Hip and knee osteoarthritis By Dr Brett Bairstow, Orthopaedic Surgeon, Mt Lawley & Carine Degenerative joint disease (osteoarthritis, OA) can have no clear aetiology (‘primary’ or ‘intrinsic’) or be ‘secondary’ to another pathology (e.g. trauma, sepsis, congenital). Primary and secondary factors can both be involved with the former modifying susceptibility and the latter affecting the onset age and location of disease. While symptoms include stiffness, loss of range, deformity, limp, weakness and functional limitation, pain is mainly why relief is sought. OA pain from the hip commonly presents in the groin or thigh, less commonly in the buttock or knee. OA pain from the knee is more commonly localised, but the hip and spine still need to be considered as potential sources.
The pain from hip and knee OA is usually gradual onset, mechanical (i.e. movement related) and associated with other complaints, as above, that can help with localisation. Patients with hip (not knee) arthritis often have issues with footcare and footwear. Illuminating questions focus on walking distance before stopping, use of supports (e.g. crutches or supermarket trolley) and difficulties with routine activities such as sitting in and rising from chairs. Examination starts in the waiting room. Evaluate walking, standing, sitting and any use of walking aids. Walking pattern can reveal stiffness (short swing), pain (short stance) and weakness (e.g. Trendelenburg). When supine, passive joint movement assesses symmetry, stiffness, range and stability.
Measures of joint range need not be absolute to help localise issues. Assessing leg length discrepancy, both apparent (to eye) and true (accounting for deformities) helps. Radiology is important and doesn’t need to be invasive (e.g. arthrograms) or expensive (e.g. MRI) if the diagnosis is suspected OA. For the hip an AP pelvis and AP/lateral hip (of the affected side) provides information regarding morphology and relative leg length. If surgical referral is likely, ask for films at 120% template magnification (allows for preoperative prosthesis sizing) and centred on pubis (shows more femur). Most hip surgeons still prefer hardcopy films. For the knee, AP weightbearing knees and lateral/skyline/notch views of the affected knee define the location and extent of degenerative
Cosmetic breast injections Bilateral cranio-caudal mammogram views of a woman with silicone injections
osmetic breast augmentation may involve the direct injection of C foreign substances into the breast, including silicone, Macrolane (a gel based on hyaluronic acid), polyacrylamide hydrogel (PAAG)
or fat. Often these foreign substances make the interpretation of screening mammograms difficult, as the substance and associated reactive calcification obscures normal breast tissue. The sensitivity of screening mammograms is severely reduced for women with cosmetic breast injections and the rate of false positives increased. When a woman attending BreastScreen WA indicates that she has had a foreign substance injected into her breasts, only one mammographic view is performed in the first instance. If this image confirms the presence of a foreign substance injected into the breast the screening procedure is stopped to prevent unnecessarily irradiating women when there is no prospect of obtaining an adequate study. An explanation to the woman is provided that screening mammography is not a suitable test for her to detect breast cancer. The woman and her GP will receive a letter explaining the reason for not completing the mammogram and that she will no longer receive invitations to attend for screening mammography. GPs may consider performing regular clinic examinations and breast ultrasound if the woman requests screening options.
www.breastscreen.health.wa.gov.au 42 | OCTOBER 2020
MEDICAL FORUM | MUSCULOSKELETAL ISSUE
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