Fibrotic Contracture of the Infraspinatus Muscle with or without Contracture of the Teres Minor Muscle: A Retrospective Study in Eight Dogs

TL;DR

This study reports on eight dogs with fibrotic contracture of the infraspinatus muscle and finds that surgical treatment resolves lameness effectively.

Contribution

This is the first study to report the coexistence of fibrotic contracture in both the infraspinatus and teres minor muscles in dogs.

Findings

Surgical tenotomy of the infraspinatus muscle resolved lameness in all eight dogs.

Three dogs also had teres minor muscle contracture, which was successfully treated with tenotomy.

Postoperative recovery was rapid, with all dogs returning to full activity within 15 days.

Abstract

Muscle contracture refers to the pathologic process that results in fibrosis and permanent damage to a muscle. Theoretically, any muscle can be affected. This study retrospectively reviewed eight cases of the fibrotic contracture of the canine infraspinatus muscle. The treatment was the tendon’s tenotomy at its insertion and the release of all adhesions. In three cases, a teres minor simultaneous contracture was detected intraoperatively, which was treated via the tenotomy of the affected muscle. This is the first study to report the contracture of the teres minor muscle and its simultaneous coexistence with the fibrotic contracture of the infraspinatus muscle. Postoperatively, strict limitation of physical activity for two weeks followed by a gradual return to the full limb’s activity and analgesic and anti-inflammatory drugs were prescribed. The outcome was excellent, as the lameness resolved within two weeks in all cases. This retrospective study aims to compare its results with the literature to enrich the data on muscle contracture. Contracture of the infraspinatus and teres minor muscle should routinely be considered as a cause of thoracic limb lameness.

(1) Background: Fibrotic contracture of the canine infraspinatus muscle (FCIM) is considered an uncommon musculotendinous condition mainly affecting hunting dogs. After an acute onset of a painful non-weight-bearing lameness over a period of one to four weeks, a characteristic circumducted gait is developed in the affected thoracic limb. (2) Methods: Eight client-owned dogs of varying breeds, both sexes, aged 4–9 years old, and weighing 14–26 kg participated in the study. The duration of lameness prior to their first consultation ranged from 10 to 450 days. All participants were thoroughly examined clinically, orthopedically, and radiographically. (3) Results: The dogs underwent infraspinatus tenotomy, resulting in improved limb function. In three cases, a teres minor muscle contracture was revealed intraoperatively and resolved via a tenotomy at its insertion. The findings showed that 15 days post-operation, all dogs returned to full activity. The results obtained confirm and reinforce the literature data around FCIM and describe the first recorded condition of the simultaneous contracture of the infraspinatus and teres minor muscles. (4) Conclusions: In every case of shoulder lameness, contractures of all shoulder muscles should be included in the differential diagnosis and patients should be assessed for concurrent contractures even if infraspinatus contracture is identified.

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