The TL Hex (Orthofix) is a relatively new hexapod frame system that we have been using at our institution since August 2013 to treat acute fractures and correct tibial and femoral deformity. We report our initial experience of 48 completed treatments with this novel system in 46 patients and discuss illustrative cases. For acute fracture, 30 patients (24 male, 7 female) required framing with a mean age of 43 years (range 19–80). One patient underwent bilateral framing. The tibia was involved in all cases. In two cases, the femur also required framing. Open fractures occurred in 13 cases (43.3%). For elective limb reconstruction, 16 patients (14 male, two female) required framing with a mean age of 35 years (range 16–67). One patient underwent bilateral framing. The tibia was involved in all but one case, which affected the femur. Surgical indications included congenital deformity in four cases, malunion in eight cases, non-union in three cases and chronic infection in two cases. For acute fractures, the mean frame time was 164 days (range 63–560) and all but one fracture achieved union. Complications included pin, wire or strut failure requiring adjustment (three patients) and pin site infection (six patients). Three patients are being considered for residual deformity correction or treatment of non-union. In the elective limb reconstruction group, mean frame time was 220 days (range 140–462). All treatments successfully achieved deformity correction and bone union. Complications included two pin site infections. There was no evidence of recurrence of infection in the two osteomyelitis cases. In conclusion, the TL Hex frame system appears to be a safe and reliable tool for limb reconstruction. We have observed acceptable frame times, low complication rates and almost 100% bony union.
Initial stability of the tibial component influences the success of uncemented total knee arthroplasty. In uncemented components, osseointegration provides long-term fixation which is particularly important for the tibial component. Osseointegration is facilitated by minimising bone-implant interface micromotion to within acceptable limits. To investigate initial stability, this study compares the micromotion and initial seating of two uncemented hydroxyapatite-coated tibial components, the Genesis II and Profix. This is the first stability comparison of two hydroxyapatite-coated tibial components. Six components of each type were implanted into synthetic tibias by a single orthopaedic surgeon. Good coverage was achieved. No screws or articular inserts were used. Initial seating was measured using ImageJ software at five areas on each tibia. Tibias were transected and their proximal section implanted into a molten alloy parallel to horizontal. Dynamic mechanical testing was performed using a hydraulic 858-Bionix machine. Prostheses underwent unilateral axial point-loading of 700N cyclically applied four times. The load was applied to three locations approximating femoral loading points. The loading cycle was repeated six times at each point, allowing micromotion to be recorded at three contralateral locations. Micromotion was measured by optical lasers. After dynamic testing, two tibial components of each type were removed with claw pliers while measuring the force required on the 858-Bionix machine. Implant under-surfaces were photographed for wear.Introduction
Methods
