Eli Bryk

Neurohistology of the subacromial space

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.

Histologic comparison of posterior cruciate ligaments from arthritic and age-matched knee specimens

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.

Lead Poisoning from an Intra-Articular Shotgun Pellet in the Knee Treated with Arthroscopic Extraction and Chelation Therapy. A Case Report*

The signs and symptoms of lead poisoning are subtle, and recognition of this entity may be difficult2. Plumbism is most commonly caused by ingestion of lead-based paint by children2-4,9; by occupational exposure, such as with painters, lead miners, and workers in battery factories20; and by the consumption of contaminated beverages, such as moonshine3,16. Lead intoxication is a rare yet well documented complication of gunshot injuries1,13,17,20-22, especially when the lead is exposed to synovial fluid3,7,11,17,22. The dissolution rate of lead is higher in synovial fluid than in either serum or water1-3,7,10,14,21, which explains the association of plumbism with lead in an intra-articular space. The rarity of plumbism as a sequela to gunshot injuries to non-articular sites has been attributed to the usual encapsulation of metallic foreign bodies by dense, avascular fibrous tissue, which inhibits degradation of the material17,21. Plumbism from this mode often occurs after years of exposure, although acute onset has been reported3,4. A review of the literature revealed no previous report of lead poisoning treated with arthroscopic removal of the lead pellet and chelation therapy. A forty-one-year-old woman with a long history of pain in the right knee was evaluated at our institution because of acute exacerbation of this pain. Twenty-three years earlier, in Trinidad, she had been shot in both knees with a shotgun and some pellets had been removed operatively. The pellets had grazed the left knee but had directly impacted on the right knee. No fractures were noted at that time. She …

Endoscopic carpal tunnel release: An atomic study

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.

Neovascularity in chronic posterior tibial tendon insufficiency.

Insufficient posterior tibial tendons in 28 specimens from patients with clinical Stage II or III disease were examined to clarify the etiology of adult-acquired flatfoot deformity. Hematoxylin and eosin and Masson trichrome-stained sections of formalin-fixed tissue were viewed in plain and polarized light. We performed a qualitative analysis for abnormalities in collagen orientation, degree of vascularization, tenocyte cellularity, mucinous change, and chondroid metaplasia. Tendons were divided into three zones: tenosynovial lining cell layer, subtenosynovial lining cell layer, and tendon proper. All tendons showed neovascular infiltration causing collagen fibril disruption; 50% of specimens had diffuse involvement. Increased mucin content and chondroid metaplasia occurred in 28% and 36% of specimens, respectively. The tenosynovial lining cell layer showed hyperplasia in 28% of specimens. The subtenosynovial lining cell layer showed thickening and neovascularization in 79% of specimens, which appeared to be the source for the diffuse neovascular infiltrative process. There is little histopathologic evidence to support an inflammatory etiology to the posterior tibial tendons in acquired-adult flatfoot deformity. Neoangiogenesis, the prominent histologic finding, is consistent with an obscure insult. We postulate that overuse, tension, or stretching may activate the tenosynovial lining cells and incite angiogenesis.

Collagen scaffold meniscus implant integration in a canine model: a histological analysis.

In the situation of an irreparable meniscus tear, an implant comparable to a normal meniscus is an attractive option. Using a canine model, we assessed the early and late histologic response to a tissue engineered meniscal collagen scaffold (CS). All animals received bilateral arthrotomies, and all joints receiving the CS had an 80% resection of the meniscus. Animals were sacrificed at 3 and 6 weeks, and 12, 13, and 17 months. The CS/tissue complex and host meniscal rim were sectioned for histologic examination with specific focus on the extracellular matrix, angiogenesis, cellular resorption of the scaffold, scaffold appearance, and CS/Host integration. Early histologic samples (3–6 weeks) revealed active angiogenesis and fibrin clots evolving into cellular granulation type tissue. At 12 months, a mature fibrochondrocytic matrix was depositing with gradations of dissolution and integration of the CS implant. Maturing CS/host integration was observed at 18 months. Active cellular resorption of the implant decreased over time. Four cases showed a mild non‐specific chronic inflammation and one additional case showed inflammatory engulfment of the scaffold with giant cells at 3 weeks. No evidence of infection either clinically or histologically was observed at any time point. Overall, this histologic analysis demonstrated the active integration of a meniscal like cartilage into a tissue engineered biological scaffold in a canine model.

Pigmented villonodular synovitis in a child

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.

Experimental lead arthropathy: an animal model.

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

Ultrastructural features of giant cell tumors in Paget's disease.

Giant cell tumor is a rare complication of Paget’s disease. This association is especially notable in patients originating from Avellino, Italy. Many types of evidence point to a viral etiology for Paget’s disease and giant cell tumors arising in it. Three patients who had giant cell tumors and Paget’s disease were studied. Two of the patients have a connection to Avellino (one was born in Avellino, and one descended from natives of Avellino). Distinctive light microscopic and ultrastructural features common in these three patients were identified. In all three patients, the giant cell tumors had peculiar irregular aggregates of microfilaments of uncertain genesis. The possibility that these reflect viral infection is discussed.

Neural anatomy of the transverse carpal ligament.

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.