Background:. The Orthopaedic In-Training Examination (OITE) is used by orthopaedic residency training programs to evaluate the knowledge base of orthopaedic surgery trainees and to predict future performance on the American Board of Orthopaedic Surgery (ABOS) certifying exams. The pathology section of the OITE has changed over the years, both in terms of the content assessed and the format of the questions. This study aims to describe such trends. Methods:. This study analyzed OITE questions from 2012 to 2023, focusing on tumors and tumor-like conditions of bone and soft tissue to guide resident preparation and core curriculum design. Questions were categorized by histologic photomicrographs, preferred responses, possible options, and implied entities. Additionally, questions were classified into four domains: diagnosis, treatment, next step, and multifactorial. Results:. Tumor-related questions constituted 10–16% of each OITE, with an equal number of questions concerning benign and malignant entities. Bone tumor questions averaged nine per year, while soft tissue tumor questions averaged four. The most frequently tested bone tumors were osteosarcoma and giant cell tumor, while pleomorphic sarcoma and liposarcoma were the most frequently tested malignant soft tissue tumors. Metabolic bone diseases such as osteoporosis, osteomalacia, and osteonecrosis were also frequently tested. Histologic photomicrographs were included in 120 questions over the study period, with osteosarcoma being the most depicted. A shift in question focus was observed, with diagnosis questions declining in favor of treatment and next-step management questions in recent years. Conclusion:. These findings provide a comprehensive overview of tumor-related content on the OITE, highlighting trends in question composition and format. This information can guide program directors in designing curricula that align with tested material, ensuring residents are well-prepared for both the OITE and ABOS exams. Emphasizing highyield topics and adapting to evolving question patterns can optimize educational outcomes and improve board pass rates.

Although adverse local tissue reactions (ALTR) have been reported for metal-on-metal implants (MoM) requiring early revision surgery, no study has looked at the accuracy of surgical pathologists in diagnosing ALTR. This study aims to investigate the accuracy of reporting adverse local tissue reactions in tissue samples following revision surgery from metal-on-metal implants. The authors reviewed histology glass slides as well as the original pathology reports of tissue processed in revision arthroplasties in 23 cases. These samples were microscopically analyzed for tissue necrosis and cystic degeneration, the presence of metal particles, corrosion byproducts, membrane formation, histiocytic cells, lymphocytic cells, and vascular pathology. The authors’ findings were then compared to their corresponding original pathology reports. The authors found consistent under-reporting of the tissue findings. Most importantly, 18 samples showed evidence of metal present compared to 2 samples on original pathology reporting. The authors found that 15 samples showed evidence of pathological membranous tissue compared to just 6 on original pathology reporting. While just 3 of the original pathology reports indicated the presence of areas of predominantly lymphocytic inflammatory cells, the authors found 13 examples of such areas. Although ALTR reactions have been described as a sequala of failed MoM, the authors’ data suggest that ALTR may occur more frequently than previously described. Under-reported findings of ALTR deprive both the patient and orthopaedic surgeon of important information that can help guide further follow-up.

CASE A 37-year-old man presented with pain and macrodactyly of a toe. Imaging and histology demonstrated findings consistent with macrodystrophia lipomatosa (MDL). We compared our findings with control tissue obtained from an identical site of a fresh-frozen cadaveric foot from the same anatomical site. Pacinian corpuscles (PCs) in the MDL tissue were increased in number, size, and shape compared with the control tissue and demonstrated edematous interstitial lamellae and vacuolar degenerative change. We also document the magnetic resonance imaging findings of the PCs. CONCLUSION Peculiar abnormalities of PCs in MDL underline nerve damage and may be a contributing factor in the pain associated with this unusual condition.

We present the case of a 38-year-old man who presented 7 years after primary total hip replacement with a fracture of the neck of a lateral flare femoral stem and catastrophic polyethylene wear. The unique design of the lateral flare hip stem has been shown previously to be associated with accelerated polyethylene wear, whereas the stem remains well fixed. The resultant polyethylene wear results in the harder cobalt chrome head abrading the titanium shell generating metallic debris. This may have resulted in proximal migration of the implant neck into the cup with subsequent neck-cup impingement and implant fracture.

