Capped hock, also known as “pseudobursitis” of the hock, is a fairly common ailment that affects all breeds and disciplines of horses equally. It occurs as a consequence of direct trauma to the point of the hock (or tuber calcaneous).
Separation of tissue planes at the time of injury may result in the accumulation of subcutaneous fluid along the point of the hock. In essence, a “false” bursa (or synovial sac) is created. With time, the bursa develops a permanent lining that continually produces synovial-like fluid.
Lameness may or may not be present in association with a capped hock. In most cases, a capped hock is merely a cosmetic blemish. Swelling is usually fluctuant (soft) initially, but can eventually become quite firm with time/ chronicity. In many cases swelling becomes permanent unless it has been successfully treated during the acute stage.
Due to the nature of the disease, capped hocks tend to recur and become worse with each recurrence. Therefore, it is important to treat capped hocks aggressively at their onset.
Stall rest. This is most effective in acute cases (i.e. if injury is recent).
Cold-water hosing and/or application of ice. Again, more effective in the acute stage.
Topical therapy (we recommend Dexamethasone Sweat Spray). Although this strategy is most effective in the acute phase, we have also observed positive response in subacute and chronic cases.
External pressure via wrapping of the area. Although this method can be effective at reducing swelling, bandaging of the hock area is very difficult and often results in secondary complications, such as skin compromise/ devitalization along the point of the hock and associated gastrocnemius (Achilles) tendon. We therefore try to avoid wrapping of the hock in most cases.
Drainage of bursal fluid via needle aspiration. Although this provides temporary relief, fluid quickly re-accummulates within the bursa unless some measure(s) are taken to prevent recurrence.
Intrasynovial injection. Although this technique doesn't work in every situation, it has proven to be an effective approach for treatment of capped hocks. Recurrence occurs in about 40% of cases treated via this technique.
Surgical debridement of the psuedobursa. Although fluid-producing synovial lining is removed with this technique, subsequent develop of fibrosis (scar tissue) in the area usually negates the positive effect of surgery. Since most horses with capped hocks are not lame, surgical treatment poses a considerable risk with regard to creating chronic postoperative lameness and is therefore rarely recommended.
At The Atlanta Equine Clinic we typically drain the fluid pocket and subsequently infuse a combination of steroid, atropine and antimicrobial (antibiotic) in an attempt to “dry up” synoviocytes (fluid-producing cells) that have developed within the pseudobursal lining. Following treatment, a thin layer of Dexamethasone Sweat Spray is applied daily to support and enhance the effect of the injection. The sooner treatment is implemented, the better it tends to work.