Tendon and Ligament Injuries in Older Horses
During the British Equine Veterinary Association’s 51st annual Congress, held Sept. 12-15 in Birmingham, U.K., Munroe described practical ways to tackle tendon and ligament injuries in senior horses.
Geriatrics often suffer these injuries for reasons unique to their age group. For instance, explained Munroe, they often go hand-in-hand with less-than-ideal hoof care (e.g., long toes or low heels), laminitis, age-related tissue breakdown, reduced exercise, self-inflicted trauma during turnout, or obesity.
“Owners (of senior horses) are more likely to use conservative, noninvasive treatments and have less expectations (of recovery),” he said, noting that these horses are less likely to be insured and more likely to be simply retired. And some owners might delay veterinary involvement for economic reasons.
Although older horses can develop a range of major soft tissue injuries, Munroe highlighted five of particular importance. These included inferior check ligament of the deep digital flexor tendon (DDFT, running from the back of the knee down to the fetlock) desmitis (ligament inflammation), digital flexor tendon sheath injuries, suspensory ligament desmopathies (disease), superficial digital flexor tendonitis (tendon inflammation), and traumatic injuries following skin wounds.
Inferior Check Ligament Desmitis
This inferior check ligament is an important structure that prevents overstretching of the DDFT in the forelimb, whereas its function in the hindlimb is less obvious, said Munroe. Problems in the forelimb structure can result from acute injury or adhesions, or they can occur secondary to a previous case of tendonitis or due to chronic severe desmitis.
“Forelimb desmitis is probably an age-related degeneration that predisposes to an acute tear,” Munroe explained. “It is more common in older horses, unusual in Thoroughbreds; common in ponies and draft crosses; and seen in older Warmblood sport horses.” He noted that injury rarely occurs in the hind limbs and when it does, it’s not likely to be age-related.
Clinical signs in acute cases include swelling, heat, and acute lameness. Signs of chronic cases are less obvious but include lower grade lameness or postural deformities of the affected limb, said Munroe. He noted that ultrasonography is essential for diagnosis.
Treatment for this injury includes aggressive anti-inflammatory measures such as cryotherapy, non-steroidal anti-inflammatory (NSAID) administration, compression bandaging, physical therapy, stall rest, and controlled walking. Chronic recurrent cases or those with postural deformities might require surgical repair.
“This injury can be slow-healing in older ponies,” Munroe added. He said the prognosis for acute cases is good; however, it’s guarded in aged horses with recurrent injury, hind limb cases, or with postural deformities.
Digital Flexor Tendon Sheath Injuries
Usually affecting the hind limbs, digital flexor tendon sheath injuries are “not uncommon in older ponies, Cob types, and large sport horses,” said Munroe. In these cases the digital sheath is distended, with pain upon flexing the lower limb, and thickening noticeable under the skin in Cobs and ponies, explained. Injury typically occurs during exercise or turnout.
Munroe also noted that these injuries are often associated with internal damage to structures such as the DDFT and secondary thickening of the annular ligament. Again, ultrasonography is essential for diagnosis.
Management of affected senior horses includes stall rest, hand walking, NSAIDs, cold therapy, and physical therapy. Corticosteroid therapy can help, Munroe said, but sometimes only temporarily.
“The prognosis is guarded to poor in geriatrics, especially without surgery,” he concluded.
Suspensory Ligament Desmopathies
Munroe noted that he sees suspensory ligament desmophaties in geriatrics either as recurrences of previous injuries due to excessive field exercise or as chronic age-related breakdown problems in older broodmares and sport horses. In these cases he often sees hyperextension of the hock, dropped fetlocks, and suspensory ligament thickening. Veterinarians are much less likely to treat these horses surgically and instead encourage conservative and medical management such as that listed previously. Severe bilateral (affected both sides) cases can be difficult to treat and carry a poor long-term prognosis, said Munroe.
Superficial Digital Flexor Tendonitis
Superficial digital flexor tendonitis cases typically occur in older horses as a recurrence of an old injury, particularly in racehorses, Munroe explained. Tendonitis can also occur in older animals on pasture without previous injury and might have poorer healing responses than younger animals. Recurrent injury could lead to adhesions and postural limb deformities. Older ex-show jumpers and dressage horses can also suffer from tendonitis of the upper portion of the tendon above the carpus (knee). Many veterinarians find it challenging to diagnose these cases accurately, said Munroe.
Recent publications have highlighted that older animals (greater than 20 years old) can rupture their tendon, probably as a result of age-related degeneration. The good news, however, is that with stall rest, bandaging, NSAIDs, and controlled exercise these horses can often return to their previous level of exercise.
Traumatic injuries are common in older animals, usually those on pasture, due to excessive exercise leading to new injuries or exacerbating old problems, or from kicks, falls, or crashes into objects with subsequent wounds, fractures, or infections.
Owners of senior horses should be on the lookout for soft tissue injuries such as these if their golden oldie turns up lame–just because he’s not in heavy work anymore does not mean he’s immune to tendon and ligament issues, Munroe relayed. Discuss treatment options with your veterinarian when injury occurs to identify which method will be most effective in helping your senior horse heal.
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