Locked versus nonlocked plate fixation for hallux MTP arthrodesis

Dorsal plate fixation is used commonly for arthrodesis of the hallux first metatarsophalangeal (MTP) joint. Custom dorsal plates incorporating locking technology have been developed recently for applications in the foot to provide relative ease of application and theoretically superior mechanical properties. The purpose of this study is to compare the radiographic and clinical outcomes of patients undergoing hallux MTP joint arthrodesis using a locked plate, or a nonlocked plate.

We compared consecutive patients who underwent hallux MTP arthrodesis for a variety of diagnoses with either a precontoured locked titanium dorsal plate (Group 1) or a precontoured, nonlocked stainless steel plate (Group 2). All patients were evaluated with radiographs, visual analog pain scale, American Orthopaedic Foot and Ankle Society (AOFAS) hallux score, and a detailed patient satisfaction survey.

There were 73 feet in Group 1 and 107 feet in Group 2. There was a trend toward a higher nonunion rate in Group 1 compared to Group 2. When considering only patients without rheumatoid arthritis (RA), the union rate was significantly higher in Group 2 compared to Group 1. Hardware failure and the overall complication rate was equivalent between the two Groups.

As locked plate technology continues to gain popularity for procedures in the foot, it is important that clinical outcomes are reported. Locked titanium plates were associated with higher nonunion rates. Improved plate design, patient selection, and an understanding of plate biomechanics in this unique loading environment may optimize future outcomes for hallux MTP arthrodesis.