Hypothesis: Anatomical insertions of the anterior cruciate ligament have relationships to bony landmarks of the tibia and femur.

Study Design: Descriptive laboratory study.

Methods: Eight cadaveric knees were scanned by computed tomography, reconstructed 3-dimensionally, and examined from simulated arthroscopic, sagittal, and axial perspectives. Volume-rendering software was used to document the relationship of the anterior cruciate ligament to the bony anatomy.

Results: A bony ridge (Resident’s Ridge) at the anterior border of the anterior cruciate ligament was readily noted on the medial wall of the lateral femoral condyle. Superiorly, anterior cruciate ligament fibers inserted up to the roof of the notch and to 3 to 3.5 mm of the articular surface posteriorly and inferiorly. The anterior cruciate ligament inserted into a fovea anterior to the tibial eminence. Posteriorly, anterior cruciate ligament fibers inserted up to a ridge between the medial and lateral intercondylar tubercles. Medially, anterior cruciate ligament fibers inserted onto the ridge at the lateral border of the medial tibial condyle. There was no distinct anterior or lateral bony border with anterior cruciate ligament fibers blending into the anterior horn of the lateral meniscus.

Conclusion: The anterior border of the femoral anterior cruciate ligament origin is Resident’s Ridge. The ridge between the medial and lateral intercondylar tubercles at the base of the tibial eminence is the posterior margin of the anterior cruciate ligament on the tibia.

Clinical Relevance: Bony landmarks can be used to aid in anatomical anterior cruciate ligament reconstruction.

Hypothesis: Unsatisfactory outcome after ACI is associated with technique-related typical complications.

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

Methods: A total of 309 consecutive patients with 349 ACI procedures of the knee joint were analyzed. Three different ACI techniques were used: periosteum-covered ACI in 52 cases (14.9%), Chondrogide (Geistlich Biomaterials, Wolhusen, Switzerland) membrane-covered ACI in 215 cases (61.6%), and a 3-dimensional matrix-associated ACI (BioSeed-C, Biotissue Technologies, Freiburg, Germany) in 82 cases (23.5%). In 52 patients, revision surgery was performed for persistent clinical problems. These patients were analyzed for defect size and location, technique of ACI, and intraoperative findings during revision surgery. The mean time of follow-up for patients after ACI was 4.5 years (standard deviation, ± 1.5).

Results: Four typical major complications were identified: hypertrophy of the transplant, disturbed fusion of the regenerative cartilage and the healthy surrounding cartilage, insufficient regenerative cartilage, and delamination. These diagnoses covered a total of 88.5% of the patients who underwent revision surgery. The overall complication rate was highest in the group of patients treated with periosteum-covered ACI (P = .008). The incidence of symptomatic hypertrophy was 5.2% for all techniques and defect locations; the highest incidence was in patients treated with periosteum-covered ACI (15.4%) (P = .001). The incidence of disturbed fusion was highest in the Chondrogide-covered ACI (3.7%) and the matrix-associated ACI group (4.8%). Concerning the incidence of complications by defect location, there was a tendency for increased complications in patellar defects (P = .095). Within the patellar defects group, no correlation was found for the occurrence of delamination, insufficient regeneration, and disturbed fusion. As a statistical trend, an increased rate of hypertrophy was found for patellar defects (P = .091).

Conclusion: A major proportion of complications after ACI can be summarized by 4 major diagnoses (symptomatic hypertrophy, disturbed fusion, delamination, and graft failure). Among those, the overall complication rate and incidence of hypertrophy of the transplant were higher for periosteum-covered ACI. Furthermore, an increased rate of symptomatic hypertrophy was found for patellar defects. Therapeutic concepts need to be developed to treat these typical complications of ACI.

Hypothesis: There is no difference in effectiveness between radial extracorporeal shock wave therapy and placebo in the treatment of chronic plantar fasciitis.

