MRI diagnosis of carpal boss and comparison with radiography

Os Styloideum and Third Metacarpal Partial Coalition Nonunion After Traumatic Fracture: A Report of Three Cases

The Os Styloideum (OS) is an accessory carpal bone located in the dorsal aspect of the wrist between the base of the second and third metacarpal bones and the trapezoid and the capitate. It is frequently partially coalited with the metacarpal bones and is usually asymptomatic. It may become symptomatic after a traumatic fracture, developing swelling, edema, and pain. We report 3 cases with a fracture of an OS partial coalition with the third metacarpal bone with signs of delayed consolidation. They all complain of persistent pain at the dorsal aspect of the hand that increased with activity. One patient rejected surgery, had a platelet-rich plasma injection, shock wave therapy, and afterward did physiotherapy rehabilitation without complete solution; the other two patients underwent surgical excision with local anesthesia and had a complete recovery after 2 months of follow-up. The OS is an infrequent entity yet must be correctly diagnosed as a possible cause of dorsal pain in the hand and wrist. If symptoms are refractory to medical treatment, surgical excision should be considered. Open excision under local anesthesia is a simple, reproducible procedure with excellent results.

High-resolution ultrasound approach to quadrangular joint in carpal boss: Everything musculoskeletal sonographer should know

At the quadrangular joint (QAJ) of the carpus, a rare bony protuberance called carpal boss (CB) may occur. This bone abnormality may be due to osteophytes development or os styloideum. Symptomatic patients may complain pain, swelling, and restrictions in hand motion. These symptoms result from joint degenerative-inflammatory changes, development of ganglion cyst/bursitis, or tendons pathology. Correct diagnosis and appropriate management can be achieved through high-resolution ultrasonography (HR-US). The purpose of this review is to define the pathology spectrum around and within the QAJ in CB. The role of HR-US is highlighted and the standard technique for the QAJ assessment is described.

Carpal Boss: A Case Series of a Radiological Enigma in Dorsal Wrist Pathology

Carpal boss, a relatively rare and often underdiagnosed condition, is characterized by a bony protuberance at the dorsal aspect of the carpometacarpal (CMC) joint. It is commonly misdiagnosed due to its nonspecific clinical presentation, which can mimic other conditions, such as ganglion cysts or fractures. This case series aims to document and analyze the clinical presentations and radiological findings of three patients diagnosed with carpal boss, highlighting the importance of advanced imaging techniques in accurate diagnosis and management. A case series was conducted at Tenet Diagnostics, Bengaluru, Karnataka, involving three patients with dorsal wrist pain and swelling at the CMC joint. All patients underwent clinical evaluation followed by imaging studies using 3T magnetic resonance imaging (MRI) (United Imaging, Shanghai, China) and 32-slice computed tomography (CT) (Siemens Somatom Go; Siemens Healthineers, Munich, Germany). The MRI sequences included T1-weighted and proton density (PD) fat-saturated images, while CT imaging focused on axial and sagittal sections to assess bony structures. All three patients were diagnosed with carpal boss based on imaging findings. MRI revealed hypertrophied bony protuberances at the bases of the second and third metacarpal bones, forming pseudoarthrosis with associated osteoarthritic changes. CT imaging confirmed these findings, providing high-resolution views of the bony abnormalities. Combining MRI and CT was crucial in differentiating carpal boss from other potential diagnoses, such as ganglion cysts or fractures. This case series underscores the importance of advanced imaging modalities, such as MRI and CT, in diagnosing carpal boss. Accurate and early diagnosis can prevent mismanagement and guide appropriate treatment strategies, improving patient outcomes. Increased awareness of carpal boss among clinicians and radiologists is essential for promptly recognizing and managing this condition.

Glossary of terms for musculoskeletal radiology

Members of the International Skeletal Society compiled a glossary of terms for musculoskeletal radiology. The authors also represent national radiology or pathology societies in Asia, Australia, Europe, and the USA. We provide brief descriptions of musculoskeletal structures, disease processes, and syndromes and address their imaging features. Given the abundance of musculoskeletal disorders and derangements, we chose to omit most terms relating to neoplasm, spine, intervention, and pediatrics. Consensus agreement was obtained from 19 musculoskeletal radiology societies worldwide.