Although joint replacement surgery to relieve pain due to osteoarthritis is generally a successful operation, adverse local tissue reactions can occur in hip arthroplasty in patients who receive metal-on-metal (MoM) implants and lead to early failure. This has led to revisions, lawsuits, and manufacturing recalls. An understanding of the pathological process initiated by metal wear debris is essential in clinical surveillance of cases. We retrospectively reviewed six cases of patients who underwent MoM hip arthroplasties and required early revision. Tissue removed at revision surgery was analyzed histologically by two independent reviewers. All six patients (four males, two females) underwent revision hip arthroplasty after early failure. Revision occurred between 18 and 56 months after the index procedure. Four patients received MoM implants from Depuy, one from Stryker, and one from Wright Medical. A consistent array of pathological findings was associated with these failed MoM implants. Beginning with the development of metal debris, a histiocytic response and proliferation occurred with subsequent corrosion product formation. Membranes were formed, many with cellular infiltrates and pseudosynovial linings and often with ulceration and bleeding. The tissue also demonstrated lymphocytosis and perivascular infiltrates with atypical changes of the endothelial lining cells. Our findings document a predictable cascade of harmful local tissue changes initiated by metal debris in failed MoM hip arthroplasties.

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.

ABSTRACT 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. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1914–1919, 2013

The human knee meniscus is important for the protection of the knee joint from degeneration. Because it is so commonly injured, several methods have been developed to replace damaged meniscal tissue with either transplanted menisci or other synthetic implants. Here we review these different approaches, with a clinical and histological focus on the collagen meniscal implant (CMI or Menaflex), a tissue-engineered bovine collagen product. Clinical trials in patients receiving the CMI have demonstrated good clinical outcomes in follow-ups as long as 10 years. We review the findings of second-look biopsies of implanted CMI constructs; they demonstrate the fibrochondrocytic ingrowth of tissue mimicking a native meniscus. Integration of the CMI to host meniscus is also confirmed. The histologic inflammation occasionally observed around the graft appears to be of little clinical significance. We conclude that tissue-engineered menisci from bovine collagen are safe in the time period examined and that they hold promise for future repair of the meniscus in appropriate individuals.

Medial parameniscal cysts of the knee are typically 0.3 to 9 mm in diameter. Few cases of unusually large medial parameniscal cysts have been reported. We describe the treatment of a patient with osteoarthritis of the knee who presented with an extraordinarily large, ipsilateral, medial parameniscal cyst, 10 cm in diameter. We believe this to be the largest medial parameniscal cyst reported in the English literature. Based on the patient's severe tricompartmental arthritis and associated symptoms, total knee arthroplasty (TKA) was indicated with simultaneous excision of the parameniscal cyst. Perioperativley, the cyst was found to have penetrated beyond the menisco-capsular attachments that were adjacent to a degenerative posterior horn horizontal medial meniscal tear. Following excision of the cyst, the mass was measured with surgical tape to be 10x10x5 cm. After complete excision of the parameniscal cyst, TKA was performed. Histological examination confirmed a benign parameniscal synovial cyst. At 2-year follow-up, the patient was ambulating unassisted without difficulty. The wound had completely healed with no evidence of recurrence of the cyst. The patient's range of motion was 0 degrees to 110 degrees with no signs of instability. Our patient's pathology was most significant for the heretofore unseen large size of the paramensical cyst. Open excision of this giant parameniscal cyst followed by TKA was effective in treating the patient's degenerative joint disease and extraordinarily large, painful soft tissue mass.

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.

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.

