Integrity of pronator quadratus repair and grip strength after anterior plating of distal radial fractures

Between February 2020 and May 2023, distal radial fractures treated with anterior locking plate fixation at a tertiary referral centre were prospectively screened. Of 87 fractures treated during the study period, 42 AO/OTA type A fractures met the eligibility criteria. Patients with open fractures, associated neurovascular injury, primary distal radioulnar joint instability, previous wrist surgery or injuries requiring additional fixation were excluded. During intraoperative assessment, two patients had irreparable pronator quadratus (PQ) disruption and were also excluded, leaving 40 patients for final analysis.

All procedures were carried out using a standardized anterior approach by three national board-certified orthopaedic trauma surgeons with upper limb trauma experience (KT, HC). The pronator quadratus (PQ) muscle was elevated in continuity and repaired after fixation whenever tissue quality allowed. A distal muscle cuff was preserved whenever feasible, and repair was done with interrupted absorbable sutures to the radial periosteum or residual radial PQ tissue, according to local anatomy. To permit postoperative assessment of repair integrity, two radiopaque haemoclips were placed along the radial border of the repaired PQ. Serial radiographs obtained during routine follow-up were compared with immediate postoperative radiographs, and disruption was defined as clip displacement of ⩾1 cm. Measurements were independently assessed by two orthopaedic surgeons (TE, OGM) and disagreements resolved by consensus.

At a minimum of 12 months follow-up, the integrity of the PQ repair was preserved in 34 patients and disrupted in six. Grip strength, expressed as a percentage of the contralateral side, was greater in patients with preserved repair integrity than in those with disrupted repair (86 vs. 64%; independent samples t-test, p = 0.006). Quick Disabilities of the Arm, Shoulder and Hand scores and wrist motion, including flexion, extension, pronation and supination, were similar between groups (Figure 1). Complications were infrequent and showed no clear association with PQ integrity. One patient developed a postoperative distal radioulnar joint instability requiring secondary treatment; however, this was not clinically apparent at initial presentation and therefore did not meet the exclusion criteria.

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Figure 1.

Grip strength (percentage of contralateral side) according to the integrity of pronator quadratus repair at final follow-up. Each dot represents an individual patient. The box represents the interquartile range (IQR), the central line indicates the median and the whiskers extend to the minimum and maximum values. The density curve illustrates the distribution of values within each group.

The role of PQ repair after anterior plating is debated (Mulders et al., 2017; Sonntag et al., 2019; Ying et al., 2023). Randomized studies and meta-analyses have generally reported limited benefit from repair with respect to patient-reported outcomes and wrist motion. Our findings are consistent with these observations, although preserved PQ integrity may make a limited contribution to recovery of postoperative grip strength. As PQ contributes to forearm pronation and distal forearm stability, maintenance of muscle continuity may improve force transmission during gripping without necessarily altering global upper limb function. Recent randomized evidence reported no substantial improvement in overall clinical outcomes after PQ repair (Lamas et al., 2024; Sonntag et al., 2019). However, these studies compared repair with no repair, whereas the present study explored the functional relevance of the preserved integrity of repair. Nevertheless, the present findings should be interpreted cautiously because clip displacement has not been validated as a surrogate marker of PQ failure; radiographic obliquity and absence of calibration may have influenced clip-based measurements and the disrupted repair group was small. Grip strength was normalized to the contralateral limb, although hand dominance could not be formally adjusted because of the limited sample size. These findings should therefore be regarded as exploratory and hypothesis-generating and warrant confirmation in larger studies.