Replacement of the medial collateral ligament with polypropylene mesh or a polyester suture in dogs.

The medial collateral ligament of one stifle in 20 adult dogs was excised and replaced with polypropylene mesh or a polyester suture. After 26 weeks, the fibrous tissue-prosthesis composites were evaluated clinically, morphologically, and biomechanically. Clinical lameness was not significantly different after 10 days. The polypropylene mesh reconstructions consistently had more fibrous tissue and greater collagenous ingrowth than the polyester suture reconstructions. There were four complications related to fixation of the polypropylene mesh prosthesis and one to the polyester suture. The polypropylene mesh reconstructions had greater stability and were biomechanically more similar to the natural ligaments than the polyester suture reconstructions. Although the results with polypropylene mesh were favorable, more challenging biomechanical testing and alternative anchoring techniques are required before polypropylene mesh can be recommended as a collateral ligament replacement in dogs.

Delayed and nonunion fractures.

Failures in bone healing can result from technical problems, biologic failures, or a combination of the two. Inadequate stabilization of bone fragments against the effects of rotational forces is a common cause of nonunion. Early identification of a pseudoarthrosis can be difficult; the diagnosis is usually delayed, thus the morbidity associated with this disorder is significant. Often, the nonunion is complicated by atrophy of surrounding soft tissues, muscle contracture, and stiff joints. The goals in the treatment of the nonunion are to identify and correct the underlying causes, with the primary objective being the return of function. The type of treatment depends on the classification of the pseudarthrosis, including the condition of the surrounding soft tissues, blood supply, and viability of the nonunion, location, and presence or absence of infection.