Arthrodesis to correct deviation of the phalanges in the horse

Proximal Interphalangeal Arthrodesis in Horses: A Meta-Analysis of Retrospective Studies

The aim of this study was to determine the clinical outcomes reported in retrospective studies of proximal interphalangeal arthrodesis (PIA) in horses through a meta-analysis of retrospective studies. CAB Abstracts, PubMed, ScienceDirect, Web of Science, and Scopus were searched. The primary outcomes included survival and surgical site infection (SSI) rates, return to activities, and time of hospital stay and casting. Subgroups were formed for fractures and other conditions. Meta-analyses were performed with fixed and random effects models to estimate proportions, mean values, and effect size by odds ratio (OR) with 95% confidence intervals (CI). Twenty-one full articles were included, totaling 458 horses. The survival rate was 90% (95% CI [86%-93%]), return to activities was 65% (95% CI [61%-70%]), and SSI was 12% (95% CI [8%-16%]). The mean hospitalization was 25 days (95% CI [18-35 days]) and time of casting was 29 days (95% CI [21-42 days]). The OR of survival (P = .769), return to activities (P = .576), and SSI (P = .467) were similar between cases of fractures and other conditions. PIA is an efficient and safe method to treat injuries in the pastern region, with a high survival rate and low SSI. However, the rate of return to soundness for intended use was modest, being potentially lower for fracture cases. Thus, investigations of more efficient interventions are needed to improve this outcome.

Modified Proximal Interphalangeal Joint Arthrodesis in a Yearling Filly with an Osseous Cyst-Like Lesion in the Proximal Phalanx

After the medial femoral condyle (MFC), the phalanges are the second most common site for osseous cyst-like lesions (OCLLs). Conservative treatment of phalangeal cysts on the convex surface of proximal phalanx presents a technical problem with access to the stoma of the cyst. Surgical therapy options usually aim to avoid cyst enlargement through drilling or screw placement or to encourage lesion filling with osteoconductive material. This paper describes a case of treatment of the OCLL in a yearling Czech warmblood filly with surgical arthrodesis, together with the packing of the OCLL with calcium phosphate biocement (CPB). The filly showed a chronic, moderate to severe, intermittent left hindlimb lameness. Dynamic examination combined with regional anesthesia and radiography confirmed a clinically significant large OCLL on the distal joint surface of the first phalanx. Treatment of the OCLL was performed by surgical arthrodesis of the proximal interphalangeal joint, using two paraxial and one axial crossed lag screw, after curetting of the cyst and filling with CPB.

Endotoxin, interleukin-6 and tumor necrosis factor concentrations in equine acute abdominal disease: relation to clinical outcome

Serial peri-operative plasma and serum samples from 55 horses suffering from acute abdominal disease and presented for surgical intervention were assayed for the presence of endotoxins (lipopolysaccharides; LPS), tumor necrosis factor (TNF) and interleukin-6 (IL-6). At study entry, venous blood was collected for blood cultures. Intra-operatively collected ascitic fluid samples were assayed for the presence of LPS. The clinical course of the disease was documented. Four horses were excluded from the study. At study entry, 21 of the 51 horses (41%) had increased platelet-rich plasma LPS concentrations, i.e. ≥ 5 ng/l (mean 35.5; range 7-197 ng/l), in 34 horses (67%) IL-6 concentrations were increased, i.e. exceeding 35 ng/l (mean 364; range 36—1762 ng/l). Detectable TNF was present in 5 horses (10%); 3 of them died spontaneously during surgery. In all TNF positive samples, markedly increased LPS and IL-6 concentrations were detected. Study entry IL-6 concentrations were significantly higher in non-surviving (mean 394; range < 20—1762 ng/l) than in surviving horses (mean 116; range < 20—894 ng/l; P < 0.0002). This was most evident when non-surviving horses with inflamed bowel disease were considered (mean 1096; range 650—1762 ng/l; P < 0.0001). Positive ascitic fluid LPS concentrations (≥ 3 ng/l) were encountered in 18 horses. There was no significant correlation between the LPS concentrations in ascites and plasma. Study entry concentrations of IL-6 were significantly correlated with LPS concentrations (r = 0.62; P < 0.001) and were inversely correlated with platelet counts (r = -0.46; P < 0.002). The magnitude of a calculated LPS-cytokine score strongly correlated with mortality (P < 0.001). Receiver operating characteristic (ROC) curve analysis showed that the IL-6 assay had reasonable accuracy for the prediction of unfavorable outcome (i.e. the area under the curve equalled 0.72), in contrast to the LPS assay. The results indicate that LPS, TNF and IL-6 are predominantly released in the systemic circulation of horses suffering from inflamed and ischemic bowel disease. IL-6 concentrations have predictive value for unfavorable outcome and the simultaneous presence of increased LPS, TNF and IL-6 concentrations is especially associated with a poor clinical condition and outcome.

