Endoscopic examination of the carpal flexor tendon sheath in horses

Arthroscopic removal of palmar intermediate carpal bone fracture fragments in four horses using a transthecal approach through the carpal flexor tendon sheath

Objective

Study design

Animals

Methods

Results

Conclusion

Clinical significance

Determination of the anatomic communications among compartments within the carpus, metacarpophalangeal and metatarsophalangeal joints, stifle joint, and tarsus in llamas

OBJECTIVE

To determine the anatomic communications among compartments within the carpus, metacarpophalangeal and metatarsophalangeal joints, stifle joint, and tarsus in llamas.

SAMPLE POPULATION

88 limbs from 22 llamas necropsied because of reasons unrelated to disease of the carpus; tarsus; or metacarpophalangeal, metatarsophalangeal, or stifle joints.

PROCEDURE

1 compartment (randomly assigned) of each joint was injected with blue latex solution. Communication between joint compartments was determined by observation of latex in adjacent compartments following frozen sectioning.

RESULTS

Of the 44 carpi, 30 (68%) had anatomic separation between the radiocarpal and middle carpal joints, whereas the remaining 14 (32%) had communication between the radiocarpal and middle carpal joints. In the metacarpophalangeal or metatarsophalangeal joints, medial and lateral joint compartments remained separate in 83 of 88 (94%) joints injected. The tibiotarsal and proximal intertarsal joints communicated in all tarsi examined, whereas 14 of 38 (37%) communicated between the proximal intertarsal and distal intertarsal joints. Communication between the distal intertarsal and tarsometatarsal joints was detected in 17 of 25 (68%) specimens; all 4 tarsal joints communicated in 11 of 42 (26%) specimens examined. Examination of 33 stifle joints that were successfully injected revealed communication between the femoropatellar, medial femorotibial, and lateral femorotibial joints.

CONCLUSIONS AND CLINICAL RELEVANCE

These data suggest that it is important to determine the joint communications specific to each llama prior to treatment of septic arthritis. The metacarpophalangeal or metatarsophalangeal joint compartments may be considered separate, although the lateral and medial compartments infrequently communicate along the proximal palmar or plantar aspect.

Exostoses of the caudal perimeter of the radial physis as a cause of carpal synovial sheath tenosynovitis and lameness in horses: 10 cases (1999-2003)

OBJECTIVE

To determine the clinical, radiographic, ultrasonographic, and arthroscopic findings associated with tenosynovitis of the carpal synovial sheath induced by exostoses that originate from the caudal surface of the physeal scar of the distal radius and determine the results of surgical removal of those exostoses in horses.

DESIGN

Retrospective study.

ANIMALS

10 horses.

PROCEDURE

Medical records of horses with effusion in the carpal synovial sheath and lameness evaluated from 1999 to 2003 were examined.

RESULTS

All horses had a history of intermittent mild to moderate effusion of the carpal synovial sheath and lameness of 1 forelimb. Results of regional perineural and intrathecal anesthesia of the carpal synovial sheath confirmed that the lameness originated in the carpal synovial sheath. Radiography revealed exostoses originating from the caudal cortex of the distal radius at the level of the closed physis. Arthroscopy was performed for confirmation and removal of exostoses that penetrated the carpal synovial sheath and impinged on the deep digital flexor tendon. All horses returned to previous athletic activity. One horse had a recurrence of clinical signs 12 months after surgery, which resolved with medical treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Tenosynovitis of the carpal synovial sheath and lameness were caused by impingement of exostoses of the caudal radius on the lining and contents of the carpal synovial sheath. Although the clinical signs and surgical treatment were similar to that caused by osteochondromas, these exostoses developed at the level of the closed physis of the distal radius and were not radiographically or histologically similar to osteochondromas.

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.

Endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses

This study was designed to develop a reliable technique for endoscopic examination of the tarsal sheath of the lateral digital flexor tendon of horses. The anatomy of the tendon sheath and associated structures was studied in detail in cadavers before determining portals for the insertion of an arthroscope into the sheath. Approaches into the sheath through the proximal pouch and through the flexor retinaculum, at the level of the sustentaculum tali, were performed and compared in cadavers. The proximal pouch portal permitted visualisation only of the proximal half of the sheath, while the approach through the retinaculum allowed examination of the entire sheath. The normal endoscopic appearance of the tarsal sheath was studied. The endoscopic approach was subsequently used to examine and treat 5 horses with tarsal sheath tenosynovitis, including 2 cases of chronic, traumatic tenosynovitis and 3 of subacute septic tenosynovitis. Four of these horses had fragmentation of the sustentaculum tali. The technique allowed adequate examination of the sheath and debridement of adhesions and lesions within the lumen of the sheath. Fragments dorsal to the medioplantar edge of the sustentaculum tali could not be visualised endoscopically and had to be removed after widening of the wound. All 5 horses survived. Follow-up enquiries (8-31 months) revealed that the horses were all reported to be sound. Four were performing at their previous level of activity, 1 was used for hacking. The 2 cases presented with chronic tenosynovitis had residual sheath distension with no associated loss of function. A prospective study, including longer term follow-up investigation, is currently being performed.