Perilunate fracture-dislocations: clinical and radiological results of 21 cases.

Background: Perilunate dislocations and fracture-dislocations are a subcategory of the carpal instability complex. Herein, we report our university hospital experience with this complex injury. The goal of our study was to find predictive factors and quantify the development of arthritis and lunate necrosis. We tried to measure the impact of arthritis on hand function.

Methods: Between January 2000 and December 2014, 21 patients underwent surgery for perilunate dislocations and perilunate fracture-dislocations of the wrist in our tertiary university center. Mean patient age was 29.3 ± 10.0 years (range 18-49 years). All displacements were posterior. They were reviewed both clinically and radiologically.

Results: Complications included misdiagnosed Essex-Lopresti-like lesion in one case, insufficient reposition of the carpus in two cases (LT in one case, SL in one case), and iatrogenic injury to the radial artery immediately sutured in one case. All 3 cases underwent a second procedure with satisfactory outcome. After a mean follow-up of 112 ± 60 months (range 12-210 months), the average Cooney score was 80 ± 19 (range 50-125). The mean PRWE score was 10 ± 8 (range 0-25). The mean DASH score was 40 ± 13 (range 30-75 months). Mean pain on load, measured with VAS was 1.1 ± 1.6; Clinical examination assessed a mean wrist extension/flexion of 42.4° ± 17.2°/48.4° ± 15.2°. Mean wrist ulnar/radial deviation was, respectively, 22.9° ± 11.3°/15.3° ± 7.0°. Mean pro/supination was, respectively, 75.2° ± 11.5°/76.3° ± 8.1°. Mean pinch strength was 9.4 ± 2.2 kg (87.4 ± 17.7% of the contralateral side). Mean power strength was 41.9 ± 9.9 kg (76.2 ± 19.2% of the contralateral side). Two patients had a scaphoid non-union identified on their most recent imaging. The mean carpal height ratio was 0.53 ± 0.05 (range 0.44-0.65). All except one patient developed arthritis: Grade 1 in 11 patients, Grade 2 in 3 patients, and Grade 3 in the remaining 6 patients. Age, length of follow-up, and loss of reduction were significantly associated with wrist arthritis (p < 0.001). Lunate avascular necrosis assessed by magnetic resonance imaging was present in 6 patients: Stage 2 in 4 patients, Stage 3a in 1 patient, and Stage 3b in the remaining patient. All these patients' intraoperative findings showed lesion of the cartilage of the radial side of the lunate. However, the small number of patients who developed lunate necrosis did not allow satisfactory statistical analysis.

Conclusions: This retrospective study demonstrates good functional results despite the high rate of radiological wrist arthritis. Age, length of follow-up, and loss of reduction were significantly associated with wrist arthritis in our series.