Page 2 - Methodology Continued

All patients had to stay in the vicinity until the end of the distraction phase, do daily physiotherapy at our center throughout the distraction phase, comply with weight-bearing restrictions until radiographic bone consolidation (distraction and consolidation phases), and come in for biweekly follow-up radiographs and examination by the surgical team during the distraction phase. The purpose of these visits is to monitor their muscle flexibility, nerve function, joint range of motion, and bone formation, as well as, to monitor that the amount of lengthening expected is confirmed by radiographic measurement. Although the ERC device has a digital read out of length, it only displays the presumed amount of lengthening. If a patient does not push the device down deep enough, they can get behind on the lengthening because the ERC magnet needs to be within 5.5 cm of the nail magnet to rotate it. It is not uncommon for patients to get behind on lengthening one side compared with the other. Typically, they are always on track on the right side if they are right-handed and vice versa. It seems they put less pressure on their thigh with the ERC device on the side opposite their dominant hand. Initially, the FDA required distraction with ERC to be done at the physician’s office. The FDA approved home use of the ERC as of October 2012 (Fig. 2). Before this date, the lengthening was performed daily by our orthopedic technologist. After October 2012, all patients were taught to perform the lengthening at home using the ERC device and the lengthening was performed by the patient or their personal care giver. All patients underwent preoperative physical and psychological evaluation by the surgeon. Psychologically, we evaluated patient motivation and objectives in an effort to evaluate how realistic patients’ goals were, compared with the achievable safe lengthening goal. A detailed mental health history was obtained, and the patient’s mood, thought form, suicidal risk, and reality conformance were assessed by the surgeon. Evaluation by a psychologist or psychiatrist was required when the surgeon believed that the mental health history was concerning or the patient reported major psychiatric disorder, extended previous use of psychiatric drugs, or any history of self-injury, suicidal ideation, or attempt. Only 1 patient in the study group was mandated to have a psychiatric evaluation before the lengthening.

The physical examination included documentation of preoperative gait, lower limb joint range of motion of the hips, knees, ankles, and subtalar joints, including prone hip and knee rotation profiles. Muscle length tests were performed to identify preoperatively tight soft tissues so as to plan for prophylactic soft tissue releases. For femur lengthening, these included measurement of the popliteal angle [flexion of the hip to 90 degrees with extension of the knee joint; (Fig. 3A); the angle measured between the vertical and the maximum knee extension position of the tibia] to assess hamstring muscle length, prone knee bend to assess the rectus femoris length by seeing if the prone knee bend was less than the supine knee bend before there was flexion of the pelvis (Ely test, Fig. 3B); and seeing if the knee would drop below horizontal in the lateral decubitus position with hyperextension of the hip and 90 degrees flexion of the knee (Ober test) to assess contracture of the iliotibial band (ITB) (Fig. 3C). For tibial lengthening, we measured the dorsiflexion of the ankle in maximum knee extension and compared it with the dorsiflexion with the knee flexed (Silfverskiold test) (Fig. 3D). If a muscle length test was positive, it indicated that the tight soft tissue would become contracted irrespective of the results of the Ober test. The gastroc soleus recession, according to the author’s (D.P.) previously published method,18 is performed when the Silfverskiold test is positive, especially for tibial lengthening >5 cm. In this study no gastroc soleus recessions were performed.

Preoperative templating was done in all cases to determine nail diameter, length, and osteotomy level. The osteotomy level was planned to ensure that, at the end of desired lengthening, the wider portion of the nail remained engaged in the distal femur or tibia with approximately 3 cm of overlap. The senior author’s detailed description of femoral and tibial lengthening has been published previously.16 The surgery is done with the aid of fluoroscopy through a minimally invasive method with very small percutaneous incisions so as to leave minimal scarring (Fig. 4). Standard starting points for tibial and femoral antegrade (femoral: piriformis or trochanteric) nail insertion were used. (Retrograde femoral nailing is avoided due to greater knee complications, such as loss of knee flexion motion. It is also better to start the lengthening process without a knee hemarthrosis). The osteotomy was performed using a sharp osteotome after first predrilling the osteotomy site with 4.8mm drill holes. A total of 3 entrance and 3 exit holes were made in the femur.