[Slipped Capital Femoral Epiphysis]. / Epiphyseolysis capitis femoris (ECF).

Slipped capital femoral epiphysis is the most common hip disease during infancy and adolescence. The incidence of this disease increases continuously. The reason is the likewise increasing body mass index of these age groups. Early diagnostic and treatment are necessary to avoid complications and consequential damages. Primary aims of the treatment are to avoid a further slip of the epiphysis and to reduce the resulting cam-deformity by reposition or osteotomy. After the end of physiological remodelling the rest of cam-deformity should be treated before an early osteoarthritis after slipped capital femoral epiphysis can be developed. There are open as well as arthroscopic surgical procedures for recontouring the femoral neck. The question at hand is to find out which surgical procedure will lead to an improvement of the long term results of slipped capital femoral epiphysis.

Non-invasive determination of frontal plane lower limb alignment using motion capture technique - An alternative for full-length radiographs in young patients treated by a temporary hemiepiphysiodesis?

BACKGROUND: Multiple full-length standing anteroposterior radiographs are common practice to quantify the mechanical axis angle (MAA) in young patients with lower limb malalignment in the frontal plane treated with a temporary hemiepiphysiodesis. RESEARCH QUESTION: Is it possible to predict the MAA measured with gold-standard radiographs from a non-invasive method using the marker-based motion capture technique in a standing position and has an increased body mass index (BMI) a negative effect on this prediction? METHODS: Forty-six children and adolescents with valgus or varus malalignment of the knee were measured several times during the treatment period. In total 175 data sets were evaluated in this prospective study. BMI was included into the linear mixed effect regression to detect the influence of this variable on the prediction model. Bland and Altman plots were obtained to examine methods' agreement. RESULTS: The X-ray-based MAA highly correlated (r = 0.808, p <  0.001) with the marker-based MAA. The association between measurements was stronger in patients with a BMI < 25 (r = 0.881, p <  0.001) than in patients with a BMI ≥ 25 (r = 0.747, p <  0.001). The Bland and Altman plots illustrated a better agreement between both methods for patients with a BMI < 25 (bias of 0.7°) than for patients with a BMI ≥ 25 (bias of 3.7°). SIGNIFICANCE: Determination of frontal plane lower limb alignment using motion capture technique is an alternative method to assess the MAA non-invasively. The approach is therefore relevant for clinical and scientific use when cumulative radiation dosage becomes a problem or when radiation may be prohibited (e.g. healthy control group). A higher BMI overestimates the valgus malalignment in the motion capture method which may result from excess body tissue and the difficulty in palpating bony landmarks on the skin.

Effect of guided growth intervention on static leg alignment and dynamic knee contact forces during gait.

BACKGROUND: Lower limb malalignment in the frontal plane is one of the major causes of developing knee osteoarthritis. Growing children can be treated by temporary hemiepiphysiodesis when diagnosed with lower limb malalignment. RESEARCH QUESTION: Is there a difference between medial or lateral knee contact force (KCF) before (PRE) and after (POST) hemiepiphysiodesis in patients with valgus malalignment and compared to a typically developed control group (TD)? Does a linear relationship exist between the static radiographic mechanical axis angle and dynamic medial/lateral KCF? METHODS: In this prospective study, an OpenSim full body model with an adapted knee joint was used to calculate KCFs in the stance phase of 16 children with diagnosed genu valgum and 16 age- and sex-matched TDs. SPM was applied to compare KCFs before and after guided growth and to test a linear relationship between the mechanical axis angle and KCFs. RESULTS: After the intervention, POST revealed a significantly increased medial KCF (p < 0.001, 4-97 % of stance) and decreased lateral KCF (p < 0.001, 6-98 %) compared to PRE. Comparing POST with TD, short phases with a significant difference were found (medial: p = 0.039, 84-88 %; lateral: p = 0.019, 3-11 %). The static mechanical axis angle showed a longer phase of a significant relation to KCFs for POST compared to PRE. SIGNIFICANCE: This study showed that temporary hemiepiphysiodesis in patients with valgus malalignment reduces the loading in the lateral compartment of the knee and thus the risk of developing osteoarthritis in this compartment. The determination of dynamic KCFs can be clinically relevant for the treatment of lower limb malalignment, especially for decision making before surgery, when compensatory mechanisms may play an important role. Additionally, the static radiographic mechanical axis angle does not necessarily represent the dynamic loading of the lateral knee compartment.

Development of gait performance and dynamic hip and knee joint loading after containment improving surgery in patients with Legg-Calvé-Perthes disease.

