Fusion of the septic knee with external hybrid fixator

Abstract

Arthrodesis is a well-recognized salvage procedure in patients with septic destruction of knee joints. It offers the opportunity for restoring weight bearing capability and significant pain relief as well as eradication of infection, but at the expense of joint motion. However, arthrodesis in order to joint sepsis may be difficult to achieve because of poor bone stock, persistent infection and soft tissue compromise. From 2000 to June 2004, in 70 consecutive patients arthrodesis of the knee was indicated. Nineteen patients were considered to have external hybrid fixator (EHF) and were therefore included to the prospective study protocol. Forty-three stabilisations of destructed knee joints were done by a modular titanium rod. In these cases bony fusion was very unlikely to be achieved because of devastating defects due to infected total knee arthroplasties. Eight patients were treated by compression nailing. In these situations EHF was not indicated. In three patients minor complication occurred. In two out of 17 patients fusion failed because of primary underestimated bony defects (11.8%). The use of EHF for arthrodeses after septic destruction of knee joints can be recommended according to our results. However, EHF will not be successful or applicable in each case. Therefore, physicians and institutions that offer this special method should have not only experiences with EHF but also with arthrodeses and alternative procedures.

Salvage Procedures for Management of Prosthetic Joint Infection After Hip and Knee Replacements

“…Different designs have also been used for EF. These included the Hoffman EF with multiplanar pin insertion [72], the Ilizarov or circular ring fixators [73-76], unilateral EFs [77, 78], hybrid EFs [79] and a combination of EF and Steinmann pin application [80]. …”

“…Independent mobility (with walking aids) reached 100% in all fixation methods. Pain relief reached 100% with EF [73, 79] whereas this was variable with IMN as reported rates of residual pain reached as high as 62% despite complete union [91]. Arthrodesis using cannulated screws produced significant improvement in pain scores [90].…”

“…Of the most commonly used techniques, EF was associated with the lowest re-infection rates with no recurrence seen in 4 studies [73-75, 97] and recurrence rates ranging from 14 - 17.7% in 3 other studies [79, 78, 80]. On the other hand, re-infection rates ranged from 3 - 28.6% for IMNs.…”

“…[91] found pain persisting in 62% of their patients following IMN even after complete bony union. A painful wire that requires removal could cause residual pain following EF [79]. Residual pain was less noted in patients who received the Stanmore prosthesis for knee arthrodesis as they reported improvement of the mean pain scores from 7.9 to 3.3 [81].…”

“…Further surgical interventions were necessary in 5.9% - 66.6% of EF cases and included wire removal or exchange, posteromedial release for equinovarus deformity, hematoma evacuation and surgical curettage for osteitis [73, 79, 99, 80]. For IMN cases, 4.7% - 28.6% of the patients underwent further surgery in the form of implant removal for persistent or recurrent infection, nail exchange and repeat fixation for metal failure, and bone grafting for nonunion [64-67, 71].…”