Prognostic Factors Of Arthroscopic Debridement In Osteoarthritis Of The Knee

Background:The role of arthroscopic debridement in treating osteoarthritis of the knee has been controversial along time.History of OA,age,mechanical symptoms, synovitis,joint effusion,joint space and alignment are considered to be factors that have effects on the outcome of arthroscopy in knee OA.Our hypothesis is that the outcome of arthroscopic debridement in OA paients who mainly complain of knee pain is in association with clinical and radiograghic characteristics and serverity of cartilage impair.Patients with some features are more likely to respond to the procedure while others are not.Objective:To find out some factors that are related to the outcome of arthroscopic debridement in knee OA by retrospective analysis of a cross-sectional case series. These factors are some preoperative characteristics of patients including general status, clinical and radiographic features.Methods:A total of 143 cross-sectional patients who mainly complain of knee pain, do not respond to NSAIDs and has a radiographic Kellgren-Lawrence grade 2 or more, are included for this study.The mean follow-up is 19 month.Pain is assessed by a 10 cm visual analogue scale(VAS).Daily activity function of knee are estimated by the function domain of Knee Society Score(KSS-F).The severty of arthritis is evaluated by the Kellgren-Lawrence grading system.Intraopertive cartilage impair is graded by Outerbridge grading system.A limited athroscopic debridement is applied and no drilling,microfracture or abrasion is taken.The postoperative VAS score are considered to be the primary measurement of outcome.We define VAS≤40 a good result,VAS 40 to 60 a fair result,and VAS＞60 a poor result.Results:38 patients(26.6%) had a good result;63 patients(44.1%) had a fair result; 42 patients(29.4%) had a poor result.Single-factor analysis demostrates that age, body mass index,history of OA,Kellgren-Lawrence grading,preoperative VAS score, preoperative KSS-F score,Outerbridge grading and number of involved compartments are factors that have significant effects on the outcome.Patients with a good result have a lower Kellgren-Lawrence grading,a lower VAS score(74.8±7.8) and a lower Outerbridge grading.Patients with a poor result have a higher Kellgren-Lawrence grading,a higher propotion of BMI＞26 cases,a higher VAS score (79.1±7.5) and a lower KSS-F score(54.3±12.6).These factors above are independent factors detected by Logistic regression module that have significant effects on the good or poor outcome.Conclusions:The outcome of arthroscopic debridement of knee OA is related to the patients' clinical and radiographic features and severity of cartilage impair.Lower preoperative Kellgren-Lawrence grading,lower preoperative VAS score and lower Outerbridge grading are independent factors of good prognosis.Higher preoperative Kellgren-Lawrence grading,BMI＞26,higher preoperative VAS score and lower preoperative KSS-F score are independent factors of poor prognosis.Surgeons should evaluate patients' clinical(including general status,pain and activity ability) and radiograpghic menifestation to know whether they have the factors above in order to make the proper treatment decision and give them some essential information.