Thomas J. Gill

Anatomical Glenoid Reconstruction for Recurrent Anterior Glenohumeral Instability With Glenoid Deficiency Using an Autogenous Tricortical Iliac Crest Bone Graft

Background Anterior shoulder instability associated with severe glenoid bone loss is rare, and little has been reported on this problem. Recent biomechanical and anatomical studies have suggested guidelines for bony reconstruction of the glenoid. Hypothesis Anatomical glenoid reconstruction will restore stability in shoulders with recurrent anterior instability owing to glenoid bone loss. Study Design Case series; Level of evidence, 4. Methods Eleven cases of traumatic recurrent anterior instability that required bony reconstruction for severe anterior glenoid bone loss were reviewed. In all cases, the length of the anterior glenoid defect exceeded the maximum anteroposterior radius of the glenoid based on preoperative assessment by 3-dimensional CT scan. Surgical reconstruction was performed using an intra-articular tricortical iliac crest bone graft contoured to reestablish the concavity and width of the glenoid. The graft was fixed with cannulated screws in combination with an anterior-inferior capsular repair. Results At mean follow-up of 33 months, the mean American Shoulder and Elbow Surgeons score was 94, compared with a preoperative score of 65. The University of California, Los Angeles score improved to 33 from 18. The Rowe score improved to 94 from a preoperative score of 28. The mean motion loss compared with the contralateral, normal shoulder was 7° of flexion, 14° of external rotation in abduction, and one spinous process level for internal rotation. All patients returned to preinjury levels of sport, and only 2 complained of mild pain with overhead sports activities. No patients reported any recurrent instability (dislocation or subluxation). The CT scans with 3-dimensional reconstructions obtained 4 to 6 months postoperatively demonstrated union of the bone graft with incorporation along the anterior glenoid rim and preservation of joint space. Conclusion Anatomical reconstruction of the glenoid with autogenous iliac crest bone graft for recurrent glenohumeral instability in the setting of bone deficiency is an effective form of treatment for this problem.

Bankart Repair for Anterior Instability of the Shoulder. Long-Term Outcome*†

Anterior instability of the shoulder is a commonly encountered entity in orthopaedic practice. The Bankart procedure is considered by many surgeons to be the treatment of choice for this condition. Despite its widespread popularity, there have been no studies on the long-term outcome of the Bankart procedure as far as we know. Sixty shoulders (fifty-six patients) that had been followed for a minimum of eight years after a Bankart procedure were evaluated for range of motion, stability, and strength according to the data form of the American Shoulder and Elbow Surgeons for examination of the shoulder. The results for the involved shoulder were compared with the findings for the contralateral, normal shoulder. All patients completed a questionnaire regarding the history of the instability of the shoulder, the level of participation in sports before and after the operation, the preoperative and postoperative level of pain, and whether the patient had ever sustained a dislocation that needed reduction by a physician. Information about the current ability of the patient to function at home, at work, and during sports also was requested. In addition, the patients were asked to rate the results of the operation and to indicate whether they would have the same procedure again for the same problem. At a mean of 11.9 years after the operation, the mean loss of external rotation was 12 degrees (range, 0 to 30 degrees) (p < 0.0001). There were no significant differences in forward elevation, abduction, or internal rotation between the involved shoulder and the contralateral, normal shoulder. One patient had crepitus on glenohumeral motion. Fifty-five of the fifty-six patients returned to the occupation that they had had preoperatively, without having to alter their activities. Twenty-eight patients had mild pain with strenuous activity, and one patient had pain at rest. Three patients had a dislocation of the involved shoulder because of a new traumatic event more than three years postoperatively. Fifty-two patients rated the result as good or excellent; three, as fair; and one, as poor. Fifty-four patients said that they would have a Bankart procedure performed again for the same problem. We present a new system for rating the shoulder that emphasizes function and is based specifically on the goals stated by the patients to be most important with regard to the shoulder. Using this system, we found that the Bankart procedure offers an excellent objective long-term outcome with a high degree of patient satisfaction.

