Review Question - QID 218093

Avascular necrosis (AVN) of the capitate is an exceedingly rare phenomenon without a standardized treatment protocol, however, most surgeons recommend following a pragmatic approach. Pre-collapse stages without arthritic changes in young patients should be treated with a trial of conservative management followed by decompression or vascularized bone grafts (Answer 2).

Most encountered cases of AVN in the carpus are seen in the scaphoid secondary to trauma or in the lunate secondary to idiopathic causes. The overall prevalence of AVN in the other carpal bones occurs in the following descending order: capitate, hamate, trapezium, trapezoid, triquetrum, and pisiform. Despite being the third most common carpal bone afflicted by AVN, the overall number of cases involving the capitate renders it an exceedingly rare disease without a dedicated treatment protocol. The majority of cases are described in case reports or small case series with <10 patients. Updated systematic reviews involve <100 patients. However, the recommendations throughout these reports include following a pragmatic approach similar to the treatment of Preiser (idiopathic scaphoid AVN) and Kienbock disease (idiopathic lunate AVN). In this manner, there lie 3 general groups of patients: (1) AVN without fracture/collapse, (2) AVN with fracture/collapse but no arthritic changes, and (3) AVN with fracture/collapse and arthritic changes. This patient falls within the first group which can be managed conservatively or with decompression and bone grafting (i.e. local vascularized bone graft). The second group can be treated with capitate proximal pole excision and interposition grafting, bone grafting, partial pyrocarbon replacement, or fusion. The final group entails arthritic changes that should be managed with fusion procedures. In summary, this is a young patient that has failed a trial of conservative management. Of the options provided, this patient would best be managed with curettage and interposition of a local vascularized bone graft. The 4+5 extensor compartment vascularized bone graft serves as one potential option using a local pedicled rotational bone graft that does not require microvascular anastomosis.

Afshar and Tabrizi provided a brief review article regarding AVN of the carpal bones. They review the overall prevalence of each carpal bone AVN and overview of potential treatment options. They note that the early stages of the disease can be treated with conservative management, vascularized bone grafting for pre-collapse stages, and arthrodesis for end-stage disease. The authors conclude that the aims of treatment should be to prevent the eventual collapse of the bone and restore carpal height/alignment or, in the setting of arthritis, improve pain to allow for functional usage of the afflicted hand.

Peters and colleagues performed a retrospective case series review of their 6 patients treated for capitate AVN. They performed arthrodesis in all patients with overall mixed outcomes at an average 9-year follow-up. Additionally, they performed a systematic review of available cases (n=42) in the literature for comparison of outcomes. They noted potentially better outcomes in patients treated during the pre-collapse stages with non-fusing procedures. The authors concluded by providing their level V recommended treatment algorithm for this rare pathology.

Figure A demonstrates a T2 coronal MRI image of this patient’s wrist with fluid accumulation and cystic changes of the capitate proximal pole without subchondral collapse or fracture.

Answer 2: Proximal pole excision with pyrocarbon resurfacing has been described for the treatment of AVN of the capitate with collapse, however WITHOUT arthritic changes.
Answer 3: Arthritic changes to the capitate is considered a contraindication to proximal row carpectomy (PRC), which is why PRC has not been described for treating capitate AVN.
Answer 4&5: Scaphocapitolunate arthrodesis and four-corner wrist fusion would both be considered appropriate treatment options if collapse with arthritic changes are present at the initial presentation or in patients who have failed salvage procedures (i.e. if this patient fails the vascularized bone graft).