Biodegradable interference screw augmentation reduces tunnel expansion after ACL reconstruction.

This study assessed 40 patients who underwent anterior cruciate ligament reconstruction with hamstring autografts using our standard technique. Twenty patients underwent tibial fixation augmentation with a biodegradable interference screw, and the remaining 20 patients did not. Patient groups were compared using radiographic evaluation of bone tunnel diameter, physical examination, and arthrometer measurements. The two groups differed in only one way: the placement of the tibial biodegradable interference screw. Biodegradable interference screw augmentation resulted in decreased distal tibial and some femoral tunnel diameters at both 3- and 12-month follow-up. There was no significant difference in the Lachman and arthrometer testing in either group of patients at the termination of this study. These results indicate that although distal tibia tunnel diameter reduction is significant, it does not appear to have any clinical significance in the first year.

Patella fracture after anterior cruciate ligament reconstruction with the patellar tendon: a comparison between different shaped bone block excisions.

Tensile failure of a patella after anterior cruciate ligament (ACL) reconstruction with autogenous patellar tendon graft is an uncommon but serious complication. One factor that may affect post-harvest patella strength is the shape of the bony defect. The effect of patella defect shape on ultimate tensile strength and mode of failure of the extensor mechanism has not been studied using physiologic moments. Twelve matched pair knee specimens were randomly distributed within three groups comparing rectangular versus triangular, rectangular versus circular, and circular versus triangular shaped patella defects. Specimens were loaded in tension to failure using physiologic moments. Patella fracture occurred in 21 of 24 specimens. Mean ultimate strength for all patellae with a circular defect was 2540 N (+/-651), rectangular defect was 3267 N (+/-920), and triangular defect was 3009 N (+/-1057). There was no significant difference in mean ultimate tensile strength between defect shapes or between matched pairs within the groups. Mode of failure also was similar in all three groups. No defect shape was found to be superior in this investigation comparing ultimate tensile strength or mode of failure between different shaped patella defects.

Tunnel expansion after hamstring anterior cruciate ligament reconstruction with 1-incision EndoButton femoral fixation.

In this study, we compared a study group of 20 patients who underwent anterior cruciate ligament (ACL) reconstruction with hamstring autografts using a 1-incision endoscopic technique verses a control group of 20 patients using a 2-incision technique. The patient groups were compared based on increase of bone tunnel diameter seen radiographically, physical examination, and arthrometer measurements. The 1-incision technique differed from the 2-incision technique in 2 ways: an EndoButton femoral fixation system and drilling of the femoral tunnel through the tibial tunnel (transtibial). This study shows that the majority of tunnel diameter measurements for the 1-incision ACL reconstruction technique were greater than those of the 2-incision ACL reconstruction technique using autologous hamstring tendons, at both 3 and 12 months of follow-up. Between 3 and 12 months follow-up, there was no statistical differences in tunnel enlargement between the 2 groups of patients. The measured tunnel enlargement, therefore, would have occurred before the 3-month follow-up. There was no significant difference in the Lachman or arthrometer testing in either group of patients at the termination of this study. This indicates that, although tunnel expansion is significant, the increased expansion is not related to increased knee laxity in the first year.

Anterior cruciate ligament injuries in the skeletally immature patient.

Injuries of the anterior cruciate ligament (ACL) in children are more frequent than once thought. Special factors must be taken into consideration when treating ACL injuries in the skeletally immature patient. Risks of surgery must be weighed against potential damage to the knee caused by repeated injury. The authors prefer the use of both tibial and femoral centrally placed drill holes, hamstring tendon autografts, fixation distant from the physis, and avoidance of dissection near the physis. This technique will minimize damage to the physis and should not hinder normal growth.

Arthroscopic treatment of infrapatellar tendonitis.

Infrapatellar tendonitis is a chronic overload lesion in the patellar ligament at the attachment to the lower pole of the patella. This lesion is found primarily in athletes who participate in jumping sports. Magnetic resonance imaging or ultrasound can show the extent of tendon pathology. Patellar tendonitis is treated with modification of activities, medications, and therapy. When conservative measures fail, operative debridement has been recommended. Previous reports have described a technique of open debridement of the patellar tendon, followed by an extended period of rehabilitation before returning to sports. Two athletes with persistent infrapatellar tendonitis were treated with an arthroscopic debridement. Both athletes returned to full activities without restrictions within 8 weeks of surgery. Arthroscopic treatment of infrapatellar tendonitis has not been previously described. This technical note describes the technique and two case reports of the arthroscopic treatment of infrapatellar tendonitis.

Assessment of morbidity of semitendinosus and gracilis tendon harvest for ACL reconstruction.

