Case study series written by ACPAT Scotland members
Ted is a seven year old Highland Pony who has been with his current owner since being a yearling. He initially presented to his Veterinary Surgeon with a four week history of intermittent left forelimb lameness and underwent a full lameness examination. He was subsequently diagnosed with a chronic annular ligament injury, confirmed by ultrasound scan. In consultation with the owner, a conservative, rather than surgical, approach was decided and Ted was referred by his Veterinary Surgeon for physiotherapy.
In devising any treatment plan, the affected structures and underlying pathology has to firstly be considered. The annular ligament is a fibrous band that wraps around the flexor tendons, forming a passage for the tendons to travel over the back of the fetlock (Image 1). The tendons normally glide through the band smoothly with each stride. Thickening of the annular ligament may or may not involve the digital sheath and associated structures. Injury, particularly when chronic inflammation is present, means the gliding movement through this passage becomes constricted. Lameness then results due to the limitation of normal free movement.
If we then consider tissue healing in very basic terms, it occurs in three overlapping stages:
- Inflammation to trigger the whole healing process
- Repair of the damaged areas, replacing with scar tissue
- Remodelling of the repair, enabling the new tissue created to do its required job
When an injury is chronic, the healing process remains in one, or more, of these stages. Treatment for a chronic complaint is therefore aimed at reactivating the process with the intention, in this case, of producing an end result of a functional annular ligament.
Fortunately in Ted’s case, the tendons were deemed unaffected, but he was still demonstrating lameness due to the thickening of the ligament. As characteristic with thickened annular ligaments, there was also a swollen contour of the back aspect of his affected fetlock. Having considered his presenting problems, the treatment plan devised incorporated several aspects of rehabilitation.
Deep friction massage was performed to the annular ligament, with the aim of inducing an inflammatory reaction, as well as mobilising adhered scar tissue. Therapeutic ultrasound was also applied to both control and to direct the process of tissue healing. To prevent further adhesions being formed, as the tissue repaired, Ted’s owner was shown a regime of passive movements and controlled exercises. With agreement from his Veterinary Surgeon, Ted was allowed restricted paddock rest rather than remaining on box rest. It was felt that this gentle movement would also encourage normal gliding of the tendons beneath the annular ligament, and so limit any possible secondary tendonitis caused by ongoing constriction. Due to the initial presence of lameness, compensatory muscle tension through his latissimus dorsi and triceps muscles was apparent and required intermittently releasing through the use of manual techniques.
Following any injury, retraining of the awareness of the body in a given space is required. This is more formally known as proprioception and is an aspect often overlooked, resulting in re-injury being more likely to occur. Think of the commonly sprained ankle in people whereby no balance exercises were performed as part of the recovery. How many complain of suffering recurrent sprains? As part of Ted’s rehabilitation, proprioceptive exercises were introduced, and he performed daily pole exercises, gradually adjusting and progressing as able. He also undertook in-hand work over varying surfaces and terrains including traversing slopes to provide some side to side stress to the fetlock and surrounding soft tissues.
The final aspect included general strengthening and conditioning work as well as exercises specific to tendon-muscle functioning. A phase of muscle work known as eccentric (pronounced e-centric) movement provides a braking mechanism for muscle and tendon groups. It is considered that through eccentric training, greater protection from injury or re-injury can be gained and so eccentric exercises were also incorporated into Ted’s recovery. Specific pole exercises and utilising natural slopes around the yard provide this retraining.
Throughout the above process Ted was closely monitored by his Veterinary Surgeon with ultrasound scans at four weeks and then again at ten weeks into treatment. This was pivotal in the decision for dictating the rate of progression of treatment and exercises. The 4 week scan showed a 50% reduction in ligament thickening, while the following scan demonstrated a further 30% improvement, confirming a positive outcome of the conservative approach. Although recovery is not yet fully complete, Ted is continuing with his rehabilitation, now progressing under saddle.
- Chartered Veterinary Physiotherapist
- BSc(Hons) Physiotherapy
- MSc Veterinary Physiotherapy
- MCSP, ACPAT Cat A
Tel: 07892 679393
Based in Alnwick, covering Northumberland, Tyne and Wear and Borders
For more information on Veterinary Physiotherapy or to find a Chartered Veterinary Physiotherapist in your area go to www.acpat.org