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In recent years, metal-on-metal (MoM) orthopaedic implants have been associated with significant adverse tissue reactions, prompting revision surgeries and recalls by manufacturers. Adverse tissue reactions consist of a wide range of pathologic findings but are generally characterized by a histiocytic reaction to metal debris, with or without an inflammatory response. Inflammation is generally that of a lymphocytic infiltration that prompts concern of an immune reaction. Only occasionally have eosinophils been documented-never as a marked infiltrate. In this article, we present the first histologic description of a dominant eosinophilic infiltrate associated with MoM arthroplasty. In our case report, the patient is a 53-year-old woman who presented with recurrent fluid collections surrounding the hip after a MoM total hip arthroplasty. At the time of surgical revision, tissue samples were taken and found to consist of lymphocytes and a prominent infiltrating eosinophilia. To our knowledge, no factors predictive of this type of tissue response have been identified, and its significance remains unclear despite ongoing research about the nature of the immune response to metal. Future work may help to elucidate whether the type and significance of this response can be predicted preoperatively and modulated, if necessary, postoperatively.

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We present the case report of a 35-year-old man with Gorham's disease (disappearing bone disease, massive osteolysis) with initial clinical findings of small bowel lymphangiomatosis and multicentric osteolysis. The patient, who otherwise was healthy, had a chylothorax develop and he died 9 months later of thoracic and pulmonary complications. An autopsy revealed absence of the proximal thoracic duct and significant lymphangiectatic abnormalities of the pleural, peritoneal, diaphragmatic, splenic, and small bowel tissue with lymphangiomatous masses in the thoracic and mediastinal regions. The findings suggest a subtype of Gorham's disease characterized by a dysplastic lymphatic system. Osteolysis was correlated anatomically with lymphangiectatic tissue, suggesting mediation of osteoclastic resorption via local lymphatic tissue factors.

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Carpal tunnel syndrome is one of the most commonly diagnosed disorders of the upper extremity. The etiology of the neuropathy is known to be associated with many disorders, with the etiology of carpal tunnel syndrome mainly attributable to ischemia of the median nerve. The purpose of this study was to determine the presence of neural elements within the transverse carpal ligament. Fourteen transverse carpal ligaments were harvested from seven male and seven female fresh frozen cadavers with an average age of 76 years. The tissues were stained with S-100 using a standard immunoperoxidase technique used to localize neural tissue. The transverse carpal ligament consisted of interwoven bundles of fibrous connective tissue. It was found to have an intraligamentous and extraligamentous neural network consisting mostly of free nerve endings and pacinian corpuscles. Ruffini's corpuscles were not identified. This study showed that there is neural innervation to the transverse carpal ligament. Pacinian corpuscles have been shown to be mechanoreceptors which respond to changes in joint position, whereas free nerve endings have been identified as nociceptors. Neural innervation were present in the transverse carpal ligament, and the nociceptive information relayed by these neural elements may contribute to the pain associated with carpal tunnel syndrome. In addition to being a mechanical wrist stabilizer, the transverse carpal ligament also may play a role in proprioception of the wrist.

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BACKGROUND: We previously demonstrated short-term effects of intra-articular lead on joint structures in an animal model. We now present histopathologic findings in animals studied over a more extended period. METHODS: Twelve female New Zealand White rabbits had identical lead or stainless steel pellets, or a sham arthrotomy (without implant) inserted in both front knees. The rabbits were killed 4 at a time at 6, 10, and 14 weeks after implantation, and the knee joint structures were evaluated histologically for changes in the synovium, articular cartilage, and meniscus. RESULTS: Histology of the tibial articular surface, femoral articular surface, medial meniscus, lateral meniscus, and synovium showed greater signs of degeneration in the knees with lead implants than controls at all time periods. CONCLUSION: Intrasynovial lead, which does not undergo fibrous encapsulation, has been linked to lead intoxication. Clinical and experimental reports support removal of lead bodies from articular areas in an attempt reduce or slow the degeneration of affected joints. Nonmechanical effects of lead on intraarticular structures may lead to degenerative changes

