The American Journal of Sports Medicine

We dissected 30 cadaveric knees to provide a detailed anatomic description of the biceps femoris muscle complex at the knee. The main components of the long head of the muscle are a reflected arm, a direct arm, an anterior arm, and a lateral and an anterior aponeurosis. The main components of the short head of the biceps femoris muscle are a proximal attachment to the long head's tendon, a capsular arm, a confluens of the biceps and the capsuloosseous layer of the iliotibial tract, a direct arm, an anterior arm, and a lateral apo neurosis. We examined 82 consecutive, acutely in jured knees with clinical signs of anterolateral-antero medial rotatory instability for the incidence and anatomic location of injuries to the biceps femoris mus cle. Injuries to components of that muscle were iden tified in 59 (72%) of these knees; 29 knees (35.4%) had multiple components injured. There were 3 injuries to the long head of the biceps femoris muscle (all in the reflected arm) and 89 to the short head. A statistically significant correlation (P = 0.01) was found between increased anterior translation with the knee at 25° of flexion as demonstrated by the Lachman test and in jury to the biceps-capsuloosseous iliotibial tract conflu ens. Additionally, adduction laxity at 30° of flexion cor related with a Segond fracture (P = 0.04). These data establish, in part, the relationship of the biceps femoris complex injury to anterior translation instability.

We conducted a cross-sectional survey of 52 nonelite gymnasts (32 girls, 20 boys; average age, 11.8 years) to assess their history of training and wrist pain within the last 6 months. An intensity index was created using the number of training hours per week and the athletes' skill levels. Wrist pain was prevalent in 38 (73%) of the gymnasts. Gymnasts with wrist pain were older (12.6 years versus 9.7 years; P = 0.0002), trained more hours per week (13.5 versus 7.7; P = 0.0002), trained at a higher skill level (P = 0.01), and began training at an older age (7.0 years versus 5.1 years; P = 0.006). Analysis of intensity versus age suggested that a threshold of training intensity may be important in the development of wrist pain. Logistical regression found these factors to be independently associated with wrist pain: intensity (P = 0.036), age >10 years (P = 0.018), age <14 years (P = 0.016), and the age of initiation of training (P = 0.020). This study demon strates that wrist pain is a common problem among nonelite young gymnasts. Training intensity, relative to the age of the participant and the age when training was initiated, appears to be an important determinant of the development of wrist pain in this population.

We performed an epidemiologic survey to estimate the number of grip lock injuries occurring among male high school and college gymnasts. These injuries occur when dowel grips used by the gymnast become locked on the bar as the gymnast's momentum carries him through the skill being performed. We also questioned injured gymnasts to obtain details of their injuries. Thir ty-eight high school coaches reported 17 injuries and 32 college coaches reported 21 injuries for a 10-year period; 36% of the coaches responding reported at least one such injury in their program. Of the 23 injured gymnasts who returned detailed questionnaires, 20 had sustained fractures and 9 required surgery. The distal forearm or wrist were the areas injured most often. Fourteen gymnasts had residual pain, seven had functional limitations, and eight had limited motion in the wrist. Fifteen of the 23 athletes were using a cubital (hyperpronated) grip at the time of injury and 19 were using dowel grips. Among the reasons cited for the injury, 18 gymnasts thought that their grips were either too large, worn, or stretched; 8 said the grips slid up their wrists, and 7 cited technical errors.

The popliteal tendon has a significant attachment to the fibula, the popliteofibular ligament. The role of this ligament in knee stability has not been determined. In this study we used selective cutting techniques to measure the static contribution of the popliteal tendon attachments to the tibia and the popliteofibular liga ment for stability of the knee. Sectioning of all the posterolateral structures except the popliteal tendon attachments to the tibia or the popliteofibular ligament resulted in increased primary posterior translation, va rus rotation, external rotation, and coupled external rotation. Although statistically significant, these in creases were small. Sectioning of all the posterolateral structures resulted in larger increases in primary pos terior translation, varus rotation, external rotation, and coupled external rotation. Our data indicate that the popliteal tendon attachments to the tibia and the pop liteofibular ligament are important in resisting posterior translation and varus and external rotation. If an iso lated injury to the posterolateral structures occurs, an atomic reconstruction of the major ligaments that re strain posterior translation and varus and external rotation may provide the best functional result. Recon struction for isolated posterolateral instability should include anatomic attachment of the popliteal tendon to the tibia and the popliteofibular ligament.

