Radiographic interpretation of carpometacarpal arthroplasty: correlation between radiographic loosening and clinical outcome.

OBJECTIVE: To assess the radiographic appearance and interpretation of loosening in patients following first carpometacarpal joint pyrohemisphere arthroplasty. MATERIALS AND METHODS: A retrospective review over a 6-year period was performed identifying patients with first carpometacarpal pyrohemisphere implants. All postoperative radiographs were reviewed and compared with clinical information. Loosening was defined as greater than 1 mm of periprosthetic lucency or increasing lucency on serial studies. Adverse clinical outcome was defined as infection, complex regional pain syndrome, subluxation or an inability to return to activities of daily living. Statistical analysis included Cohen's Kappa coefficient to measure inter-reader agreement for radiographic interpretation and the agreement between radiographic loosening and an undesired or adverse clinical outcome. RESULTS: Thirty-one implants in 26 patients were reviewed. A total of 73 postoperative radiographs were reviewed. The mean age of the study subjects was 58 years. The mean radiographic follow-up was 13 months (range: 1-56). All arthroplasties were performed for osteoarthritis. Only one repeat surgery was performed. There was good agreement amongst readers with regard to radiographic interpretation, but the strength of agreement between radiographic loosening and adverse clinical outcome was poor. The sensitivity of radiography in predicting an adverse clinical outcome was 63%, specificity 65%, positive predictive value 39%, and negative predictive value 83%. CONCLUSION: Although radiography may be useful in the correct clinical context, it should not be utilized as the sole predictor of adverse clinical outcomes following carpometacarpal arthroplasty.

3D-MR vs. 3D-CT of the shoulder in patients with glenohumeral instability.

OBJECTIVE: To determine whether 3D-MR osseous reformats of the shoulder are equivalent to 3D-CT osseous reformats in patients with glenohumeral instability. MATERIALS AND METHODS: Patients with glenohumeral instability, who were to be imaged with both CT and MRI, were prospectively selected. CT and MR were performed within 24 h of one another on 12 shoulders. Each MR study included an axial 3D isotropic VIBE sequence. The image data from the isotropic VIBE sequence were post-processed using subtraction and 3D software. CT data were post-processed using 3D software. The following measurements were obtained for both 3D-CT and 3D-MR post-processed images: height and width of the humeral head and glenoid, Hill-Sachs size and percent humeral head loss (if present), size of glenoid bone loss and percent glenoid bone loss (if present). Paired t-tests and two one-sided tests for equivalence were used to assess the differences between imaging modalities and equivalence. RESULTS: The measurement differences from the 3D-CT and 3D-MR post-processed images were not statistically significant. The measurement differences for humeral height, glenoid height and glenoid width were borderline statistically significant; however, using any adjustment for multiple comparisons, this failed to be significant. Using an equivalence margin of 1 mm for measurements and 1.5% for percent bone loss, the 3D-MR and 3D-CT post-processed images were equivalent. CONCLUSION: Three-dimensional-MR osseous models of the shoulder using a 3D isotropic VIBE sequence were equivalent to 3D-CT osseous models, and the differences between modalities were not statistically significant.

Tibial osteochondroma with thick cartilage which mimicked a chondrosarcoma: A case report.

We report a case of tibial osteochondroma in a 25-year-old female who presented with a palpable calf mass. This mass was associated with a thick cartilaginous cap on cross-sectional imaging, suggesting chondrosarcoma. A CT-guided biopsy was performed, and histology, however, was consistent with osteochondroma. Orthopedic oncology recommended surgical excision due to the potential high sampling error with chondroid lesions. The patient underwent surgical resection, resulting in a final diagnosis of osteochondroma. No post-surgical complications occurred, and a 12-month follow-up showed no evidence of local recurrence. This case highlights the atypical imaging feature of a thick cartilaginous cap in a benign etiology without malignant transformation.

A Humeral Osteosarcoma Mimicking Osseous Leiomyosarcoma: A Case Report.

Osteosarcoma stands as one of the primary mesenchymal bone neoplasms commonly encountered in clinical practice. This malignancy often presents with a wide range of distinctive imaging characteristics. Here, we present a unique case wherein a delayed diagnosis of high-grade osteosarcoma occurred due to the absence of an osteoid matrix in the initial imaging studies. A 61-year-old female, initially presented with a left humeral fracture. As the healing of the fractured bone was delayed and the possibility of a pathologic fracture was considered, a CT-guided biopsy was performed. Histological examination of the biopsy sample initially suggested an osseous leiomyosarcoma. The lack of osteoid matrix on radiographs including aggressive intra-medullary mass seen on MRI, combined with the patient's age, appeared consistent with a diagnosis of leiomyosarcoma of bone. As a result, the initial diagnosis was not called into question. Due to neurovascular involvement, this led to a forequarter amputation. However, upon microscopic examination of the amputation specimen, certain areas exhibited features indicative of malignant osteoid deposition, ultimately supporting a revised diagnosis of high-grade osteosarcoma. This case underscores the critical importance of considering the limitations of core biopsy samples, especially when dealing with suspected limb masses associated with pathological fractures. Radiographs and CT scans can prove invaluable in ruling out subtle adjacent osteoid, and ultimately a multidisciplinary approach to the diagnosis of osteosarcoma is imperative to ensure accurate identification.