American Association for Hand Surgery
Theme: Beyond Innovation

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The Addition of an Oblique Lag Screw to T-Plate Fixation Decreases Rate of Nonunion in Trapeziometacarpal Arthrodesis
Lacey R. Pflibsen, MD; Mayo Clinic Arizona, Phoenix, AZ; Shelley S. Noland, MD; Mayo Clinic, Phoenix, AZ; Anthony A. Smith, MD
Division of Plastic and Reconstructive Surgery, Mayo Clinic Arizona, Phoenix, AZ

Introduction: T-plate fixation is a popular method for trapeziometacarpal arthrodesis in the osteoarthritic patient. 1,2 Previous studies report 8-18% rate symptomatic nonunion, 26% rate radiographic nonunion.1,2 The addition of an oblique lag screw to T-plate fixation may compress the arthrodesis site and decrease nonunion rate.
Materials & Methods: A retrospective review of all trapeziometacarpal arthrodeses for osteoarthritis by a single surgeon between 2010- 2018 was completed. Preoperative demographics, pain score, and Eaton classification were included. The technique was identical in all surgical cases, utilizing an oblique lag screw across the arthrodesis site from the metacarpal to the trapezium (Figure 1). Postoperative nonunion rate and time to clinical healing (absence of pain) and radiographic union were reviewed. Statistical analysis included t-test and standard deviation. Outliers greater than 3 standard deviations above the mean were excluded. The study was adequately powered based on previously published radiographic nonunion rates.
Results: A total of 22 trapeziometacarpal arthrodeses were performed on 17 patients using the above technique. The average age was 53, 71% female, 53% involving the dominant hand. All patients preoperatively reported constant pain refractory to conservative management. Mean preoperative Eaton classification was 2.74 ( 0.73). Mean time to clinical healing was 34 days ( 12 days), and mean time to radiographic union was 55 days ( 23 days). Mean follow up was 9 months, and no patients were found to have symptomatic or radiographic nonunion (Figure 2). Hardware removal was required bilaterally in one patient after complete healing.
Conclusions: The addition of an oblique lag screw to T-plate fixation is a novel technique in trapeziometacarpal arthrodesis. Patient demographics and Eaton classification were similar to previously reported studies. 1,3,4 In this study, no patients were found to have symptomatic or radiographic nonunion, which is lower than other published rates utilizing other techniques. 1,2

Figure 1. Postoperative radiograph of left first trapeziometacarpal arthrodesis utilizing an oblique lag screw and T-plate.

Figure 2. 21 months after trapeziometacarpal arthrodesis and 14 months after symptomatic hardware removal with continued trapeziometacarpal radiographic union.

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