Biomechanical Study on the Stress Distribution of the Knee Joint After Distal Femoral Fracture Malunion With Residual Varus-valgus Deformity

BackgroundThis study aims to examine the biomechanical influence of residual varus and valgus deformity after malunion of distal femoral fractures on the knee joint. MethodsWe selected 14 adult cadaver specimens to establish the femoral fractures models and subsequently fixed them at neutral position and malunion positions, i.e. at 3°, 7° and 10° at valgus and varus positions, respectively. Ultra-low pressure sensitive film technology was used to quantitatively measure the stress distribution on the medial and lateral plateau of the tibia.ResultsAt neutral position, with 400 N vertical load applied, the stress values of the medial and lateral plateau of tibia were 1.162±0.114 MPa and 1.103±0.144 MPa, respectively. Compared with those measured at neutral position, the stress on the medial plateau of the valgus tibia significantly increased, while that on the lateral plateau of the valgus tibia significantly decreased (both P<0.05). In contrast, the stress on the lateral plateau of the valgus tibia significantly increased, while that on the medial plateau of the valgus tibia significantly decreased (both P<0.05). The medial plateau of tibia demonstrated significantly higher stress values than those on the lateral plateau at neutral position and 3°, 7°, 10° varus deformities, respectively (all P<0.05), but showed significantly lower values than the those on the lateral plateau at 3°, 7°, 10° valgus deformities, respectively (all P<0.05). ConclusionsThe residual varus and valgus deformities after mulunion of the distal femoral fracture resulted in significant changes of the stress distribution of the knee joint. Anatomical reduction and firm fixation of distal femoral fracture should be as possible to be obtained to avoid possible varus and valgus deformities.

Outcome of Distal Femoral Fracture Treated with Locking Plate

Objective: The aim of this study is to determine the outcome of distal femoral fracture treated with locking plate. Study Design:Prospective study Place and Duration: Conducted at Orthopaedic Unit Ayub Medical Teaching Institute, Abbottabad for one year duration from 1stJanuary 2020 to 31st December 2020. Methods: Total 90 patients of both genders were presented in this study.Patients were aged between 18-80 years of age. Patients’ detailed demographics including age, sex and body mass index were recorded after taking informed written consent. All the patients had distal femoral fracture treated with locking plate. Radiological assessment was done. Mean union time and complications associated to procedure were examined.Functional outcomes were analyzed according to the Flyn’s criteria. Follow-up was taken at 6 months postoperatively. Complete data was analyzed by SPSS 24.0 version. Results:There were 58 (64.4%) patients were males and 32 (35.6%) were females. Mean age of the patients were 42.61±12.88 years with mean BMI 27.65±9.56 kg/m2. According AO/OTA classification 55 (61.1%) had A1, A2 fracture was among 18 (20%) cases and the rest were 17 (18.9%) had A3. 62 (68.9%) fractures were caused due road traffic accidents, falling from height were among 17 (18.9%) cases and 11 (12.2%) cases were due to sports. Right side fracture was the most common side of fracture among 54 (60%). Mean union time among patients was 5.16±1.27 months.According to Flyn’s criteria, 38 (42.2%) cases had excellent results, 32 (35.6%) patients had good, fair results were among 16 (17.8%) cases and poor results were among 4 (4.4%) cases. Complications were delayed union, stiffness, varus deformityand non union observed among all cases. Conclusion: We concluded in this study that the locking plate for the treatment of distal femoral fractures was effective in terms of good results with fewer complications. Keywords:Distal femoral fracture, Locking plate, RTA, Complications

