Introduction: Failed total knee replacement due to the daemage of bone stock and infection requires removal of prosthesis. Successful arthrodesis is strongly related to the quality of bone stock. Both external fixators and KAFO are not comfortable and thus poor tolerated by elderly patients. Instable knee is very disabling condition. Custom-made femoro-tibial nail combined with acrylic cement spacer offers maintenance of supportive function of extremity after removal of knee prosthesis. Avoidance of leg length discrepance is possible. Nailing can be considered only as salvage procedure for one knee. Material and Method: Six elderly patients underwent unilateral arthrodesis of the knee after removal of knee prosthesis due to the daemage to the bone stock and periprosthetic infection. They have had conical shape of the lower leg and poor quality to the bone. Thus they were not suitable for conventional knee arthrodesis using external fixator or for pseudoarthrosis and KAFO. After removal of TKR and debridement of periprosthetic tissues an ortograde, custom-made femoro-tibial interlocking nail was inserted. The gap betveen distal femur and proximal tibia was filled with hand-made acrylic cement spacer loaded with vancomycin (2g per 40 g cement) so that the spacer finally gained tubular shape. Results: No recurrence of infection was noted. Early postoperative full-weight bearing was possible. Implant failure occurred in one case and required replacement of nail and cement spacer. Stress fracture of femoral neck occurred in another case. Despite of this problems all patients has better ADL than with KAFO or after. Conclusion: femoro-tibial nail for failed TKR is good accepted and comfortable for patient. Disadvantage of this type of nail is stiff knee and risk for nail fracture

Abstract

Introduction

Arthrodesis is usually offered to patients in whom a two stage exchange arthroplasty has already failed or is likely to fail because of local factors (such as soft tissue damage, bone loss or poor perfusion), or because of systemic conditions which categorise the patient as a C-host (e.g. immune deficiency, diabetes and malnutrition). In other words arthrodesis is selected for patients with the worst prognosis.

The purpose of our study was to assess the success rate of methods used for knee arthrodesis in failed total knee arthroplasty and to do a functional evaluation after arthrodesis of the knee. A physiotherapist and occupational therapist assessed 10 patients who had undergone knee arthrodesis, using either the Orthofix or Ilizarov methods.

Both methods were successful. There were no failures. The functional outcomes were satisfactory.

Introduction

Fifteen percent of the primary total knee arthroplasties (TKA) fails within 20 years. Among the main causes for revision surgery are instability and patellofemoral pain. Currently, the diagnostic pathway requires various diagnostic techniques to reveal the original cause for the failed knee prosthesis and is therefore time consuming and inefficient.

Accordingly, there is a growing demand for a diagnostic tool that is able to simultaneously visualize soft tissue structures, bone and TKA. Magnetic resonance imaging (MRI) is capable of visualising all the structures in the knee although a trade- off needs to be made between metal artefact reducing capacities and image quality. Low-field MRI (0.25T) results in less metal artefacts and a lower image quality compared with high-field MRI (1.5T). The aim of this study is to develop a MRI imaging guide to image the problematic TKA and to evaluate this guide by comparing low-field and high-field MRI on a case study.

Purpose: To assess the outcome of customised hinged knee replacements when used to salvage catastrophically failed knee replacements in elderly patients.

Methods: Since 1993, 30 of the 280 (10.7%) revision knee replacements at the Avon Orthopaedic Centre, Bristol have used Endo customised hinged knee pros-theses (21 rotating, 9 fixed) for salvage of limb threatening situations in elderly patients. All were prospectively recorded and regularly reviewed. The average age was 75 years with a predominance of females. Surgical indications were 22 periprosthetic fractures (with or without aseptic loosening), 5 massive aseptic osteolyses, and 3 deep infections.

