Temporal trends and regional variation in the rate of arthroscopic knee surgery in England: analysis of over 1.7 million procedures between 1997 and 2017. Has practice changed in response to new evidence?

Objectives We investigated trends and regional variation in the rate of arthroscopic knee surgery performed in England from 1997-1998 to 2016-2017. Design Cross-sectional study of the national hospital episode statistics (HES) for England. Methods All hospital episodes for patients undergoing a knee arthroscopy between 1 April 1997 and 31 March 2017 were extracted from HES by procedure code. Age and sex-standardised rates of surgery were calculated using Office for National Statistic population data as the denominator. Trends in the rate of surgery were analysed by procedure both nationally and by Clinical Commissioning Group (CCG). Results A total of 1 088 872 arthroscopic partial meniscectomies (APMs), 326 600 diagnostic arthroscopies, 308 618 knee washouts and 252 885 chondroplasties were identified (1 759 467 hospital admissions; 1 447 142 patients). The rate of APM increased from a low of 51/100 000 population (95% CI 51 to 52) in 1997-1998 to a peak at 149/100 000 (95% CI 148 to 150) in 2013-2014; then, after 2014-2015, rates declined to 120/100 000 (95% CI 119 to 121) in 2016-2017. Rates of arthroscopic knee washout and diagnostic arthroscopy declined steadily from 50/100 000 (95% CI 49 to 50) and 47/100 000 (95% CI 46 to 47) respectively in 1997-1998, to 4.8/100 000 (95% CI 4.6 to 5.0) and 8.1/100 000 (95% CI 7.9 to 8.3) in 2016-2017. Rates of chondroplasty have increased from a low of 3.2/100 000 (95% CI 3.0 to 3.3) in 1997-1998 to 51/100 000 (95% CI 50.6 to 51.7) in 2016-2017. Substantial regional and age-group variation in practice was detected. In 2016-2017, between 11% (22/207) and 16% (34/207) of CCGs performed at least double the national average rate of each procedure. Conclusions Over the last 20 years, and likely in response to new evidence, rates of arthroscopic knee washout and diagnostic arthroscopy have declined by up to 90%. APM rates increased about 130% overall but have declined recently. Rates of chondroplasty increased about 15-fold. There is significant variation in practice, but the appropriate population intervention rate for these procedures remains unknown.