Simultaneous Bilateral Femoral and Tibial Lengthening in Achondroplasia

Previous studies on lengthening for achondroplasia have reported bilateral extensive femoral lengthening followed by bilateral extensive tibial lengthening. To decrease trauma on soft tissues and joints, we propose bilateral simultaneous moderate femoral lengthening and moderate tibial lengthening followed by a similar repeat lengthening a few years later. Fifty patients with achondroplasia underwent 65 simultaneous bilateral femoral and tibial lengthening procedures. Segment lengthening amount and adverse events were obtained from medical records. Mean follow-up after bone healing was 35.6 months. Mean tibial lengthening was 52 mm; mean femoral lengthening was 72 mm. Average healing index was 1.4 months/cm for the tibia and 1 month/cm for the femur. Mean duration of treatment with external fixation was 6.7 months (range, 4.4–10.5 months). Thirty-eight (76%) of 50 patients experienced one or more adverse events during lengthening. We observed 78 adverse events, 35 (45%) of which required additional surgical procedures. All resolved by the end of treatment. Mechanical axis deviation improved from a mean of 15 mm medially to 8 mm medially. Simultaneous lengthening of four segments in patients with achondroplasia is a feasible strategy. Compared with isolated femoral or tibial lengthening, distributing the lengthening between the femur and tibia decreases total external fixator time.

Genu valgum deformity – correction by a wedgeless implantless femoral “V” osteotomy

Coronal malalignment of the knee joint is very common in developing countries especially because of nutritional rickets. Significant valgus deformity needs to be treated surgically to improve appearance, gait and function of the patient. The purpose of this prospective study was to evaluate the results of supracondylar “V” osteotomy as a surgical technique for correction of the valgus knee deformity. This study was conducted in a tertiary level teaching hospital and 30 cases were included in the study. For all the patients deformity was assessed using ana- tomical tibiofemoral angle, mechanical axis deviation and intermalleolar distance preoperatively and post- operatively. The average age of our patients was 13.7 years and the average follow up was3.29 years (1.39-14.22 yrs). Clinically the average value of intermalleolar distance preoperatively was 16cm and 3.2 cm postperatively. Average pre-operative tibiofemoral angle was 23° and the average postoperative angle was 6 0 which was found to be statistically significant using the Paired t test (p<0.005). The average value of preoperative mechanical axis deviation was 3.1 cm which decreased to an average value of 1.1 cm postoperatively. The results with this technique have been encouraging. The advantages of this technique are low morbidity, good stability allowing early ambulation, ability to adjust alignment postoperatively by casting and no need for internal fixation. Few studies have been conducted on osteotomies that do not require internal fixation and are inherently stable. This technique has the advantage of practically no occurrence of any infection or a second surgery to remove hardware in children and adolescents. Since no specialized instrumentation, image intensifier and implants are required, it is cost effective and can be used in any primary care or district level surgical setup in a developing country like ours.

Relationships between reference lines altered during leg shape correction as requested by the patient

Introduction Patients who want their leg shape changed often identify the O- or X-shaped legs with varus or valgus deformity striving for ideally shaped legs as classified by A. A. Artemiev. The purpose of the study was to compare changes in the relationship between reference lines as mechanical axis deviation (MAD), mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal tibial angle (mLDTA) and the associated duration of the correction (CP), fixation (FP) and frame-on periods (FoP) in patients who underwent correction to have the legs shape as requested and those who underwent tibial deformity correction. Material and methods There were 43 patients (84 segments operated on) in the cosmesis group and 15 participants (28 segments operated on) in orthopedic group. Preperative MAD, mMPTA, mLDTA measured 17.48 ± 1.14 mm medially, 84.90 ± 0.35° and 90.61 ± 0.39° in the cosmesis patients; 19.18 ± 2.86 mm medially, 84.04 ± 0.35°, 89.09 ± 0.37° in orthopaedic patients with no statistically significant differences observed between the groups. Results CP, FP and FoP lasted for 41.93 ± 3.96, 97.67 ± 7.78 and 139.60 ± 5.15 days in the cosmesis group, and 18.22 ± 3.05, 134.89 ± 9.42 and 153.00 ± 8.49 in controls. FP/CP, CP/FoP, FP/FoP measured 0.57 ≈ 1/2, 0.31 ≈ 1/3, 0.69 ≈ 2/3 in the cosmesis group and 0.15 ≈ 1/7; 0.12 ≈ 1/8; 0.88 ≈ 7/8 in controls. MAD, mMPTA, mLDTA measured 6.08 ± 0.87 mm laterally, 90.80 ± 0.31°, 88.62 ± 0.35° in the cosmesis participants, and 0.61 ± 0.82 mm laterally, 89.46 ± 0.54°, 87.68 ± 0. 63° in controls. Discussion There were no statistically significant differences in FoP with different duration of CP (≈ 1/3 FoP for the cosmesis group and ≈ 1/8 FoP for controls). The means of MAD, mMPTA of measured up to tibial valgus in cosmesis patients and were well within acceptable limits of normal in controls.Tibial valgus was caused by too much overcorrection (by ¼ on average).

