Adel Ebrahimpour - Department of Orthopedic Surgery, Shohadaye Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohamad Okhovatpour - Department of Orthopedic Surgery, Shohadaye Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Ali Tabrizi - Department of Hand and Microsurgery, Panzdahe Khoradad Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Background: Ulnar collateral ligament(UCL) fracture-avulsion of the thumb which involves small osseous fragments is among common injuries to the thumb metacarpophalangeal (MCP) joint.Methods: This case series was conducted on ۱۱ patients (۹ males and ۲ females) with a mean age of ۲۵.۴±۴.۸ years with acute traumatic UCL fracture-avulsion with instability and Stener Lesion. A low-profile ۲-mm stainless steel hook plate with a ۲-mm screw was used for the internal fixation. Immobilization was performed for ۱۰ days. Range of motion movements (ROM), grip power, and pinch strength were measured after three months. At the end of the follow-up period, functional outcomes were determined by the visual analog scale (VAS), and Quick Disabilities of the Arm, Shoulder, and Hand (Quick DASH). Results: The mean follow-up period was reported as ۱۲.۴±۲.۳ months. the union of avulsed small osseous fragments occurred at the end of the three-month follow-up. A number of ۱۰ patients were treated by one hole ۲-mm plate with a screw and a mean VAS score of ۲۲.۵±۲.۴, while a female patient had more severe pain with a mean score of ۴۵. This patient complained about the irritation of the plate, especially in the thumb grip. The mean Quick DASH score was ۹.۶±۱.۴. The postoperative ROM was similar to that of the other side. Grip power and pinch strength were lower in the treated thumb, as compared to that in the opposite side; nonetheless, the difference was not statistically significant. Conclusion: As evidenced by the obtained results, it can be concluded that the hook plate technique is a strong fixation method for thumb UCL fracture-avulsion, raising the possibility of earlier joint movements and rapid recovery; nevertheless, in some cases, it can reduce efficiency and induce painful grip.Level of evidence: I

Fracture-avulsion, hook plate fixation, Ulnar collateral ligament, Skier’s thumb, Thumb