Scoping review of comminuted fractures of the proximal phalanx in horses.

Background: Comminuted fractures of the proximal phalanx (CFPP) occur in adult horses. Various treatments have been described. It remains uncertain which is the best therapeutic option.

Objectives: This study aims to review systematically the existing literature on CFPP in horses, evaluate treatment modalities, synthesise outcomes to assess treatment efficacy and survival rates, and identify knowledge gaps for future research.

Study Design: Scoping review.

Methods: A literature search was conducted using online databases. The bias quality of each article was evaluated. Chi-squared analysis was used to detect differences between types of CFPP in each paper (based on the presence [moderately comminuted, MCFPP] or absence [severely comminuted, SCFPP] of an intact cortical strut between both adjacent joints).

Results: Thirty-nine papers met the criteria for inclusion in this review. In total, 409 cases were identified. The survival rate (SR) was 77% for MCFPP and 51% for SCFPP with a significant difference between fracture types (odds ratios [OR]: 3.16; 95% confidence interval [CI]:1.64-6.24; p < 0.001). For MCFPP, the SR was 85% following lag screw fixation (SF). SF yielded significantly better outcomes compared to SF with transfixation cast (TFC) (SF vs. SF + TFC: p = 0.02). Cast immobilisation (CI) alone was associated with a SR of 50% (1/2) and 85% (11/13) for MCFPP and SCFPP, respectively. For SCFPP fractures, treatment with Ci showed significantly superior results compared to SF and TFC (CI vs. SF + TFC: OR: 6.65; 95% CI: 1.11-73.96; p = 0.04) and plate fixation with arthrodesis of two joints (PF2) (CI vs. PL2: OR: 9.60; 95% CI: 1.54-110.23; p = 0.006).

Main Limitations: All reviewed studies were retrospective. Fracture definitions, data collection periods, follow-up time and methods varied between studies.

Conclusions: This study showed that SRs between 35% and 85% may be expected for CFPP. In MCFPP, SF appears to be a good treatment option. The merits of cast immobilisation alone should be discussed with owners if surgery is not an option in MCFPP or SCFPP.