Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera.

The purpose of our study was to describe the gross anatomy of the adult acetabular labrum and to determine its contribution to the depth, surface area, and volume of the acetabulum. Fifty-five embalmed hips were studied. Each hip was disarticulated, and standardized measurements were taken. Calculations of the acetabular articulating surface area and volume, with and without the labrum, were performed based on these measurements. Average width of the acetabular labrum was 5.3 mm (SD, 2.6 mm). The labrum was wider anteriorly and superiorly than posteriorly. The surface area of the acetabulum without the labrum was 28.8 cm2; with the labrum, it was 36.8 cm2 (P < .0001). The volume of the acetabulum without the labrum was 31.5 cm3; with the labrum, it was 41.1 cm3 (P < .0001). There was no side-to-side difference in contribution of the labrum to either surface area or volume between right and left hips. Comparison of these indices for males and females showed statistically significant differences in absolute but not relative increases.

Surgical treatment of combined injury to anterior cruciate ligament, posterior cruciate ligament, and medial structures.

Injuries involving the anterior cruciate, posterior cruciate, and medial collateral ligaments represent one combination of injuries representing knee dislocation. Prompt reduction and neurovascular evaluation are necessary when treating these injuries. Operative management involving reconstruction and repair of the injured structures produces optimal results. This article outlines the principles involved in evaluating and managing these injuries, combined with specifics of the authors' treatment approach, and review of the literature.

Revision total hip arthroplasty in patients with avascular necrosis.

This retrospective study compared the results of revision total hip arthroplasty (THA) in patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

The acromioclavicular capsule as a restraint to posterior translation of the clavicle: a biomechanical analysis.

Excessive posterior translation of the residual clavicle after distal clavicle resection can be associated with significant postoperative pain. Although the acromioclavicular capsule has been identified as the primary restraint to translation of the clavicle along this axis, the individual contributions of the anterior, posterior, superior, and inferior components of the capsular ligament have not been established. The purpose of this study was to define the relative roles of the individual acromioclavicular capsular ligaments in preventing posterior translation of the distal clavicle in normal acromioclavicular joints in a human cadaver model. Six fresh-frozen human cadaveric acromioclavicular joints were mounted on a specially designed apparatus which, when attached to a standard servohydraulic materials testing device, allowed translation of the distal clavicle along the anteroposterior axis of the acromioclavicular joint (i.e., parallel to the articular surface). Resistance to posterior displacement was measured for standardized displacements in the normal specimens and after serial sectioning of each of the acromioclavicular ligaments was performed. Sectioning of the anterior and inferior capsular ligaments had no significant effect on posterior translation at the 5% significance level. However, sectioning of the superior and posterior ligaments had statistically significant effects (P < .05). These capsular structures contributed 56% +/- 23% (+/- SEM) and 25% +/- 16%, respectively, of the force required to achieve a given posterior displacement. To avoid excessive posterior translation of the clavicle after distal clavicle excision, surgical techniques that spare the posterior and superior acromioclavicular capsular ligaments should be used.

Mechanism for superior subluxation of the glenohumeral joint in fibrodysplasia ossificans progressiva.

Progressive heterotopic ossification leads to ankylosis of the major joints in patients who have fibrodysplasia ossificans progressiva. Joint subluxation has not been recognized widely in patients with this disease. The clinical records and radiographs of 79 patients with fibrodysplasia ossificans progressiva were reviewed and, it was found that humeral to chest wall synostosis and subluxation of the glenohumeral joint had occurred in 21% of skeletally immature patients and in 74% of skeletally mature patients. In fibrodysplasia ossificans progressiva, synostosis of the humeral shaft to the chest wall commonly occurs by 7 years of age, well before the age of proximal physeal closure. The continued growth of the proximal humeral physis in the presence of a humeral to chest wall synostosis causes the humeral head to migrate superiorly, thus promoting growth related subluxation. The clinical significance of this finding for patients who have fibrodysplasia ossificans progressiva is unknown, but this unique model will be useful in the study of shoulder biomechanics and growth plate physiology.

A new in vivo technique for three-dimensional shoulder kinematics analysis.

OBJECTIVE: The field of shoulder kinematics research has long relied upon the use of cadaveric models or invasive techniques in human volunteers. In this paper, a novel method is presented that utilizes magnetic resonance imaging (MRI) and a software system called 3DVEWNIX. This method permits non-invasive, repetitive evaluation of living patients for glenohumeral kinematics analysis. The objectives of this study were twofold: to validate the quantitative accuracy of this technique; and to demonstrate glenohumeral relationships in asymptomatic volunteers during internal and external rotation of the arm. DESIGN: The translational accuracy was first assessed by comparing known cadaveric glenohumeral translations with calculations from MR images of the cadaver. Nine asymptomatic volunteers were subsequently placed in an external shoulder positioning device in the scanner and imaged in 10 degrees increments of actively achieved internal and external rotation. Three-dimensional reconstructions of the glenoid and humerus were used to evaluate the glenohumeral relationships in the tested positions of rotation. RESULTS: The quantitative analysis revealed an error of 0.61 mm (SEM 0.11 mm). Examination of the volunteers demonstrated normal relationships about the glenohumeral joint in internal and external rotation. In addition, this method provided detailed images of the bony surface architecture from any perspective. These images can be transformed into a cinematic three-dimensional depiction of active shoulder rotation. CONCLUSION: This new technique offers an accurate, non-invasive method for assessing the normal glenohumeral relationships in shoulder kinematics. We now possess the capability to investigate the kinematics of normal and abnormal shoulder conditions non-invasively in a large patient population.

Impact of CT scan on treatment plan and fracture classification of tibial plateau fractures.

OBJECTIVE: To evaluate the interobserver and intraobserver agreement for both treatment plan and fracture classification of tibial plateau fractures using plain films alone and with computed tomography (CT) scans. DESIGN: Prospective study to assess the impact of an advanced radiologic study on the agreement of treatment plan and fracture classification of tibial plateau fractures. SETTING/PARTICIPANTS: Two orthopaedic traumatologists, two orthopaedic residents, and two skeletal radiologists were presented with twenty-one cases of tibial plateau fractures imaged with plain films and with CT scans. MAIN OUTCOME MEASURES: Agreement was measured using kappa coefficients. RESULTS: Using plain films alone, the mean interobserver kappa coefficient for classification was 0.62, which decreased to 0.61 after addition of CT scans. Using plain films alone for formulating a treatment plan, the mean interobserver kappa coefficient was 0.58, which increased to 0.71 after addition of CT scans. The mean intraobserver kappa coefficient for fracture classification using plain films was 0.70, which increased to 0.80 with addition of CT scans. The mean intraobserver kappa coefficient for treatment plan based on plain films alone was 0.62, which increased to 0.82 after addition of CT scans. Class was changed in an average of 12 percent of cases after addition of CT scans. Treatment plan was changed an average of 26 percent of the time after addition of CT scans. CONCLUSION: Addition of CT scans to plain roentgenograms increases the interobserver and intraobserver agreement on treatment plan.

Compartment syndrome after isolated perfusion of the leg: a case report.

The authors present a case of a lower leg compartment syndrome that developed after a regional chemotherapy technique was used for recurrent melanoma of the foot in a 74-year-old woman. The diagnosis was based on the results of physical examination, with confirmation by intracompartmental pressures. Prompt consultation of orthopedic surgeons and fasciotomy helped avoid potentially crippling sequelae.