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

Methods: Three interventions of radial extracorporeal shock wave therapy (0.16 mJ/mm²; 2000 impulses) compared with placebo were studied in 245 patients with chronic plantar fasciitis. Primary endpoints were changes in visual analog scale composite score from baseline to 12 weeks’ follow-up, overall success rates, and success rates of the single visual analog scale scores (heel pain at first steps in the morning, during daily activities, during standardized pressure force). Secondary endpoints were single changes in visual analog scale scores, success rates, Roles and Maudsley score, SF-36, and patients’ and investigators’ global judgment of effectiveness 12 weeks and 12 months after extracorporeal shock wave therapy.

Results: Radial extracorporeal shock wave therapy proved significantly superior to placebo with a reduction of the visual analog scale composite score of 72.1% compared with 44.7% (P = .0220), and an overall success rate of 61.0% compared with 42.2% in the placebo group (P = .0020) at 12 weeks. Superiority was even more pronounced at 12 months, and all secondary outcome measures supported radial extracorporeal shock wave therapy to be significantly superior to placebo (P < .025, 1-sided). No relevant side effects were observed.

Conclusion: Radial extracorporeal shock wave therapy significantly improves pain, function, and quality of life compared with placebo in patients with recalcitrant plantar fasciitis.

Hypothesis: The predicted patellar tendon strains that occur as a result of the tendon loads and patella–patellar tendon angles (PPTAs) experienced during a jump landing will be significantly increased in the area of the patellar tendon associated with patellar tendinopathy.

Study Design: Descriptive laboratory study.

Methods: A 2-dimensional, computational, finite element model of the patella–patellar tendon complex was developed using anatomic measurements taken from lateral radiographs of a normal knee. The patella was modeled with plane strain rigid elements, and the patellar tendon was modeled with 8-node plane strain elements with neo-Hookean material properties. A tie constraint was used to join the patellar tendon and patella. Patella–patellar tendon angles corresponding to knee flexion angles between 0° and 60° and patellar tendon strains ranging from 5% to 15% were used as input variables into the computational model. To determine if the location of increased strain predicted by the computational model could produce isolated tendon fascicle damage in that same area, 5 human cadaveric patella–patellar tendon–tibia specimens were loaded under conditions predicted by the model to significantly increase localized tendon strain. Pre- and posttesting ultrasound images of the patella–patellar tendon specimens were obtained to document the location of any injured fascicles.

Results: Localized tendon strain at the classic location of the jumper’s knee lesion was found to increase in association with an increase in the magnitude of applied patellar tendon strain and a decrease in the PPTA. The principal stresses and strains predicted by the model for this localized area were tensile and not compressive in nature. Applying the tendon strain conditions and PPTA predicted by the model to significantly increase localized strain resulted in disruption of tendon fascicles in 3 of the 5 cadaveric specimens at the classic location of the patellar tendinopathy lesion.

Conclusion: The localized increase in patellar tendon strain that occurs in response to the application of tendon loads and decreased PPTA could induce microdamage at the classic location of the jumper’s knee lesion.

Clinical Relevance: The association of decreasing PPTA with increasing localized tendon strain would implicate the role of knee-joint angle as well as tendon force in the etiopathogenesis of jumper’s knee.

Hypothesis: The posterior region of the proximal patellar tendon is subjected to greater tendinous forces than is the corresponding anterior region.

Study Design: Descriptive laboratory study.

Method: An optic fiber technique was used to detect forces in both the anterior and the posterior regions of the proximal patellar tendon in 7 healthy persons. The optic fiber force sensor works on the principle of the amplitude modulation of transmitted light when the optic fiber is geometrically altered owing to the forces acting on it. Longitudinal strain in the tendon or ligament produces a negative transverse strain, thus causing a force that effectively squeezes the optic fiber. Measurements were recorded during the following exercises: closed kinetic chain quadriceps contraction (eccentric and concentric), open kinetic chain quadriceps contraction (eccentric and concentric), a step exercise, and a jump exercise.

Results: During all the exercises, the peak differential signal output in the posterior location of the proximal patellar tendon was greater than in the corresponding anterior location. The greatest differential signal output was found in the jump and squat exercises.