The 6 Degrees of Freedom Kinematics of the Knee After Anterior Cruciate Ligament Deficiency An In Vivo Imaging Analysis

Background Previous studies of knee joint function after anterior cruciate ligament deficiency have focused on measuring anterior-posterior translation and internal-external rotation. Few studies have measured the effects of anterior cruciate ligament deficiency on 6 degrees of freedom knee kinematics in vivo. Objective To measure the 6 degrees of freedom knee kinematics of patients with anterior cruciate ligament deficiency. Study Design Controlled laboratory study. Methods The knee joint kinematics of 8 patients with unilateral anterior cruciate ligament rupture was measured during a quasi-static lunge. Kinematics was measured from full extension to 90° of flexion using imaging and 3-dimensional modeling techniques. The healthy, contralateral knee of each patient served as a control. Results Anterior cruciate ligament deficiency caused a statistically significant anterior shift (approximately 3 mm) and internal rotation of the tibia (approximately 2°) at low flexion angles. However, ligament deficiency also caused a medial translation of the tibia (approximately 1 mm) between 15° and 90° of flexion. Conclusion The medial shift of the tibia after anterior cruciate ligament deficiency might alter contact stress distributions in the tibiofemoral cartilage near the medial tibial spine. These findings correlate with the observation that osteoarthritis in patients with anterior cruciate ligament injuries is likely to occur in this region. Clinical Relevance The data from this study suggest that future anterior cruciate ligament reconstruction techniques should reproduce not only anterior stability but also medial-lateral stability.

In Vivo Kinematics of the Knee After Anterior Cruciate Ligament Reconstruction A Clinical and Functional Evaluation

Background Recent follow-up studies have reported a high incidence of joint degeneration in patients with anterior cruciate ligament reconstruction. Abnormal kinematics after anterior cruciate ligament reconstruction have been thought to contribute to the degeneration. Hypothesis Anterior cruciate ligament reconstruction, which was designed to restore anterior knee laxity under anterior tibial loads, does not reproduce knee kinematics under in vivo physiological loading conditions. Study Design Controlled laboratory study. Methods Both knees of 7 patients with complete unilateral rupture of the anterior cruciate ligament were magnetic resonance imaged, and 3D models were constructed from these images. The anterior cruciate ligament of the injured knee was arthroscopically reconstructed using a bone–patellar tendon–bone autograft. Three months after surgery, the kinematics of the intact contralateral and reconstructed knees were measured using a dual-orthogonal fluoroscopic system while the subjects performed a single-legged weightbearing lunge. The anterior laxity of both knees was measured using a KT-1000 arthrometer. Results The anterior laxity of the reconstructed knee as measured with the arthrometer was similar to that of the intact contralateral knee. However, under weightbearing conditions, there was a statistically significant increase in anterior translation of the reconstructed knee compared with the intact knee at full extension (approximately 2.9 mm) and 15° (approximately 2.2 mm) of flexion. In addition, there was a mean increase in external tibial rotation of the anterior cruciate ligament–reconstructed knee beyond 30° of flexion (approximately 2° at 30° of flexion), although no statistical significance was detected. Conclusion The data demonstrate that although anterior laxity was restored during KT-1000 arthrometer testing, anterior cruciate ligament reconstruction did not restore normal knee kinematics under weightbearing loading conditions. Clinical Relevance Future reconstruction techniques should aim to restore function of the knee under physiological loading conditions.

Anterior Cruciate Ligament Deficiency Alters the In Vivo Motion of the Tibiofemoral Cartilage Contact Points in Both the Anteroposterior and Mediolateral Directions

