[Long-term results in total knee arthroplasty. A meta-analysis of revision rates and functional outcome].
BACKGROUND
Total knee arthroplasty (TKA) is one of the most common procedures in orthopedic surgery and clinical success can be characterized by the revision rate and improvement of function. To quantify both characteristics two independent meta-analyses have been performed.


METHODS
A search in Medline provided a total of 96 studies on revision rates and 63 studies with functional results with a minimum follow-up of 5 years.


RESULTS
A total of 911 revisions among 20,873 TKAs were identified corresponding to a meta-revision rate of 4.4% after a mean follow-up of 10.7 years. Most common causes for revision were aseptic loosening (31%), infection (23%), polyethylene wear (16%) and patellar problems (14%). Revision rates were higher in younger patients (7.0% <60 years at time of operation, 5.0% between 60 to 70 years and 2.2% >70 years), after cementless TKA (8.3% cementless versus 3.6% cemented) and in studies with a higher rate of patients with rheumatoid arthritis. The second meta-analysis revealed a meta-improvement based on the Knee Society Knee Score of 51.3%, for the Knee Society Function Score of 30.6%, for the Hospital for Special Surgery Score of 36.1% and for the New Jersey Orthopedic Hospital Knee Evaluation System of 33.6%.


CONCLUSIONS
TKA is a successful treatment for osteoarthritis of the knee with an expectable revision rate of less than 5% within 10 years and a long-lasting functional improvement of more than 30% in any assessment score.
Orthopädische Klinik, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstrasse 74, Dresden, Germany. Joerg.Luetzner@uniklinikum-dresden.de
J
J
Lützner
U
U
Hübel
S
S
Kirschner
K-P
KP
Günther
F
F
Krummenauer
D000367:Age Factors; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011183:Postoperative Complications / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000601:surgery*; D012086:Reoperation
Ann Rheum Dis. 2004 Jan;63(1):4-10
14672883
J Bone Joint Surg Br. 2001 Apr;83(3):339-44
11341416
J Bone Joint Surg Am. 1976 Sep;58(6):754-65
956219
Clin Orthop Relat Res. 1997 Dec;(345):134-9
9418630
Cochrane Database Syst Rev. 2005 Oct 19;(4):CD004803
16235383
Rheumatology (Oxford). 2002 Apr;41(4):390-4
11961168
J Bone Joint Surg Br. 2009 Jul;91(7):889-95
19567852
Clin Orthop Relat Res. 1989 Nov;(248):13-4
2805470
J Bone Joint Surg Am. 2005 Jul;87(7):1438-45
15995109
J Bone Joint Surg Am. 2005 Aug;87(8):1889
16085638