Conclusion: The posterior region of the proximal patellar tendon is subjected to greater tendinous forces than is the corresponding anterior region. This finding supports the tensile-overload theory of patellar tendinopathy.

Clinical Relevance: Jump activities and deep squat exercises expose the patellar tendon to very large tendinous forces.

Hypothesis: Standardized combined cryotherapy/compression changes in midportion Achilles tendon microcirculation are superior to those with cryotherapy during intermittent application.

Study Design: Controlled laboratory study.

Methods: Sixty volunteers were randomized for either combined cryotherapy/compression (Cryo/Cuff, DJO Inc, Vista, California: n = 30; 32 ± 11 years) or cryotherapy alone (KoldBlue, TLP Industries, Kent, United Kingdom: n = 30; 33 ± 12 years) with intermittent 3 x 10-minute application. Midportion Achilles tendon microcirculation was determined (O2C, LEA Medizintechnik, Giessen, Germany).

Results: Both Cryo/Cuff and KoldBlue significantly reduced superficial and deep capillary tendon blood flow within the first minute of application (43 ± 46 arbitrary units [AU] vs 10 ± 19 AU and 42 ± 46 AU vs 12 ± 10 AU; P = .0001) without a significant difference throughout all 3 applications. However, during recovery, superficial and deep capillary blood flow was reestablished significantly faster using Cryo/Cuff (P = .023). Tendon oxygen saturation was reduced in both groups significantly (3 minutes Cryo/Cuff: 36% ± 20% vs 16% ± 15%; KoldBlue: 42% ± 19% vs 28% ± 20%; P < .05) with significantly stronger effects using Cryo/Cuff (P = .014). Cryo/Cuff led to significantly higher tendon oxygenation (Cryo/Cuff: 62% ± 28% vs baseline 36% ± 20%; P = .0001) in superficial and deep tissue (Cryo/Cuff: 73% ± 14% vs baseline 65% ± 17%; P = .0001) compared with KoldBlue during all recoveries. Postcapillary venous filling pressures were significantly reduced in both groups during application; however, Cryo/Cuff led to significantly, but marginally, lower pressures (Cryo/Cuff: 41 ± 7 AU vs baseline 51 ± 13 AU; P = .0001 and KoldBlue: 46 ± 7 AU vs baseline 56 ± 11 AU; P = .026 for Cryo/Cuff vs KoldBlue).

Conclusion: Increased tendon oxygenation is achieved as tendon preconditioning by combined cryotherapy and compression with significantly increased tendon oxygen saturation during recovery in contrast to cryotherapy alone. Both regimens lead to a significant amelioration of tendinous venous outflow.

Clinical Relevance: Combined cryotherapy and compression is superior to cryotherapy alone regarding the Achilles tendon microcirculation. Further studies in tendinopathy and tendon rehabilitation are warranted to elucidate its value regarding functional issues.

Purpose: To investigate in-shoe plantar pressure loading and comfort during running in 2 popular neutral-cushioned running shoes recommended for athletes with cavus feet.

Study Design: Controlled laboratory study.

Methods: Plantar pressures were collected using the in-shoe Novel Pedar-X system during overground running in 22 athletes with cavus feet in 2 neutral-cushioned running shoes (Asics Nimbus 6 and Brooks Glycerin 3) and a control condition (Dunlop Volley). Comfort was measured using a validated visual analog scale.

Results: Compared with the control, both neutral-cushioned running shoes significantly reduced peak pressure and pressure-time integrals by 17% to 33% (P < .001). The Brooks Glycerin most effectively reduced pressure beneath the whole foot and forefoot (P < .01), and the Asics Nimbus most effectively reduced rearfoot pressure (P <.01). Both neutral-cushioned running shoes reduced force at the forefoot by 6% and increased it at the midfoot by 12% to 17% (P < .05). Contact time and area increased in both neutral-cushioned running shoes (P < .01). The Asics Nimbus was the most comfortable, although both neutral-cushioned running shoes were significantly more comfortable than the control (P < .001).

