High Failure Rates in Comminuted Patella Fractures (AO/OTA 34-C3) Fixed With an Isolated, New Patella-Specific 2.7-mm Variable-Angle Locking Plate.

OBJECTIVES

To compare the outcomes of comminuted patella fractures fixed with a new patella-specific 2.7-mm variable-angle (VA) locking plate in isolation versus when augmentation of fracture fixation is applied with the plate.

DESIGN

Retrospective.

SETTING

Academic Level I Trauma Center.

PATIENT SELECTION CRITERIA: All acute comminuted patella fractures (AO/OTA 34-C3; complete displaced or undisplaced articular, frontal/coronal multifragmentary fractures) in adult patients primarily treated with a new patella-specific 2.7-mm VA locking plate (Synthes, Paoli, PA) between January 2021 and February 2024 at a single academic center were reviewed and divided into those fixed with the patella plate alone and those with additional bony and/or soft-tissue augmentation. Excluded were those with <90 follow-ups, set a priori, unless complications occurred <90 days.

OUTCOME MEASURES AND COMPARISONS: Comparison of patient age, sex, body mass index, American Society of Anesthesiologists score, fracture risk (FRAX) score, open fracture, polytrauma involvement, length of follow-up, and postoperative protocols was made between groups. The primary outcome measure was loss of fixation. Secondary outcomes included mode of failure and other surgical complications.

RESULTS

There were a total of 38 included patients, with no lack of or loss of follow-up, with 20 grouped into patella plate alone and 18 into patella plate plus augmentation. The plate-only group had a higher mean age (63.7 vs. 46.9, P = 0.024), with no between-group differences in sex (65% vs. 44% women, P = 0.20), body mass index ( P = 0.51), 10-year FRAX ( P = 0.06), open fractures ( P = 0.30), polytrauma involvement ( P = 0.97), or postoperative weight-bearing ( P = 0.76) or range of motion ( P = 0.06) protocols. There were 8 failures (40.0%) in the plate-only group and 2 failures in the plate with augmentation group (11.1%; P = 0.043). When controlling for known risk factors for osteoporosis and poor bone quality using the FRAX 10-year fracture risk on multivariable regression analysis, plate fixation with fracture augmentation was associated with a lower risk of fixation failure (odds ratio = 0.14, 95% CI 0.02-0.75; P = 0.036). The plate-only group failed by loss of distal (62.5%, n = 5) and proximal fixation (37.5%, n = 3). Each of the 2 failures in the plate plus augmentation group had a loss of distal fixation.

CONCLUSIONS

Treatment of comminuted patella fractures with a new patella-specific 2.7-mm VA locking plate had a high failure rate when used in isolation. Augmenting fracture fixation with soft-tissue repair and/or independent fracture fragment fixation may significantly decrease failure rates. In particular, augmentation of the tendon avulsion component to restore the extensor mechanism appears critical.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.