Prosthetic joint evaluation; assessing a patient who has a joint replacement hip or knee prosthesis

Описание: Prosthetic joint evaluation involves assessing both the functionality of the implant (mechanical performance, alignment, wear) and the clinical status of the patient (pain, mobility, infection risk). The two most critical aspects are ruling out prosthetic joint infection (PJI) and ensuring the prosthesis is biomechanically sound.

🔎 Key Components of Prosthetic Joint Evaluation
1. Clinical Assessment
History: Pain onset, swelling, instability, fever, wound healing issues.

Physical Exam: Range of motion, gait, joint stability, local warmth/redness, effusion.

Functional Outcome Measures: Patient-reported scores (Oxford Hip/Knee Score, WOMAC).

2. Imaging Studies
Plain X-rays: Detect loosening, malalignment, fractures, osteolysis.

CT/MRI (metal artifact reduction sequences): Evaluate periprosthetic bone and soft tissue.

Nuclear Medicine (bone scan, PET): Helpful in suspected infection or loosening.

3. Laboratory Evaluation
Inflammatory Markers: ESR, CRP (elevated in infection).

Joint Aspiration: Synovial fluid analysis for WBC count, differential, culture.

Novel Biomarkers: Alpha-defensin test (high accuracy for PJI).

4. Mechanical/Design Evaluation
Wear Analysis: Polyethylene wear, metal ion release (in metal-on-metal implants).

Stability Testing: Checking fixation (cemented vs. uncemented).

Material Compatibility: Longevity, corrosion resistance, biocompatibility.

Engineering Evaluation: Stress distribution, interface pressure, safety factor (often studied in prosthetic knee designs).

5. Prosthetic Joint Infection (PJI) Evaluation
Incidence: 1–2% in primary knee replacements, 0.3–1.3% in hip replacements; higher in revisions.

Risk Factors: Prior surgery, immunosuppression, systemic infection, poor wound healing.

Diagnosis: Combination of clinical signs, labs, imaging, and aspiration.

Treatment: Often requires IV antibiotics and staged revision arthroplasty

#Prosthesis