Methods: We developed a modified navigated TKA technique in which femoral rotation was set using the resected tibial plane as the reference with the aim of achieving a rectangular flexion gap. Limb alignment was assessed in a cohort of 30 knees using the navigation system. Post-operative limb alignment was measured using long-leg standing radiographs. Computed tomography was used to determine post-operative component orientation.
Results: Sagittal alignment data improved from a mean of 7.8° varus (pre-operative) to 0.0° (post-operative), assessed by intra-operative navigation. Post-operative hip-knee-ankle axis alignment was 0.9° valgus (mean; standard deviation [SD] 1.7°). Mean femoral component rotation was 0.5° internally rotated (SD 2.6°), relative to the surgical transepicondylar axis. Mean tibial component rotation was 0.9° externally rotated (SD 5.5°). No soft tissue releases were performed.
Conclusions: These results confirm that the desired femoral rotation, set using a tibia-first approach with the resected tibial plane as the reference, can be achieved without compromising overall limb alignment. Femoral component rotation was within a narrow range, with a moderate improvement in achieving more consistent tibial component rotation compared with other techniques. This technique may prove to be useful for surgeons wishing to employ a tibia-first philosophy for TKA while maximizing the benefits associated with computer-assisted navigation.
METHODOLOGY: A prospective observational study on all consecutive children with head injuries at the General Hospital Kuala Lumpur between November 1993 and December 1994. The onset, type and frequency of seizures occurring within the first week of injury were documented. Using inpatients as a cohort, logistic regression analysis was used to determine clinical and radiological variables significantly associated with seizures. The outcome 6 months post-injury was assessed using the Glasgow Outcome Scale.
RESULTS: Fifty-three of 966 children (5.5%) developed seizures within the first week of trauma. Seven (13.2%) occurred within 1 h of injury, 30 (56.6%) between 1 and 24 h and 16 (30.2%) after 24 h. Factors significantly associated with early post-traumatic seizures were female sex, age less than 2 years, loss of consciousness for more than 24h and acute subdural haematoma (P<0.01). Children with seizures had a poorer outcome (death or severe disability) than inpatients without seizures (21/53 vs 19/182, P<0.001). The outcome was worst in children with recurrent partial seizures, who had a longer injury-seizure interval and were more likely to have focal neurologic deficits compared to those with sporadic or generalized seizures.
CONCLUSIONS: Anticonvulsant prophylaxis to minimize the adverse effects of early seizures in head injury should be considered for young children (less than 2 years old) with subdural haematoma and a prolonged duration of coma. Prompt and effective control of recurrent seizures is recommended.