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In Street Clothes

Covering sports injuries from the perspective of a certified athletic trainer and backed by analytics.

Understanding Domantas Sabonis’ Thumb Avulsion Injury

The Kings revealed Monday that big man Domantas Sabonis has suffered “an avulsion fracture of the ulnar collateral ligament of his right thumb during Friday’s game versus the Wizards.”

The thumb is comprised of three bones, the first metacarpal of the hand and the proximal and distal phalanges. The proximal phalanx and first metacarpal form the metacarpophalangeal (MCP) joint at the base of the thumb. Two ligaments, the UCL and the radial collateral ligament (RCL), stabilize the MCP joint, preventing unwarranted motion while gripping or pinching.

The UCL attaches to the base of the proximal phalanx. Occasionally, when the ligament is stressed, the resulting force is so strong that it will also pull away a small piece of the bone creating an avulsion fracture.

Time lost to these types of injuries is often linked to the severity of the concurrent ligament damage, not necessarily the bone damage. UCL tears have been detailed multiple times on InStreetClothes.com when players like Bam Adebayo and Chris Paul have sustained the injury and undergone surgery. The average time lost for in-season UCL repairs in the NBA is 25.1 games (55.0 days). Unfortunately, the degree of Sabonis’ sprain has not been made public.

For now, Sabonis will attempt to play through the pain. Guard Avery Bradley suffered an avulsion fracture and UCL sprain during the 2015 season and did not miss a game. The Kings medical staff will attempt to tape and brace the area when Sabonis takes the court, and it is likely he wears a brace in between games. Surgery could still be an option if the ligament damage was substantial, but for now it seems Sabonis will continue to suit up for Sacramento.