Mid-term Outcomes in Perilunate Dislocations

Abstract

Introduction: Perilunate dislocations and fracture-dislocations are often related to fair or poor results. The goal of this study is to analyze radiographic and functional outcomes of surgically treated patients with perilunate injuries. Methods: We assessed a retrospective series of 37 patients (36 male), mean age 36 (range, 17-71), with a mean follow-up of 4 years (range, 1-10.1). All were subject to worker’s compensation. All patients had dorsal perilunate dislocations; there were 13 cases of perilunate dislocation and 24 cases of perilunate fracture-dislocations. Seventeen patients had a scaphoid fracture and 7 presented other fractures (radial styloid, triquetrum, etc.). All patients had surgical treatment with k wire carpus stabilization, open ligamentous repair (24 cases), scaphoid fixation (9 k wire, 8 headless screws), and other bone fixation when indicated. The Mayo wrist score (MWS) was used for functional evaluation. Radiographic examination was focused in osteoarthritis and instability, according to Herzberg classification. We defined poor results patients with at least one of the following: MWS < 60 points, advanced osteoarthritis, scapholunate instability (SL gap > 5 mm or SL angle > 70°), scaphoid nonunion, or major surgery: proximal row carpectomy (PRC), wrist arthrodesis, or nonunion surgery. Results: Patients had a mean flexion of 44.8° (SD 15.2) and mean extension of 46.8° (SD 16.7). Two cases had severe stiffness (less than 30° arc of motion). Mean grip strength was 66% of contralateral (SD 19.2). According to MWS, 1 patient had excellent results, 7 good (19%), 18 fair (49%), and 11 patients poor results (30%). According to our definition of poor results, 24 of 37 (65%) patients had an unsatisfactory outcome. Radiographic evaluation showed 10% of advanced osteoarthritis and 45% of instability signs. Six patients were classified as Herzberg A (normal alignment without osteoarthritis) and 11 patients as A1 (normal alignment with osteoarthritis). One patient showed instability without osteoarthritis (B) and 11 patients showed instability with osteoarthritis (B1). Seven patients had x-rays modified by the treatment (C). Five patients with trans-scaphoid fracture dislocation had nonunion, 4 of them went to bone graft and only 2 of these get union. One scaphoid nonunion went directly to PRC. There were 3 total wrist arthrodesis (2 due to arthritis and 1 due to instability) and 4 PRC, 3 in context of failed nonunion treatment and 1 in a severe and complex instability. Discussion: Perilunate dislocations and fracture-dislocations are complex injuries with a high rate of unsatisfactory outcomes. Our series showed poor clinical outcomes in 65% which correlate with the poor and fair results in the MWS. We observed a high rate of nonunion in trans-scaphoid dislocations, carpal instability, and articular degenerative changes. These factors would be independent of patient functional performance.