The reasons why many patients seemingly benefit from arthroscopic treatment of osteoarthritis of the knee remain obscure. The purpose of this pilot study was to determine if a placebo effect might play a role in arthroscopic treatment of this condition. After giving full informed consent, including full knowledge of the pos sibility and nature of a placebo surgery, five subjects were randomized to a placebo arthroscopy group, three subjects were randomized to an arthroscopic lavage group, and two subjects were randomized to a standard arthroscopic debridement group. The physi cians performing the postoperative assessment and the patients remained blinded as to treatment. Patients who received the placebo surgery reported decreased frequency, intensity, and duration of knee pain. They also thought that the procedure was worthwhile and would recommend it to family and friends. Thus, there may be a significant placebo effect for arthroscopic treatment of osteoarthritis of the knee. The small num bers in this preliminary study preclude a valid statistical analysis, and no conclusions can be drawn regarding the superiority of one treatment over another. A larger study is needed to evaluate fully the efficacy of an arthroscopic procedure for this condition and to decide if it is reasonable to expend health care resources for

Five patients with symptomatic knee hyperextension thrusting patterns due to posterolateral ligament com plex injury underwent gait analysis before and after a gait retraining program. Patients were trained to avoid knee hyperextension by 1) walking with their knees slightly flexed throughout stance, 2) maintaining ankle dorsiflexion in early stance, and 3) maintaining an erect trunk-hip attitude during stance. Kinematic and kinetic measurements were obtained using automated gait analysis. Four of the five patients significantly reduced hyperextension at the knee and abnormal motion pat terns at the hip and ankle. Patients showed increases in knee flexion throughout stance conversions of knee flexion-extension moments to more normal biphasic patterns with a 79% decrease in extension moments at terminal extension, and a 22% decrease in knee ad duction moments. Posttraining values also showed a 30% decrease in the calculated medial tibiofemoral loads (P < 0.05). At the hip, there were significant decreases in abduction and adduction moments (36% and 18%, respectively, P < 0.01). Ankle plantar flexion motion decreased significantly by 42% (P < 0.01). Gait retraining can alter the biomechanics of hip, knee, and ankle function to approximately normal levels, and therefore is recommended before ligament reconstruc tion because abnormal knee motions, if resumed post operatively, can stretch soft tissue reconstructions.

We performed a biomechanical comparison of two ro tator cuff repair techniques using fresh-frozen human cadavers. Nine pairs of cadaveric shoulders had stan dardized full-thickness tears made at the supraspina tus tendon insertion. One of each pair of the cadaveric shoulders was repaired by pulling the tendon into a bone trough in the humeral head using standard su tures. The remaining half of the pairs was repaired using anchor sutures. The repairs were tested using a servohydraulically operated material testing system. The anchor suture repair was significantly stronger than the standard suture technique irrespective of bone quality. Failure occurred predominantly through bone in the suture repairs and as a result of suture breakage in the anchor repairs. The anchors should be placed into the edge of the subchondral bone adjacent to the articular surface. The surgeon should direct the anchor so that the direction of the pull is approximately 90 degrees to the anchor, with the humerus at 30 degrees of abduction.

