Poor outcomes of isolated tibial insert exchange and arthrolysis for the management of stiffness following total knee arthroplasty

Background: Severe stiffness after total knee arthroplasty is a debilitatin g problem. In patients with securely fixed and appropriately aligned compon ents, arthrolysis of adhesions and exchange to a thinner tibial polyethylen e insert may appear to be a reasonable and logical solution. We reviewed ou r experience with this procedure to determine its efficacy. Methods: From 1992 through 1998, seven knees with marked stiffness after to tal knee arthroplasty were treated at our institution with arthrolysis of a dhesions and conversion to a thinner tibial polyethylene insert.. Only pati ents in whom the total knee prosthesis was well aligned, well fixed, and no t associated with infection were included. There were five women and two me n with a mean age at revision of sixty-one years (range, thirty-eight to se venty-four years). The average time to revision was twelve months, and the mean arc of motion prior to revision was 38.6 degrees (range, 15 degrees to 60 degrees). The duration of follow-up after the insert exchange averaged 4.2 years (range, two to eight years). Results: Mean Knee Society pain and function scores changed from 44 and 36. 4 points preoperatively to 39.6 and 46 points at the time of final follow-u p. Two knees were rerevised, one because of infection and the other because of aseptic loosening of the components. The five remaining knees were pain ful and stiff at the time of final follow-up. Four of these five knees were severely painful, and one knee was moderately and occasionally painful. Th e mean arc of motion of these five knees was 58 degrees (range, 40 degrees to 70 degrees) at the time of final follow-up. Conclusion: Isolated tibial insert exchange, arthrolysis, and debridement f ailed to provide a viable solution to the difficult and poorly understood p roblem of knee stiffness in a group of carefully selected. patients followi ng total knee arthroplasty. We therefore have little enthusiasm for the con tinued use of this strategy.