Potential Influence of Factors For Genu Valgus With Hereditary Multiple Exostoses

Background: Genu valgus is one of the most common limb deformities in hereditary multiple exostoses (HME). However, it is easily concealed and may account for subsequent osteoarthritis of the knee. The potential influence of factors for genu valgus is still not well known. Methods: The knees of 56 patients (33 male, 23 female) with HME were investigated bilaterally. The mean age at evaluation was 8.9 years (range, 1.5–15.8 years). Knee valgus was described by the mechanical axis deviation (MAD), mechanical lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA). We investigated gender, age, body mass index (BMI), total number of palpable osteochondromas, number of radiographic osteochondromas around the knee, forearm deformities, morphology and distribution of lesions, and correlations between these factors and genu valgus. The measurement of LDFA and MPTA was to identify the sources of genu valgus deformity.Results: Based on the measurement of the mechanical axis, limbs were classified as genu valgus (n = 22) or normal mechanical axis groups (n = 90). The different severities of the genu valgus patients were classified by MAD. By bivariate logistic regression, genu valgus was significantly associated with more sessile and flared metaphyseal lesions. However only the number of flared metaphyseal lesions had a significant influence on the severity of genu valgus. By analyzing the LDFA and medial proximal tibial angle MPTA, it was found that abnormalities of both proximal tibia and distal femur play important roles in genu valgus. There were no differences between the genu valgus and normal mechanical axis groups in forearm deformities caused by HME, nor did this differ by severity of genu valgus. Conclusions: Early detection of sessile and flared metaphyseal knee lesions in patients with HME can contribute to early intervention of genu valgus.Level of Relevance: Level 2.

Affecting Factors and Correction Ratio in Genu Valgum or Varum Treated with Percutaneous Epiphysiodesis Using Transphyseal Screws

This study evaluated the correction rates of idiopathic genu valgum or varum after percutaneous epiphysiodesis using transphyseal screws (PETS) and analyzed the affecting factors. A total of 35 children without underlying diseases were enrolled containing 64 physes (44 distal femoral (DT), 20 proximal tibial (PT)). Anatomic tibiofemoral angle (aTFA) and the mechanical axis deviation (MAD) were taken from teleroentgenograms before PETS surgery and screw removal. The correction rates of the valgus and varus deformities for patients treated with PETS were 1.146°/month and 0.639°/month using aTFA while using MAD showed rates of 4.884%/month and 3.094%/month. After aTFA (p < 0.001) and MAD (p < 0.001) analyses, the correction rate of DF was significantly faster than that of PT. Under multivariable analysis, the aTFA correction rate was significantly faster in younger patients (p < 0.001), in males (p < 0.001), in patients with lower weights (p < 0.001), and in the group that was screwed at DF (p < 0.001). Meanwhile, the MAD correction rate was significantly faster in patients with lower heights (p = 0.003). PETS is an effective treatment method for valgus and varus deformities in growing children and clinical characters should be considered to estimate the correction rate.

Osteochondritis Dissecans Lesion Location Is Highly Concordant With Mechanical Axis Deviation

Background: The cause of osteochondritis dissecans (OCD) is unknown. Purpose: To determine if mechanical axis deviation correlates with OCD lesion location in the knee, if degree of mechanical axis deviation correlates with size of OCD lesion, and if the deformity was primarily in the distal femur or proximal tibia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We identified 61 knees that underwent osteochondral allograft (OCA) transplantation for femoral condyle OCD lesions and used preoperative lower extremity alignment radiographs to measure lower extremity mechanical axis, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and hip-knee-ankle angle. Lesion location and area were retrieved from operative records. Results: The location of the OCD lesion was the medial femoral condyle (MFC) for 37 knees and lateral femoral condyle (LFC) for 24 knees. Among knees with MFC lesions, alignment was varus in 25 (68%). Conversely, knees with LFC lesions had valgus alignment in 16 (67%). The mLFDA was significantly more valgus in the LFC group. mMPTA was not different between MFC and LFC groups. There was no significant correlation between degree of mechanical axis deviation and lesion size. Conclusion: In this cohort, two-thirds of patients with symptomatic OCD lesions had associated mechanical axis deviation. Lesion location correlated with mechanical axis deviation (LFC lesions were associated with a deformity in the distal femur). Degree of deformity was not correlated with lesion size. Mechanical axis deviation may play a role in OCD pathogenesis. These data do not allow analysis of the role of mechanical axis deviation in causation or prognosis of OCD lesions, but surgeons treating OCD should be aware of this common association.