Conclusion: Two popular types of neutral-cushioned running shoes were effective at reducing plantar pressures in athletes with cavus feet.

Clinical Relevance: Regional differences in pressure reduction suggest neutral-cushioned running shoe recommendation should shift from being categorical in nature to being based on location of injury or elevated plantar pressure.

Hypothesis: Type I and II acromioclavicular joint disruption significantly impairs long-term shoulder function.

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

Methods: The shoulder function of 23 patients who were treated for type I or II acromioclavicular joint disruption was evaluated at a mean of 10.2 years after injury. The objective and subjective measures of the injured shoulder were assessed using Constant, University of California–Los Angeles Shoulder Scale, and Simple Shoulder Test scores and were compared with results of the uninjured shoulder.

Results: At an average follow-up of 10.2 years, 12 of 23 patients (52%) reported at least occasional acromioclavicular joint symptoms. The average Constant score for the injured shoulder was 70.5 and 86.8 for the uninjured shoulder (P < .001). The average University of California–Los Angeles Shoulder Scale score for the injured shoulder was 24.1 and 29.2 for the uninjured shoulder (P < .001). The average Simple Shoulder Test value for the injured shoulder was 9.7 and 10.9 for the uninjured shoulder (P < .002). The extent of acromioclavicular joint disruption and acromioclavicular joint width did not have any statistically significant influence on the shoulder functional scores.

Conclusion: Type I and II acromioclavicular joint disruptions impair long-term shoulder function in about half of patients 10 years after injury.

Purpose: To compare the in vivo kinematics of the uninjured contralateral knees of patients with anterior or posterior cruciate ligament deficiency with knee kinematics of age-matched patients without joint injury.

Study Design: Controlled laboratory study.

Methods: Ten subjects with bilateral healthy knees, 10 patients with acute unilateral anterior cruciate ligament injury, and 10 with acute unilateral posterior cruciate ligament injury participated in this study. Kinematics were measured from 0° to 90° of flexion using imaging and 3-dimensional modeling.

Results: No significant differences were found across the groups in all rotations and translations during weightbearing flexion (P > .9).

Conclusion: Patients with unilateral cruciate ligament deficiency did not alter kinematics of the contralateral uninjured knee during weightbearing flexion. In addition, these findings suggest that the included patients with anterior cruciate ligament or posterior cruciate ligament deficiency did not have preexisting abnormal kinematics of the knee.

Clinical Relevance: As the contralateral joint kinematics of the injured patients were not affected by the ipsilateral ligament injury in the short term, physicians and researchers might use the contralateral knee as a reliable normal kinematic control.

Hypothesis: After 6 and 12 weeks, structural properties and knee kinematics after soft tissue ACL reconstruction with 15 mm within the femoral tunnel will be significantly inferior when compared with the properties of ACL reconstruction with 25 mm in the tunnel.

Study Design: Controlled laboratory study.

Methods: In an intra-articular goat model, 36 ACL reconstructions using an Achilles tendon split graft were performed with 15-mm (18 knees) and 25-mm (18 knees) graft length in the femoral tunnel. Animals were sacrificed 6 weeks and 12 weeks after surgery and knee kinematics was tested. In situ forces as well as the structural properties were determined and compared with those in an intact control group. Histologic analyses were performed in 2 animals in each group 6 and 12 weeks postoperatively. Statistical analysis was performed using a 2-factor analysis of variance test.

Results: Anterior cruciate ligament reconstructions with 15 mm resulted in significantly less anterior tibial translation after 6 weeks (P < .05) but not after 12 weeks. Kinematics after 12 weeks and in situ forces of the replacement grafts at both time points showed no statistically significant differences. Stiffness, ultimate failure load, and ultimate stress revealed no statistically significant differences between the 15-mm group and the 25-mm group.

Conclusion: The results suggest that there is no negative correlation between short graft length (15 mm) in the femoral tunnel and the resulting knee kinematics and structural properties.