BACKGROUND Quantifying the effects of anterior cruciate ligament deficiency on joint biomechanics is critical in order to better understand the mechanisms of joint degeneration in anterior cruciate ligament-deficient knees and to improve the surgical treatment of anterior cruciate ligament injuries. We investigated the changes in position of the in vivo tibiofemoral articular cartilage contact points in anterior cruciate ligament-deficient and intact contralateral knees with use of a newly developed dual orthogonal fluoroscopic and magnetic resonance imaging technique. METHODS Nine patients with an anterior cruciate ligament rupture in one knee and a normal contralateral knee were recruited. Magnetic resonance images were acquired for both the intact and anterior cruciate ligament-deficient knees to construct computer knee models of the surfaces of the bone and cartilage. Each patient performed a single-leg weight-bearing lunge as images were recorded with use of a dual fluoroscopic system at full extension and at 15 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion. The in vivo knee position at each flexion angle was then reproduced with use of the knee models and fluoroscopic images. The contact points were defined as the centroids of the areas of intersection of the tibial and femoral articular cartilage surfaces. RESULTS The contact points moved not only in the anteroposterior direction but also in the mediolateral direction in both the anterior cruciate ligament-deficient and intact knees. In the anteroposterior direction, the contact points in the medial compartment of the tibia were more posterior in the anterior cruciate ligament-deficient knees than in the intact knees at full extension and 15 degrees of flexion (p < 0.05). No significant differences were observed with regard to the anteroposterior motion of the contact points in the lateral compartment of the tibia. In the mediolateral direction, there was a significant lateral shift of the contact points in the medial compartment of the tibia toward the medial tibial spine between full extension and 60 degrees of flexion (p < 0.05). The contact points in the lateral compartment of the tibia shifted laterally, away from the lateral tibial spine, at 15 degrees and 30 degrees of flexion (p < 0.05). CONCLUSIONS In the presence of anterior cruciate ligament injury, the contact points shift both posteriorly and laterally on the surface of the tibial plateau. In the medial compartment, the contact points shift toward the medial tibial spine, a region where degeneration is observed in patients with chronic anterior cruciate ligament injuries.

Injuries in women’s professional soccer

Objective: The injury data from the first two seasons of the Women’s United Soccer Association (WUSA) were analysed to determine the injury incidence, anatomic location of injuries, and relation of player position. Methods: Injury data on 202 players from eight teams during the first two seasons of the WUSA were prospectively collected and analysed. Results: A total of 173 injuries occurred in 110 players with an overall injury incidence rate of 1.93 injuries per 1000 player hours. The incidence of injury during practice and games was 1.17 and 12.63 per 1000 player hours, respectively. Of the injuries 82% were acute and 16% were chronic. Most of the injuries (60%) were located in the lower extremities. Strains (30.7%), sprains (19.1%), contusions (16.2%), and fractures (11.6%) were the most common diagnoses and the knee (31.8%) and head (10.9%) were the most common sites of injury. Anterior cruciate ligament (ACL) injuries accounted for 4.6% of all injuries and the incidence of ACL tears was 0.09 per 1000 player hours (practice 0.04, game 0.90). Midfielders suffered the most injuries (p<0.007). Conclusion: We conclude that the injury incidence in the WUSA is lower than the 6.2 injuries per 1000 player hours found in the corresponding male professional league (Major League Soccer); however, knee injuries predominate even in these elite female athletes.

In Vivo Articular Cartilage Contact Kinematics of the Knee An Investigation Using Dual-Orthogonal Fluoroscopy and Magnetic Resonance Image–Based Computer Models

