Incidence of osteotomies around the knee for the treatment of knee osteoarthritis – Registry-based study of Finnish population between 1987 and 2008

Introduction
Purpose of this population-based study was to assess the incidence of osteotomies around the knee performed in Finland between 1987 and 2008, and to compare it to that of TKAs performed over the same time period.

Methods
Based on data recorded into National Hospital Discharge register , we identified all patients aged 18 years or more, who had undergone either tibial or femoral osteotomy for the treatment of symptomatic knee OA. Numbers of TKAs performed over the same period were extracted from the Finnish Arthroplasty Register, and the number of eligible, 18 years or older, patients were obtained from Statistics Finland. . Incidences were separately calculated for each study year, and were also analyzed for both genders and for six different age groups

Results
A total of 6004 osteotomies were performed for 5734 patients. 50.5% of the operations were performed for female patients. Mean age was 54.6 (range, 18-86) years at the time of the operation. Indication for osteotomy was primary OA for 90.2% of cases, followed by secondary OA (5.7%), posttraumatic OA (3.5%) and undefined OA (0.6%). Between 1987 and 2008, incidence of osteotomies has steadily decreased
This decline has occurred both in female and male patients, where as the osteotomy incidence has slightly increase for patients under 50- years.

Discussion
Reason for declining osteotomy figures may very well be the improved outcome of TKA in all patient groups during the last two decades. Difference between genders may be related to that females will have worse symptoms and disability before they will undergo knee surgery (3). Because of this disparity between genders, degree of knee OA may be worse in female than males at the time of surgery and they are more likely to undergo TKA than osteotomy