Miscellaneous conditions of tendons, tendon sheaths, and ligaments

The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (fibularis tertius) and ligaments injuries of the back.

Tenoscopic release of the equine carpal canal

OBJECTIVE

To develop a tenoscopic method to divide the carpal flexor retinaculum and decompress the carpal canal.

STUDY DESIGN

Cadaver specimen study and prospective trial.

ANIMALS

Twelve cadaveric limbs, 4 clinically normal horses, and 2 clinically affected horses. Methods-A tenoscopic approach to the proximolateral aspect of the carpal sheath was used to identify and facilitate endoscopic division of the inner and outer layers of the carpal flexor retinaculum in cadaver limbs. The technique was further evaluated in 4 normal and 2 clinically affected horses.

RESULTS

Anatomic dissection, intraoperative observation, necropsy, histologic evaluation, and both short- and long-term clinical follow-up indicate that a tenoscopic approach that divides the inner layer of the carpal retinaculum can successfully decompress the equine carpal canal. No iatrogenic damage to surrounding structures was evident, division of the retinaculum was adequate and permanent, and clinical morbidity was negligible. Resolution of effusion was evident in both clinical cases of carpal canal syndrome and lameness resolved in the 1 horse in which long-term follow-up was possible.

CONCLUSIONS

Tenoscopic release of the carpal flexor retinaculum could provide a minimally invasive method to quickly, safely, and effectively decompress the carpal canal.

CLINICAL RELEVANCE

Tensocopic release of the carpal flexor retinaculum is a safe alternative to open division of the retinaculum to decompress the carpal canal in horses with carpal canal syndrome.

Arthroscopic removal of a palmar radial osteochondroma causing carpal canal syndrome in a horse

A 5-year-old Arabian stallion with moderate effusion in the right carpal canal and intermittent lameness in this limb was diagnosed to have an osteochondroma projecting from the distal portion of the radius into the carpal canal. oral phenylbutazone treatment over the next 3 years allowed the stallion to continue its show career. Right forelimb lameness returned at that time, and ultrasonography revealed the osteochondroma impinging on the dorsal surface of the deep digital flexor tendon. The owner elected to have the osteochondroma surgically removed. The horse was anesthetized, and the carpal sheath was distended with balanced polyionic solution. A 4-mm arthroscope was inserted into the carpal sheath, and the osteochondroma projecting into the sheath was identified. The osteochondroma was removed by use of a Ferris-Smith bone rongeur, which was inserted into the carpal sheath through a stab incision over the osteochondroma. The effusion in the carpal sheath and the lameness resolved by 2 months, and the horse was returned to training 4 months after surgery.

Quantitative Analysis of the Carpal Tunnel and Its Inner Structures in Primates

To explore the anatomical factors potentially involved in the high incidence of carpal tunnel syndrome in humans, we have quantified the anatomical variations of the carpal tunnel and its inner structures in humans, non-hominoid primates (monkeys), and hominoid primates (apes). In specimens of six humans, eight monkeys, and three apes, we assessed the size of the carpal tunnel, the tendons of the digit flexor muscles, and the median nerve. We compared the size of the carpal tunnel normalized by the wrist size, and the size of the median nerve and the tendons of the digit flexors normalized by the size of the carpal tunnel. Differences between humans and monkeys were calculated using the T test or Mann-Whitney U test, as appropriate. Data on the apes were not included in the statistical analyses due to the small sample size. The normalized size of the carpal tunnel was similar in all specimens. The normalized size of the tendons of the digit flexors was smaller in humans, while that of the median nerve was significantly larger. The median nerve was also larger in apes than in monkeys. The relatively larger median nerve observed in humans could suggest a greater vulnerability of the nerve to compression, which could predispose humans to carpal tunnel syndrome. However, the tendons of the digit flexor muscles were smaller in humans, and moreover, the proportional size of the median nerve was similar in apes, leading us to suggest that the factors predisposing humans to carpal tunnel syndrome must be sought beyond anatomical features and may be more closely related to functional or personal parameters.