Kyla Ortved

Objective Chronic foot pain, a common cause of forelimb lameness, can be treated by palmar digital neurectomy (PDN). Complications include neuroma formation and lameness recurrence. In humans, neuroanastomoses are performed to prevent neuroma formation. The aim of the study was to evaluate the outcome of horses undergoing dorsal‐to‐palmar branch neuroanastomosis following PDN. Study design Retrospective case series. Animals Eighty‐five horses with PDN and dorsal‐to‐palmar branch neuroanastomosis. Methods Medical records for horses undergoing this procedure at two hospitals between 2015 and 2020 were reviewed. Palmar and dorsal nerve branches of the PDN were transected and end‐to‐end neuroanastomosis was performed by apposition of the perineurium. Follow‐up was obtained from medical records and telephone interviews. Success was defined as resolution of lameness for at least one year. Results Lameness resolved following surgery in 81/85 (95%) horses with 57/84 (68%) sound at one year. Postoperative complications occurred in 19/85 (22%) cases. The main limitations of the study were an incomplete data set, inaccurate owner recall, and variations in procedure. Conclusion Compared to previous studies, this technique resulted in similar numbers of horses sound immediately after surgery, a comparable rate of postoperative neuroma formation but a higher recurrence of lameness rate at 1 year postoperatively. Clinical significance End‐to‐end neuroanastomosis of the dorsal and palmar branches of the PDN does not reduce the rate of neuroma formation in horses. Long‐term outcome was less favorable compared to previously reported PDN techniques.

Background Increasing accessibility and advancements in computed tomographic (CT) imaging improve understanding of the contributors to poor performance in the Thoroughbred racehorse. Objectives To characterise an unreported site of tarsal subchondral bone injury (SBI) in Thoroughbred racehorses. Study design Retrospective, cross‐sectional analytical study. Methods Tarsal CT scans of 108 horses were reviewed for evidence of SBI in the dorsodistolateral calcaneus (DDLC). Signalment, including age, breed, sex, and discipline of horses, was recorded. The association of DDLC SBI with Thoroughbred racehorse compared to other breeds/disciplines was calculated. Nuclear scintigraphic scans of the hindlimbs of Thoroughbreds between 2007 and 2022 were also reviewed for increased radiopharmaceutical uptake (IRU) suggestive of DDLC SBI. Results Tarsal CT scans of 108 horses were analysed and lesion location and type were recorded. DDLC SBI was identified in 8/108 (7.3%) horses. All lesions were found in racing Thoroughbreds (Fischer's exact test p = 0.002) and in 20% (8/40) of racing Thoroughbreds that underwent tarsal CT. DDLC SBI was determined to be the primary cause of lameness in 3/8. Third tarsal bone fracture was considered the primary cause of lameness in 3/8 horses. A total of 1663 nuclear scintigraphic scans of 1603 Thoroughbred horses were reviewed. Increased IRU in the DDLC was present in 13 horses (0.9%). Main limitations Study limitations include the retrospective nature of the study, incomplete medical records, lack of sensitivity/specificity data for lesion identification on various imaging modalities or comparison to histopathology, and limited substantive follow‐up information. Conclusions The DDLC is a previously unreported site of SBI in the Thoroughbred racehorse. The lesion can be the primary source of lameness but may also be found in horses with other clinically relevant osseous injuries. This lesion may be underestimated in the Thoroughbred population. Further investigation is required to determine the true prevalence, clinical relevance, and prognosis in Thoroughbred racehorses with this injury.