Introduction. Midcarpal instability is an uncommon but troublesome problem. Patients have loss of dynamic control of the wrist in pronation and ulnar deviation due to laxity of the volar wrist ligaments that is often congenital or due to minor trauma. For those in whom conservative measures fail, open ligament reconstruction or fusions have been described. Aim. We prospectively studied a series of fourteen patients who underwent arthroscopic thermal capsular shrinkage for midcarpal instability. Methods. All patients were assessed clinically and by fluoroscopy and arthroscopy to confirm the diagnosis. Wrist arthroscopy with four portals was performed and monopolar radiofrequency capsular shrinkage was performed using a 2.3mm probe. Post-operatively the wrist was immobilised in a splint for 6 weeks. Results. Fourteen wrists in eleven patients were treated. Mean length of follow-up was 44 months. Symptoms of instability never occurred in three wrists and rarely occurred in eleven. The patient's subjective overall assessment of the wrist was ‘much better’ in ten wrists, ‘better’ for one wrist and ‘worse’ for three wrists. These three cases had persistent pain but improvement of instability symptoms. Two of these cases belonged to the same patient who had Ehlers Danlos syndrome. All patients were satisfied with the outcome and would have the same procedure again. The mean pre-operative DASH score was 35.2 and 17.1 at the most recent follow-up. Mean flexion decreased by 25% and mean extension by 17%. There were no significant complications. Conclusion. Capsular shrinkage is an effective procedure for midcarpal instability. Although there are some concerns regarding deterioration of results over time as seen in shoulder instability, these mid-term results show that this is currently not a problem

This prospective study evaluated our results of arthroscopic electrothermal capsular shrinkage intrinsic (palmar) for midcarpal instability. This method of treatment has not been described in the wrist in current literature. Following clinical and video fluoroscopic diagnosis arthroscopy of the wrist and capsular shrinkage was performed on five patients. A radiofrequency probe was mainly used on the ulnar arm of the volar arcuate ligament and the dorsal capsule of the radiocarpal joint. One patient was lost to follow up. At a mean follow up of 11 months the results were: one excellent, two good and one fair using the Green and O’Brien wrist scoring system (. Table1. ). The average range of motion was 95 percent of the opposite wrist. We concluded that arthroscopic radiofrequency capsular shrinkage is an effective, minimally invasive method of treatment for intrinsic midcarpal instability. Table 1 . Total wrist score (Modified Green and O’Brien):. Excellent:. 90 – 100. Good:. 80 – 89. Fair:. 65 – 79. Poor:. < 65

Introduction and Aims: Midcarpal instability is a common cause of wrist pain that remains poorly understood. A simple surgical treatment has been developed involving plication of the dorsal wrist capsule and ligaments. We hypothesised that: wrist stiffness varies in the population; laxity permits excessive displacement; and plication stiffens the joint decreasing motion. Method: Twelve human cadaveric forearms were potted using bone cement and were secured to the stationary baseplate of a slider. The hand was fixed through the metacarpal bones to the mobile section of the slider, and a compressive load was applied. With the wrist positioned in neutral orientation, a force was applied by an Instron mechanical testing machine (Model 8874, Instron, Canton, MA), simulating a midcarpal shift test. Stiffness (force/displacement) was measured at baseline, with the capsule sectioned, and then following a surgical procedure consisting of plicating the ligaments and capsule with three mattress sutures at the midcarpal joint. Results: Baseline testing revealed large variability in midcarpal joint stiffness: mean baseline stiffness was 16.5 + 5.9 N/mm, ranging from 9.3 to 28.1 N/mm. Following plication/repair, mean stiffness increased significantly by 20% to 19.8 + 8.5 N/mm (p < 0.02). All surgical repairs withstood the testing without failure. These data confirm a wide range of laxity at the midcarpal joint and provide a mechanical basis for the success observed with capsular plication of the joint. This increased stiffness decreases motion under comparable loading conditions. In individuals who have excessive motion causing wrist symptoms, increasing the stiffness by capsular plication of the supporting ligaments decreases the motion to relieve symptoms. This technique has found success in clinical practice to relieve symptoms in patients with midcarpal instability. Conclusion: Midcarpal joint stiffness spanned a threefold range supporting our hypothesis that there is a large variation of ligament laxity in the population. Suturing the dorsal wrist capsule and underlying ligaments significantly increased the stiffness of the wrist when a volar force was applied across the midcarpal joint

The August 2012 Wrist & Hand Roundup³⁶⁰ looks at: the Herbert ulnar head prosthesis; the five-year outcome for wrist arthroscopic surgery; four-corner arthrodesis with headless screws; balloon kyphoplasty for Kienböck's disease; Mason Type 2 radial head fractures; local infiltration and intravenous regional anaesthesia for endoscopic carpal tunnel release; perilunate injuries; and replanting the amputated fingertip.