HIV and the Musculoskeletal System

Musculoskeletal complications of HIV affect 20-40% of patients and are tested regularly in orthopaedic examinations. With effective antiretroviral therapy, HIV-positive patients are living longer and presenting for elective and trauma orthopaedic surgery in increasing numbers. The orthopaedic surgeon must understand the spectrum of HIV-associated musculoskeletal pathology, the altered infection risk, the perioperative implications of HIV and ART, and occupational exposure management. This knowledge is essential for safe clinical practice and a common exam theme.

In HIV-positive patients, septic arthritis can mimic inflammatory arthropathy clinically. The consequences of missing septic arthritis are joint destruction and systemic sepsis. Always aspirate any swollen joint before starting disease-modifying therapy. Extended cultures (AFB, fungal) should be routine in HIV, especially when CD4 is less than 200 cells/uL.

PEP efficacy is time-dependent. Starting within 1 hour provides the highest protection. Efficacy declines rapidly after 24 hours and PEP should not be started after 72 hours. The orthopaedic theatre is a high-risk environment: K-wires, drill bits, and sharp instruments in bloody fields create frequent exposure opportunities. Know your hospital PEP protocol, where the starter pack is stored, and who to call. Do not wait for occupational health to open: start PEP in the emergency department if the starter pack is available.

Q: A 45-year-old HIV-positive man with a CD4 count of 120 cells/uL presents with a swollen, painful ankle. What is the most important investigation? A: Joint aspiration with extended microbiology (Gram stain, culture, AFB stain and culture, fungal culture). In HIV patients with CD4 less than 200, atypical organisms including Salmonella, Mycobacterium tuberculosis, and fungi must be actively sought. Aspiration is mandatory before attributing joint swelling to inflammatory arthritis.

Q: A 30-year-old man with HIV on protease inhibitor-based ART presents with bilateral hip pain. Which investigation has the highest sensitivity? A: MRI of both hips. MRI detects avascular necrosis before radiographic changes appear and identifies the characteristic serpiginous low-signal line on T1-weighted images. MRI also allows screening of the contralateral hip and other sites for multifocal disease.

Q: Should antiretroviral therapy be stopped before elective orthopaedic surgery? A: No. ART must NOT be stopped perioperatively. Interruption causes viral rebound within days, risks drug resistance, and can trigger IRIS on restarting. ART should be continued throughout, coordinating with the anaesthetist to allow administration with a sip of water if nil by mouth.

Q: A theatre nurse sustains a deep needlestick from an HIV-positive patient. What is the maximum window to start post-exposure prophylaxis? A: 72 hours, but ideally within 1 hour. PEP efficacy declines rapidly with time. The standard regimen is three drugs (tenofovir/emtricitabine plus dolutegravir or bictegravir) for 28 days. Baseline HIV, hepatitis B, and hepatitis C serology are required with follow-up at 6 weeks, 3 months, and 6 months.

Q: How does HIV affect fracture healing in a patient with a CD4 count of 500 cells/uL on ART? A: Fracture healing is comparable to the general population in well-controlled HIV (CD4 greater than 350, suppressed viral load on ART). Standard fracture management applies. Problems arise in advanced HIV (CD4 less than 200), with malnutrition or open fractures, where delayed union, non-union, and infection rates are significantly higher.

Q: Which antiretroviral agent is most associated with reduced bone mineral density? A: Tenofovir disoproxil fumarate (TDF). TDF causes proximal renal tubular dysfunction leading to phosphate wasting and reduced bone mineral density. Tenofovir alafenamide (TAF) has significantly less bone impact and should be considered as a switch when BMD loss is identified.