Clinical Relevance: Various clinical scenarios exist in which the length of available graft that could be pulled into the bone tunnel (femoral or tibial) could be in question. To address this concern, this study showed that reducing the tendon graft length in the femoral bone tunnel from 25 mm to 15 mm did not have adverse affects in a goat model.

Hypothesis: Certain intra-articular lesions affect the clinical outcome of ligament reconstruction.

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

Methods: Sixty-five ankles from 64 patients underwent a modified Broström operation for chronic lateral ankle instability with a mean follow-up of 28.7 months (range, 12–67). The results were assessed according to the Karlsson-Peterson Ankle Score. The type of intra-articular lesions and the association of clinical outcome were investigated using Pearson’s correlation coefficient and multivariate logistic regression analysis.

Results: The average Karlsson-Peterson Ankle Score was improved from 53 ± 14.63 preoperatively to 85.21 ± 11.97 at final follow-up (P < .001). Five different intra-articular lesions were described in 63 ankles (96.9%), and the ankle score negatively correlated with the number of lesions (r = –.604; P < .001). Multivariate logistic regression showed that syndesmosis widening (odds ratio, 11.1; 95% confidence interval: 2.2–55.4; P = .003), osteochondral lesions of the talus (odds ratio, 8.5; 95% confidence interval: 1.7–42.3; P = .008), and ossicles (odds ratio, 4.5; 95% confidence interval: 1.0–20.2; P = .046) are significant predictors of unsatisfactory results after ligament reconstruction.

Conclusion: Arthroscopic diagnosis and treatment of intra-articular lesions associated with chronic lateral ankle instability is a safe and effective method. The presence of any combination of associated intra-articular lesions can result in a poor outcome.

Hypothesis: Pitchers with a history of throwing-related pain will have weakened dominant-arm posterior shoulder musculature and greater dominant-arm glenohumeral total range of motion (ROM) loss compared with pitchers without throwing-related pain.

Study Design: Controlled laboratory study.

Methods: Twenty-three adolescent pitchers (age 15.7 ± 1.4 years) were tested. Twelve pitchers had throwing-related pain in the prior season and were currently symptom-free, while the remaining 11 pitchers had no such history of pain. Internal and external rotation ROM and muscle strength (lower trapezius, middle trapezius, rhomboids, latissimus dorsi, supraspinatus, internal rotators, external rotators) were measured bilaterally. Dominant versus nondominant differences in ROM and strength were compared between pitchers with and without throwing-related pain.

Results: As a whole, the group of 23 pitchers had a loss of internal rotation ROM (13° ± 10°, P < .001) and gain in external rotation ROM (11° ± 10°, P < .001) on the dominant versus nondominant arm, with no effect on total ROM (2° ± 7° loss, P = .14). There was no difference in bilateral comparison of total ROM between pitchers with and without throwing-related pain. Dominant versus nondominant muscle strength was lower (P < .05) for the pain group versus nonpain group for the middle trapezius (7% ± 19% vs 22% ± 12%) and supraspinatus (–4% ± 27% vs 14% ± 14%) and higher (P < .05) for the internal rotators (19% ± 14% vs 6% ± 12%).

Conclusion: Throwing-related pain in this population may be due to the inability of weakened posterior shoulder musculature to tolerate stress imparted on it by adaptively strengthened propulsive muscles.

Clinical Relevance: Selective posterior shoulder strengthening may be indicated in rehabilitative and injury prevention programs for adolescent pitchers.

Hypothesis: Navigated limb alignment demonstrates good reliability and accuracy in all 3 planes.

Study Design: Descriptive laboratory study.

Methods: Thirteen cadaver legs were used to examine the intra- and interobserver registration reliability of 3 observers. Initial coronal, sagittal, and axial alignment was measured on 6 legs, 3 times each, at intervals >36 hours. Navigated HTOs were then performed on all 13 legs, pre- and postoperative alignment was recorded, and data were compared with equivalent measures obtained by 3-dimensional computed tomography. Reliability and accuracy data were both analyzed using intraclass correlation coefficients with the following established thresholds: good, >0.75; fair, 0.4 to 0.75; and poor, <0.4.

