Mismatch between Conventional Femoral Arthroplasty Stems and Hip Morphology in the Elderly Chinese Hip Fracture Population

@#Introduction: The morphology of the proximal femur differs in various populations. Based on our clinical experience, conventional femoral stems used in hip arthroplasty do not fit the Chinese population well. Hence, this study aims to evaluate the suitability of conventional femoral stems in the elderly Chinese hip fracture population requiring hip arthroplasty and to establish if gender and age related differences exist within this population. Materials and methods: We retrospectively analysed radiographic data of 300 patients from a tertiary hospital’s geriatric hip fracture database who underwent either hip hemi-arthroplasties or total hip arthroplasties. Proximal femur morphological measurements were recorded, analysed and compared to that of commonly used femoral stems. Subgroup analysis was performed to compare age and gender related differences. Results: A total of 18.3% of the study population had a medial femoral offset (MFO) of less than 30mm, which is the smallest available offset for the implants studied. 22.6% of female and 3% of male subjects had MFOs that were less than 30mm. In our subgroup analysis, males had significantly larger femoral head diameters, MFO and vertical femoral offsets compared to females. Older subjects (75-90 years old) had significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles compared to younger subjects (60-75 years old). Conclusion: Commonly used femoral stem implants have measurements that do not suit our Chinese population with small medial femoral offsets. In addition, elderly males have significantly larger femoral head diameters, medial and vertical femoral offsets whereas older subjects have significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles.

Proximal Femoral Shortening after Operation with Compression Hip Screws for Intertrochanteric Fracture in Patients under the Age of 60 Years / 대한고관절학회지

PURPOSE: We aimed to quantify proximal femoral shortening after operation with compression hip screws for intertrochanteric fracture in patients under the age of 60 years. MATERIALS AND METHODS: We followed 37 consecutive patients with intertrochanteric fractures treated with compression hip screws from March 2005 to February 2014. We designated the aspect of the fracture, a defect of the postero-medial wall, a defect of the lateral wall, and the degree of reduction as four potentially important factors we assumed would strongly affect proximal femoral shortening. We quantified proximal femoral shortening and compared the effects of above factors. We divided femoral shortening into two plane vectors; femoral offset in the horizontal plane and leg length discrepancy in the vertical plane. We measured shortening separately during two periods: during operation and after weight bearing (called dynamic compression). RESULTS: After bone union, the average femoral offset shortening was 5.45 mm. Patient groups with anatomic reduction and intact postero-medial wall showed lower femoral offset shortening than the respective opposite groups. As to functional score using modified Harris hip score, low femoral offset shortening group showed more 2.35 scores than high groups. None of the factors significantly affected leg length shortening. CONCLUSION: We found that a stable medial buttress is involved in lower femoral offset shortening. Thus, surgeons need to attempt to recover the defect of the medial wall and to reduce anatomically when operating intertrochanteric fractures with compression hip screws.

Femoral offset and its relationship to femoral neck-shaft angle and torsion angle / Desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión

The aims to study the femoral offset and its relationship to femoral neck-shaft angle and torsion angle. One hundred paired (50 males and 50 females) Chinese femurs were used to measure the femoral offset, femoral neck-shaft angle and torsion angle. The data were analyzed by SPSS software. Femoral offsets were male right 44.40±4.56 mm, left 42.70±4.95 mm; female right 39.90±6.00 mm, left 38.90±6.18 mm. Femoral torsion angles were male right 6.02±10.85°, left 7.08±9.30°; female right 10.02±11.69, ° left 6.02±10.85°. Neck-shaft angles were male right 131.80±4.36°, left 134.00±4.78°; female right 132.10±5.94°, left 132.80±4.93°. There were no sexual differences in the two femoral angles (P>0.05) while there was a significant sexual difference in the femoral offset (P<0.01). The differences between left and right femoral offset and neck-shaft angle were significant (P<0.01). Clinically, our results indicate that FO could be obtained using the regression equation when the torsion angle and/or neck-shaft angle is measured.

