1.54 mm, P = .012). In knee laxity testing at manual maximum load, greater laxity was noticed during ovulation (14.43 ± 2.60 mm, P = .018), as compared with the follicular phase (13.35 ± 2.53 mm). A reduction in knee stiffness of approximately 17% (ovulation: 12.48 ± 5.46 N/mm vs luteal: 15.02 ± 7.71 N/mm, P = .042) during ovulation was observed. However, there were no differences in hormone levels between responders and nonresponders at 89 N.

Conclusion: Female hormone levels are related to increased knee joint laxity and decreased stiffness at ovulation. To understand subject variations in knee joint laxity during the menstrual cycle in female athletes, further investigation is warranted.

Background: The posterior cruciate ligament heals to some extent after injury. However, results after conservative treatment may diminish with long-term follow-up. Bone morphogenetic protein-12 can induce formation of ligament tissues.

Hypothesis: Bone morphogenetic protein-12 gene transfer can improve the histologic and biomechanical properties of healing posterior cruciate ligaments.

Study Design: Controlled laboratory study.

Methods: Bilateral posterior cruciate ligaments of 32 rabbits were injured. The cut ends in 1 limb received an injection containing 3 × 107 pfu recombinant bone morphogenetic protein-12 adenovirus, and the posterior cruciate ligament in the contralateral limb served as an untreated control. Eight rabbits were sacrificed at each time point of 3, 6, 12, and 26 weeks after the operation. In addition, 6 rabbits receiving a sham operation were used to obtain normal control data. The posterior cruciate ligament specimens were evaluated biomechanically and histologically.

Results: The repair tissue of the treatment group at 26 weeks was similar to the normal posterior cruciate ligament in collagen arrangement, collagen formation, and mechanical properties. At weeks 6, 12, and 26, the ultimate load, stiffness, and energy absorbed at failure of the treatment group were significantly greater than those of the untreated group.

Conclusion: Adenovirus-mediated bone morphogenetic protein-12 gene transfer in a partial posterior cruciate ligament laceration rabbit model resulted in an obvious improvement of histologic properties, tensile strength, and stiffness of the repaired ligaments, indicating improved posterior cruciate ligament healing.

Clinical Relevance: Bone morphogenetic protein-12 gene transfer is a potential future strategy to improve the repair of injured posterior cruciate ligaments.

Pathologic abnormality of the peroneal tendons is an uncommon but underappreciated source of lateral hindfoot pain and dysfunction that can be difficult to distinguish from lateral ankle ligament injuries. When left untreated, peroneal tendon disorders can lead to persistent lateral ankle pain and substantial functional problems. Unfortunately, the treatment recommendations for these disorders are primarily based on case series and expert opinion. The goals of this review are to develop a current understanding of the anatomy and diagnostic evaluation of the peroneal tendons, and to present current treatment options and the authors’ preferred surgical techniques for operative management of peroneal tendon lesions.