This study evaluates the morbidity of harvest of both the semitendinosus and gracilis tendons for anterior cruciate ligament reconstruction on nine patients at a minimum of 3 year follow-up. Specifically, the effect on knee function, knee extension and flexion strength, the size of the individual posterior thigh muscles, and the extent of retraction of the semitendinosus and gracilis tendons were evaluated. At final follow-up, each patient was evaluated using the following functional scales: International Knee Documentation Committee (IKDC), Hospital for Special Surgery (HSS), Lysholm, and Tegner. Each patient also had a dynamometer evaluation and a comprehensive magnetic resonance imaging study of both the operated and nonoperated knees. The average functional evaluation scores were: HSS-47.9, Lysholm-88, and Tegner-0.27. The average percent quadriceps and hamstring strength of the operated compared with the nonoperated extremities were 93.7% and 95.3%, respectively; neither decrease was significant. Magnetic resonance imaging evaluation of the cross-sectional areas of the biceps femoris, semimembranosus, and sartorius muscles of both thighs at the same level above the joint were not significantly different. The distal-most insertion of the semitendinosus and gracilis tendons after harvest were always more proximal than the nonoperated side; the average difference was 26.7 mm (range: 11 to 32 mm) for the semitendinosus (unable to calculate in three patients) and 47.1 mm (range: 17 to 72 mm) for the gracilis. We conclude that tendon harvest of the semitendinosus and gracilis muscles does not significantly compromise function and strength despite a more proximal insertion of the retracted tendons. In addition, the majority of cases demonstrated some but never complete regrowth or scar formation of these tendon remnants.

Semitendinosus augmentation of acute patellar tendon repair with immediate mobilization.

We report four cases of acute midsubstance rupture of the patellar tendon that were treated with primary surgical repair along with semitendinosus autograft augmentation. The goal of this treatment was to allow immediate mobilization of the knee with a single operative procedure. We also demonstrate a technique for determining patellar position intraoperatively. Patients were tested for functional performance at an average final followup of 40 months (range, 20 to 66) including hamstring and quadriceps muscle strength evaluation, completion of a functional questionnaire, functional test performance, range of motion assessment, and patellar tendon length measurement. In evaluating the results, all cases were essentially identical to the nonoperated side, except one knee that had multiple associated ligament injuries. The multitude of injuries to this knee are likely the cause of the discrepancy. Immediate midsubstance patellar tendon repair with semitendinosus augmentation allowed immediate mobilization, which decreased the recovery period and improved the outcome of rehabilitation. Furthermore, a second surgery for hardware removal was not needed. These two factors--early and improved rehabilitation and the decreased chance of a second surgery--affect the cost of treatment of this injury. All isolated patellar tendon injuries in the study had excellent function at followup. For these reasons, we recommend this procedure for acute patellar tendon ruptures.

Reliability of the Genucom Knee Analysis System. A pilot study.

Instrumented knee laxity testing is now common practice in many orthopedic and rehabilitative practices around the country. The Genucom Knee Analysis System is marketed as a comprehensive quantitative knee joint laxity testing device. To examine the intrarater reliability of the Genucom, the authors evaluated five normal subjects, each on three independent occasions. All testing was done by a single examiner. Anteroposterior (AP) drawer, valgus/varus, and tibial rotation tests were performed. The average variability for repeated testing was determined and this variability was then used to estimate the smallest statistically significant difference for a single repeat examination that would represent true change, i.e., change over and above the inherent variability of the measurement. The results indicate that: (1) anterior drawer variability and tibial rotational variability are dependent on the knee flexion angle; (2) reporting anterior drawer may be more reproducible than reporting total AP motion; and (3) on average, changes exceeding 3 mm for anterior drawer tests, 5 mm for total valgus-varus motion, and 7 degrees-17 degrees of tibial rotation are needed to be 95% confident that the change in a measure from one time to the next is real and not due to measurement variability.

Tibial rotation in anterior cruciate deficient knees: an in vitro study.

The role of the anterior cruciate ligament in controlling tibial rotation was evaluated in four cadavera knee joints. Tibial rotation and anterior drawer tests were performed at multiple angles of knee flexion both before and after arthroscopic surgical section of the anterior cruciate ligament. Measurements were made using an instrumented electrogoniometer and force transducer system (GenucomTM). The results suggest that under clinically applied loads, rotation of the tibia is not constrained by the anterior cruciate ligament. The results also indicate an interpretation for anterior drawer tests when accompanied by an imposed tibial rotation. J Orthop Sports Phys Ther 1989;11(4):146-149.

Ligament length relationships in the moving knee.

This article presents an investigation of potential ligament attachment sites for surgical reconstruction of the anterior and posterior cruciate ligaments as well as for the lateral extraarticular iliotibial band tenodesis. Our methodology was based on quantitative measurements of knee anatomy and motion in fresh cadavers, not on biomechanical modeling. Using computer search techniques, we located all the ligament insertion sites that were nearly isometric for motion of the intact knee.

High resolution sonography of the menisci of the knee.

High-resolution real-time ultrasonography (5, 7.5, and 10 MHz) was used to examine the menisci of the knee in ten normal volunteers and in ten patients with knee injuries. The posterior horns of the medial and lateral menisci were easily demonstrated. Normal anatomy and pathologic changes could be imaged in the menisci, capsular ligaments, and articular cartilage. While the menisci were seen in all subjects, the weight-bearing portion of the femoral articular cartilage could not be seen in several of the symptomatic patients who could not flex their knees. Ultrasound promises to be a useful, noninvasive adjunct to conventional techniques in evaluating the injured knee--especially in assessing the posterior horns of the menisci, an area difficult to assess with arthroscopy.