There are many reasons why a total knee replacement (TKR) may fail and qualify for revision. Successful revision surgery depends as much on accurate assessment of the problem TKR as it does on revision implant design and surgical technique. Specific modes of failure require specific surgical solutions. Causes of failure are often presented as a list or catalogue, without a system or process for making a decision. In addition, strict definitions and consensus on modes of failure are lacking in published series and registry data. How we approach the problem TKR is an essential but neglected aspect of understanding knee replacement surgery. It must be carried out systematically, comprehensively and efficiently. Eight modes of failure are described: 1) sepsis; 2) extensor discontinuity; 3) stiffness; 4) tibial- femoral instability; 5) patellar tracking; 6) aseptic loosening and osteolysis; 7) periprosthetic fracture and 8) component breakage. A ninth ‘category’, unexplained pain is an indication for further investigation but not surgery.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):105–11.

In this paper, we consider wound healing after total knee arthroplasty.

Seven stiff total knee arthroplasties are presented to illustrate the roles of: 1) manipulation under general anesthesia; 2) multiple concurrent diagnoses in addition to stiffness; 3) extra-articular pathology; 4) pain as part of the stiffness triad (pain and limits to flexion or extension); 5) component internal rotation; 6) multifactorial etiology; and 7) surgical exposure in this challenging clinical problem.

Purpose: Stiffness following TKA is devastating and poorly understood. This study was conducted to determine if rotational positioning of tibial and/or femoral components was related to the development of stiffness following TKA. In addition, post-revision rotational alignment was studied to determine if it contributed to improvement.

Method: Patients who presented with stiffness and either a fixed flexion contracture > 15 and/or flexion < 105 degrees were included in the study. 34 revisions were investigated preoperatively by computerized tomography (CT) for rotational evaluation of the components. Clinical and radiographic data were also recorded.

Results: All 34 revisions had some degree of combined internal rotation on the preoperative CT-scan. The net combined angle averaged fourteen point eight degrees of pathologic internal rotation (in excess of the normal eighteen degrees)[1]. The most significant source of internal rotation was the tibial component, with 33 of the 34 patients having internal rotation with a mean pathological (in excess of the normal eighteen degrees) angle of 13.3 degrees (one to 35 degrees). Postoperatively, the combined rotation angle was restored to an average of five point one degrees of external rotation for the eighteen patients with available CT-scans (p < 0.0001). The 34 revised knees were clinically followed for an average of 22 months. The mean preoperative Knee Society knee and function scores were respectively 41.6 and 47.9. The mean preoperative range of motion was 61.4 degrees. Postoperatively, the knee and function scores increased respectively to 77.3 and to 65.7 (p < 0.0045). The mean postoperative range of motion averaged 98.1 degrees (p < 0.0001).

Conclusion: Rotational positioning of the components should be investigated with CT-scan in stiff knees following TKA. Revision surgery of all the components with restoration of an adequate rotational alignment has been shown to improve range of motion, function and pain.

Aim: To present the experience of a highly specialized total knee arthroplasty revision center with the use of femoral and tibial components with modular press-fit offset stem extensions.

Methods: Intramedullary press-fit offset stem extensions were developed to offer an additional option when doing a revision total knee arthroplasty in the presence of periarticular bone loss. The radiological and clinical results of a cohort of 28 patients that had been previously subjected to a revision total knee arthroplasty utilizing modular press-fit offset stem extensions, were studied. Mean follow-up time of these patients was 3.5 years (range, 2–7 years). The NexGen Legacy Knee System was used in all our patients (25% LCCK, 75% LPS). The use of bone cement was restricted to the femoral and tibial articular surfaces only, without any intra-medullary use.

Results: Femoral intramedullary fit and fill was measured 87.9% in anteroposterior x-rays and 85.5% in laterals. Tibial intramedullary fit and fill was measured 94.5% in anteroposterior x-rays and 89.9% in laterals. Femoral components were implanted in 6.4 degrees of valgus angle (mean values) and 2.5 degrees of flexion (mean values). Tibial components were implanted in 2.2 degrees of valgus angle (mean values) and 3 degrees of posterior slope (mean values). Knee Society Score was 89.5 points, while Function Score was 84.8. One year post-revision follow-up evaluation revealed 89% satisfaction rate among these patients.

Conclusion: The use of these press-fit offset stem extensions, with the best possible intramedullary femoral and tibial fit and fill, offer a very rewarding method and an alternative option to deal with complex reconstructive problems during a revision total knee arthroplasty.

Aim of the study: Compromised patellar bone stock poses significant technical challenges in knee revision surgery. The alternatives that have been proposed include reinsertion of a biconvex patellar component, patellar bone grafting, patellectomy, and leaving the unresurfaced patellar bone remnant in place. Various results have been reported with these methods, but not one of them has yet been widely accepted.

Methods: A novel sagittal osteotomy that was used in four patients is described.

Results: This osteotomy leaves the extensor mechanism intact and allows the medial and lateral halves of the residual patella to hinge open in the shape of a “gull wing.” This conforms to the femoral trochlear groove and when combined with particulate bone grafts, it consolidates as a mass resembling a patella.

Conclusion: The procedure has been limited to severe cases and obviates the need for patellectomy.