Background: Total knee replacement (TKR), a last resort for treating knee pain due to osteoarthritis (OA), is not always medically indicated or preferred by many patients. Hylan G-F 20 is a cross-linked hyaluronan derivative approved for the treatment of pain due to OA of the knee after other conservative approaches have failed.
Objective: The objectives of this study were to (1) determine the effect of hylan G-F 20 on patient need for TKR as measured by time from hylan G-F 20 injection to TKR, and (2) assess patient factors that might influence time from hylan G-F 20 therapy to TKR.
Methods: This is a retrospective case series review of the medical records of patients seen in 1 orthopedic specialty practice. The incidence and time to TKR in patients who were TKR candidates (100% grade IV OA [severe]) treated with 1 or more courses of intra-articular hylan G-F 20 injections (3 weekly injections per course) were determined from October 1997 to November 2003. Survival analysis was used to evaluate time to TKR and the effects of age, gender, ethnicity, body mass index (BMI), and presence of effusion on this outcome. Logistic regression was also used to assess these covariates.
Results: The incidence of TKR in hylan G-F 20-treated knees (1,187 knees; 863 patients) was 19% (n=225 knees). The median time to TKR in these patients was 638 days (1.8 years; minimum of 14 days, maximum of 2,147 days). For patients in whom a TKR had not yet occurred during the observation time, the median time of hylan G-F 20 treatment and patient follow-up was 810 days (2.2 years; minimum of 7 days, maximum of 2,222 days). A total of 1,978 courses of hylan G-F 20 given to 1,187 knees (average 1.67 courses per knee) resulted in an average cost of $1,419.76 per knee to delay TKR by a median of 2.1 years (772 days, minimum 7, maximum 2,222), the median time of all knees to either TKR or time of last observation. Survival analysis showed that 75% of knees had not had a TKR by 1,370 days (3.8 years). Survival analysis and logistic regression indicated that of age, gender, ethnicity, BMI, and presence of effusion, only age significantly affected time to TKR.
Conclusion: In patients who are candidates for TKR, the need for TKR can be delayed with hylan G-F 20 when used for the treatment of OA knee pain.