SOCIO-DEMOGRAPHIC AND CLINICAL CHARACTERISTICS OF THE PATIENTS SUFFERING FROM DISTAL FEMORAL FRACTURE

Background: Distal femoral fractures are the fractures which occurs in distal femur involving the intercondylar and supracondylar region. Currently they account for less than 1% of all fractures whereas among femoral fractures they account for 3% to 6%.These fractures are difficult to treat and notorious for the complications. Aim: To find the socio-demographic and clinical characteristics of the patients suffering from distal femoral fracture. Methodology: The present observational and prospective study was conducted in theDepartment of Orthopaedic, Govt. Medical College, Jammu, J&K for period of 1 year on 27 patients. General information including age, sex, residence, religion, marital status, side of fracture etc. were noted on separate sheet. All fractures were classified as per AO/Müller’s classification. Results: Majority of patients i.e. 40.8% were between 18-30 years age group. 66.6% patients were males and only 33.4% were females. 63% patients were from rural area and 37% patients from urban area. Maximum percentage of patients i.e. 59.3% from Hindu community and 66.7% were married. RTA was the most common mode of injury involving 74.1% patients whereas, right limb fractures were most commonly involving 66.7% patients. As per AO/Muller’s classification B3 and C1 were most common fractures affecting 18.6% patients each. Conclusion: From present study we conclude that the distal femoral fractures were more common in young age group and RTA is the most common cause. Hence it is recommended to the authorities to implement strict traffic rules so that over speeding of vehicle can be prevented which may lead to decrease in incidence of high velocity trauma. Key words: Fractures, Road traffic accidents, Injury.

Biomechanical study on the stress distribution of the knee joint after distal femoral fracture malunion with residual varus-valgus deformity

Background: To investigate the effect of residual varus and valgus deformity on the stress distribution of knee joint after distal femoral fracture malunion. Methods: Fourteen adult cadaver specimens with formalin were selected to establish the femoral fractures models, which were fixed subsequently at neutral position (anatomical reduction) and malunion positions (at 3 degrees, 7 degrees, 10 degrees valgus positions and 3 degrees, 7 degrees, and 10 degrees varus positions). The stress distribution on the medial and lateral plateau of the tibia was quantitatively measured using ultra-low pressure sensitive film technology. The change of stress distribution of knee joint after femoral fracture malunion and the relationship between stress value and residual varus varus or valgus deformity were analyzed.Results: Under 400 N vertical load, the stress values on the medial and lateral plateau of the tibia at the neutral position were 1.162±0.114 MPa and 1.103±0.144 MPa, respectively. When compared with the stress values measured at the neutral position, the stress on the medial plateau of tibia were significantly higher at varus deformities and lower at valgus deformities, and the stress on the lateral plateau was significantly higher at valgus deformity and lower at varus deformities (all P<0.05). The stress values on the medial plateau of tibia were significantly higher than the corresponding data on the lateral plateau at neutral and 3 degrees, 7 degrees, 10 degrees varus deformities, respectively (all P<0.05), and significantly lower than the corresponding data on the lateral plateau at 3 degrees, 7 degrees, 10 degrees valgus deformities, respectively (all P<0.05). Conclusions: Residual varus and valgus deformity after femoral fracture malunion can cause obvious changes of the stress distribution of knee joint. Therefore, the distal femoral fracture should be anatomically reduced and rigidly fixed to avoid residual varus-valgus deformity and malalignment of lower limbs.

Anthropometric Factors on Safe Distances between Popliteal Vessels to the Femur for Cerclage Wiring of the Distal Femoral Fracture: A Magnetic Resonance Imaging Study

Background and Objectives: The proximity of the popliteal vessels in the distal femur may increase the risk of iatrogenic vascular injury during cerclage wiring. In this study, the closest location and distance of the popliteal vessels to the femur was examined using magnetic resonance imaging (MRI). The associations between anthropometric factors and the distance that would guide the placement of wires safely during surgery were also identified. Materials and Methods: We reviewed adult knee magnetic resonance images and recorded: (1) the relation and the shortest horizontal distance (d-H) from the femoral cortex to the popliteal vessels in axial images and (2) the vertical distance (d-V) from the adductor tubercle to the axial level of the d-H values in coronal images. The effects of anthropometric factors (sex, age, body height, body weight, body mass index, thigh circumference, femoral length and femoral width) on these distances were analysed. Results: Analysis of 206 knee magnetic resonance images revealed that the closet locations of popliteal vessels were at the posteromedial aspect of the femur. The d-H and d-V were 7.38 ± 3.22 mm and 57.01 ± 11.14 mm, respectively, and were both shorter in women than in men (p < 0.001). Multivariate analysis identified thigh circumference and femoral length as the most influential factors for the d-H and d-V, respectively (p < 0.001). Linear regression demonstrated a strong positive linear correlation between the thigh circumference and the d-H and between the femoral length and the d-V (Pearson’s r = 0.891 and 0.806, respectively (p < 0.001)). Conclusions: The closet location and distance of the popliteal vessels to the femur provide useful information for wire placement during distal femoral fracture surgery while minimising the risk of vascular injury. Given that patients with a smaller thigh circumference and a shorter femoral length are more likely to have a smaller d-H and a shorter d-V, respectively, cautious measures should be taken in such cases.