Effect on knee motion of gradual intramedullary femoral lengthening.

Gradual femoral lengthening causes loss of knee motion due to soft tissue tightness. Lengthening with an intramedullary device would be expected to retain good knee movements since it avoids soft tissue transfixation. To ascertain this we looked at the knee movements recorded in 27 patients before, during and after bilateral simultaneous femoral lengthening using Albizzia nails. The mean gain was 6.2 cm and the mean follow-up 28.6 months. No significant difference was noted between the mean preoperative and final knee flexions (148.3 degrees vs. 148.4 degrees) and the mean preoperative and final knee extensions (2.3 degrees vs. 3.4 degrees). By their last visit, all patients were flexing to at least 120 degrees and only one patient had a flexion deformity over 5 degrees. Thus maintenance of good knee motion and early return to activities is possible when an intramedullary device like the Albizzia nail is used for femoral lengthening.

Effect of the foot on the mechanical alignment of the lower limbs.

The authors evaluated the effect of the foot on the loading axis of the lower limb measured from radiographs in 30 pediatric patients. Deviation at the knee was calculated for the hip-ankle (traditional) and the hip-foot lines (heel lined up with a metal wire). A trigonometric model of the limb loading axis was developed with predicted mechanical axis deviations at the knee. Statistics were based on the methods of Bland and Altman. Mechanical axis deviation at the knee in the frontal plane varies with foot height, foot-tibial angle, and genu valgum. The predicted trigonometric model was found to be in agreement with measured radiographic values. Including the foot in the radiographic measurement of limb alignment may increase validity of surgical planning for correction of malalignment and for evaluation of degenerative arthritis risk at the knee level.

Gradual femoral lengthening with the Albizzia intramedullary nail.

BACKGROUND: Gradual limb lengthening with currently used external fixation techniques can result in less than optimal outcomes, with complications including infection, stiffness of adjacent joints, and secondary axial deviation of the extremity. We describe a totally implantable lengthening device designed to provide results similar to those achieved with external fixation devices, with fewer complications and improved outcomes. METHODS: Between 1993 and 1997, thirty-one patients (forty-one femora) underwent limb lengthening with a new internal fixation technique (Albizzia) to treat a congenitally short extremity (thirteen patients), post-traumatic limb-length inequality (eleven patients), or developmental problems (seven patients). Twenty-one patients (twenty-one femora) underwent unilateral surgery to equalize the limb lengths, and ten (twenty femora) underwent bilateral surgery to correct short stature. The mean age was twenty years and one month (range, twelve to thirty-nine years). After intramedullary corticotomy of the diaphysis of the femur, an intramedullary nail was inserted in an antegrade fashion. Fifteen alternating internal and external rotation maneuvers of the lower limb elongated the nail by 1 mm. The outcomes were assessed clinically and radiographically at a mean of fifty months postoperatively. RESULTS: The gain in femoral length averaged 3.4 cm (range, 2 to 5.5 cm) after the unilateral lengthening procedures and 6.3 cm (range, 4.6 to 8.4 cm) after the bilateral procedures. Patients underwent an average of three operations on each limb; these procedures included, in addition to the nail insertion and nail removal, ratcheting under general anesthesia in thirteen limbs and eleven procedures to treat complications in nine patients. At the time of follow-up, no patient had axial deviation of the limb secondary to lengthening. CONCLUSIONS: Femoral lengthening with use of the minimally invasive Albizzia technique provides a reasonable alternative to external fixation that is well tolerated by patients and results in excellent function with little or no distortion of body image.