On January 20, 2016 a 17 year old Quarter Horse gelding was presented to us for maintenance hock injections. The owner also reports the horse usually becomes sound after he warms up, yet recently that has changed and he has been unable to become sound after warm up.
The horse was sound at the walk and a grade 2/5 left hind (LH) lameness was evident at the trot in the straight on firm footing. LH distal limb flexion revealed no abnormalities, LH upper limb flexion exacerbated the lameness and LH cross under flexion exacerbated the lameness most severely.
Regional nerve blocks and intra-articular joint blocks were performed in order to isolate the site of lameness. These blocks ruled out a lower limb lameness. An intra-articular nerve block of the medial femorotibial joint of the stifle was performed. This block improved the lameness by 60%. Interpretations of nerve blocks are difficult as they may be confusing and although in this case the lameness was not completely abolished by the stifle joint block, the result was considered significant and imaging of the stifle was the next step.
Radiographs of the stifle revealed an osteophyte (bone spur) on the medial tibial condyle. Possible soft tissue mineralization was also present within the medial collateral ligament. Ultrasound revealed an increased amount of fluid and thickening of the joint capsule and inflammation within the medial collateral ligament at the origin.
Therefore, a diagnosis of injury to the medial collateral ligament with ongoing inflammation within the medial femorotibial joint was made. Treatment options would include shockwave therapy to the medial collateral ligament as well as injection of the medial femorotibial joint. Since the joint injections may include steroids, and due to the horse’s age, we elected to evaluate his metabolic status by performing a TRH Stimulation Test and Insulin test.
This case is a good example of two important points. First, that in many instances nerve blocks do not have to completely abolish the lameness to be significant and secondly, the importance of combining x-rays with ultrasound. To the first point, although, the improvement after the stifle joint block confirms a diagnosis of inflammation of the joint, it did not abolish the lameness. The remaining lameness was due to the collateral ligament injury. Nerve blocks, which would include regional anesthesia as well as intra-articular anesthesia, can be “ambiguous, misleading, and confusing” (Dr. Boswell), and therefore interpretation of nerve block results requires considerable experience. However, when in the field, it is still our best method for locating the origin of most lameness. Nuclear scintigraphy is also an option for localizing the origin of lameness. To the second point, had we relied only on the results of the radiographs, treatment of the joint inflammation may have made the horse feel good enough to continue his exercise and lead to further injury of the medial collateral ligament.
The x-ray and ultrasound images for this case may be viewed at the links above.
An 18 month old Warmblood gelding presented to our practice with a primary complaint of severe lameness of the right forelimb. Another veterinarian had previously examined the horse and diagnosed a bone cyst in the second phalynx (P2). He treated the coffin joint with an injection of cortisone. The horse responded favorably for a short period of time, but after only a few weeks the lameness returned. The horse was then referred to our practice for a second opinion.
Our examination revealed the horse to be bright and alert and a little thin. Indeed he was grade 3-4/5 lame on the right fore. There was severe effusion in the right fore coffin joint and distal limb flexion was painful and a flexion test exacerbated the lameness. The hoof tester response was negative. The lameness was abolished with an abaxial sesamoid nerve block, which confirmed the location of pain to be in the foot/pastern region. Radiographs confirmed the presence of a sub-chondral cyst-like lesion or leucency (dark area of bone from decreased mineral density) in the distal aspect of P2 which was surrounded by sclerosis (increased bone density).
We discussed several treatment options with the owner who elected to treat the cyst by regional limb perfusion (RLP) with OSPHOS and injection of Platelet Rich Plasma (PRP) and Stem Cells (harvested from this horse) into the coffin joint. OSPHOS was recommended to decrease the reactive bone resorption. The lameness did not significantly improved following RLP with OSPHOS, but shortly after the injection of the coffin joint with PRP and Stem Cells, the horse became sound. A follow-up PRP and Stem Cell injection was performed after 30 days and this horse continues to be sound at 90 days.
This case is a good example of a couple of things I would like to touch on. First, how therapies may differ in their responses even though the proper area has been targeted. Secondly, that the use of regenerative medicine, such as PRP and Stem Cells, when used early in the course of a disease and despite the presence of severe symptoms, may have a profound impact. To the first point, although the horse responded to the cortisone injection, it didn’t last. We could have reinjected the joint with the same drug or selected a different cortisone, however regenerative therapies also have potent anti-inflammatory effects, so why not try something different? We did, and the rapid improvement is a great illustration of the potent, almost cortisone-like, anti-inflammatory effect that regenerative medicine possesses. To the second point, we knew that there was inflammation in the joint and a possible communication between the bone cyst and the joint. For this communication to exist, a full thickness crack has to be present in the cartilage. We wanted to treat not only the joint inflammation, but help the cartilage and the bone to repair. Although cortisone is good for reducing inflammation, it does little to directly promote healing and this made PRP and Stem Cells the obvious choice. Selecting PRP and Stem Cells would kill two birds with one stone, reduce inflammation and directly influence healing. This horse’s almost immediate, and long term, response has validated our choice to use regenerative cell therapy.
Case of the Month