Current surgery outcome evaluations in patients with Legg-Calvé-Perthes disease (LCPD) are usually based on static radiological changes. The aim of the present study was to assess the development of characteristic gait parameters and passive hip range of motion (ROM) measurements during the postoperative period up to healed stage of the femoral head represented by Stulberg classification. Twelve children (10 male, 2 female) with unilateral diagnosis of LCPD and 19 healthy control subjects at the same age participated in this prospective longitudinal study. Instrumented gait analysis was performed preoperatively, 13.4 (±1.7), and 28.0 (±4.4) months postoperatively. At final follow-up, the mean leg length of the involved side was reduced by 1.10 (±0.53)cm compared to the non-involved side. In addition, a significant reduction in maximum knee flexion (-26%, p=0.037) and knee flexion/extension ROM (-26%, p=0.017) in stance was still present in the patient group compared to controls indicating a "stiff knee gait pattern". In contrast, the sagittal plane hip parameters, the ipsilateral trunk lean toward the involved stance limb, and the knee and hip joint loading during gait normalized during the postoperative period. The results of the present study should motivate further exploration if patients with LCPD stiffen their knees to compensate for leg length discrepancy. Besides the standard radiological evaluation of the surgery outcome, instrumented gait analysis is a valuable method of recording functional deficits and early recognition of the need for physiotherapeutic treatment or insole supply in patients with LCPD.

Systemic mastocytosis: a rare case of increased liver stiffness.

Assessment of liver stiffness (LS) by transient elastography (Fibroscan) has significantly improved the noninvasive diagnosis of liver fibrosis. We here report on a 55-year-old patient with drastically increased LS due to previously unknown systemic mastocytosis. The patient initially presented with increased weight loss, nocturnal pruritus, increased transaminases, bilirubinemia, and thrombocytopenia. Abdominal ultrasound showed ascites, hepatomegaly, and splenomegaly. In addition, LS was 75 kPa (IQR 0 kPa) clearly exceeding the cut-off value for F4 cirrhosis of 12.5 kPa. However, histological analysis of the liver specimen indicated liver involvement by systemic mastocytosis and excluded liver cirrhosis. An additional CT scan detected disseminated bone lesions. After three months of treatment with Midostaurin, LS slightly decreased down to 31.9 kPa (IQR 8.3 kPa). This case illustrates that diffused sinusoidal neoplastic infiltrates are a pitfall in the non-invasive diagnosis of liver cirrhosis. In conclusion, refined clinical algorithms for increased LS should also include mastocytosis in addition to inflammation, congestion, and biliary obstruction.

Liver stiffness is directly influenced by central venous pressure.

BACKGROUND & AIMS: Liver stiffness (LS) as measured by transient elastography [Fibroscan] offers a novel non-invasive approach to assess liver cirrhosis. Since Fibroscan seems to be unreliable in patients with congestive heart failure, it remains to be determined whether hemodynamic changes affect LS irrespective of fibrosis. METHODS & RESULTS: Using landrace pigs, we studied the direct relationship between the central venous pressure and LS measured by Fibroscan. Clamping of the inferior caval vein increased LS from 3.1 to 27.8kPa while reopening reversed LS within 5min to almost normal values of 5.1kPa. We then studied LS as a function of venous pressure in the isolated pig liver by clamping the upper and lower caval, portal vein and hepatic artery. The stepwise increase of intravenous pressure to 36cm of water column (3.5kPa) linearly and reversibly increased LS to the upper detection limit of 75kPa. We finally measured LS in 10 patients with decompensated congestive heart failure before and after recompensation. Initial LS was elevated in all patients, in 8 of them to a degree that suggested liver cirrhosis (median 40.7kPa). Upon recompensation with a median weight loss of 3.0kg, LS decreased in all 10 patients down to a median LS of 17.8kPa. Inflammation could not account for increased LS since initial liver enzyme counts were only slightly elevated and did not change significantly. CONCLUSION: LS is a direct function of central venous pressure which should be considered when assessing the degree of fibrosis.

Effects of local application of growth and differentiation factor-5 (GDF-5) in a full-thickness cartilage defect model.

Our purpose in this study was to investigate the effects of growth and differentiation factor-5 (GDF-5) on cartilage and subchondral bone in a rabbit model harboring an osteochondral defect for a period of 6 months. Absorbable composites were implanted in adult rabbits (18 controls, 18 animals with collagen-I matrix, and 18 animals with matrix plus GDF-5). After 4, 8, or 24 weeks the specimens were studied by histology, microcomputed tomography (microCT) and flow-cytometric analysis (FACS). Implantation of GDF-5 resulted in an improved histological appearance. This was the result of significantly improved defect filling at 4 and 8 weeks. At 24 weeks, however, there was no difference between the groups. The histological examination disclosed a predominance of fibrocartilage, and remodeled subchondral bone was also observed. MicroCT documented normal bone density in all groups, excluding subchondral sclerosis. At 24 weeks, FACS analysis revealed high apoptotic activity in the GDF-5-treated group. As far as we are aware, this is the first report of the effects of GDF-5 in a full-thickness cartilage defect model. We assume that recombinant GDF-5 contained on the carrier is probably able to accelerate the regeneration of the osteochondral defect owing to its availability. However, control of the protein delivery may require further investigation.