Results: Intraclass correlation coefficients for intraobserver reliability were categorized as follows: varus-valgus, good; flexion-extension, fair; and femoral-tibial rotation, poor. For interobserver reliability, results were varus-valgus, fair; flexion-extension, fair; and femoral-tibial rotation, poor. Intraclass correlation coefficients for navigation accuracy were varus-valgus, good; tibial slope, good; and tibial torsion, poor. Maximum differences in navigation–computed tomography measurements were varus-valgus angle, 4.5°; tibial slope, 8.8°; and tibial torsion, 16.5°.

Conclusion and Clinical Relevance: Navigation may be reliable and clinically useful for dynamic monitoring of coronal leg alignment but has limits in determination of sagittal and axial plane alignment.

Purpose: The objective was to define the incidence and etiologic factors of intra- and extra-articular hip injuries in the National Football League (NFL).

Study Design: Descriptive epidemiology study.

Methods: The NFL Injury Surveillance System was used to define all hip-related injuries from 1997 to 2006. Injuries were included if the athlete missed more than 2 days. All hip and groin injuries were included for evaluation. The authors also report on NFL players with intra-articular injuries seen at their institution outside of the NFL Injury Surveillance System.

Results: There were a total of 23 806 injuries from 1997 to 2006, of which 738 were hip injuries (3.1%) with an average of 12.3 days lost per injury. Muscle strains were the most common injury. Intra-articular injuries resulted in the most time lost. Contact injuries most likely resulted in a contusion, and noncontact injuries most often resulted in a muscle strain. In the authors’ institutional experience, many of the athletes with labral tears have persistent adductor strains that do not improve despite adequate therapy.

Conclusion: Hip injuries represent a small but substantial percentage of injuries that occur in the NFL. A majority of these injuries are minor, with a return to play within 2 weeks. Intra-articular injuries are more serious and result in a significant loss of playing time. The "sports hip triad" (labral tear, adductor strain, and rectus strain) is described as a common injury pattern in the elite athlete.

Hypothesis: Anatomic ACL fibers undergo a greater change in length during anterior translation and internal rotation than a conventional SB reconstruction from the PL tibial footprint to the AM femoral footprint.

Study Design: Controlled laboratory study.

Methods: The Praxim ACL Surgetics navigation system was used to acquire kinematic data during a flexion/extension cycle and to register all points within the ACL footprint from 5 fresh-frozen cadaveric knees. Virtual fibers were placed in the center of the AM and PL bundles as well as central and conventional SB positions. After transection of the ACL, the absolute length change and apparent strain of the fibers were computed for each knee during the Lachman and anterior drawer tests and internal rotation at 0° and 30° of flexion.

Results: Each of the anatomic fibers (AM, PL, and central) had more elongation and apparent strain than the conventional SB fiber during the Lachman maneuver. During the anterior drawer test, the AM and central (but not the PL) fibers lengthened significantly more and the AM had more apparent strain than the conventional SB fiber. During internal rotation at 0° and 30° of flexion, anatomic fibers elongated significantly more than the conventional fiber. Except for the AM fiber with the knee at full extension, apparent strain was greater in all anatomic fibers than in the conventional SB fiber during internal rotation maneuvers.

Conclusion: In ACL-deficient cadaveric knees, anatomic fibers undergo greater elongation and apparent strain in response to anterior translation and internal rotation maneuvers than a conventional SB graft. Because of their optimal orientation, anatomic fibers may resist pathologic anterior translation and internal rotation more than the conventional SB position.

Clinical Relevance: Conventional placement of a single-bundle graft results in suboptimal changes in fiber length and strain, suggesting that alternatives such as anatomic placement of an SB graft or double-bundle reconstruction may result in greater control of translation and rotation.

Hypothesis: Clinical anthropometric data can be used to predict hamstring graft size.

