Abstract: BACKGROUND: The treatment of volar plate fixation for distal radius fractures has been widely recognized. However, the current research on wrist stiffness and risk factors after volar plate fixation is still unclear.  
OBJECTIVE: To understand the stiffness of the radiocarpal joint after distal radius fractures and explore the related risk factors for joint stiffness.
METHODS:  A retrospective analysis was conducted in 125 patients with distal radius fractures who underwent surgical volar plate treatment in The First Affiliated Hospital of Wannan Medical College from May 2016 to July 2019. The general data of the patients and postoperative follow-up data were statistically analyzed. The degree of swelling of wrist joint before operation was evaluated. Fracture types and ulnar styloid process fractures were collected from preoperative X-ray films. Palmar inclination, ulnar declination and radial height were measured by X-ray films during the follow-up of 12 months after operation. The motion of radial wrist joint after operation was evaluated by goniometer. If the range of motion of flexion and extension did not exceed half of the contralateral, it was considered that there was radial wrist joint stiffness. Univariate analysis showed that P < 0.2 was a potential risk factor for joint stiffness, and then multivariate Logistic regression model was used.  
RESULTS AND CONCLUSION: (1) During follow-up, about 1/3 of distal radius fractures patients developed radiocarpal joint stiffness after volar locking plate fixation. (2) Univariate analysis showed that age (P=0.13), osteoporosis (P=0.02), preoperative swelling (P=0.01), fracture type (AO classification) (P=0.01), intra-articular fractures (P=0.01), postoperative palm inclination (P=0.05), and postoperative external fixation (P =0.19) were potential risk factors for joint stiffness after volar plate internal fixation for distal radius fractures. (3) Further Logistic regression analysis showed that fracture type (AO classification) (OR=1.21, 95%CI:0.98-1.56), intra-articular fractures (OR=1.17, 95%CI:1.06-1.97), preoperative swelling (OR=1.28; 95%CI: 1.12-1.85), osteoporosis (OR=1.32, 95%CI:0.86-1.77) and postoperative palm inclination (OR=1.46, 95%CI:1.01-1.89) were the independent risk factors for joint stiffness after volar plate internal fixation of distal radius fractures. (4) It is indicated that for patients with such risk factors, adequate preoperative evaluation, accurate preoperative planning, and timely and appropriate preventive treatment measures during postoperative follow-up are worthy of attention by orthopedic surgeons.

Key words: distal radius fractures, volar, internal fixation, wrist joint, stiffness, preoperative swelling