Healing characteristics of deep digital flexor tenorrhaphy within the digital sheath of horses.
OBJECTIVE
To describe the healing characteristics of deep digital flexor tenorrhaphy within the digital sheath.


METHODS
Experimental study.


METHODS
Five mature horses.


METHODS
Right thoracic limb, deep digital flexor tenorrhaphy was performed within the digital sheath. Limbs were cast in partial flexion using a short limb cast for 6 weeks. Next, extended heel shoes were used for limb support for 14 weeks. Healing was evaluated by sequential ultrasonographic examinations, and limb use was evaluated by force plate analysis. At 26 weeks, mechanical strength and morphologic characteristics of the repair site were evaluated.


RESULTS
Gap (mean, 0.93 cm.) formation was evident in unloaded limbs at 3 weeks. This increased markedly by 6 weeks and was 5 cm at 26 weeks. Demarcation between the deep and superficial flexor tendons decreased as the transected ends adhered to the dorsal surface of the superficial flexor tendon. The intrathecal space was reduced by fibrous tissue. Mean maximum load to failure of the repair tissue was 4,616 +/- 3,556 N, with a mean stress of 12.99 +/- 2.78 MPa. The repair consistently failed at the adhesion between the transected tendon and the superficial flexor tendon.


CONCLUSIONS
Intrathecal tenorrhaphy with external coaptation (in partial limb flexion) for 6 weeks resulted in gap healing, fibrous adhesion between the deep and superficial flexor tendons, fibrous tissue reduction of the intrathecal space, and a pasture-sound horse at 26 weeks.


CONCLUSIONS
Without improved methods for immobilizing the deep digital flexor tendon, intrathecal tenorrhaphy is unlikely to result in first intention tendon healing.
Department of Veterinary Clinical Sciences, Civil and Environmental Engineering, and Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
Henry
H
Jann
Margaret
M
Blaik
Robert
R
Emerson
Michiko
M
Tomioka
Larry
L
Stein
David
D
Moll
D000818:Animals; D005260:Female; D005552:Forelimb; D005684:Gait; D006736:Horses / Q000293:injuries* / Q000601:surgery*; D007103:Immobilization; D008297:Male; D013314:Stress, Mechanical; D013536:Suture Techniques / Q000662:veterinary; D013708:Tendon Injuries / Q000000981:diagnostic imaging / Q000601:surgery / Q000662:veterinary*; D013710:Tendons / Q000601:surgery*; D014463:Ultrasonography; D014945:Wound Healing