ICD-10 Coding for Status Post Knee Surgery
For a patient status post knee surgery, use Z96.651 for presence of right knee joint prosthesis or Z96.652 for presence of left knee joint prosthesis when documenting the presence of a total knee replacement.
Primary ICD-10-CM Codes for Knee Prosthesis
- Z96.651: Presence of right artificial knee joint 1
- Z96.652: Presence of left artificial knee joint 1
- Z96.659: Presence of unspecified artificial knee joint (when laterality is unknown) 1
These codes are used to document that a patient has a knee prosthesis in place and are appropriate for routine follow-up visits, imaging studies, or when the prosthesis status is relevant to current care 2.
Additional Coding Considerations
For Complications After Knee Surgery
When complications are present, additional codes should be used alongside the prosthesis presence codes:
- T84.5: Infection and inflammatory reaction due to internal joint prosthesis (requires additional character for laterality and encounter type) 3, 4
- T84.0: Mechanical complication of internal joint prosthesis (includes loosening, displacement) 3
- M96.66: Fracture of femur following insertion of orthopedic implant, joint prosthesis, or bone plate 3
- M96.67: Fracture of tibia or fibula following insertion of orthopedic implant 3
For Routine Follow-Up
- Z47.1: Aftercare following joint replacement surgery (used during the postoperative healing phase) 1
- Z09: Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm 1
Important Coding Pitfalls
Accuracy concerns exist with ICD-10 coding for knee arthroplasty procedures. Research demonstrates that while ICD-10 codes can identify that a knee replacement occurred with 98% accuracy, coding for specific components revised drops to only 57% accuracy when both removal and replacement codes are examined 5. This means:
- ICD-10-PCS codes reliably identify that a total knee arthroplasty or revision occurred 5
- Component-specific coding (tibial, femoral, patellar, liner) has significant error rates of 25-40% 5
- Verification of complication codes against medical records is essential, as non-verified codes can overestimate complication rates by nearly 50% 4
The transition from ICD-9 to ICD-10 created minimal discontinuity for most comorbidities (congestive heart failure, hypertension, obesity showed statistically significant but clinically small changes), but medical complications like sepsis (OR 2.54) and urinary tract infection (OR 1.79) showed more substantial coding discontinuities 3.
Clinical Context for Code Selection
When selecting the appropriate ICD-10 code, consider:
- Laterality is mandatory for prosthesis presence codes—always specify right (Z96.651) or left (Z96.652) knee 1, 5
- Encounter type matters for complication codes (initial encounter "A", subsequent encounter "D", sequela "S") 3
- Multiple codes may be needed when documenting both the presence of the prosthesis and any current complications or reasons for the visit 2, 4