Tenoscopic Treatment of Physeal ‘Spike’ Remnants of the Caudal Radius in the Thoroughbred Racehorse

Introduction: New bone on the caudal distal radial physis can traumatize the surface of the deep digital flexor tendon (DDFT), resulting in hemorrhage and tenosynovitis.

Materials and Methods: Racehorses that underwent tenoscopy for removal of physeal ‘spike’ exostoses were identified. The presenting signs and surgical details were recorded. Days from surgery to first start and maximum rating were obtained from racing records. When horses had raced before surgery, ratings were compared using Wilcoxon Matched Pairs test.

Results: Sixty-nine racehorses underwent surgery on 72 occasions, aged 1 to 12 years (median 2 years). Carpal sheath effusion was identified in 59 (85%) horses. Haemorrhagic fluid or haemosiderin was found in 65 horses (94%). There was damage to the cranial surface of the DDFT in 67 horses (97%). New bone was identified on the radius in all cases and on the contralateral radius in 65 horses (94%). Fifty-three horses (77%) raced after surgery, after a median time of 211 days (range 60–690 days). Of 28 cases that raced before and after surgery, the median maximum rating fell by 3lb (p = 0.37).

Discussion/Conclusion: New bone on the caudal radial physis was consistently identified radiographically, not an unusual finding in the young Thoroughbred. In the large majority of cases the surgical findings included evidence of extensive haemorrhage in the tendon sheath. Tenoscopic surgery for impingement by a physeal ‘spike’ was a successful procedure, with the large majority of horses returning to full racing.

Acknowledgement: There was no proprietary interest or funding provided for this project.