5-year-old Quarter Horse mare used for barrel racing.
Mare was noted to be off for the previous 3 weeks after initiating training for barrels.
Initial physical and moving exam findings: Upon presentation the horse was bright, alert, and responsive. Her vital parameters were within normal clinical limits. Mild left femoropatellar joint and right forelimb fetlock joint effusion was palpable.
She was not sensitive to application of hoof testers to any foot. A RF lameness was observed and measured (Head VS 29.6 mm). A mild RH impact lameness was also measured (Diff Min Pelvis 3.3 mm). This particular ipsilateral pattern, when the hindlimb is solely lack of impact, is one suggestive of either primary RF with compensatory hind or primary hind with compensatory front.
Given the amplitude of the right forelimb lameness, the RF was considered primary (Fig 1). RF distal and RH proximal limb flexions were positive.
Figure 1 - A moderate RF lameness and mild RH Impact lameness was measured.
RF PDN Block: The VS increased to 48.0 mm, indicating a worsening of the RF lameness (Fig 2). This phenomenon is not uncommon when lameness originates higher in the limb.
Figure 2 - Baseline (left) and Post RF PDN block.
RF Abaxial Block
The RF lameness was approximately 50% improved (VS went from 48.0 mm to 26.4 mm). Note: when lameness worsens at any point in the exam, it is important to compare blocking results to this new “baseline” level of lameness (Fig 3). The RF lameness was now back to the initial baseline level of lameness before any blocks were applied.
Figure 3 - After RF PDN Vs After RF ASB.
RF Low 4-Point Block
The VS improved to 15.3 mm, which is an 83% improvement from the level of lameness after the PDN block. All hindlimb lameness also resolved (Fig 4).
Figure 4 - After RF PDN Vs After RF Low 4-Point
Radiographs of the RF fetlock revealed mild medial sesamoiditis.
Ultrasonography of the distal RF indicated mild fiber disruption and tearing of the medial suspensory branch at its insertion onto the medial proximal sesamoid bone.
DX: RF medial sesamoiditis and medial suspensory branch desmitis.
TX: Therapeutic options were discussed with the owner, including intra-lesion platelet rich plasma. Conservative treatment was elected, and an ascending rest and rehabilitation program was initiated.
The horse was re-evaluated 4 months later. On this day, the RF lameness was resolved, but a RH lameness was observed. A RH pushoff lameness (Diff Max 7.1 mm) and LH impact lameness (Diff Min -3.8 mm) was measured (Fig 5). Sensitivity to palpation and response to flexion on the RF were improved. Gradual return to full work was advised, monitoring for increased lameness. Prophylactic treatment of the distal tarsal joints was discussed as potentially necessary in the future.
The mare presented for a concern of pelvic asymmetry appreciated by the owner.
Palpation of all four limbs and hoof tester evaluation of all four feet was negative. Moderate pain was appreciated on palpation of the right sacroiliac region (and mild left side). A mild RF and RH lameness was observed and measured. Forelimb flexions were negative. Upper hind limb flexions were moderately positive (RH>LH).
Blocking of the RH limb was initiated. While the hindlimb lameness was less significant than the forelimb, the hindlimb was blocked first to rule out compensatory forelimb lameness due to a primary RH.
A RH TMT block eliminated the hindlimb lameness. The RF lameness did not improve (Fig 6).
Figure 6 - Baseline (left) and Post RH TMT joint block (right).
A RF PDN block caused a worsening of the lameness. A RF abaxial sesamoid block caused a switch to a mild LF lameness (Fig 7). The findings were discussed with the owner. The hind limb lameness localized to the lower hock joints, which was likely having secondary effects on the pelvis. The forelimb lameness localized to the foot; however, it was discussed that the block could have migrated to the previously injured suspensory branch. Given the negative palpation and flexion responses on the RF and blocking results, the owner elected a conservative approach and pursued corrective shoeing with her farrier. Treatment of the lower hock joints was also to be considered (but deferred by the owner at this time).
The mare presented for a recheck evaluation. The RF lameness had resolved with corrective farriery. The RH lameness was still visually observable. The previous RH pushoff lameness was similar, but a RH impact was now also measured (Fig 8).
The owner elected intra-articular medication of the hocks.
The owner reported on follow-up communication that the mare had recently been sold; however, was sound and competing in her intended discipline following treatment of the hocks.
Use of lameness measurement allowed me to show the owner that the case was multifactorial and would require a team approach (veterinarian, client, farrier) in achieving the desired outcome.
The intra-articular tarsometatarsal joint response to block and the objective quantification of that response was instrumental in demonstrating that this was a component of the horse's issues, and that intra-articular anti-inflammatory therapy would ultimately be necessary. Furthermore, despite keeping good medical records on subjective evaluation assessments, the objective information we had stored and available for review at each subsequent examination allowed me to be much more accurate in following this horse over time - documenting the resolution of previous issues and lack of resolution of others.