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

Methods: Fifty consecutive patients with anterior cruciate ligament deficiency scheduled for reconstruction using hamstring autograft were prospectively evaluated. Preoperatively we recorded height, weight, body mass index, age, gender, leg length, thigh length, shank length, bilateral thigh circumference, and Tegner score. Intraoperative measurements of both the gracilis and semitendinosus tendons were made, including absolute length before fashioning the graft and final diameter of the quadrupled graft using sizing tubes calibrated to 0.5 mm. Bivariate correlation coefficients (Pearson r) were calculated to identify relationships among clinical data and intraoperatively measured hamstring graft length and diameter.

Results: Strongest correlations for graft lengths were height and leg length measurements. Shorter persons with shorter leg, thigh, and shank lengths tended to have shorter gracilis and semitendinosus grafts. Likewise, the strongest correlations for graft diameter were weight and thigh circumference. Self-reported activity level and age did not correlate. Gender comparison revealed that women who were shorter, lighter, and had smaller body mass indices were more likely to have smaller graft diameters and shorter graft lengths.

Conclusion: Patients weighing less than 50 kg, less than 140 cm in height, with less than 37 cm thigh circumference, and with body mass index less than 18 should be considered at high risk for having a quadrupled hamstring graft diameter less than 7 mm. When separated by gender, small graft diameters are most likely in older, short, female subjects with small thigh circumferences or young, skinny, male subjects with small thigh circumferences and low body mass index. Common clinical measurements can be used for preoperative identification of patients at risk for insufficient graft tissue and would be useful for patient counseling and alternative graft source planning.

Hypothesis: Among active athletes, Doppler flow may partly reflect tendon adaptation to increased mechanical load and/or asymptomatic tendinopathy.

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

Methods: The Achilles tendons of 61 badminton players (24 elite, 37 recreational) were examined with gray-scale and color Doppler ultrasound. Achilles tendon pain and activity level (badminton training, badminton playing, badminton years) were measured.

Results: Doppler flow was not associated with current Achilles tendon pain but was associated with an increased anteroposterior tendon diameter (an indicator of tendinopathy) (P = .02). Athletes who had been playing badminton for longer were more likely to have Doppler flow (P < .01), and there was a trend toward an association between a greater number of badminton playing hours per week and Doppler flow (P = .07).

Conclusion: Achilles tendon Doppler flow appears to be a sign of asymptomatic tendinopathy rather than pain among active athletes. The association between weekly badminton hours and badminton years and Doppler flow suggests that Doppler flow may be a response to mechanical load in this cohort.

Hypothesis: The modified Weaver-Dunn reconstruction restores intact acromioclavicular joint motion during passive scapular plane abduction.

Study Design: Controlled laboratory study.

Methods: Acromioclavicular joint motion was recorded during passive humeral elevation in 3 states: an intact shoulder, an "injured" state in which the acromioclavicular and coracoclavicular ligaments were transected, and finally in a reconstructed state using a modified Weaver-Dunn reconstruction. Measurements were taken with an electromagnetic motion analysis system attached to rigid pins placed in the clavicle, scapula, humerus, and sternum during passive scapular plane humeral elevation.

Results: Total translatory motion of the acromioclavicular joint in the cut state was significantly greater than both the intact and reconstructed states in the medial/lateral (intact, 4.3 mm; cut, 7.9 mm; reconstructed, 2.6 mm), anterior/posterior (intact, 4.8 mm; cut, 6.1 mm; reconstructed, 4.9 mm), and superior/inferior (intact, 4.1 mm; cut, 8.0 mm; reconstructed, 4.8 mm) directions. The maximum and minimum positions of the reconstructed state were significantly more anterior and inferior than in the intact state. A significant increase in acromioclavicular axial rotation was also found between the intact and cut state.

Conclusion: The modified Weaver-Dunn reconstruction was found to restore motion of the acromioclavicular joint to near-intact values, but created a more anterior and inferior position of the clavicle with respect to the acromion.

Clinical Relevance: These kinematic data support the modified Weaver-Dunn reconstruction as a kinematically sound procedure to treat displaced acromioclavicular joint injuries.