Results: The mean length of postoperative hospital stay was just 14.6 days and all patients were discharged walking with aids. At follow up (mean 3.0 years, range 0.5–9.3 years) 9 patients had died with their prostheses in situ and functioning. 2 had undergone amputation for recurrent sepsis and 2 had received further surgery for septic problems. 2 patients required further surgery for prosthetic disarticulation and one patient had successful on table vascular repair. 25 patients had mid or long term follow up. Their mean American Knee Scores (AKS) were 69.8 for knee and 35.6 for function (maximum 100), with a mean total knee flexion of 83 degrees. Mean Oxford knee scores (OKS) and WOMAC scores (both scored between 12 and 60 with low score indicating less difficulties) were 34.0 and 30.5 respectively.

Conclusions: Customised hinge revision knee replacements gave extremely rapid rehabilitation and hospital discharge which justified the high prosthetic cost. Complications were high but at mid and long-term review, no prostheses had failed from an aseptic cause and most of the knees of this challenging group were providing both stability and flex

Arthrodesis is used most commonly as a salvage procedure for failed total knee arthroplasty (TKA). For successful arthrodesis, a stable fusion technique and acceptable limb mechanical alignment are needed. Although the use of intramedullary alignment rods might be helpful in terms of achieving an acceptable limb mechanical axis, fat embolism and intramedullary dissemination of an infection or reactivation of latent infection might occur in failed TKA cases. However, computer-assisted surgery allows precise cuts to be made without breaching medullary cavities. Here, the authors describe a case of knee arthrodesis performed by computer navigation and the Ilizarov method in a patient with a past history of infection. A 45-year-old man visited our hospital with failed total knee arthroplasy. Fortunately, even though infection was treated by debridement with component retention, mild heating was present over the knee, but ESR(erythrocyte sedimentation rate) and CRP(C-reactive protein) were within normal ranges. X-ray showed subsidence of the femoral component and a radiolucent line around the femoral component. Arthrodesis was planned for this patient due to disabling pain, a long-lasting severe functional deficit, failure of the primary TKA for ankylosed knee, and the patient’s poor economic status and his strong desire for arthrodesis. The computer navigation surgery system and the Ilizarov method were used for two reasons. The first reason was that the patient had a past history of infection. At pre-operative evaluation, even though ESR and CRP levels were within normal range, we could not completely rule out the possibility of latent infection due to suspicious findings such as long lasting disabling knee pain, mild heating over the knee, severe osteolytic radiographic changes around the femoral component. In that situation, inserting an IM rod to achieve acceptable mechanical alignment might have reactivated and disseminated a possible latent infection to the femoral or tibial medullary canals. The second reason was that we wanted to reduce the possibility of fat embolism by using computer navigation without instrumentation within the medullary canal. A CT-free, wireless computer navigation system was applied, with trackers fixed to the femur and tibia and no requirement for the use of an IM rod with component retention. Navigated femoral and tibial bone resections were then performed using Stryker software. The femoral resection was conducted at 0° of flexion to the sagittal axis, and the tibial resection at 7 ° of flexion to the sagittal axis. Arthrodesis was held in proper axial and rotational alignment with bone surfaces compressed together. Finally, knee arthrodesis was completed using the Ilizarov method. Based on our experience of the described case, we believe that arthrodesis for failed TKR, especially failure secondary to intraarticular infection, can be considered as another indication for computer navigation.

Revision total knee arthroplasty (TKA) is becoming a more frequent procedure throughout Europe. Painful patello-femoral problems, patellar dislocation, impingement pain as well as aseptic loosening and gross malalignment are among many causes. We investigated the use of CT scans in identifying alignment causes for pain in failed TKA where no other obvious cause is found.

Twenty poorly functioning TKA were analysed using the Perth CT protocol. All patients were awaiting revision TKA and had no obvious evidence of infection or loosening. They were scanned using a GE multislice CT scanner. The measurements were performed using standard CT software. Knee society scores were obtained pre- and post-operatively.