Background Quantifying the in vivo cartilage contact mechanics of the knee may improve our understanding of the mechanisms of joint degeneration and may therefore improve the surgical repair of the joint after injury. Objective To measure tibiofemoral articular cartilage contact kinematics during in vivo knee flexion. Study Design Descriptive laboratory study. Methods Orthogonal fluoroscopic images and magnetic resonance image–based computer models were used to measure the motion of the cartilage contact points during a quasi-static lunge in 5 human subjects. Results On the tibial plateau, the contact point moved in both the anteroposterior and the mediolateral directions during knee flexion. On the medial tibial plateau, flexion angle did not have a statistically significant effect on the location of the contact points. The total translation of the contact point from full extension to 90° of flexion was less than 1.5 mm in the anteroposterior direction, whereas the translation in the mediolateral direction was more than 5.0 mm. In the anteroposterior direction, the contact points were centered on the medial tibial plateau. On the lateral tibial plateau, there was a statistically significant difference between the location of the contact point at full extension and the locations of the contact points at other flexion angles in the anteroposterior direction. No significant difference was detected between the location of the contact points at other flexion angles. The overall range of contact point motion was about 9.0 mm in the anteroposterior direction and about 4.0 mm in the mediolateral direction. The contact points were primarily on the inner half of the medial and lateral tibial plateaus (the half closest to the tibial spine). The contact points on both femoral condyles were also on the inner half of the condyles (near the condylar notch). Conclusions The tibiofemoral contact points move in 3 dimensions during weightbearing knee flexion. The medial tibiofemoral contact points remained within the central portion of the tibial plateau in the anteroposterior direction. Both the medial and lateral tibiofemoral contact points were located on the inner portions of the tibial plateau and femoral condyles (close to the tibial spine), indicating that the tibial spine may play an important role in knee stability. Clinical Relevance The results of this study may provide important insight as to the mechanisms contributing to the development of osteoarthritis after ligament injuries.

Surgical dislocation of the adult hip

Surgical dislocation of the hip is rarely undertaken. The potential danger to the vascularity of the femoral head has been emphasised, but there is little information as to how this danger can be avoided. We describe a technique for operative dislocation of the hip, based on detailed anatomical studies of the blood supply. It combines aspects of approaches which have been reported previously and consists of an anterior dislocation through a posterior approach with a ‘trochanteric flip’ osteotomy. The external rotator muscles are not divided and the medial femoral circumflex artery is protected by the intact obturator externus. We report our experience using this approach in 213 hips over a period of seven years and include 19 patients who underwent simultaneous intertrochanteric osteotomy. The perfusion of the femoral head was verified intraoperatively and, to date, none has subsequently developed avascular necrosis. There is little morbidity associated with the technique and it allows the treatment of a ...

Relationships between Throwing Mechanics and Shoulder Distraction in Professional Baseball Pitchers

The extreme forces and torques and the high speeds and excessive ranges of motion of baseball pitching place tremendous stress on the soft tissues of the throwing shoulder. Little is known about the relationship between pitching mechanics and shoulder joint stress, especially in professional athletes. The purpose of this study was to quantify joint loads and kinematic parameters of pitching mechanics at the major league level and to study their relationships. Three-dimensional, high-speed video data were collected on 40 professional pitchers during the 1998 Cactus League spring training. A clinically significant distraction force was calculated at the shoulder joint, which reached an average peak value of 947±162 N (108%±16% body weight). Descriptive statistics and a multiple linear regression analysis were used to relate shoulder distraction to kinematic and kinetic parameters of pitching mechanics. This study was undertaken not only to investigate the peak forces and torques on the shoulder, but also to identify potential areas of intervention that might prevent throwing injuries. Knowledge of joint ranges of motion, angular velocities, and joint-reaction forces can provide a scientific basis for improved preventive and rehabilitative protocols for baseball pitchers.

Cell-Based Therapy for Meniscal Repair A Large Animal Study

Background The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously. Hypothesis Cell-based therapy is able to repair a lesion in the swine meniscus. Study Design Controlled laboratory study. Methods Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the avascular portion of the left medial meniscus of 4 pigs. Autologous chondrocytes were seeded onto devitalized allogenic meniscal slices and were secured inside the lesion with two sutures. Identical incisions were created in 12 other pigs, which were used as three separate control groups: 4 animals treated with an unseeded scaffold, 4 were simply sutured, and 4 were left untreated. Meniscal samples were collected after 9 weeks, and the samples were analyzed grossly, histologically, and histomorphometrically. Results Gross results showed bonding of the lesion margins in the specimens of the experimental group, whereas no repair was noted in any of the control group specimens. Histological and histomorphometrical analysis showed multiple areas of healing in the specimens of the experimental group. Conclusions This study demonstrated the ability of seeded chondrocytes to heal a meniscal tear. Clinical Relevance Cell-based therapy could be a potential tool for avascular meniscus repair.