In adults, knee replacement is a highly successful procedure for treating the pain and lack of mobility caused by end stage knee arthritis. While it is fortunately rare, children and young adults who develop juvenile idiopathic arthritis (JIA) can also have their arthritic condition progress to the point of needing total knee arthroplasty (TKA).
Because so few of these procedures are performed, an international, multi-center collaboration – combining patient data from five institutions – was required to study outcomes in TKA for JIA.
A total of 217 patients with 335 TKAs, were treated by experienced arthroplasty surgeons at five hospitals between 1979 and 2011. The patients had all been diagnosed with JIA, though some patients were well past childhood by the time their juvenile arthritic condition had advanced to the stage that they required a TKA. The average age at surgery was 28.1, with the patients ranging in age from 11 to 58.
The patients were identified by chart review and then contacted to survey their outcomes. Of these surgeries, 294 TKAs had a minimum follow up of two years. Those patients were assessed using a standardized test known as the Kaplan Meier survival analysis. In joint replacement, “survival” is the medical term for “still working,” indicating that the implant is still performing successfully for the patient and has not failed or been revised.
The collaborators also examined data on revision surgery, as well as the patients’ walking tolerance, ability to ascend and descend stairs, and use of walking aids.
Knee replacements do not last as long in patients with JIA as they do in elderly osteoarthritic patients. The 10-year Kaplan Meier survival was 92.2%, and the 20-year survival was 75.5%. This is especially disconcerting as younger patients, having more years they need their implants to last, require better durability, not less.
Survivorship may be negatively impacted by the patient’s poor bone quality, severe joint deformities, and the immunosuppressive medications used to treat their disease.
Of the patients studied, at latest follow up, 49% had unlimited walking tolerance, 22% could walk five to 10 blocks, and 27% could only walk less than 5 blocks.
11% percent could not manage stairs, and another 59% depended on railings. A cane was used by 11.7% and crutches by 6.7%. 11.7% were wheelchair dependent.
Surprisingly, over the 32 years studied, the number of procedures performed each year remained relatively consistent, in spite of the advent of new medications over those decades.
Thomas J. Heyse, MD
University Hospital, Marburg, Germany
Michael D. Ries, MD
UC, San Francisco
Johan Bellemans, MD
Catholic University Hospital, Belgium
Stuart B. Goodman, MD, PhD
Lucile Packard Children’s Hospital, Stanford
Richard D. Scott, MD
New England Baptist Hospital, Boston
Ran Schwarzkopf, MD