Bone loss management in total knee revision surgery

Abstract

Purpose: Bone stock reconstruction in TKR surgery is one of the biggest challenges for the surgeon. According to some, authors causes of bone stock loosening are multiple, including stress shielding, osteolysis from wear, septic or aseptic loosening, and bone loss caused by a poorly balanced implant. Moreover, bone loss may be iatrogenic at the time of implant removal, indicating that bone preservation during implant removal is critical.

Methods: Defect localization and extension affect the surgeon's decisions about the choice of the surgical technique and the type of plant to be taken. Today there are several options available for bone deficiency treatment. The treatment choice is undoubtedly linked to the cause of revision, experience and personal philosophy, but it is necessary to consider also the patient's age, expectations of life, functional requirements and bone quality. Many authors prefer bone stock reconstruction techniques in patients with high bone quality and a better quality of life with more prospects. In patients with lower lease on life and lower bone quality the best bone replacement techniques are of modular systems, wedges, and augments. In cases with septic bone loss, more or less extended, different authors recommend reducing bone grafts in favor of modular prostheses to reduce the risk of graft contamination.

Results: All of these techniques have been shown to be durable in midterm outcomes, but concerns exist for a number of reasons, including disease transmission, resorption, fracture, immune reaction to allograft, the cost of custom prostheses, the inability to modify the construct intraoperatively and the overall technical challenge of applying these techniques.

Conclusions: The choice between different surgical options depends on bone defect dimension and characteristics but are also patient-related. Reestablishment of well-aligned and stable implants is necessary for successful reconstruction, but this can't be accomplished without a sufficient restoration of an eventual bone loss.

Fig. 1

Femoral and tibial defects classification

Fig. 2

AORI TYPE II bone defect (a) treated with impacted morsellized bone grafts (b)

Fig. 3

AORI TYPE III bone defect in a case of total knee revision in treatment with antibiotic spacer (a). Radiographic results after bone loss treatment with cones and stemmed prosthesis (b). A particular type of cone used to fill metaphyseal bone loss (c)

Fig. 4

AORI TYPE III bone defect treated with metaphyseal sleeves (a Preoperative X-ray. b Postoperative X-ray). An intraoperative particular of the defect (c)