Background: Failed conservative treatments of knee osteoarthritis (OA) in the elderly have traditionally been treated with TKA (Total Knee Arthroplasty). Although TKA is a gold standard and cost-effective treatment in elderly patients, it should be considered as the last resource for patients with pain that cannot be controlled by the usual conservative therapeutic approaches. Numerous studies showed that intra-articular
Sodium Hyaluronate (IA-HA) (Hyalgan®) is effective for treatment in various stages of knee OA.
Objectives: To compare cost of treatment between two groups of knee OA patients who failed conservative treatments. The first group includes the patients who responded to IA-HA treatment leading to delay or cancel surgical treatments (response group). The second group includes the patients who did not respond to IA-HA treatment and they had to undergo surgical procedures (non-response group).
Material and Method: A cost analysis from the retrospective data in Police General Hospital from year 2001-2004. One hundred and eighty three patients with knee OA (208 knees) who failed conservative treatments and did not have contraindications for surgery were enrolled. All patients were treated with one course of three IA-HA injections (500-730 KDA, Hyalgan) at weekly intervals and followed up for a minimum 2-year period. In case of successful treatment (response group), repeated doses were recommended. If the patients did not improve in the average Western Ontario and McMaster Universities Osteoarthritis Index (the average WOMAC) score within one month after completion of the injections, they would be classified as a non-response group and the surgical procedures would be considered. Cost of direct medical costs (drugs), hospitalization, and resource utilization were recorded and analyzed.
Results: One hundred and forty six patients (164 knees) responded to the treatment and did not need any surgical procedures within the 2-year follow-up period. Thirty-seven patients (44 knees) did not respond and needed surgical procedures. In the response group, 83 patients repeated the second course of treatment and 14 patients repeated the third course. The total average cost for the response group were 47,044.18 Baht per patient, which was an average cost of IA-HA; 12,240.41 Baht and an average cost of other medications following the injection of 34,803.77 Baht. The ratio of the IA-HA cost and medications following the injection cost was 1:2.84. In the non-response group, the total average cost was 144,884 Baht per patient including average cost of surgery of 135,559.95 Baht per patient or 113,993.59 Baht per knee and cost of IA-HA treatment of 9,324 Baht per patient, which was only 6.44% of the total costs of treatment. However, when considered in the response group, the IA-HA treatment provided cost saving from cancellation or delayed surgical procedures at 63.26%.
Conclusion: IA-HA should be considered as a medical intervention before surgical procedures in knee OA patients who failed conservative treatments. Even though the cost of IA-HA treatment would increase the total costs of treatment and some patients might fail, it was only 6.44% of the total costs. On the other hand, if patients responded to IA-HA treatment, then the surgical procedures were not required. This treatment could save the cost from cancellation or delayed surgical procedures at 63.26%.

Keywords: Cost analysis, Sodium hyaluronate, Knee osteoarthritis, Total Knee Arthroplasty (TKA), Surgical procedures