Revision total knee arthroplasty with a cemented posterior stabilized, condylar constrained or fully constrained prosthesis: a minimum 2-year follow-up analysis

Abstract

Background: The clinical and radiological outcomes of revision total knee arthroplasty with a cemented posterior stabilized (PS), condylar constrained knee (CCK) or a fully constrained rotating hinge knee (RHK) prosthesis were evaluated.

Methods: This study reviewed the clinical and radiological results of 36 revision total knee arthroplasties with a cemented PS, CCK, and RHK prosthesis in 8, 25, and 13 cases, respectively, performed between 1998 and 2006. The mean follow-up period was 30 months (range, 24 to 100 months). The reason for the revision was aseptic loosening of one or both components in 15, an infected total knee in 18 and a periprosthetic fracture in 3 knees. The average age of the patients at the time of the revision was 65 years (range, 58 to 83 years). The original diagnosis for all primary total knee arthroplasties was osteoarthritis except for one case of a Charcot joint. All revision prostheses were fixed with cement. The bone deficiencies were grafted with a cancellous allograft in the contained defect and cortical allograft fixed with a plate and screws in the noncontained defect. A medial gastrocnemius flap was needed to cover the wound dehiscence in 6 of the 18 infected cases.

Results: The mean Knee Society knee score improved from 28 (range, 5 to 43) to 83 (range, 55 to 94), (p < 0.001) and the mean Knee Society function score improved from 42 (range, 10 to 66) to 82 (range, 60 to 95), (p < 0.001) at the final follow-up. Good or excellent outcomes were obtained in 82% of knees. There were 5 complications (an extensor mechanism rupture in 3 and recurrence of infection in 2 cases). Three cases of an extensor mechanism defect (two ruptures of ligamentum patellae and one patellectomy) were managed by the RHK prosthesis to provide locking stability in the heel strike and push off phases, and two cases of recurrent infection used an antibiotic impregnated cement spacer. The radiological tibiofemoral alignment improved from 1.7 degrees varus to 3.0 degrees valgus in average. Radiolucent lines were observed in 18% of the knees without progressive osteolysis.

Conclusions: Revision total knee requires a more constrained prosthesis than primary total knee arthroplasty because of the ligamentous instability and bony defect. This short to midterm follow-up analysis demonstrated that a well planned and precisely executed revision can reduce pain and improve the knee function significantly. Infected cases showed as good a result as those with aseptic loosening through the use of antibiotics-impregnated cement beads and proper soft tissue coverage with a medial gastrocnemius flap.

Keywords: Prosthesis design; Revision; Total knee replacement; Treatment outcome.

Fig. 1

The large segmental allograft was generally secured to the host bone with plates and screws, and served as structural support for the implant. (A) Preoperative radiograph showing loosening of both components and liner wear. (B) Severe bone deficiency in the distal femur and tibia. (C) Large segmental defects were filled with cortical allograft bone and fixed with plates and screws.

Fig. 2

A cemented posterior stabilized prosthesis was used if both collateral ligaments were felt to be competent and a condylar constrained knee or rotating hinge knee prosthesis was used if more than one of collateral ligaments were incompetent or in the case of extensor mechanism failure. The radiograph shows the revision performed by cemented posterior stabilized (A), condylar constrained knee (B) and fully constrained rotating hinge knee prosthesis (C).

Fig. 3

Medial gastrocnemius flap was performed to cover the wound dehiscence of the infected cases. (A) Wound dehiscence after revision total knee arthroplasty. (B) Preparing medial gastrocnemius by posteromedial approach. (C) Wound coverage by a medial gastrocnemius flap. (D) Five months after a skin graft was placed over the exposed medial gastrocnemius muscle.