Anatomical Variations of the Distal Radius and Their Influence on Functional Outcomes After Open Reduction and Internal Fixation

Background: Distal radius fractures are common injuries with highly variable outcomes despite advances in surgical fixation. Anatomical parameters such as radial height, inclination, volar tilt, and lunate fossa morphology are key determinants of wrist biomechanics. Variations in these parameters may significantly influence recovery following open reduction and internal fixation (ORIF). Objective: To evaluate anatomical variations of the distal radius and their impact on functional outcomes in patients undergoing ORIF with volar locking plates. Methods: This prospective observational study was conducted at tertiary care hospitals in Pakistan from June 2024 to March 2025. Seventy patients aged 18–70 years with acute distal radius fractures (AO types A–C) underwent ORIF using volar locking plates. Preoperative and postoperative radiographs were analyzed for radial height, inclination, volar tilt, and lunate fossa morphology. Functional outcomes were assessed using the Disabilities of the Arm, Shoulder, and Hand (DASH) score, Visual Analog Scale (VAS) for pain, wrist range of motion, and grip strength at 6 weeks, 3 months, and 6 months. Results: The mean age of patients was 44.6 years, with 58.6% females. At final follow-up, mean radial height was 11.2 mm, inclination 21.1°, and volar tilt 9.3°. Restoration of these parameters correlated significantly with improved DASH scores (p < 0.05) and grip strength. Patients with shallow or irregular lunate fossae demonstrated slower functional recovery and early radiographic arthritic changes. Complications occurred in 20% of patients, most commonly stiffness. Conclusion: Anatomical variations of the distal radius significantly affect functional outcomes following ORIF. Accurate restoration of native radial height, inclination, and volar tilt, alongside recognition of lunate fossa morphology, is essential for optimizing postoperative recovery.