ARTHRODESIS OF KNEE WITH INTRAMEDULLARY NAIL “WICHITA”. MULTICENTRIC PROSPECTIVE-RETROSPECTIVE STUDY

Abstract

Knee arthrodesis is a useful procedure in difficult cases such as failed total knee arthroplasty, bone tumors and infected knee joints. A review of 27 cases treated using a modular locked intramedullary nail “Wichita” in 4 hospitals was performed. This fusion nail is a device designed to provide simultaneous compression and intramedullary fixation. The device is implanted through a single knee incision using three main components after femoral and tibial reaming. The femoral components inserts retrograde and has two holes in its proximal end to accept transverse locking screws. The tibial component inserts anterograde into the proximal tibia and has some holes for transverse screw placement. The compression screw component is used to lock the femoral and tibial components together and simultaneusly compression is generated across the joint line. Teorical advantages are single incision, inmediate and solid stability, posibility of compression, adjust of length, high fusion rates and less risk of infection than other procedures. An individual study protocol was made and it includes previous primary or revision failed total knee replacement, severe articular trauma and infection. No bone tumors were includes. Protocol includes aspects such as operative time and blood loss,intraoperative complications, radiographic evaluation (tibiofemoral alignement, contact tibiofemoral surface area...) shortenning of extremity, time to union, posoperative complications and patient subjective evaluation.10 patients are being studied prospectively in our institution since january 2000 and the mean follow-up is 16 months. 17 patients were retrospectively studied in 3 differents hospitals using the same protocol and the mean follow-up is 26 months. Global results show a solid fusion in 26 (96 per cent) of the 27 patients at an average time of 15 weeks (range 12 to 22 weeks) after the operation. There were one mechanical failure of the implant (thecnical mistake during assembly of the compression screw component). There were 2 non desplaced fractures in the end of the nail. There was 1 desplaced fracture and removed of implant was required, osteosynthesis was performed with a long intramedullary nail. No infections were detected. These results and others are related. Although good results observed, with high fusion rates and minimal complications, a potential disadvantage is the difficult to remove the nail if this is necesary.