Lameness case 5

Introduction to Case Study

  • Patient Background:

    • Local dressage rider brings two Warmblood geldings, Bert and Ernie.

    • Both are 3 years old, nearly 17 hands tall.

    • Recently started training with increased intensity.

    • Owner concerned over gradual worsening hind limb lameness.

    • No known specific injuries or previous history of lameness.

    • Both are unshod and regularly trimmed (last done 3 weeks ago).

Static Examination

  • General Observation:

    • Examination from a distance shows good conformation and symmetrical muscling.

    • Findings:

      • Fluid-filled joint effusions identified in front and inside of the right stifle in both horses.

      • Mild discomfort noted upon palpation of swelling.

    • Joint Analysis:

      • Femoro-patellar Joint:

        • Located on the cranial aspect of the stifle joint.

        • Usually easily palpated, effusion clearly visible.

      • Medial Femoro-tibial Joint:

        • Found on the medial aspect; effusion can be difficult to palpate.

        • Communicates with femoro-patellar joint in approximately 65% of horses.

      • Lateral Femoro-tibial Joint:

        • Also part of the stifle joint configuration.

Dynamic Examination

  • Lameness Assessment:

    • During straight walk, horses appear sound.

    • Observed while trotting from behind shows right gluteal muscles move more significantly:

      • Indication of lameness on the right hind leg.

  • Lameness Grading:

    • Severity Assessment:

      • Right hind lameness graded as3/5 (moderately severe and consistent).

Dynamic Exam – Lunging and Flexion Tests

  • Examination Results:

    • Lameness Scores on Various Surfaces:

      • 3/5 right hind lame at trot on right lunge (hard surface)

      • 2/5 right hind lame at trot on left lunge (hard surface)

      • 2/5 right hind lame at trot on right lunge (soft surface)

      • 1/5 right hind lame at trot on left lunge (soft surface)

    • Negative responses to left hind distal, right hind distal, and left hind proximal flexion.

    • Significantly positive response for right hind proximal flexion.

Baseline Lameness Findings

  • Establishment of Baseline:

    • Identified large effusions in right hind femoro-patella and medial femoro-tibial joints.

    • Confirmed as 3/5 right hind lame in straight line.

    • Variation: Lameness more severe on right hind proximal limb flexion, unaffected by distal flexion.

Regional Anaesthesia Decision

  • Anaesthesia Considerations:

    • Option to undertake regional anaesthesia for confirmation of lameness location.

    • Due to signalment and signs indicating stifle pathology, often skip to diagnostic imaging.

    • If pursuing anaesthesia: Focus on intra-articular anaesthesia of the stifle joints as this can abolish lameness.

Diagnostic Imaging Choice

  • Imaging Modalities:

    • The preferred initial imaging modality is radiography due to high suspicion of bone-related diseases in young warmbloods that show lameness at training onset.

Radiographic Findings for Bert

  • Description of View:

    • It’s a latero-medial image of Bert's right hind stifle. Positioning is not perfect, but lesions identifiable.

Lesion Analysis for Bert

  • Findings:

    • Multiple small, rounded radiodense lesions adjacent to the dorsal aspect of the lateral trochlear ridge of the right hind distal femur analyzed.

    • Represents multiple small bone fragments - diagnosis is osteochondritis dissecans (OCD) of the lateral trochlear ridge.

Treatment Plan for Bert

  • OCD Management:

    • Recommended treatment involves arthroscopic removal of loose bone fragments and debridement of necrotic bone/cartilage.

    • Prognosis for full athletic use is generally good, as seen in initial arthroscopic images.

Radiographic Findings for Ernie

  • Ernie's Radiography View:

    • Caudo-cranial image observed. Focus on radiographic abnormalities is necessary when describing for remote assessment.

Lesion Description for Ernie

  • Lytic Lesion Identification:

    • Single, large, oval, radiolucent lesion noted in the medial condyle of the femur depicting an area of bone lysis.

    • This indicates a subchondral bone cyst.

Treatment Options for Ernie

  • Subchondral Bone Cyst Management:

    • Treatments include corticosteroid injection or arthroscopic debridement of cyst contents.

    • Preferred method: Lag screw insertion across the cyst, promoting bone formation. Prognosis remains poor for athletic careers if untreated.

Osteochondrosis Overview

  • Conditions Explained:

    • OCD and bone cysts are manifestations of osteochondrosis.

    • Develop due to rapid growth (12-24 months) and poor endochondral ossification.

    • Symptoms can appear during exercise training at ages of 2-3 years for racehorses, and 3-5 years for dressage/eventing horses.

    • Predilection sites for OCD are where one bone surface over another, e.g., the lateral trochlear ridge of the femur; cysts at medial femoral condyle.