The objective of our study was to elucidate the char acteristic pathoanatomy associated with patellar dislo cation and report the preliminary results of early surgi cal repair. Twenty-three patients with documented patellar dislocation had standard radiographs and a magnetic resonance imaging scan. Intraarticular le sions were evaluated and treated arthroscopically fol lowed by an open exploration of the medial aspect of the knee in 16 patients. Twelve patients were observed for a minimum of 2 years after surgical repair (average, 34 months). Eleven patients returned for a follow-up examination. Magnetic resonance imaging revealed ef fusion (100%), tears of the femoral insertion of the medial patellofemoral ligament (87%), increased signal in the vastus medialis muscle (78%), and lateral fem oral condyle (87%) and medial patellar (30%) bone bruises. Arthroscopic examination revealed osteo chondral lesions involving the patella and the lateral femoral condyle in 68% of cases. Open surgical explo ration revealed tears of the medial patellofemoral liga ment off the femur in 15 of 16 patients (94%). After medial patellofemoral ligament repair, none of the pa tients experienced recurrent dislocation. Overall 58% of the results were considered to be good or excellent and 42% were fair. Fifty-eight percent of the group returned to their previous sport with no or minor limitations.

The purpose of this prospective study was to evaluate the efficacy of a patellar taping program in the conser vative management of patellofemoral pain. Twenty-five patients with patellofemoral pain were randomized into two groups. One group underwent a standard physical therapy program for patellofemoral pain. The other group underwent the same physical therapy program, but use of a patellar taping technique was added to this program. Results of a subjective visual analog scale and changes in isokinetic strength and electromyo graphic activity of the quadriceps muscle were ana lyzed. Both the tape and no-tape groups experienced a statistically significant decrease in symptoms (P < 0.05), but no difference in improvement of patellofemo ral pain was noted between the groups. Likewise, both groups demonstrated significant improvement in quad riceps muscle isokinetic strength (P < 0.05) and activ ity (P < 0.001), but no difference in improvement was noted between groups. The results of this study sug gest no beneficial effect of adding a patellar taping program to a standard physical therapy program in the conservative treatment of patellofemoral pain. Larger prospective studies are warranted to support this opinion.

The purpose of this study was to determine normal rotation of the anterior cruciate ligament and to provide a technique for reproduction of this rotation. Ten fresh- frozen knees were dissected of all soft tissue except for the anterior cruciate ligament. Specimens were se cured in a vise in 60° of flexion. Each tibia was allowed to spin freely on the femur, and rotation was recorded. Anterior cruciate ligament reconstructions, using bone- patellar tendon-bone grafts, were then performed on all specimens using four graft rotations. Each specimen was then tested to assess how the graft twist affected tibial rotation. The average tibial rotation of the normal anterior cruciate ligaments was 55° internally. Previous descriptions of anterior cruciate ligament reconstruc tions have advocated medial or internal rotation of the graft to reproduce normal anatomic rotation of the an terior cruciate ligament. Our cadaveric dissections have demonstrated that the anterior cruciate ligament normally produces internal rotation of the tibia in rela tion to the femur. Reproduction of this anatomic rota tion is accomplished with 90° of lateral rotation of the tibial plug toward the fibula.

We examined seven cadaveric knees to determine the radiographic location of the native anterior cruciate ligament insertion sites as well as the location of tun nels used in anterior cruciate ligament reconstruction. Posteroanterior and lateral views at several flexion angles were taken with radiopaque markers around the insertions of the native anterior cruciate ligament and subsequent reconstruction tunnels. The femoral inser tion was best seen on the 60° notch view. On the lateral view, the femoral tunnel was easily seen as it crossed the roof of the intercondylar notch; however, because of the angle of the tunnel, the actual entrance into the knee may be well distal and anterior to this location. The tibial insertion and tunnel were easily seen at any flexion angle. The center of the insertion was 40% of the tibial diameter from the anterior mar gin. The lateral view in extension allowed determina tion of the tibial tunnel's location in relation to the intercondylar notch roof, but by itself did not allow accurate determination of the femoral tunnel's position. Notch and extension lateral radiographs together pro vided sufficient information for evaluation of anterior cruciate ligament graft position in a convenient, cost- effective format. Neither view by itself provides enough information to evaluate the position of the graft.

