Periprosthetic osteolysis is a known complication after cementless total knee replacement (TKR), including cases in which the implant is well fixed and properly aligned [
Osteolysis is a well-recognized complication after THR that presents diagnostic and treatment challenges [
Similar to THR, periprosthetic osteolysis associated with polyethylene wear can occur adjacent to the metal components of TKR. The traditional course of treatment is complete TKR revision [
The purpose of this study is to systematically assess patients who presented with progressive periprosthetic osteolysis adjacent to well-fixed and well-aligned uncemented TKR and were treated with bone grafting and isolated insert exchange. We define the preoperative and intraoperative surgical decision models used in the clinical evaluation and surgical treatment of these patients and present a retrospective review of outcomes at 1 to 10 years of followup.
We retrospectively reviewed 9 patients (10 cases) who presented with osteolysis adjacent to well-fixed and well-aligned uncemented TKR and were treated with bone grafting and isolated exchange of the tibial polyethylene insert and retention of the femoral and tibial components. The senior surgeon (TP) performed all index TKR between December 1996 and January 2003 and all subsequent bone grafting and isolated insert exchanges between December 2002 and December 2011. Approval for clinical records review was obtained from our Institutional Review Board.
At index TKR, all patients presented with an underlying diagnosis of osteoarthritis. Surgical technique included a subvastus approach with resection of the posterior cruciate ligament, a tibial cut aligned parallel with the posterior slope of the articular surface, and the patella left unresurfaced. All knees were implanted with an uncemented TKR prosthesis (Natural Knee II with Ultracongruent insert, Sulzer Medica, Austin, TX, USA). Femoral and tibial component fixation was enhanced by spreading the cut bone surfaces with a bone slurry reamed from the cancellous bone of the tibial wafer [
The main indication for subsequent surgery, including bone grafting and isolated insert exchange, was periprosthetic osteolysis observed on routine clinical radiographs. All patients were counseled for possible complete revision of all components and the risks associated with the insert exchange and bone grafting procedure were discussed in depth. The preoperative surgical decision for bone grafting and isolated insert exchange, rather than complete revision, was indicated in patients presenting with osteolysis with well-aligned components that appeared well-fixed on pre-operative clinical radiographs (Figure
Preoperative surgical decision model.
Intraoperative surgical decision model.
The surgical technique for bone grafting and isolated insert exchange followed an uniform intra-operative surgical decision model (Figure
At last followup, clinical outcomes were assessed according to Knee Society Guidelines [
Radiographs of a 67-year-old male who underwent bone grafting and isolated insert exchange for femoral osteolytic region. (a) The prerevision radiograph. (b) Three-month postrevision radiograph.
Radiographs for a 64-year-old female patient who underwent bone grafting and isolated insert exchange. (a) prerevision AP view radiograph showing osteolytic region. (b) Three-month postrevision AP view radiograph.
There were seven male patients and two female patients treated with bone grafting and isolated insert exchange, including one patient with bilateral procedures completed 4.6 years apart. Patient age averaged
Clinical followup of these 10 cases revealed no further complications in 100% of the patients, with no reported clinical symptoms of pain and no new areas of osteolysis noted on follow-up radiographs. None of the knees have required additional surgical intervention. One patient suffered multiple long bone fractures including a periprosthetic femoral fracture 2 years later due to a motorcycle trauma but the index TKR components remained intact without a need for revision. The average Knee Society Score improved from
Detailed review of the radiographs revealed findings consistent with the criteria defined in the pre-operative surgical decision model (Figure
In cementless total joint replacement, periprosthetic osteolysis associated with polyethylene wear is a known complication [
Bone grafting proved useful for treating osteolytic lesions adjacent to both femoral and tibial components, with full graft incorporation effectively eliminating the lesion site and preventing recurrence at 1 to 10 years of followup. These results are more favorable than those of previous studies. Whiteside and Katerberg [
This study utilizes a historical control group for comparison, which is an appropriate comparison for this study because had the femoral and tibial components been removed the residual defect would have required revision-stemmed implants of metal augments, structural bulk allografts, and cancellous allografts options. This control group includes patients who required a revision surgery in which auto- or allograft bone grafts (structural, bulk, or morselized), metal wedges, and modular components were used [
The clinical use of demineralized bone matrix and cancellous bone chips is well supported in the literature [
Several aspects of the current study limit the ability to generalize these results. Adhering to our pre- and intraoperative surgical decision models, the number of cases available for inclusion was limited. Based on our favorable outcomes in this small population, continued use and investigation of this treatment method is justified. While a single surgeon’s patient data eliminated variation due to surgical technique, it is recognized that reporting results from one experienced surgeon may not represent outcomes from more widespread use of this technique. This method for treating progressive periprosthetic osteolysis in cementless TKR is primarily dependent on having well-fixed components at the time of revision, which in our study was enhanced through use of bone slurry at index TKR. Its effectiveness for other TKR designs or cemented TKR is unknown.
Fully incorporated grafts occurred in all ten cases in this study, including 7 large defects. These results are similar to other published results for insert exchange in TKR, ranging from 84.6% to 97% complete or near complete graft incorporation into treated osteolytic lesions [
This series of 10 TKRs with progressive periprosthetic osteolysis around well-fixed and well-aligned components that were treated with curettage of the osteolytic lesions, bone grafting of the resultant defect, and polyethylene insert exchange demonstrated excellent results at an average of 5 years of followup with no cases requiring rerevision surgery. The senior surgeon (TP) continues to selectively use this approach and recommends incorporating the surgical decision models (Figures
All the authors declare that there is no conflict of interests for this work. They have received no funds from any commercial party in relation to this work.
The authors acknowledge Sandra Fowler and Becky Snider for their assistance with the medical record reviews.