Ray A. Moyer

Testing for isometry during reconstruction of the anterior cruciate ligament. Anatomical and biomechanical considerations.

Instrumented tibiofemoral (bone-to-bone) excursion wires were implanted in the mid-substance of the anteromedial, central, and posterior fiber-regions of the anterior cruciate ligament through limited anterior and posterior arthrotomies in eight fresh knees from cadavera. The change in the distance of linear separation between each pair of osseous fiber-insertion sites was measured and was plotted against the angle of flexion of the knee as the knee was cycled through a 120-degree range of motion. Testing conditions likely to be present during intraoperative testing for isometry were used (anterior cruciate fibers transected, quadriceps relaxed, femur stabilized with the patient in the supine position and the leg freely dependent, and motion of the knee induced in neutral rotation by force applied at the level of the foot). In no instance did the insertion-site centers of any fiber-region exhibit isometric behavior (change in the distance of linear separation of 1.0 millimeter or less). The least deviations from isometry (range, 1.4 to 3.1 millimeters) were observed for the anteromedial sites, under conditions when the gravitational dependency of the lower leg was constrained. When the leg hung in a dependent manner during passive motion, the deviation from isometry of the anteromedial sites of insertion increased significantly (range, 2.8 to 5.6 millimeters). The central sites of insertion were generally less isometric than the anteromedial sites, and the posterior sites were the least isometric, regardless of testing conditions.

Biophysical Factors in Range-of-Motion Exercise

In brief: Studies of the physical properties of connective tissue have helped determine improved techniques for therapeutic range-of-motion exercise. Laboratory studies indicate that the best way to permanently lengthen connective tissue structures without compromising their structural integrity is prolonged, low-intensity stretching at elevated tissue temperatures and cooling the tissue before releasing the tension. This article provides some practical therapeutic guidelines for physicians, trainers, and therapists who prescribe range-of-motion exercise for both rehabilitation and physical conditioning.

Accuracy of MRI patterns in evaluating anterior cruciate ligament tears

Abstract The purpose of this study was to determine the different patterns of anterior cruciate ligament (ACL) tears on MRI and the prevalence and accuracy of these patterns. Images were obtained on high-tesla and low-tesla units and the results compared to determine whether field strength affects the interpretation using the grading system. In 172 patients who underwent knee MRI (109 knees with high-tesla units and 63 knees with low-tesla units) and arthroscopy, there was a total of 91 arthroscopically proven ACL tears. Five patterns of ACL tears were observed and designated as type 1 (diffuse increase in signal on T2-weighted images and enlargement of the ligament, 48%); type 2 (horizontally oriented ACL, 21%); type 3 (nonvisualization of the ACL, 18%); type 4 (discontinuity of the ACL, 11%); and type 5 (vertically oriented ACL, 2%). The positive predictive value (PPV) for type 2, 4, and 5 patterns was 100% for both field strengths; for type 3 PPV was just above 80% for both field strengths. The PPV value for type 1 was 90% for the high-tesla unit and 79% for the low-tesla, unit, which was not statistically significant. Combining the results of both field strengths, the overall sensitivity and specificity were 93% and 89%, respectively. Arthroscopic results were also used to determine the association between meniscal and ACL tears. Only 13% of ACL tears were isolated, the rest being associated with meniscal tears. Forty-five percent of medial meniscal and 50% of lateral meniscal tears were associated with an ACL tear, and 94% of ACLs were torn when both menisci were torn.

Anatomy and Kinematics of the Lateral Collateral Ligament of the Knee

The anatomy and kinematics of the lateral collateral ligament were studied in 10 unembalmed limbs and 20 isolated femurs and fibulas. The ligaments average overall length was 66 mm (range, 59 to 74) and the average greatest dimension of its thin middle portion was the anteroposterior dimension of 3.4 mm (range, 3 to 4). The center of the femoral attachment site was 3.7 mm posterior to the ridge of the lateral epicondyle, not at it apex. A potential radiographic technique for operatively locating the femoral attachment site to within 3 mm is described. During knee flexion in neutral rotation the distance between the femoral and fibular attachment sites of the lateral collateral ligament decreased to 88% of its value in full extension. With 6.5 N m of applied external rotation force, beyond 30° of flexion the attachment sites rapidly approximated. With the same internal rotation force, beyond 15° of flexion the attachment sites separated. From 60° to 105° they were greater than 100% of the value in full extension, suggesting significant distraction between the attachment sites. These changes correlated well with the ligaments change from an 11° posterior slope in extension to a 19° anterior slope in flexion with no applied rotation.