A 12-year-old Iranian Jewish boy was seen in the orthopaedic a clinic at our institution in 1989. The presenting complaint was a painful deformity of the right foot. The patient had been slow to reach all developmental milestones and was mildly cognitively delayed. He was delivered by spontaneous vaginal delivery, with no history of perinatal complications. The right foot deformity had been noted at birth but had worsened over the last several years. He had difficulty with shoewear and was unable to participate in sports activities. There was no history of bony anomalies in the parents or siblings. Other than developmental delay, he had no other medical problems or deformities. Physical examination of the right foot revealed a small cleft between the fourth and fifth digits on the plantar surface. There was a palpable bony deformity over the dorsal aspect of the fourth metatarsophalangeal joint. The deformity was firm, indurated, nonfluctuant, and tender. The proximal phalanx of the fifth toe was dorsiflexed because of plantarflexion of the fifth metatarsal (Figure 1, A). There was a large cutaneous callosity over the plantar aspect of the fifth metatarsal (Figure 1, B). The contralateral foot was normal,

Osteosarcoma of the hand is rare. We present a case report and a literature review that indicates an older median age of onset than conventional osteosarcoma. The predilection for these lesions to manifest in the metacarpophalangeal joints, particularly in the second and third digits, is in contrast to the more symmetrical distribution of metastatic cancer and correlates with the sites of most active growth during development of conventional osteosarcoma.

Osteosarcoma of the hand is rare. We present a case report and a literature review that indicates an older median age of onset than conventional osteosarcoma. The predilection for these lesions to manifest in the metacarpophalangeal joints, particularly in the second and third digits, is in contrast to the more symmetrical distribution of metastatic cancer and correlates with the sites of most active growth during development of conventional osteosarcoma.

The objective of the study was to investigate occult abnormalities in bone bank allograft with the use of histomorphometry that may otherwise go unidentified with current screening techniques. This was a prospective pathology review in which 40 transcortical trephine bone biopsies were taken from the iliac crest of bone donors and examined by light microscopy and semiautomated histomorphometry. Current routine screening techniques for allograft bone donors include history, serology, and culture. Additional screening for unsuspected pathology and for parameters related to metabolic bone disease may predict the effectiveness of the donor bone. Light-microscopic findings showed 1 case suspicious for chronic myeloproliferative disorder, which had otherwise not been detected by standard screening techniques. On histomorphometric analysis, 3 specimens showed severe osteoporosis. In conclusion, iliac crest bone biopsy may need to be considered as an adjunct in screening for both unsuspected hematological disease and metabolic bone disease.

It is important for clinicians treating musculoskeletal complaints to be aware of the possibility of the diagnosis of osteonecrosis in HIV-infected patients. It has been suggested in the literature that when a patient is diagnosed as having osteonecrosis with no other apparent risk factors, the patient should be tested for HIV infection. Further work needs to be carried out to determine any association between HIV infection and osteonecrosis of the femoral head before any such guidelines can be suggested.

Six iliac crest bone biopsies were obtained from five patients with renal osteodystrophy and osteosclerotic lesions to investigate the mechanism of osteosclerosis in renal osteodystrophy. Each specimen was prepared in an undecalcified fashion and measured under light microscopy for routine analysis and histomorphometry. Osteoclast resorptive lacunae were estimated by measuring the lacunar length and depth. Histomorphometric studies revealed an increase in all parameters with a mean trabecular bone volume of 66% (normal: 19%-26%), mean trabecular osteoid surface of 71% (normal: 16%-22%), and a mean trabecular osteoid volume of 15% (normal: 1%-2%). In one patient, there was a ten-fold increase over the norm of osteoclasts/mm2 (0.3; normal: 0.02-0.04), whereas the mean width of trabecular bone was twice the norm. In all biopsies, the calculated lacunar area was markedly diminished compared to published controls. These results support the hypothesis that osteoclast function is impaired in patients with renal osteodystrophy.

A right ischial ulcer recurred after 6 months in a 79-year-old man with a history of recent hip fracture and Girdlestone procedure. Soft-tissue calcification was detected radiographically. The mass, hyperplastic bursal tissue with chondroid metaplasia, was excised. Bursal osteochondromatosis is reviewed.