Functional and biomechanical assessment of the hand following ulnar forearm free flap transfer: Prospective self-controlled study.

[BACKGROUND] There is a shortage of well-designed self-controlled studies evaluating hand biomechanics following ulnar forearm flap (UFF) harvest. This study was conducted to evaluate objective and subjective functional outcomes of the donor's hand following UFF harvest.

[METHODS] All patients undergoing UFF were included for analysis. Grip strength, wrist movement, forearm supination and pronation, pinch strengths, sensation to light touch and temperature, and hand dexterity were assessed preoperatively and at 1, 3, and 6 months postoperatively. In addition, DASH score (disabilities of the arm, shoulder, and hand score) and Patient and Observer Scar Assessment Scale (POSAS) were analyzed.

[RESULTS] A total of 18 patients were enrolled. A significant reduction in grip strength for donor's hand was observed between preoperative and postoperative 1 and 3 months (mean difference = 14 kg, 7.38 kg, respectively, p = 0.000 for all). A similar trend was observed for pinch strength and range of motion (p < 0.05). Three months after surgery, there is still a significant reduction in tip pinch, tripod pinch, wrist extension, and supination. All biomechanics outcomes returned to preoperative baseline at 6 months after surgery. No patients suffered significant changes in sensation to light touch, temperature, and numbness by 6 months. There was a significant increase in DASH score by 3.37 points 6 months after operation (p = 0.000). The POSAS score indicates satisfaction with the appearance of the donor site.

[CONCLUSIONS] UFF is a safe and reliable option for oral cavity reconstruction with minimum donor site morbidities, mainly when cosmesis is paramount. Furthermore, objective hand biomechanics ultimately returns to its preoperative state within 6 months after surgery.