Association of Burners with Cervical Canal and Foraminal Stenosis

The purpose of this study was to determine whether the burner phenomenon is associated with cervical canal and foraminal stenosis in a scholastic population. Lateral cervical radiographs were reviewed for 64 athletes, 15 to 18 years of age, who had sustained at least one burner. Controls consisted of age-matched athletes who had sustained head or neck trauma without evidence of the burner phenomenon (N 32). Pavlov ratios were calculated for levels C-3 through C-6; both mean minimum and mean average ratios were determined. Available oblique radiographs from both the study (N 31) and control (N 15) groups were then used to calculate the foramen/vertebral body ratio—a measure of relative foraminal height. Significant differences were found between the burner and control groups for the mean minimum and mean average Pavlov ratios and foramen/vertebral body ratios. Scholastic athletes sustaining the burner phenomenon have an increased risk of cervical canal and foraminal stenosis as measured by the Pavlov and foramen/vertebral body ratios, respectively. The foramen/vertebral body ratio is an easily reproducible and reliable means of assessing foraminal dimensions from oblique radiographs and controls for x-ray magnification and rotation. Foraminal stenosis assessment may prove useful in predicting burner risk, especially in athletes with extension-compression injuries.

Delayed Repair of a Ruptured Pectoralis Major Muscle A Case Report

Repair of a pectoralis major muscle rupture at the tendinous insertion into the humerus was successfully performed 13 years after the initial injury. Repair was possible only because the ruptured sternal portion of the muscle was scarred to the intact clavicular portion and therefore had not retracted. The attachment of the avulsed sternal head to the intact clavicular head enabled successful restoration of strength and function, as well as normal contour and appearance of the pectoralis major muscle complex.

Acute compartment syndrome of the lower extremity secondary to noncontact injury

We retrospectively reviewed the cases of three patients with injuries similar to the mechanism of an ankle sprain which resulted in compartment syndrome of the lower extremity. All three patients presented with sharp, proximal, anterolateral pain in the leg after an indirect, twisting injury. None of the injuries involved direct contact. Two of the three athletes initially presented to local hospitals, where the injury was misdiagnosed as an ankle sprain. The mechanism appears to be a muscle strain or tear with resultant hemorrhage in the compartment. All three patients returned to high-level athletics after prolonged recovery periods.

Delayed Fracture of the Tibia Following Anteromedialization Osteotomy of the Tibial Tubercle A Report of 5 Cases

patients with anterior knee pain and patellofemoral malalignment. The Fulkerson procedure, transfer of the tibial tubercle anteromedially, is indicated in patients with certain types of patellofemoral instability with either concomitant patellar pain or articular degenerative changes. This procedure has favorable results with comparably low complication rates compared with other surgical techniques in the treatment of anterior knee pain. Previously, Bellemans et al and Stetson et al reported fractures to the proximal tibia that occurred no longer than 13 weeks post–Fulkerson procedure, with the average time to fracture occurring approximately 6 weeks postsurgery. The authors recommended a more subdued modification to the rehabilitation process. Patients were urged to either perform protected weightbearing until there is radiographic evidence of healing or refrain from resistance training and impact for at least 8 weeks. We concur with these recommendations and wish to illustrate that the period of fracture vulnerability may exceed several weeks.

Giant synovial cysts

Giant synovial cysts (GSC) are large, well-defined cavities, containing synovial fluid and lined by a synovium-like membrane, which extend for a variable distance outside the joint cavity. We are reporting 15 cases of GSC of various joints. Rheumatoid arthritis is the most common disease process reported in association with GSC. We suggest that trauma may be a more important cause of GSC than has previously been described. Arthrography and ultrasonography are both helpful in diagnosing these large cysts, especially in the knee to aid in differentiating GSC from thrombophlebitis.

Arthroscopic reconstruction of the anterior cruciate ligament with hamstring tendons

The technique of anterior cruciate ligament reconstruction has evolved from an open procedure with augmentation to an arthroscopic procedure. Details of the harvesting of the hamstring tendons, selection of the intra-articular fixation points, means of tendon fixation, and postoperative rehabilitation are presented.