THE EFFICACY OF ARTHROSCOPY FOLLOWING TOTAL KNEE REPLACEMENT

We evaluated the utility and safety of arthroscopy for diagnosing and treating symptoms in problematic total knee replacements. From 1988 to 1995, 40 arthroscopies were performed on 38 patients with an average age of 68.4 years. The average onset of symptoms post knee replacement was 33.7 months (range 1 month to 15 years), and the average duration of symptoms prior to arthroscopy was 15.6 months (range 1 month to 5 years). Presenting symptoms included pain in 73%, catching or soft tis sue impingement in 35%, and stiffness in 20% of patients. Our protocol involves 24 hours of perioperative, intravenous antibiotics, and two or three routine arthroscopic portals. There were no arthroscopy-relat ed complications or infections. Athroscopy successfully diagnosed the etiology of the patient's symptoms in all but one case (97.5%). Operat ive diagnoses included impinging soft tissue under the patella consist ent with the ''clunk'' syndrome (43%), impinging hypertrophic synoviti s elsewhere in the knee (15%), impinging PCL stump (10%), prosthesis l oosening or wear (10%), and arthrofibrosis (20%). Arthroscopic treatme nt consisted of removal of impinging tissue or loose body as indicated . Additionally, eight of the patients had a manipulation under anesthe sia with an average improvement in flexion of 26.3 degrees postoperati vely. At an average follow-up of 19.9 months, 27.5% of knees had devel oped recurrent symptoms. Two of these patients had repeat arthroscopy for recurrent impinging hypertrophic synovitis. The rates of successfu lly relieving symptoms without recurrence according to operative diagn osis were 82% for ''clunks,'' 60% for other impinging synovium or soft tissue, and 63% for arthrofibrosis. Three patients underwent total kn ee revisions. Knees were rated at follow-up using the Knee Society rat ing system with patients divided according to functional category. The average Knee Society knee scores and function scores respectively wer e 93 and 92 for group A patients, 91 and 88 for group B patients, and 81 and 76 for group C patients, Arthroscopy successfully identified al l cases of soft tissue impingement and prosthetic loosening or wear, a nd successfully treated 73% of patients without recurrence. There were no arthroscopy associated complications or infections. Thus, arthrosc opy is a safe, effective tool for managing certain problematic knee re placements, especially ''clunks,'' and may help to avoid revision or a rthrotomy in some cases.