Bulletin of the Hospital for Joint Diseases Orthopaedic Institute最新文献

Two commercial adhesive preparations--fibrin glue and mussel adhesive protein (MAP)--were tested in-vivo for their ability to fix a chondrocyte allograft internally. While results for the fibrin, including additional testing for chondro inductive/conductive properties, were at best inconclusive, the results for MAP are highly promising.

Metal ions have various and significant effects on the skeletal system. Aluminum accumulation in renal dialysis patients causes osteomalacia, while gallium is an effective therapeutic agent for treating the hypercalcemia accompanying certain malignancies. Using in-vitro systems that stimulate in-vivo mineralization, the authors have investigated the physical-chemical mechanisms of the actions of aluminum and gallium and report some of their findings.

Infection following total knee arthroplasty can be one of the most challenging problems in orthopaedic surgery. This article discusses the pertinent clinical factors to be considered and the treatment options in the management of patients with infection following total knee replacement.

A case of a dissociation of a metal-backed patellar component with a resultant metallic synovitis is presented. The mechanism of failure is discussed and an analysis of patellar component design is reviewed.

A new triaxial dynamometer to quantify the performance of trunk muscles has been developed, and a study was conducted to determine the best control parameters to use with this triaxial isodynamic mode of testing. Nine male subjects were tested at three resistance levels in the sagittal, coronal, and transverse planes. The purpose was to establish the reproducibility of the performance parameters in each plane at all resistance levels, and to identify those parameters which gave the most reliable information for objective assessment of the low back functional state. Measured torque had the highest reproducibility rate, and the most reliable assessments were obtained at the highest resistance level.

A rigid constructionist view of Wolff's trajectorial theory of trabecular architecture, called the "orthodox theory," requires that the trabeculae of cancellous bone intersect at right angles exactly like the stress trajectories with which they are associated by the theory. It is well established that trabeculae do not always intersect at right angles. The author discusses the fallacy in the orthodox interpretation of Wolff's law, and suggests that a "resolution length restriction" be imposed on the trajectorial theory to avoid interpretations that lead to the fallacy.

A case of Nocardia asteroides infection of a hip prosthesis in a nonimmunocompromised patient is presented. The infection developed soon after the operation, and did not respond to empiric treatment by multiple antimicrobial drugs. Reoperation and removal of the prosthesis was necessary. The authors found no previous cases of nocardiosis complicating arthroplasty reported in the literature.

Heterotopic ossification (HO) status post total hip arthroplasty is a relatively common phenomenon with clinical significance in approximately 5% of all cases. Risk factors appear to include males with osteoarthritis, particularly with marked osteophyte formation, and those with ankylosing spondylitis or diffuse idiopathic spinal hyperostosis. Previous hip surgery, or previous ectopic bone in the same or contralateral hip are definite predisposing factors. Although meticulous surgical technique is critical in any operation, the suggestions that carelessness in dissection or tissue handling, or inadequate hemostasis or debridement of devitalized tissues or of bony debris can cause HO are unproved. Similarly, there is no solid evidence that the surgical approach, prosthesis type, use of trochanteric osteotomy, or the presence of cement influence the incidence of HO. Whether postoperative complications such as infection, dislocation, or hematoma are causally related is speculative; and the role of alkaline phosphatase in predicting those at risk remains controversial. Despite the number of studies designed to elucidate risk factors, critical analysis suggests that this question remains largely unanswered and that there is a need for well-designed, prospective, controlled studies to determine which hip arthroplasty patients are at risk. Treatment of established HO depends upon recognizing the "maturity" of the ectopic bone, which can best be determined by serial scans but is approximately one year postop. Excision followed by prompt initiation of radiotherapy or of one of several reported nonsteroidal anti-inflammatory drug protocols will produce successful results in a majority of cases. Prophylaxis depends upon recognizing those at significant risk and initiating the appropriate protocol within the first few postoperative days.

A loading or "balance" point was sought that could serve as a functional reference for mechanically testing spinal motion segments. This point is located above the in-vitro motion segment where, when an axial compressive load is applied, the segment exhibits minimal coupled rotation. The balance point is a reliable indicator of the mechanical characteristics of the segment. Segments exhibited increasing rotation as axial compressive loads were applied further and further away from the balance point. The location of the balance point was significantly affected by sustained static or cyclic flexion-compression loading and by brief flexion-compression overloads.