gms | German Medical Science

Objectives/Interrogation: In order to restore the anatomy after a fracture and ensure complete biomechanical functionality of the thumb, osteosynthesis (ORIF) of the fractured first metacarpal bone is advised. Nonetheless, secondary displacement regularly occurs despite the use of variable angle locking plates, screws and k-wires. The objective of this retrospective study was to assess the anatomical and functional outcome of secondary displaced fractures after ORIF.

Methods: Between January 2013 and December 2017 65 patients were diagnosed with a fracture of the first metacarpal bone which was subsequently reduced and fixed with locking plates, screws or k-wires in our clinic. 12 (18%) of 65 patients developed a secondary displacement. We analysed the radiological and clinical records in terms of malpositioning, treatment and functional outcome.

Results and Conclusions: The majority (10/12) of malpositions included a volar dislocation (mean 34.4°) after using a T-shaped locking plate (TLP). One patient of the TLP-group (1/10) had to undergo revision with a corrective osteotomy and a change to a double-row locking plate. Additional six patients from the entire cohort (8/12 or 66%) underwent metal removal after a healed fracture. For the other 6 patients no metal removal was performed. Range of motion (ROM) and pinch strength (PS) was comparable to the contralateral side in all analysed patients. Secondary displacement of ORIF of first metacarpal fractures is probably more frequent than desired despite variable angle locking plates. Despite secondary displacement of fractures of the first metacarpal bone, there was no significant impairment of the ROM and PS. However, we suspect that using TLPs might bear an increased risk for secondary displacements especially in intraarticular fractures of the first metacarpal bone. Depending on the type of fracture grid plates or double plating, bone graft and adjustment screws should be considered.