What are the prevalence and risk factors for repeat ipsilateral knee arthroscopy?

The number of arthroscopic knee surgeries performed annually has increased over the last decade. It remains unclear what proportion of individuals undergoing knee arthroscopy is at risk for subsequent ipsilateral procedures. Better knowledge of risk factors and the incidence of reoperative ipsilateral arthroscopy are important in setting expectations and counselling patients on treatment options. The aim of this study is to determine the incidence of repeat ipsilateral knee arthroscopy, and the risk factors associated with subsequent surgery over long-term follow-up.

The New York Statewide Planning and Research Cooperative Systems outpatient database was reviewed from 2003 to 2016 to identify patients who underwent elective, primary knee arthroscopy for one of the following diagnosis-related categories of procedures: Group 1: cartilage repair and transfer; Group 2: osteochondritis dissecans (OCD) lesions; Group 3: meniscal repair, debridement, chondroplasty, and synovectomy; Group 4: multiple different procedures. Subjects were followed for 10 years to determine the odds of subsequent ipsilateral knee arthroscopy. Risk factors including the group of arthroscopic surgery, age group, gender, race, insurance type, surgeon volume, and comorbidities were analysed to identify factors predicting subsequent surgery.

A total of 765,144 patients who underwent knee arthroscopy between 2003 and 2016, were identified. The majority (751,873) underwent meniscus-related arthroscopy. The proportion of patients undergoing subsequent ipsilateral knee arthroscopy was 2.1% at 1-year, 5.5% at 5 years, and 6.7% at 10 years of follow-up. Among patients who underwent subsequent arthroscopic surgery at 1-, 5-, and 10-year follow-up, there was a greater proportion of patients with worker's compensation insurance (p < 0.001), index operations performed by very high volume surgeons (p < 0.001), and cartilage restoration index procedures (p < 0.001), compared with those who never underwent repeat ipsilateral surgery.

Understanding the incidence of subsequent knee arthroscopy after index procedure in different age groups and the patterns over 10 years of follow-up is important in counselling patients and setting future expectations. The majority of subsequent surgeries occur within the first 5 years after index surgery, and subjects tend to have higher odds of ipsilateral reoperation for up to 10 years if they have worker's compensation insurance, or if their index surgery was performed by a very high volume surgeon, or was a cartilage restoration procedure.

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