Intra-articular osteoid osteoma accompanied by extensive bone marrow edema. A clinical and micro-morphological analysis.

Osteoid osteoma (OO) is a benign bone tumor producing non-mineralized bone matrix (i.e., osteoid). While peritumoral edema is commonly found in OO, extensive bone marrow edema has been reported less frequently. Furthermore, the micro-morphological characteristics of the nidus and its central calcification remain unclear. In this study, a consecutive series of four patients suffering from extensive bone marrow edema triggered by intra-articular osteoid osteoma underwent clinical examination, magnetic resonance imaging (MRI) and computed tomography (CT) as well as dual-energy X-ray absorptiometry (DXA) and laboratory bone turnover analyses. The obtained resection specimens were processed by undecalcified histology and were subsequently analyzed by light microscopy and quantitative backscattered electron imaging (qBEI). We report an entity of intra-articular osteoid osteoma in the knee and foot, in which an extensive and persistent bone marrow edema syndrome masked the correct diagnosis. While metabolic bone diseases were excluded in all cases, the reassessment of the patients' clinical history including pain characteristics (nocturnal, aspirin sensitivity) led us to perform additional CT, where the tumor was diagnosed. The micro-morphological analysis of the OO biopsies revealed that the nidus was surrounded by hyperosteoidosis, while central mineralization was detected in all cases. This mineralized area showed a significantly higher mineralization heterogeneity than the surrounding trabecular bone and more disorganized collagen fibers detected by qBEI and polarized light microscopy, respectively. Taken together, our results indicate that osteoid osteoma should be considered when persistent and extensive, peri-articular bone marrow edema is diagnosed. The central calcification that is found inside the nidus in conventional imaging was mirrored by bone matrix with a heterogeneous mineralization pattern.

Periosteal chondroma of the cuboid with secondary aneurysmal bone cyst in a setting of secondary hyperparathyroidism.

We report the case of a 35-year-old woman with painful, nontender mass at the right lateral hindfoot. Computed tomography (CT) and magnetic resonance imaging (MRI) indicated the suspect of a chondroid tumour in the cuboid. The tumour was resected en bloc and histology revealed the presence of a periosteal (juxtacortical) chondroma with secondary aneurysmal bone cyst. Secondary hyperparathyroidism was detected in laboratory tests and put into context with the histopathologic findings. In conclusion, a rare case of periosteal chondroma of the cuboid with secondary aneurysmal bone cyst in a setting of secondary hyperparathyroidism due to vitamin D deficiency is presented. LEVEL OF CLINICAL EVIDENCE: 4.

[Refixation of tibial bony avulsions of the posterior cruciate ligament with a hook plate]. / Refixation von tibialen knöchernen Ausrissen des hinteren Kreuzbandes mit einer Krallenplatte.

OBJECTIVE: Posteromedial approach to the knee. Exact reduction and fixation of avulsed tibial attachment of posterior cruciate ligament with small-fragment plate. INDICATIONS: Avulsed tibial attachment of posterior cruciate ligament. CONTRAINDICATIONS: Ligamentous rupture of the posterior cruciate ligament. Local soft-tissue problems. SURGICAL TECHNIQUE: Posteromedial approach with mobilization and retraction of the medial gastrocnemius muscle. Subperiosteal detachment of the popliteal muscle. Identification of fracture site. Longitudinal incision of the posterior capsule of the knee. Debridement of the fracture site, reposition and stabilization with small-fragment plate. POSTOPERATIVE MANAGEMENT: Partial weight bearing with 15 kg for 6 weeks, limitation of knee flexion to 90° for 6 weeks. A special joint orthesis is not necessary. The use of an EMT unit is recommended to prevent muscular atrophy. RESULTS: Six patients (four female, two male) with avulsed tibial attachment of posterior cruciate ligament were treated using the posteromedial approach.