Solving the 67-year-old lady's right elbow RA exam
Key Takeaway
Learn more about Solving the 67-year-old lady's right elbow RA exam and how to manage it. A radiograph of a 67-yearold ladys right elbow typically shows extensive articular cartilage erosion, radial head dislocation, and peri-articular osteopenia. This characteristic presentation is indicative of inflammatory arthropathy, specifically rheumatoid arthritis, often leading to a "flail elbow" due to significant joint instability. Management may involve an elbow brace or total elbow replacement.
A 67-year-old lady presents with a painful right elbow. Please describe the findings on this radiograph (Figure 214).
Candidate: The radiograph shows generalized peri-articular osteopenia and marked joint space narrowing affecting both the ulnohumeral and radiocapitellar joints. There is a dislocation of the radial head. The features are characteristic of an inflammatory arthropathy, likely rheumatoid arthritis, resulting in a flail elbow.
Candidates often jump straight to a diagnosis like "Rheumatoid Arthritis" without systematically describing the radiographic features (e.g., bone quality, joint spaces, and secondary effects like dislocation) that justify their conclusion. Failing to identify the "flail elbow" indicates a lack of biomechanical understanding of the pathology.
Systematically address: 1. Bone quality: Generalized peri-articular osteopenia. 2. Joint spaces: Uniform narrowing of the ulnohumeral and radiocapitellar compartments (suggesting inflammatory process rather than OA). 3. Deformity: Radial head dislocation and ligamentous collapse. 4. Diagnosis: Explicitly contrast findings against OA (lack of osteophytes and subchondral sclerosis) to confirm Rheumatoid Arthritis.
The patient has advanced Rheumatoid Arthritis and is complaining of weakness in her right hand. How do you distinguish between a Posterior Interosseous Nerve (PIN) palsy and a rupture of the extensor tendons (Vaughn–Jackson syndrome)?
Candidate: I would perform the tenodesis test. If the fingers extend passively when the wrist is flexed, it suggests the tendons are intact and the issue is likely nerve-related (PIN palsy). If there is no passive extension of the MCP joints, it indicates an extensor tendon rupture. I would also note that these conditions can coexist in RA.
Candidates often forget to mention that these pathologies can overlap in long-standing RA. Providing a rigid "either/or" answer without acknowledging the possibility of both is a common error that demonstrates a lack of clinical nuance.
Clearly explain the tenodesis effect: 1. PIN Palsy: Active MCP extension is lost, but the tenodesis effect is preserved (wrist flexion causes passive finger extension). 2. Vaughn–Jackson (Tendon rupture): Loss of active extension and loss of the tenodesis effect. 3. Caveat: Explicitly state: "I would examine for co-existent pathology, as both conditions can be present simultaneously in advanced rheumatoid arthritis."
The patient is booked for a total elbow replacement. What specific pre-operative considerations are mandatory for a patient with long-standing Rheumatoid Arthritis undergoing general anesthesia?
Candidate: I would obtain a cervical spine radiograph to evaluate the atlanto-axial joint for instability. I would also seek a formal anaesthetic opinion, as these patients may have associated systemic involvement like pulmonary fibrosis or cardiac disease.
Missing the cervical spine assessment is a major safety concern. A failing candidate might only focus on the elbow surgery itself and ignore the systemic risks of rheumatoid arthritis, particularly potential atlanto-axial subluxation which could lead to spinal cord injury during intubation.
Prioritize patient safety: 1. Cervical Spine: C-spine X-ray to rule out atlanto-axial subluxation (essential for safe intubation). 2. Pulmonary: Screen for rheumatoid lung (fibrosis) via history/exam/CXR. 3. General: Multidisciplinary assessment (Rheumatology/Anaesthetics) to optimize medications (DMARDs/Biologics) and manage systemic comorbidities prior to GA.