Previous studies of the shoe-surface interface corre lated foot fixation with cleat length, configuration, and material composition as well as turf type and surface conditions. Our study examined the effect of tempera ture on the rotational torsion resistance of artificial turf football shoes. Five football shoe models, a flat-soled basketball-style turf shoe, a natural grass soccer-style shoe, and three multistudded turf shoes, were studied on dry AstroTurf at five temperatures (range, 52°F to 110°F). An assay device, a prosthetic foot mounted on a loaded stainless steel shaft, was used to determine the force necessary to release a shoe from the turf's surface. We used a torque wrench to apply a rotational force so that each shoe was pivoted counterclockwise through an arc of 60°. Our results indicated that re lease coefficients differ within and among the shoe models at various turf temperatures. We also found that an increase in turf temperature, in combination with cleat characteristics, affects shoe-surface inter face friction and potentially places the athlete's knee and ankle at risk of injury. Based on an established risk criterion, which correlated shoe-surface interface com binations in the laboratory with documented clinical occurrences, only the flat-soled basketball-style turf shoe could be designated "safe" or "probably safe" at all five temperatures.

We evaluated 200 patients who had a positive McMur ray test and found atypical McMurray test results in 24 patients (12%). These patients revealed pain or click ing or both either in the medial compartment of the knee when the leg was internally rotated or in the lateral compartment of the knee when the leg was externally rotated. The authors analyzed these para doxical findings at arthroscopic examination to identify the relationship between the type of meniscal tear and the direction of leg rotation that elicited the catching and displacement of the torn meniscal portion during the McMurray test. Contrary to conventional McMurray test findings, three different types of meniscal tears were found on the side of the knee where pain or a clicking sound occurred. The three types were 1) an teriorly based posterior oblique tears with anterior dis placement of the meniscus, 2) bucket-handle tears in the posterior half of the menisci, and 3) peripheral detachment of discoid menisci in the posterior half of the torn portions.

A descriptive study was conducted to investigate inju ries sustained at a major off-road bicycling race at Mammoth Mountain, California, July 6 to 10, 1994. A total of 4027 individual starts in five events during the race were reported. Overall, the total number of com petitors in the 5 events was 3624, with some cyclists participating in multiple events. Injuries were consid ered significant if they occurred during competition and prevented the rider from completing the event. Sixteen cyclists had injuries that met these criteria for an over all injury rate of 0.40%. These 16 cyclists had 44 injuries. Abrasions were the most common injury, fol lowed by contusions, lacerations, fractures, and con cussions. The mean injury severity score was 3.0 (range, 1 to 5) with 81.2% of the injuries resulting from cyclists going downhill. Injuries were more severe when the riders were thrown from the bicycles (P = 0.03). We observed different mechanisms of injury in various events, suggesting that the risk factors for sustaining a traumatic injury may vary according to the type of competition involved.

We reviewed radiographs and magnetic resonance im ages of 77 young athletes with spondylolysis and spon dylolisthesis (more than 5% vertebral slip) (slip group). The results were compared with similar studies in 88 patients with spondylolysis only (nonslip group). End- plate lesions were found in all patients in the slip group and in 60 (68%) of those in the nonslip group. Slippage between the osseous and cartilaginous endplates was identified in the T1-weighted sagittal magnetic reso nance images and categorized according to the type of slippage: total slip of L-5 or S-1, partial slip of L-5 or S-1, or a combination of these (mixed type). In a study of 31 patients whose slippages progressed, no slip page was associated with the early stage of a pars interarticularis defect. Most vertebral slippages devel oped or progressed in the cartilaginous or apophyseal stage of the lumbar skeletal age. Wedging of the L-5 vertebral body and rounding of the sacrum progressed as the slippage developed; these did not occur in the nonslip group. These results indicate that the ad vanced stage of a pars interarticularis defect in an immature spine is a risk factor for spondylolisthesis. The deformities of the lumbosacral spine are thought to be the secondary changes caused by vertebral slippage.

