The rates of osteolysis and loosening associated with a modular posterior stabilized knee replacement. Results at five to fourteen years.
BACKGROUND
Osteolysis and increased polyethylene wear have been reported in association with several designs of modular total knee prostheses. The purpose of the present study was to evaluate a modular posterior stabilized prosthesis to determine its clinical performance as well as the rates of component loosening and osteolysis.


METHODS
We performed a prospective, consecutive study of 193 knees in 131 patients who were managed with the modular Insall-Burstein II posterior stabilized total knee prosthesis by one surgeon. The mean age of the patients at the time of surgery was sixty-eight years, and the mean duration of follow-up was seven years (range, five to fourteen years). Clinical evaluation was performed with use of standard knee-scoring systems. Radiographs were evaluated for the presence of radiolucent lines, osteolysis, and loosening.


RESULTS
The overall result (as determined with the Hospital for Special Surgery scoring system) was rated as excellent for 112 knees, good for sixty, fair for fifteen, and poor for six. The mean postoperative flexion was 112 degrees. No clinical or radiographic loosening of the tibial component was noted. Eight knees had osteolytic lesions of the tibia. Thin, incomplete, nonprogressive radiolucent lines were noted around thirty tibial components (16%). There were three reoperations.


CONCLUSIONS
Despite previous reports of osteolysis, polyethylene wear, and loosening in association with some modular total knee implant designs, there was no loosening in this series of posterior stabilized total knee replacements and only eight knees had tibial osteolysis after a mean duration of follow-up of seven years. We believe that total knee arthroplasties that are performed with use of cemented modular posterior stabilized components can have a high rate of intermediate-term success.


METHODS
Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.
Lachiewicz
Paul F
PF
Department of Orthopaedics, University of North Carolina, Chapel Hill, 242 Burnett Womack Building, CB 7055, Chapel Hill, NC 27599, USA.
Soileau
Elizabeth S
ES
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation*; D001843:Bone Cements / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology; D007719:Knee Joint; D007720:Knee Prosthesis / Q000009:adverse effects* / Q000592:standards; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D010014:Osteolysis / Q000209:etiology*; D020959:Polyethylene; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000706:statistics & numerical data; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome
D001843:Bone Cements; D020959:Polyethylene