Location Of Distal PQ Repair In Distal Radius Fractures: A Cadaveric Biomechanical Study
Julianna Y Lee, BA1; Brendan Stewart, BS1; Ian J Wellington, MD2; Elifho Obopilwe, MS2; Benjamin Hawthorne, BS1; Caitlin G. Dorsey, BS2; Craig Rodner, MD2
1University of Connecticut School of Medicine, Farmington, CT; 2University of Connecticut, Farmington, CT
Introduction In the repair of distal radius fractures, there is still much debate about how to best repair the pronator quadratus (PQ) muscle or whether the muscle needs to be repaired at all. If done properly, repairing the PQ can provide a protective layer between the overlying flexor tendons and the volar plate. The purpose of this study was to evaluate the tendinous insertion distal to the PQ and to compare two locations of distal transection on the strength of the subsequent repair during surgical management of distal radius fractures.
Methods Eighteen fresh-frozen cadaveric forearms were dissected to the PQ muscle. The PQ muscle and the distal zone was measured using a MicroScribe digitizer. Specimens were randomly allocated (n = 9/group) for transection of the distal PQ at the myotendinous junction (red group – images A, B) or parallel to the myotendinous junction at the midsection of the distal tendinous zone (white group – images C, D). The distal PQ was repaired for both groups using two figure-of-8 sutures. The radius and ulna were positioned in 90° of wrist extension and load-to-failure testing of the repair was performed at 1 mm/second. The maximum amount of force applied to the PQ was recorded for each specimen.
Results The PQ had a mean width of 31.41 ± 5.74 mm, mean height of 53.79±7.46 mm, and a mean area of 1604.27 ± 429.20 mm2. The tendinous zone had a mean width, height, and area of 29.71 ±5.83 mm, 12.22 ±2.79 mm, 282.94 ±148.30 mm2 respectively. Independent samples t-test showed the average load to failure for the white group was significantly higher than that of the red group (White group: 29.46 ± 4.24 N; Red Group: 13.78N ± 6.66 N; p = 0.012).
Conclusions Our results contribute to the literature a better understanding of the PQ anatomy via assessment of the tendinous zone that spans the PQ width distal to the muscle belly. We demonstrate that transection and subsequent repair of the PQ in this distal white tendinous region is stronger than incision and repair at the red myotendinous junction. These findings propose an optimal location to incise and repair the PQ in distal radius fractures as a method to protect the flexor tendons and possibly decrease the likelihood of tendon rupture.
Back to 2023 Abstracts