To prospectively evaluate the clinical value of magnetic resonance imaging of the knee in a referral sports medicine practice, we performed a three-part study. First, we asked 72 consecutive patients a series of clinically relevant questions regarding the ordering of their magnetic resonance imaging scans. Second, we asked the treating physicians at our center if the mag netic resonance imaging findings changed the diagno sis or treatment. Third, we compared the clinical eval uation with the findings on magnetic resonance imaging scans for 37 patients who had arthroscopic confirmation. From the physician's perspective, in only three cases would the results of the scan have changed the diagnosis. Information from the scans was judged to contribute to patient treatment in only 14 of 72 patients. Finally, comparison of clinical evaluation and magnetic resonance imaging findings with findings during arthroscopic procedures showed that clinical evaluation had a sensitivity and specificity of 100% for diagnosis of anterior cruciate ligament injuries, whereas magnetic resonance imaging was 95% sen sitive and 88% specific. For isolated meniscal lesions, the clinical assessment had a sensitivity and specificity of 91 % compared with 82% and 87%, respectively, for magnetic resonance imaging. For evaluation of articu lar surface damage, the predictive value of a positive test was 100% for clinical assessment and 33% for the

We assessed the reliability of the KT-2000 knee ar thrometer at 67, 89, 134, and 178 N and at manual maximum forces on 30 college students who were free from present or previous knee injuries. Two examiners tested all subjects on two occasions. Anterior laxity (P < 0.0001) and side-to-side difference (P < 0.05) sig nificantly increased as force increased. There was a significant difference (P < 0.0001) between testers for anterior laxity but not for side-to-side difference. We used intraclass correlation coefficients to estimate rel ative reliability. Anterior laxity intraclass correlation co efficients (2,1) between testers ranged from 0.81 to 0.86 and within tester correlations ranged from 0.92 to 0.95. Intraclass correlation coefficients for between testers for side-to-side differences ranged from 0.38 to 0.58 and within tester correlations ranged from 0.53 to 0.64. Subject-to-subject variability needs to be taken into account when interpreting intraclass correlation coefficient values. Our absolute reliability estimates (95% confidence intervals) were small, indicating little variability. Our data demonstrate the KT-2000 arthrom eter to be reliable. Researchers should present both relative and absolute reliability estimates, although we believe absolute estimates are of greater clinical value. Side-to-side differences are better discriminators than individual absolute values. We recommend that a <3 mm side-to-side difference be used to indicate stable knees.

To test the healing of the partially torn anterior cruciate ligament, we transected the posterolateral bundle in 11 adult female goats and tested the ligaments at 12, 24, and 52 weeks and 3 years after surgery. As early as 12 weeks after surgery translucent fibrous tissue covered the wound. The differences in anteroposterior laxity between right and left knees measured at 45° and 90° of flexion were not significantly different at each period. Results of Instron testing of the posterolateral bundle revealed the normalized changes in load-relaxation and Young's modulus were not significantly different at each period, but the ultimate tensile strength and stiff ness at 3 years were significantly higher than at 12 weeks ( P < 0.05). Failure started at the repair site for the 12-week group, but at 24 and 52 weeks the failure occurred throughout the ligament. At 3 years, the spec imens failed with bony avulsion, indicating the repaired tissue was not the weakest link of the bone-ligament- bone complex. This study shows that under favorable conditions, partial anterior cruciate ligament injuries are capable of repair. What is more important, the high ultimate tensile strength and stiffness of the 3-year repaired tissue indicate full structural repair of such an artificial transection injury may be possible.

During a collaborative review at three institutions, we documented 19 cases of stress fractures of the ribs in golfers. There were 13 men and 6 women with an average age of 39 years (range, 29 to 51). The 4th to 6th ribs were the most commonly injured. All fractures occurred along the posterolateral aspect of the ribs, and nine patients had fractures in more than one rib. Sixteen golfers sustained injury on the leading arm side of the trunk. Eighteen golfers were beginners, and the one experienced golfer had dramatically increased his practice time on the driving range before injury. Plain radiographs were usually diagnostic. However, bone scintigraphy was necessary to reach a diagnosis in three cases. A delay in diagnosis of 6 to 8 months occurred in two cases that were originally misdiag nosed as back strains. Stress fractures of the ribs in golfers may be more common than previously realized and may be incorrectly diagnosed as recalcitrant back strains. Based on the findings of other studies, we think fatigue of the serratus anterior is the mechanism of injury. We recommend strengthening the serratus an terior as rehabilitation after this injury and in a general conditioning program for golfers.