Muscle lacerations are generally deep and can understandably worry a horseowner that his horse will never return to work. However, unless a muscle is cut all the way through or has obvious nerve damage, the prognosis for the horse returning to full use is better than with tendon/ligament damage or joint disease.
Even gaping, unsutured wounds with extensive muscle damage heal well with time and proper care. However, returning the horse to his previous work level involves more than healing the cosmetic, outside injury. It may also involve some ingenuity.
Muscle tears always heal with scar tissue, even when they've been sutured back together, and the scarred area is not functional. A scar within a muscle is a stiff bit of tissue that lacks the characteristics of a normal muscle. Scar tissue can't contract or relax, lengthen, shorten or stretch.
Periods of swelling and discomfort are expected when exercise resumes, as the scar tissue undergoes minor breakdowns and remodeling to suit the stresses being applied to it. However, as long as some of the original muscle remains intact, eventually the horse learns to move the area normally and usually return to work.
For the first two to four weeks following a muscle laceration, it's important to restrict motion in that area, so that a bridge of connective tissue/scar can form between cut edges of the muscle. Too much movement during this healing time will lead to repeated breakdowns of the still weak tissue, resulting in more scarring.
Incomplete healing is indicated when there's heat and swelling at the injury site (assuming any infection is cleared up) and the horse is in pain when he moves. Once the horse can move around normally at a walk, it's time to begin a rehab-exercise program, starting slowly.
• Horses with injuries that cut into a muscle need two to four weeks after any infection clears for the initial scarring to become strong enough to hold up to exercise. Stall confinement during this time is advisable.
• Hand walk the horse once he can move comfortably.
• Rehab to full performance can be lengthy and requires an exercise routine that will regularly stretch the injured muscle.
• Be alert for signs of stress in other areas due to the horse shifting weight to other legs during rehab.
• Anticipate nine to 12 months before the horse can return to his original work level. Setbacks are common, as the scarred areas break down and remodel.
• Liniments or capsaicin rubs and pulsed electromagnetic therapy can help ease soreness and spasms.
Case History
We followed the struggles of a racehorse after suffering damage to the extensor muscles of a front leg. He made it back to racing, but it was a tough year. In fact, the setbacks were severe enough to indicate permanently impaired ability.
While it's important to limit movement until sufficient scar tissue has formed, you need to start mobilizing the horse as soon as you can, so the scar tissue doesn't shorten and tighten, making it that more difficult for the horse to regain full range of motion. For some horses, progression from stall rest to hand walking to turnout works perfectly.
