So within one year of getting a knee replacement many patients received an arthroscopy.  Follow the money.

Arthroscopy. 2013 Nov 27. pii: S0749-8063(13)00973-0. doi: 10.1016/j.arthro.2013.09.002.
[Epub ahead of print]
An Epidemiologic Analysis of Clinical Practice Guidelines for Non-Arthroplasty Treatment of Osteoarthritis of the Knee.

Source

Department of Orthopaedic Surgery, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, U.S.A.. Electronic address: amandhawan@hotmail.com.

Abstract

PURPOSE:

To analyze the current practice patterns of non-arthroplasty treatment of knee osteoarthritis (OA) and to assess the impact of the American Academy of Orthopaedic Surgeons clinical practice guidelines on the management of OA of the knee, particularly as they relate to the use of arthroscopic treatment.

METHODS:

The United Healthcare Database (2004-2009, 11 million patients, 216 million records) was used for the study and was searched using Boolean language for International Classification of Diseases, Ninth Edition, Clinical Modification and Current Procedural Terminology, fourth revision codes. A reference group was defined as patients treated with knee arthroplasty in 2009 and diagnosed with knee OA in the same record. Clinical practice patterns in the 5 years preceding arthroplasty were analyzed in this group.

RESULTS:

The reference group consisted of 12,806 patients undergoing total knee arthroplasty in 2009 with a documented diagnosis of OA at the time of surgery, with prior nonoperative treatment strategies analyzed during the preceding 5 years (2004-2009); 10.0% of patients were prescribed physical therapy specific to OA, 2.6% received an unloader brace, 0.52% underwent acupuncture, 43.5% were administered intra-articular corticosteroids, and 15.4% received viscosupplementation injections. During the 5 years before arthroplasty, 2,505 patients (19.6%) underwent arthroscopy and debridement/lavage, 35% of whom did not have a diagnosis code for mechanical pathology. Within 1 year of knee arthroplasty, 2,028 of the 2,505 knee arthroscopies (80.9%) were performed.

CONCLUSIONS:

The findings show that significant gaps do exist between the evidence-based American Academy of Orthopaedic Surgeons recommendations and actual practice patterns in the United States between 2004 and 2009.