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Twenty-four posterior cruciate ligaments (PCLs) harvested at the time of total knee arthroplasty (TKA) were histologically compared with an age-matched group of 36 PCLs harvested from above-knee amputations, cadavers, and bone bank donors. Ligaments were considered histologically abnormal and degenerative if either loose, mucoid, myxoid, or cystic changes were noted. The magnitude of degeneration was defined as normal, slight, mild, moderate, or marked, based on the amount of tissue demonstrating change. Examination of the PCLs from the TKA group demonstrated 17% normal ligaments, 20% with mild focal changes, and 63% with marked degenerative changes. The control group demonstrated 45% normal cruciate ligaments and 33% with slight, 11% with mild, and 11% with moderate focal changes. No PCL from the control group showed marked changes. The overall degenerative changes between these two groups were found to be statistically significant (P < .001). This study demonstrated that the PCL obtained at the time of TKA is characterized by distinct histologic degenerative changes that are different from age-related changes (P < .001) and that the PCL is not spared degenerative changes in involved osteoarthritic knees. This may help explain the finding that the PCL in osteoarthritic knees is biomechanically abnormal. Many studies have reported excellent results with TKA systems that retain the PCL, implying that a completely normal PCL is not required or that neural input is sufficient for proper kinematic knee function in knees that have undergone total joint arthroplasty.

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Subacromial decompression is one of the most commonly performed shoulder procedures. Debridement of the subacromial soft tissues is a critical part of the procedure. However, the extent of soft tissue debridement is not well defined. The purpose of this study was to identify neural elements within the soft tissues composing the subacromial space. Using special immunohistochemical stains and electron microscopy, neural elements were identified within the subacromial bursa, rotator cuff tendon, biceps tendon and tendon sheath, and transverse humeral ligament. There was a significantly richer supply of free nerve fibers in the bursa compared with the other tissues. The nociceptive information relayed by these fibers may be responsible for the pain associated with impingement syndrome.

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OBJECTIVE: To study the effects of intra-articular lead fragments on articular cartilage, synovium, and menisci in rabbit knees. DESIGN: Animal model. MATERIALS AND METHODS: Cylindrical lead implants were inserted into a nonarticulating area of the medial femoral condyle. Identically sized stainless steel implants were used as a control for the mechanical effects of the material, and arthrotomies were performed on some of the animals as a control for the effects of surgery. MEASUREMENTS AND MAIN RESULTS: Histologic evidence of articular degeneration was significantly greater in rabbit knees implanted with lead compared with knees with steel implants (p = 0.0625), knees with arthrotomies, or those with no procedure performed (p = 0.0325). Changes were also greater in the synovium of knees implanted with lead compared with all other specimens. No significant degenerative changes were noted in the menisci of any specimen. CONCLUSIONS: Such changes may be early signs of degenerative joint disease and may lead to chronic damage. Gunshot wounds affecting joints may cause intra-articular retention of lead fragments, which are not physiologically inert and may cause degenerative joint changes. Even if no mechanical impingement is evident, removal of lead may be warranted to prevent early arthropathies in humans.

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Case management is a patient care delivery system that is transforming health care in the 1990s. The key to its success is its primary tenet of collaboration among all disciplines. Case management enhances communication among all disciplines and coordinates patient care services. Multidisciplinary action plans have been developed as a tool for the multidisciplinary team, to guide health care practitioners toward the highest quality, cost-effective care possible. At Beth Israel Medical Center in New York City, the Multidisciplinary Care Model has proven successful on both the Orthopaedic and Rehabilitation services.

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The authors present a case of pigmented villonodular synovitis (PVNS) in an adolescent with monarticular involvement of the ankle and without congenital anomalies or sibling involvement. Its rarity in the ankle and in childhood is discussed; a review of the clinical, radiological, and pathological features of PVNS is presented.

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In summary, we have reported on an unusual form of fibrous dysplasia, presumptively monostotic, localized to the middle phalanx of the second pedal digit, and presenting as a mass. Monostotic fibrous dysplasia of phalanges of the foot is rare, but should be considered in the differential diagnosis of a mass in the foot.

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Endoscopic carpal tunnel release has been shown to decrease postoperative recovery time in patients undergoing surgery for carpal tunnel syndrome. There is, however, some controversy concerning the safety and reliability of the procedure. We performed endoscopic carpal tunnel release utilizing the two portal technique described by Chow on 20 fresh cadaver specimens. There were no injuries noted in any of the vital structures including the ulnar artery, superficial palmar arch, third common digital nerve or flexor tendons. The transverse carpal ligament was found to be completely transected in 95% of the specimens. Hyperextension of the wrist significantly displaces the vital structures both dorsally and distally. The use of a slotted cannula and specially designed blades protect the surrounding structures during the procedure. Based on this study, endoscopic carpal tunnel release using the technique described by Chow may be performed reliably without injury to any of the vital structures.

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