A Computer Model Assessment of the Effect of Hindfoot Alignment on Mechanical Axis Deviation and Ankle Fractures

Category: Basic Sciences/Biologics Introduction/Purpose: Conventional mechanical axis is calculated from the center of the femoral head to the center of the ankle. Mechanical axis deviation of the lower limb can be associated with a pes planus hindfoot. Malalignment of the lower limb has been shown to increase progression of osteoarthritis of the knee and ankle and decrease joint arthroplasty longevity. Clinically, a pes planus hindfoot has also been seen with patients who present with a stress fracture of the lateral malleolus. This biomechanical study aims to utilize computer modeling to evaluate the hypothesis that altered force transmission on the lateral malleolus with resultant stress fractures in a pes planus model is attributable to mechanical axis deviation. Methods: A free-body diagram of the fibula in single leg stance was generated by modeling the fibula as a uniform cylinder. It includes the axially applied load and a single evertor muscle force as an eccentric load applied to the mid-diaphysis . Previously derived relationships between body weight (BW = 667 N, 150lbs) and a) normal axial fibula load (BW*0.17) and b) muscle force (BW*0.25) were used. Fibula length (286.5 mm) and diameter (8 mm) were derived from anthropological data. Mechanical axis deviation in pes planus was simulated in two manners: 1) increased (2 and 3 times normal) axial fibula load and 2) increased evertor muscle force. The compressive stress along the length of the bone was determined through static analysis and the total applied load was compared to theoretical Euler buckling load. Results: Increasing the load on the fibula, either by increasing the axial load (Figure 1A) or the muscle load (Figure 1B), increases the maximum compressive stress below the lateral muscle origins, namely the section between the distal tibiofibular ligaments and the evertor muscles. The compressive stress for both cases was less than the compressive yield stress of cortical bone (200 MPa) and cancellous bone (100 MPa) even as the force was increased to the critical buckling value. This model serves as a first attempt to relate the spatial distribution of stress in the fibula with muscle force, axial load, and compressive stress in light of distal fibular fractures associated with pes planus. Conclusion: The importance of lower extremity mechanical axis deviation is well established in the progression of arthritis in the knee and ankle. The role of the mechanical axis in the predisposition of stress fractures around the ankle has not been evaluated in the literature. This biomechanical study represents the first attempt to understand how deviation of the mechanical axis can result in stress fractures of the lateral malleolus. Future studies including a finite element analysis will provide further information and the results of these studies may alter how clinicians treat patients with stress fractures of the fibula.

Treatment of pediatric patients with lower leg deformities associated with physeal arrest: analysis of 28 cases

Aim. To retrospectively analyze the results of two treatment methods for lower leg deformities associated with partial growth arrest. Materials and methods. Group I comprised 15 children who underwent osteotomy, acute overcorrection, and external fixation by Ilizarov with subsequent lengthening of the segment. Group II comprised 13 patients who underwent epiphysiodesis of the healthy part of the growth plate by drilling, osteotomy with external fixation by use of an Ortho-SUV Frame, and subsequent gradual deformity correction and lengthening. Results. In group I, overcorrection of varus deformities by mechanical axis deviation (MAD) was 18.28 ± 5.25 mm, overcorrection by mechanical medial proximal tibial angle (mMPTA) was 14.86 ± 4.45°, and overcorrection by mechanical lateral distal tibial angle (mLDTA) was 12.85 ± 3.02°. Overcorrection of valgus deformities according to MAD was 15.12 ± 8.28 mm, overcorrection by mMPTA was 10.38 ± 2.77°, and overcorrection by mLDTA was 7.5 ± 3.9°. Recurrence of the deformity was observed in 11 (73%) cases (range, 5–16 months). In group II, the accuracy of correction (AC) in varus deformities for MAD was 98% and 94% for mMPTA and mLDTA. For valgus deformities, AC for MAD was 90% and 96% for mMPTA and mLDTA. The AC for anatomical proximal posterior tibial angle and anatomical anterior distal tibial angle was 96% for procurvation deformities and that for recurvation deformities was 92%. Deformity recurrence was observed in only one case within 6 months after frame removal. In 2 cases, repeat limb length discrepancy correction surgeries were performed. Conclusion. Use of epiphysiodesis of the healthy portion of the growth plate in combination with osteotomy, computer-assisted external fixation with subsequent gradual deformity correction, and lengthening in patients with deformities associated with partial physeal arrest significantly decreased the number of deformity recurrences.