Surgical or Medical Therapies for Stifles; When and Why

This represents a common clinical conundrum when working up a subtle hindlimb lameness/poor performance case, and this presentation will focus on this scenario. In these cases, lameness is often localised to the stifle joint(s) with a complete or partial response to intra-articular local analgesia. When there are minimal changes on diagnostic imaging, and with the lack of a specific diagnosis, the optimal treatment option is often unknown. This question will remain hard to answer objectively, as many diagnoses are only made at surgery and thus are treated surgically. The precise diagnosis often remains elusive in medically treated cases, so comparing the outcomes in surgically vs. medically treated cases will be difficult.

In acute cases of stifle pain the site of pain may be obvious, as with the development of localised joint distension and inflammation. In most cases, however, diagnostic local analgesia is required. Blocking all three compartments of the stifle concurrently is the most thorough approach to localisation to the entire stifle, although the medial femorotibial joint is the most commonly affected joint in adult sports horses, and blocking this in isolation may allow more specific localisation.

Diagnostic imaging of the area should include both radiography and ultrasonography. Unfortunately, there can be a tendency to overinterpret the latter, which is a particular problem when survey imaging is undertaken, rather than it being directed by thorough diagnostic local analgesia. Scintigraphy is rarely useful in the stifle. Three-dimensional imaging is rarely employed in this decision-making process, as both computed tomography and magnetic resonance imaging currently require general anaesthesia and are not widely available. If a surgically amenable lesion is identified on diagnostic imaging, then surgical intervention will be the treatment of choice.

The harder decision is in those cases where there is not a definitive lesion identified. If the degree of lameness is moderate or severe, there may be a greater indication for diagnostic arthroscopy, whereas milder cases may be manageable medically. Medical management would normally involve intra- articular medication with corticosteroids and hyaluronic acid. Rest would be appropriate in an acute injury, but is rarely effective in chronic, insidious onset cases. The expense of orthobiological treatment is hard to justify without a more specific diagnosis. Polyacrylamide hydrogel has the advantage of not having the potential side effect of laminitis, but can be expensive given the number and size of joints that may require treatment.

If the horse has a concurrent problem that requires surgical treatment under general anaesthesia, then it may be practical and cost-effective to perform diagnostic arthroscopy at the same time. Conversely if the lameness is mild, and the horse has athletic targets in the near future, then medical management may be chosen. If the horse has failed to respond to medical management then surgical intervention is likely to be indicated.

Common findings at diagnostic arthroscopy in these cases are chondromalacia of the axial aspect of the medial femoral condyle, and tearing of the medial meniscus or meniscotibial ligament. Tears can be debrided, and micropicking chondromalacia cases can also be performed. Biological therapies can then be utilised as appropriate as a diagnosis has been made, and the author will often employ these in the early post-operative period. Medical treatment with corticosteroids may be helpful as the horse comes back into work.

Out of the last 122 cases of stifle-related pain treated by the author, 70% underwent surgery. A detailed analysis of these cases is underway, and will be presented in the talk.

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