Proximal interphalangeal joint arthrodesis in 34 horses using two parallel 5.5-mm cortical bone screws

OBJECTIVE

To report clinical experience with arthrodesis of the proximal interphalangeal joint in horses using two parallel 5.5-mm cortical bone screws placed in lag fashion.

STUDY DESIGN

Retrospective, clinical study.

ANIMALS

Thirty-four horses, aged 1 to 19 years.

METHODS

Medical records for all horses admitted (1991-1997) for pastern arthrodesis using two 5.5-mm ASIF cortical bone screws, in parallel orientation, and placed in lag fashion by use of a combined aiming device to facilitate accuracy were reviewed. Signalment, lameness diagnosis, duration of lameness, limb(s) involved, and outcome were recorded. Criteria for successful outcome were determined as return to previous level of function or future intended athletic use.

RESULTS

Thirty-nine proximal interphalangeal joint arthrodeses were performed on 34 horses. One horse was euthanatized in the recovery room and was excluded from data analysis. Successful outcome occurred in 85% of frontlimbs and 89% of hindlimbs. Failure occurred in 5 joints; 1 horse had lameness directly associated with surgery, whereas 4 horses had unrelated lameness.

CONCLUSION AND CLINICAL RELEVANCE

Age, breed, and initial disease did not affect outcome. Arthrodesis of the proximal interphalangeal joint by use of two 5.5-mm ASIF cortical bone screws, in parallel orientation, placed in lag fashion by use of a combined aiming device, resulted in sound use of the limb in >85% of the joints with shortened postoperative coaptation.

Arthrodesis of the equine proximal interphalangeal joint: a biomechanical comparison of three 4.5-mm and two 5.5-mm cortical screws

OBJECTIVE

To compare the biomechanical characteristics and mode of failure of 2 parallel-screw techniques for proximal interphalangeal joint arthrodesis in horses.

STUDY DESIGN

Randomized block design, blocking for horse (1-5), method of screw fixation (three 4.5-mm vs two 5.5-mm), side (left limb vs right limb), and end (front limb vs hind limb). Constructs were loaded to failure in 3-point bending in a dorsal-to-palmar (plantar) direction.

SAMPLE POPULATION

Twenty limbs (10 limb pairs) from 5 equine cadavers.

METHODS

A combined aiming device was used to facilitate consistent screw placement. Three parallel 4.5-mm cortical screws were placed in lag fashion in 1 limb of a pair, and 2 parallel 5.5-mm cortical screws were placed in lag fashion in the contralateral limb. Arthrodesis constructs were tested in 3-point bending in a dorsal-to-palmar (plantar) direction using a materials-testing machine. Loading rate was 19 mm/s. Maximal bending moment at failure and composite stiffness were obtained from bending moment-angular deformation curves. Data were analyzed using ANOVA and chi(2) analysis.

RESULTS

There were no significant differences in bending moment (P >.05, power = 0.8 @ delta = 19%) or composite stiffness (P >.05, power = 0.8 @ delta = 19%) between the 2 fixation techniques. Higher maximal bending moment was found in front limbs than hind limbs, and front limbs with two 5.5-mm screws than hind limbs with two 5.5-mm screws. In all cases, constructs completely failed. A greater number of 4.5-mm cortical screws failed than 5.5-mm cortical screws. CONCLUSIONS-In pastern arthrodesis constructs loaded in 3-point bending, end (front limb vs hind limb) affected maximal bending moment at failure of constructs. There was no significant effect of horse, treatment, or side on maximal bending moment or stiffness. Two 5.5-mm cortical screws should provide a surgically simpler pastern arthrodesis than three 4.5-mm cortical screws while maintaining similar biomechanical characteristics.

CLINICAL RELEVANCE

Three 4.5-mm screws or two 5.5-mm screws will provide similar biomechanical characteristics in bending when performing equine pastern arthrodesis.