Abstract

Management of chronic scapholunate instability without osteoarthritis remains controversial. Some surgeons favor partial wrist arthrodesis; others, soft tissue stabilization. Many techniques for soft tissue repair have been described but with few or unpredictable results. We reviewed all our cases of scapholunate instability without osteoarthritis treated by soft tissue stabilization. Since 1979, 37 soft tissue stabilization procedures have been performed to correct dynamic (25) or static (12) scapholunate instability without osteoarthritis. The average time from injury to surgical treatment was 7.2 mos. (range 0.25 to 36 mos.). Three cases were treated within the first month of injury. The choice of repair was determined intraoperatively. The scaphoid shift must be easily reducible to make the case eligible for soft tissue repair. The scapholunate ligament was usually disrupted from palmar to dorsal, and the average amount of disruption was 74%. When scapholunate ligament remnants were of sufficient quality, secondary repair was performed; but if not, ligament reconstruction using tendon grafts or capsulodesis was performed. The procedures used were secondary ligamentous repair in 16 (by direct suture, reinsertion using anchor and/or transosseous reattachment), ligament reconstruction using tendon grafts in 6, capsulodesis in 7 and a combination of these procedures in 8. The mean follow-up was 27 mos. (range 2 to 62 mos.). Postoperatively, there was an 83% decrease in pain. The average wrist motion was 60 degrees extension, 47 degrees flexion, 18 degrees radial deviation and 28 degrees ulnar deviation (92%, 84%, 106% and 88% of preoperative values and 88%, 75%, 78% and 76% of the uninvolved wrists, respectively), and the grip strength was 28 kg (117% of preoperative value and 78% of the uninvolved wrists). On roentgenograms, the mean static scapholunate distance was 4.2 mm (a 26% loss of reduction compared to the early postoperative gap), but scapholunate and radiolunate angles were within normal values (58 degrees and 9 degrees, respectively). At follow-up, one patient presenting a small zone of chondromalacia on the scaphoid at the time of secondary ligamentous repair developed severe radioscaphoid arthritis 15 months postoperatively. The results were further assessed according to the form of instability, delay before surgery, severity of disruption and type of repair. Patients with static instability showed worse clinical and radiological findings than those with dynamic instability. Surgical delay did not influence the outcome. The more severe the ligament disruption was, the poorer were the results. All types of repair had a comparable outcome except those treated by ligament reconstruction using tendon grafts. The results in the latter group were unsatisfactory in terms of motion, grip strength and radiological findings. This technique has been abandoned by the group. In conclusion, soft tissue stabilization is part of the armamentarium in the management of reducible chronic scapholunate instability without osteoarthritis. Ligament reconstruction using tendon grafts gave, in our hands, unsatisfactory results. Otherwise, all types of repair achieved a relatively pain-free wrist, with acceptable motion, grip strength, scapholunate and radiolunate angles but with a wider than normal static scapholunate distance. A longer follow-up is needed to assess the effect of this abnormal gap. Factors that favorably affected the outcome were: dynamic type of instability and partial disruption of the ligament.