Rehabilitation, Prosthetics/Orthotics, Functional Assessment, Ethics, Safety, and Research
What this domain tests
Outcome measurement, orthotic and prosthetic principles, appraisal of study design and diagnostic statistics, and professional conduct.
Core rules
- Know which instrument fits which question: ODI for lumbar disability, NDI for neck, DASH or QuickDASH for upper limb, WOMAC or KOOS for knee osteoarthritis, MSTS for tumor resection, AOFAS for foot and ankle, and the SF-36 or EQ-5D for general health.
- Orthoses work by three-point bending, load redistribution, or immobilization. A well-fitted ankle-foot orthosis controls drop foot in swing phase; a thoracolumbosacral orthosis limits motion but does not correct scoliosis in a skeletally mature patient. Prosthetic prescription follows K-levels and ischial containment principles for transfemoral limbs.
- Research appraisal: sensitivity and specificity describe a test, but positive predictive value depends on prevalence. Level of evidence runs from systematic reviews of randomized trials down to case reports; power depends on effect size, variance, alpha, and sample size.
- Ethics and safety: informed consent must disclose alternatives, material risks, and the role of trainees; conflicts of interest with device manufacturers must be declared; medical errors should be disclosed honestly; capacity and resource allocation decisions require documentation.
Worked example
A new synovial biomarker for periprosthetic joint infection has 90% sensitivity and 95% specificity. In a population with 5% prevalence, PPV = (0.90 × 0.05) / [(0.90 × 0.05) + (0.05 × 0.95)] = 0.045 / 0.0925 ≈ 49%. Half of the positive results are false despite excellent test characteristics, so the test must be interpreted alongside clinical and laboratory criteria.
Traps that cost marks
- Quoting sensitivity and specificity as if they were predictive values in your patient.
- Prescribing an orthosis without a defined mechanical goal.
- Discussing an industry conflict only in private rather than disclosing it.