A Comparison of Repair Methods for Gap Healing in Equine Flexor Tendon

Abstract

In nine horses (18 forelimbs), a 3 cm section of superficial digital flexor tendon was removed and the tendons were repaired with immobilization for 6 weeks and (1) no suture (n = 6); (2) a double locking loop tenorrhaphy with carbon fiber (n = 6); or (3) a double locking loop tenorrhaphy with size 2 nylon suture (n = 6). Clinical assessment, gross evaluation, morphometry, histology, and mechanical testing were performed on two limbs from each treatment group at weeks 6, 12, and 24. At weeks 6 and 12, the unsutured tissue was less mature than the tissue sutured with nylon. By week 24, the carbon fiber repair had breaking stress (mean, 12.5 M Pa) similar to the unsutured repair (mean, 10.6 M Pa). There was necrosis and a granulomatous foreign body reaction around the carbon fiber. The nylon suture repair had significantly greater strength per unit area (mean breaking stress, 20.4 M Pa) because of a smaller area of repair tissue in the gap (mean, 3.6 cm2). At week 24, the nylon suture repair tissue was the most mature with the least inflammation of the three repair methods. A nylon double locking loop suture was the preferred method for equine flexor tenorrhaphy of a tendon gap because of greater breaking stress, histologic maturity, biocompatibility, and the adequate functional and cosmetic outcome.

Surface-active phospholipid (surfactant) in equine tendon and tendon sheath fluid

“…This lubricating potential becomes relevant during tendon injuries. Adhesions and reduced function are common sequelae to tendon damage and/or surgery in the horse (Bertone et al 1990;Easley et al 1990). These adhesions do not appear to aid the healing process and clinical management of tendon injuries should attempt to limit the formation of adhesions (Manske et al 1984).…”

The effects of bone marrow stromal cell transplants on tendon healing in vitro

“…This hypocellularity is worsened after injury and surgical repair [19,20]. Furthermore, in tendon healing there is a risk of gap healing rather than a contact healing, due to the effect of muscle tension on the repaired tendon, especially with postoperative rehabilitation [20–23]. This effect may be potentiated by the inherent delay in healing associated with tendon hypovascularity.…”

“…They found that a gap with a mean value of 3.2 mm was present at the final follow-up in 24 of 34 repaired FDP tendons in zone II [24]. Gap healing following flexor tendon injury and repair has also been observed in animal models [20,22,25]. Delivery of new cells directly to the injury site could therefore be a useful therapeutic strategy both to accelerate healing and reduce the risk of late gapping.…”

Mid Metacarpal-Metatarsal Tendon Laceration Repair

“…If the free cut ends of the flexor tendon are cleanly transected and appear healthy, primary repair should be performed to improve alignment and early strength of the repair. 4,5 If the ends of the flexor tendon are extensively retracted, swollen, or discolored or the wound appears to be significantly infected, the area should be debrided and allowed to heal by second intention. In select cases, delayed primary closure can be performed with or without tendon suturing.…”

“…4,9,10 Therefore, during the early stages of tendon healing, the repair must be protected from weight-bearing forces with cast application or other external support. External support should be provided for a minimum of 6 to 8 weeks following repair.…”