Felix Stief

The correction of valgus leg malalignment in children using implant-mediated growth guidance is widely used and effective. Despite the minimal invasive character of the procedure, a relevant number of patients sustain prolonged pain and limited mobility after temporary hemiepiphysiodesis. Our aim was to investigate implant-associated risk factors (such as implant position and screw angulation), surgical- or anesthesia-related risk factors (such as type of anesthesia, use, and duration), and pressure of tourniquet or duration of surgery for these complications. Thirty-four skeletally immature patients with idiopathic valgus deformities undergoing hemiepiphysiodesis plating from October 2018–July 2022 were enrolled in this retrospective study. Participants were divided into groups with and without prolonged complications (persistent pain, limited mobility of the operated knee between five weeks and six months) after surgery. Twenty-two patients (65%) had no notable complications, while twelve patients (35%) had prolonged complications. Both groups differed significantly in plate position relative to physis (p = 0.049). In addition, both groups showed significant differences in the distribution of implant location (p = 0.016). Group 1 had a shorter duration of surgery than group 2 (32 min vs. 38 min, p = 0.032) and a lower tourniquet pressure (250 mmHg vs. 270 mmHg, p = 0.019). In conclusion, simultaneous plate implantation at the femur and tibia and metaphyseal plate positioning resulted in prolonged pain and a delay of function. In addition, the amplitude of tourniquet pressure or duration of surgery could play a factor.

The mechanisms underlying the altered postural control and risk of falling in patients with osteoporosis are not yet fully understood. The aim of the present study was to investigate postural sway in women with osteoporosis and a control group. The postural sway of 41 women with osteoporosis (17 fallers and 24 non-fallers) and 19 healthy controls was measured in a static standing task with a force plate. The amount of sway was characterized by traditional (linear) center-of-pressure (COP) parameters. Structural (nonlinear) COP methods include spectral analysis by means of a 12-level wavelet transform and a regularity analysis via multiscale entropy (MSE) with determination of the complexity index. Patients showed increased body sway in the medial–lateral (ML) direction (standard deviation in mm: 2.63 ± 1.00 vs. 2.00 ± 0.58, p = 0.021; range of motion in mm: 15.33 ± 5.58 vs. 10.86 ± 3.14, p = 0.002) and more irregular sway in the anterior–posterior (AP) direction (complexity index: 13.75 ± 2.19 vs. 11.18 ± 4.44, p = 0.027) relative to controls. Fallers showed higher-frequency responses than non-fallers in the AP direction. Thus, postural sway is differently affected by osteoporosis in the ML and AP directions. Clinically, effective assessment and rehabilitation of balance disorders can benefit from an extended analysis of postural control with nonlinear methods, which may also contribute to the improvement of risk profiles or a screening tool for the identification of high-risk fallers, thereby prevent fractures in women with osteoporosis.