The mean coronal position of the components was three degrees of valgus for the femoral component and 2.5 degrees of varus for the tibial component. Fourteen knees had errors of femoral component rotation, which ranged from one degree of external rotation to nine degrees of internal rotation. The cumulative error of implantation ranged from 6–24 degrees in all planes. Knee society scores improved post-operatively from a mean of 52 pre-operatively to 83 at one year. Compound error also improved to a range of 6 to 10 degrees in all planes.

Revision TKA remains a difficult procedure that is increasing in frequency. The use of a CT protocol allows all coronal, sagital and rotational errors of an implant to be accurately identified prior to surgery. This could be useful in the small groups of patients with painful TKA that have no obvious cause for failure. Total knee replacement failure in these cases maybe explained by a cumulative error in alignment and correction of which may improve their Knee Society Scores.

We believe that a CT scan of a failed TKA is useful as part of the pre operative planning and also in investigating painful TKA where no obvious cause is found.

Introduction Revision total knee arthroplasty is becoming a more frequent procedure throughout Europe. Painful patello-femoral problems, patellar dislocation, impingement pain as well as aseptic loosening and gross malalignment are among many causes. We investigated the routine use of CT scans in identifying alignment causes for failure as well as in the pre operative planning of the procedure.

Method Twenty poorly functioning total knee arthroplasties were analysed using the Perth CT protocol. All patients were awaiting revision total knee arthroplasty and were scanned using a GE multislice CT scanner. The measurements were performed using standard CT software.

Results The mean coronal position of the components was 3 degrees of valgus for the femoral component and 2.5 degrees of varus for the tibial component. Fourteen knees had errors of femoral component rotation, which ranged from 1 degree of external rotation to 9 degrees of internal rotation. Nine knees had errors of tibial base-plate rotation with all being internally rotated relative to the PCL/Tibial tuberosity axis from 3 to 12 degrees.

The cumulative error of implantation ranged from 6- 24 degrees in all 7 planes.

Discussion Revision total knee arthroplasty remains a difficult procedure but is increasing in frequency. The use of a CT protocol allows all coronal, sagittal and rotational errors in previous implantation to be accurately identified prior to surgery. We believe that all knee revision operations should have a CT scan as part of the pre operative planning.

Aim

External fixator knee arthrodesis is a salvage procedure mainly used in cases of end-stage infected total knee replacement (iTKR). A stable fixation combined with bone-ends compression is basic to achieve knee fusion in such a scenario but providing enough stability can be challenging in the presence of severe bone loss after multiple previous procedures. Compared with monoplanar configuration, a biplanar frame achieves improved coronal stiffness, while providing the advantages of good access to the wound and allowance of early ambulation. Our primary hypothesis stated that a biplanar frame would achieve higher and quicker fusion rate than a monolateral configuration.

Introduction

While knee arthrodesis is a salvage option for recalcitrant total knee arthroplasty (TKA) periprosthetic joint infection (PJI) it is used relatively uncommonly and contemporary data are limited. We sought to determine the reliability, durability and safety of knee arthrodesis as the definitive treatment for complex, persistently infected TKA in a modern series of patients.

Purpose: To introduce our surgical technique and report the clinical results of the knee arthrodesis with a Huck-step nail after a failed infected TKA

Materials and Methods: We retrospectively reviewed four patients who underwent knee arthrodesis with a Huck-stepnail after failed infected total knee arthroplasty. The average age of the patients at the time of the arthrodesis was 73 years (range: 70–79 years) and the mean number of previous surgical procedures was 3.2 (range:3–4 procedures). All patients had medical problems including diabetes mellitus and hypertension. We performed local bone graft in all cases. The duration of average follow-up was 20.2 months (range:12–36 months).

Results: Bone union was achieved within 1 year after arthrodesis radiologically. There was neither displacement of nail nor loosening. The average limb-length discrepancy was 3cm, measured clinically. All patients had a discrepancy that was corrected with a shoe-lift.

Conclusion: Arthrodesis with a Huckstep nail after failed infected total knee arthroplasty provides immediate axial and rotational stability and allows weight-bearing without use of external support.