Avascular necrosis of the triquetrum: a case report

The morphologic and morphometric features of the triquetrum

Fractures of the triquetrum are the second most common form of isolated carpal bone fracture after the scaphoid. However, data on triquetrum morphology and morphometry are sparse. The aim of this study was to describe the morphology of triquetrum using anatomical landmarks, evaluate its morphometric features, and determine its vascular entry points. The morphological and morphometrical features of 87 adult dry triquetral bones (39 left, 48 right) were determined by measuring length, width and thickness. The number and locations of nutrient foramina wider than 0.5 mm were recorded. Mean length, width and thickness were 17.37 mm (range, 14.26-22.13), 12.65 mm (range, 10.37-15.85) and 11.41 mm (range, 8.98-18.23), respectively. The facet articulating with the pisiform was oval in 40 bones, round in 8 and amorphous (neither round nor oval) in 39. The mean length of the interarticular ridge was 7.09 ± 0.9 mm. The mean number of nutrient foramina was significantly greater on the dorsal than on the other aspects. The dorsal predominance of nutrient foramina makes the bone weaker in the dorsal region, which could explain why fractures are more common in this region. Also, the dorsal aspect is rich in blood supply, which could explain why avascular necrosis is less common in triquetral fractures. As most of the vascularization is on the dorsal side, there is need for caution when performing triquetrum surgery. LEVEL OF EVIDENCE: Level 2.

Avascular Necrosis of Capitate and Other Uncommon Presentations of Carpal Avascular Necrosis

Outside of Preiser and Kienbock disease, avascular necrosis (AVN) of the remaining carpal bones is a rare cause of wrist pain and disability with a natural history that is incompletely understood. At present, much of the available clinical information exists in the form of isolated case reports or small case series. Although reported surgical treatment options are numerous, there is a dearth of comparative studies and long-term outcomes data with which to guide management.

Pathophysiology of Avascular Necrosis

Avascular necrosis is a complicated, multifactorial disease with potentially devastating consequences. Although the underlying root cause is a lack of appropriate vascular perfusion to affected bone, there are often varying patient-specific, anatomic-specific, and injury-specific predispositions. These factors generally fall into 3 categories: direct vascular disruption, intravascular obliteration, or extravascular compression. The initial stages of disease can be insidiously symptomatic because edematous bone marrow progresses to subchondral collapse and subsequent degenerative arthritis. Although much of the current literature focuses on the femoral head, other common areas of occurrence include the proximal humerus, knee, and the carpus. The low-incidence rate of carpal avascular necrosis poses a challenge in establishing adequately powered, control-based validated treatment options, and therefore, optimal surgical management remains a continued debate among hand surgeons. Appreciation for expectant fracture healing physiology may help guide future investigation into carpal-specific causes of avascular necrosis.

Avascular Necrosis of the Carpal Bones Other Than Kienböck Disease

Avascular necrosis (AVN) of the carpal bones other than Kienböck disease is a rare cause of chronic pain of the wrist. The scaphoid, capitate, and a smaller percent of lunates are at greater risk to develop AVN because of their peculiar intraosseous circulation; however, AVN has been reported in all the carpal bones. On the plain radiograph, AVN of the carpal bones may evolve through a normal radiograph, sclerosis, fragmentation, cyst formation, fracture, bone collapse, change of the carpal height, and alignment and progressive degenerative changes of the wrist joint. In the early stage of AVN, magnetic resonance imaging enhanced with gadolinium is a more sensitive and specific diagnostic tool than plain radiograph to demonstrate the bone marrow viability. Because of the rarity of case reports, the natural history of AVN of the carpal bones other than Kienböck disease is not well understood. The aims of different treatments are to prevent bone collapse, restore normal carpal height and alignment, and reduce the risk of progressive degenerative changes of the wrist joint.

Avascular Necrosis with Cystic Changes in the Triquetrum after Trauma in Combination with Heavy Smoking and Local Corticosteroid Injections

The triquetrum is rarely affected by avascular necrosis compared with other carpal bones. We report a case of avascular necrosis of the triquetrum in a 50-year-old patient, with a history of wrist trauma, local corticosteroid injections, and heavy smoking. She presented with severe wrist pain and signs of cystic changes and avascular necrosis determined by magnetic resonance imaging. She was effectively treated with a proximal row carpectomy. We suspect that the combination of the injury in combination with local corticosteroids and smoking may have led to the necrosis.

Idiopathic bilateral lunate and triquetrum avascular necrosis: A case report

We report on the case of bilateral avascular osteonecrosis (AVN) of the lunate and triquetrum in a 45-year-old woman without any relevant medical history for which the cause could not be established. She was treated conservatively with splinting and analgesics. The patient was able to pursue her work and hobbies with subnormal range of motion at 1-year follow-up. AVN of the triquetrum is very rare, as it is a richly vascularized bone. The presence of AVN in multiple carpal bones has only been described in patients receiving high doses of corticosteroids. To our knowledge, there are no other cases of idiopathic AVN of multiple carpal bones in the literature.

Cystic avascular necrosis of the triquetrum

Carpal bones are rarely affected by avascular necrosis (AVN) in the absence of fractures. The lunate is the most frequently affected carpal bone, followed by the scaphoid and the capitate. The triquetrum is rarely affected by AVN. We report a case of multiple cystic changes in the triquetrum in a patient with a history of trauma. He was treated by below elbow Colles plaster cast for 3 months, with no improvement. Cystic changes resulted from irreversible AVN of the triquetrum. This is the first case to be reported in the literature with cystic AVN changes in the triquetrum.