Clinical study of the Pronator Quadratus muscle: anatomical features and feasibility of Pronator-Sparing Surgery

Background: No clinical data for the relationship of pronator quadratus (PQ) muscle to distal radius had been reported. The aim of this study was to investigate the anatomical features of the PQ muscle related to plate osteosynthesis for distal radius fractures in clinical cases. The feasibility of PQ muscle sparing surgery was investigated as well. Methods: Fifty two distal radius fractures (23-A2) were enclosed in this study. The whole width of the muscle and the distance from the distal edge of the muscle to the joint surface of the distal radius were measured. The distance from the fracture site of the radius to the joint surface was measured as well. Results: The average width of the pronator quadratus muscle was 37.6 mm. The average distance from the pronator quadratus muscle to the lunate fossa surface was 12.2 mm, and the average distance from the pronator quadratus muscle to the scaphoid fossa surface was 13.6 mm. The average distance from the lunate fossa of the distal radius to the fracture site was 12.2 mm (range, 7.3-17 mm), and the scaphoid fossa of the distal radius to the fracture site was 13.2 mm (range, 9.4-18.8 mm). Conclusions: This PQ muscle sparing surgery is feasible and can be performed without difficulty. The data might provide a useful basis for the preservation of pronator quadratus muscle applied to a functionally reduced fracture regarding the potential efficacy of conventional volar plate osteosynthesis.