El objetivo fue estudiar el desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión. Se utilizaron 100 pares de fémures (50 hombres y 50 mujeres) y se tomaron las medidas del desplazamiento femoral, ángulo cuello-diáfisis femoral y ángulo de torsión. Los datos fueron analizados con el software SPSS. El desplazamiento femoral en los hombres fue 44,40±4,56 mm en el lado derecho y 42,70±4,95 mm en el lado izquierdo, y en las mujeres, fue de 39,90±6,00 mm y 38,90±6,18 mm para el lado derecho e izquierdo, respectivamente. El ángulo de torsión femoral del lado derecho en los hombres fue 6,02±10,85° y 7,08±9,30° del izquierdo; mientras que en las mujeres, fue de 10,02±11,69° y 6,02±10,85° para el lado derecho e izquierdo, respectivamente. Los ángulos cuello-diáfisis fueron 131,80±4,36° en el lado derecho, y 134,00±4,78° en el izquierdo, para los hombres, mientras que en las mujeres fueron de 132,10±5,94° en el lado derecho y 132,80±4,93° en el izquierdo. No hubo diferencias según sexo en los dos ángulos femorales (P>0,05), mientras que si hubo una diferencia significativa en el desplazamiento femoral (P<0,01). Las diferencias entre el desplazamiento femoral izquierdo y derecho, y el ángulo cuello-diáfisis fueron significativas (P<0,01). Clínicamente, nuestros resultados indican que el desplazamiento femoral podría obtenerse utilizando la ecuación de regresión cuando se mide el ángulo de torsión o el ángulo cuello-diáfisis.

Effect of Posterior Femoral Condylar Offset and Posterior Tibial Slope on Maximal Flexion Angle of the Knee in Posterior Cruciate Ligament Sacrificing Total Knee Arthroplasty

PURPOSE: To evaluate the effect of femoral condylar offset and posterior tibial slope on maximal flexion angle of the knee in posterior cruciate ligament (PCL)-sacrificing total knee arthroplasty (TKA, Medial-Pivot Knee System). MATERIALS AND METHODS: Forty-five knees in 35 patients who could be followed up more than 1 year after PCL-sacrificing TKA were evaluated retrospectively. We measured and analyzed the preoperative and postoperative maximal flexion angle, posterior femoral condylar offset difference, posterior femoral condylar offset ratio difference, and tibial slope. RESULTS: The mean maximal flexion angle after TKA was 118.44degrees+/-9.8degrees and significantly related to postoperative tibial slope (11.78degrees+/-6.2degrees) in correlation analysis (R=0.451, p=0.002). There was no statistical relationship between the postoperative maximal flexion angle and the posterior femoral condylar offset difference (3.24+/-3.862 mm, R=0.105, p=0.493) and posterior femoral condylar offset ratio difference (0.039+/-0.029 mm, R=-0.163, p=0.284). CONCLUSIONS: The maximal flexion angle of the knee after PCL-sacrificing TKA was significantly related to the postoperative tibial slope. Therefore, posterior tibial slope can be considered as a factor that affects maximal flexion angle after PCL-sacrificing TKA.

Effect of femoral offset on hip joint function reconstruction after arthroplasty in femoral neck fractures / 中华创伤骨科杂志

Objective To study the effect of femoral offset reconstruction ON the Harris hip score and the hip ROM (range of motion) after artificial hip replacement in femoral neck fractures. Methods Follow-ups were conducted for 47 patients who had undergone artificial hip replacements for their unilateral femoral neck fractures. We took X-ray pictures to compare the femoral offsets at the affected and unaffected hips. The operated hips were evaluated by the Harris hip score. Statistical analyses were performed with SPSS l2.0 software. Results The Harris hip score of the operated hip was positively related to femoral offset reconstruction(t=7.25,P＜0.001).There was a significant and positive correlation between femoral offset and the hip abductor ROM(r=0.80,P＜0.001).The rate of femoral offset reconstruction had no significant difference between total hip arthroplasty and bipolar hip arthroplasty (χ2=0,P＞0.05).Conclusions Reconstruction of femoral offset after artificial hip replacement in the femoral neck fractures can improve funetional recovery and ROM of the hip. Femoral offset reconstruction is uncorrelated to the selection of total hip arthroplasty or bipolar hip arthroplasty.

Effect review of femoral offset and hip joint center on joint function after total hip replacement / 中国矫形外科杂志

[Objective]To study the effect of femoral offset and hip joint center on joint function after total hip replacement,radiographic measurements were taken postoperation.[Method]A series of 92 hip joints(87 patients)were followed up.The average follow up priod was 25 monthes.The femoral offset and the position of the prothesis head center were measured in the orthophoric hip joint X-ray photograph and were compared with anatomic Fo and HJC.H arris evaluation system was used to evaluate joint function in four groups.The results were statistically analyzed,with Fisher' exact probability and P value less than 0.05 indicating significant difference.[Result]The coincidence rate of group A(both FO and HJC,27 hips)was 29.35%,group B(only Fo,23 hips)25.00%,group C(only HJC,31 hips)33.70%,group D(neither FO nor HJC,11 hips)11.96%.93.0% patients got the Harris score more than 80 for group A,73.19%(group B),74.19%(group C),27.27%(group D).The difference of Harris evaluation between A and B,A and C,A and D was significant statistically.[Conclusion]Based on the results of the study,the recovery of femoral offset and hip joint center should be considered to contribute to the healing effect after total hip replacement directly.