Midcarpal arthrodesis (MCA) with excision of the scaphoid is in our opinion a reliable procedure. Pitfalls and unsatisfactory results can be attributed to technical shortcomings during the operation or to poor indication.
From 1993 to 2001, 64 MCA were performed in 62 patients. Patients' subjective assessment of the results were evaluated according to the clinical records and telephone interviews concerning pain, function and patient satisfaction. Pre- and postoperative standard X-rays were analyzed.
Among 27 patients operated because of SNAC wrist, the following severe complications were observed: three painful non-unions, which healed after revision doing the same procedure, one deep infection, treated by complete wrist arthrodesis later on. Among 25 patients operated because of SLAC wrist there was one non-union, treated by complete arthrodesis, two transient dystrophies, one marked malposition of the lunate and two patients with persistent pain without any recognisable reason on X-rays. Among seven patients operated because of SLAC-wrist due to chondrocalcinosis, three had pain correlating to a too proximal position of the triquetrum, one of them together with a malposition of the lunate in the p.a. view. One other patient was dissatisfied without any obvious reason. Among three patients operated because of carpal instability persisting after closed reduction of perilunar dislocation, two had persistent pain also correlating to a proximal position of the triquetrum. One patient operated because of destruction of only the midcarpal joint complained of persistent pain on loading the wrist. The overall non-union rate was 6 %. After treating the complications 14 patients remained with unsatisfactory results, seven of them due to a special preoperative situation, four due to technical shortcomings during surgery. The other patients have been free of pain or much improved and able to work. Optimum results may only be obtained, if the lunate is carefully aligned.
After SNAC and SLAC without more complex lesions of the carpal ligaments, good results may be predicted, a correct operative technique provided. Chondrocalcinosis is a relative contraindication to MCA.