Review article: the differential diagnosis of bone marrow edema on wrist MRI

There is a large variety of conditions that can result in 'bone marrow edema' or 'bone marrow lesions' (BML) in the wrist on magnetic resonance imaging (MRI). The combination of clinical history and the distribution of the BML can serve as a valuable clue to a specific diagnosis. This article illustrates the different patterns of BML in the wrist to serve as a useful guide when reviewing wrist MRI studies. Imaging artefacts will also be briefly covered.

Endoscopic Resection of Carpometacarpal Boss and Synovectomy of the Second Carpometacarpal Joint

Carpometacarpal boss is a symptomatic bony prominence on the dorsal surface of the wrist at the base of the second and/or third metacarpal. Wedge excision of the carpometacarpal boss is indicated if conservative treatment fails to relieve the symptoms. Complications of wedge resection include symptomatic recurrences and carpometacarpal instability. The purpose of this Technical Note is to describe the technical details of endoscopic resection of carpometacarpal boss and synovectomy of the second carpometacarpal joint. This may reduce the amount of bone and joint resection and risk of carpometacarpal instability.

MRI of a painful carpal boss: variations at the extensor carpi radialis brevis insertion and imaging findings in regional traumatic and overuse injuries

OBJECTIVE

To report patterns of MRI findings involving carpal boss and extensor carpi radialis brevis (ECRB) tendon insertion in individuals with overuse-related or post-traumatic wrist pain.

MATERIALS AND METHODS

Eighty-four MRI cases with carpal bossing between December 2006 and June 2015 were analyzed by two fellowship-trained musculoskeletal radiologists. The following MRI findings were reviewed: type of carpal bossing (bony prominence, partial coalition, os styloideum), insertion of ECRB tendon (to the 3rd metacarpal, to carpal boss or to both), bone marrow edema (BME), insertion site, and tenosynovitis/tendinosis of ECRB tendon. Clinical information on wrist pain was available on 68 patients.

RESULTS

Fused carpal bossing was detected in 21%, partial coalition in 35%, and os styloideum in 44% of the cases. Regional BME was observed in 64% of the cases. When BME specifically at the carpal boss was assessed, 78% of stable and 50% of unstable bosses showed BME (p = 0.035). ECRB tendon inserted on a carpal boss in 20%, on the 3rd metacarpal bone in 35%, and on both sites in 45% of the cases. As BME at the carpal boss was assessed, BME was detected at the respective insertion sites in 71%, 35%, and 66% of the cases (p = 0.015). Dorsal wrist pain was associated with BME as 75% of the patients had regional BME in the vicinity of the carpal boss (p = 0.006).

CONCLUSION

A spectrum ranging from complete fusion of a boss to an entirely unfused os styloideum exists with a variable ECRB insertional anatomy. BME at the carpal boss is a consistent MRI finding.

Secondary Abutment Syndromes of the Wrist in Trauma: A Pictorial Essay

Traumatic lesions of the wrist occur frequently and may give rise to underdiagnosed secondary abutment syndromes. The latter are a common cause of incapacitating pain and limited range of motion, despite minimal or even absent alterations on radiographs. Moreover, the complex wrist anatomy often results in ignorance or underappreciation of these syndromes.

This paper presents a pictorial review of frequent and rare secondary abutment syndromes at the wrist joint, which – in contrast to primary abutment syndromes – are not based on anatomical variants or congenital deformations. The merit of each imaging modality is briefly mentioned.

Imaging Findings at the Quadrangular Joint in Carpal Boss

A carpal boss was initially described as a bony, sometimes painful mass at the quadrangular joint. Clinical examination and plain radiography will usually reveal the diagnosis. US and CT may add information. MRI may illustrate a variable bony morphology and additional bony and soft tissue pathologies. Bone marrow edema shows a significant correlation with a painful carpal boss. Hence, MRI may be of additional diagnostic value in patients with persistent pain and preoperatively. This paper presents a review of the anatomy and pathology in carpal boss. The merit of each imaging modality - in particular MRI - is mentioned.