Article
Corrective intra-articular osteotomy after malunion in Bennett fractures: surgical technique and first results
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Published: | February 6, 2020 |
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Objectives/Interrogation: A malunion with an intra-articular gap after a Bennett's fracture can lead to a painful trapeziometacarpal (TMC) joint and patients can develop early osteoarthritis of the thumb base. We hypothesized a correction through an intra-articular osteotomy to be a valid procedure for those patients who present with pain and impaired strength.
Methods: Three patients were seen with a painful and debilitating malunion after a period of minimum 8 months that did not respond to conservative treatment. The malunion was diagnosed using conventional radiographs and confirmed with a cone beam CT scan. A Gedda-Moberg incision was used to expose the TMC joint and the intra-articular gap was identified. A closing wedge osteotomy was then performed under fluoroscopic control, thus excising the intra-articular gap and restoring joint congruency. The osteotomy was fixed with 3 1.5 mm screws. Patients were immobilized for a period of two weeks before active movement was initiated. Pain, mobility of the thumb and strength were assessed before the intervention and 6 months postoperative. A cone beam CT scan was used to control union of the osteotomy after 6 months.
Results and Conclusions: Mean pain according to the visual analogue scale decreased from 88/100 to 7/100. Opening of the first web, MP mobility, opposition and retropulsion did not change. Mean grip strength improved from 34 kg to 40 kg (42 kg contralateral), mean key pinch improved from 4 kg to 10 kg (10 kg contralateral) and mean precision pinch improved from 5 kg to 7 kg (7 kg contralateral). All three fractures showed union and restoration of the joint congruency after 6 months.
Intra-articular osteotomy of the first metacarpal base is a new technique to treat a malunited Bennett's fracture. The first results show excellent pain relief, preservation of the joint mobility and restoration of strength to a near normal level. Larger studies with longer follow-up are needed to evaluate whether the procedure can prevent the natural progression towards osteoarthritis of the TMC joint.