The Basic Mechanism And Clinical Imaging Research Of Proximal Fibular Osteotomy To Treat Medial Compartment Knee Osteoarthritis

Part one Mechanism and influencing factors in proximal fibular osteotomyto treat medial compartment knee osteoarthritisA prospective studyObjective: Knee osteoarthritis(OA)is a common chronic,progressive and degenerative disease in elderly individuals.We found that after removal of the proximal section of the fibula,patients with medial compartment knee OA showed greater improvement in lower extremity alignment,knee range of motion(ROM)and local pain at an early stage.It may well be that early rebalancing of peri-articular soft tissue and ligaments also play a significant role in symptom improvement.This prospective study aimed to explore the mechanism of proximal fibular osteotomy for the treatment of medial compartment knee osteoarthritis(OA)and to evaluate the relevant factors influencing the treatment outcome over a mean follow-up period of 18 months.Methods: From March 2014 to May 2014,fifty-two cases with OA in the medial compartment complicated with varus deformities of the knee were randomly selected at the author’s hospital.A 2-cm-long section of the fibula was resected with its periosteum 6 below the fibular head.Radiographs,including anteroposterior,lateral and full-length standing radiographs of the knee joints of both lower extremities,were recorded preoperatively and at follow-up.Knee function and OA severity were evaluated using The Hospital for Special Surgery(HSS)knee score and the Kellgren/Lawrence(K/L)score,respectively,for all patients at baseline and at each follow-up visit.Experimental data measurements and evaluation indicators.Based on age,gender,height,weight,HSS score,and all imaging data mentioned above,influencing factors related to fibulectomy outcome were measured as follows:(1)body mass index(BMI);(2)pre-op and post-op HSS score and the difference value;(3)tibiofemoral arthritis K/L score;(4)tibiofibular arthritis K/L score;(5)pre-op and post-op femoro-tibial angle(FTA)and difference value of the lower extremity;(6)inclination of proximal tibiofibular articulation;(7)distance from the level of fibular osteotomy to the top of the fibular head;(8)length of the resected fibular section;and(9)pre-op and post-op distance from the top of the fibular head to the tibial plateau and the difference value.Multivariable linear regression models were used to examine the associations of increased HSS score with selected influencing factors of knee OA.Results: A total of 45 females and 7 males(mean age 62.5±6.7 years),corresponding to 67 knees(35 right knees and 32 left knees),underwent proximal fibular osteotomy.The HSS scores were significantly improved immediately after surgery through 18 months post-operation;this result reflected improvements in both OA symptoms and knee function.According to the statistical results on the 10 factors affecting a patient’s surgical outcome,a statistically significant relationship was observed for 5 factors(P<0.05,Table 2),including BMI,pre-op HSS score,proximal tibiofibular arthritis K/L score,inclination of the proximal tibiofibular articulation(intersection angle with the horizontal plane),changes in the vertical distance between the top of the fibular head and the tibia plateau,based on univariate linear regression analysis.These factors were then included in multivariate linear regression analysis;no statistically significant difference was found in the remaining 5 variables(tibiofemoral arthritis K/L score,pre-op FTA of the lower extremity,changes in the FTA at 18 months post-op,the distance between the fibular head and the resected plane,and length of the resected fibula),according to univariate linear regression analysis.Based on the univariate linear regression analysis,a statistically significant relationship was found in 5 variables(X);these variables were then analyzed together with the increased value of the HSS score(Y)using multiple linear regression analysis.This analysis resulted in values of R2=0.769,F=17.613,and P=0.0002,indicating that the sample data in the present study fit the linear regression model well.The regression equation was Y=66.282-0.651 BMI-0.474 pre-op HSS score-7.199 the proximal tibiofibular arthritis K/L score + 0.562 inclination of proximal tibiofibular articulation + 15.198 changes in distance from the fibular head to the tibial plateau;P<0.05 was considered statistically significant.In terms of the regression coefficients,the influence of the above 5 variables on changes in the HSS score after fibular osteotomy in descending order was as follows: changes in the vertical distance between the fibular head and the tibial plateau(15.198)>knee tibiofibular arthritis K/L score(-7.199)> BMI(-0.651)>inclination of the tibiofibular joint(0.562)> pre-op HSS score(-0.474).Conclusions: Proximal fibula osteotomy is a simple and effective procedure to reduce knee pain and varus deformity in medial compartment knee OA.After the surgery,a free proximal fibula head was present,generating a biomechanical structure on the lateral knee similar to a “patella” to counteract knee varus deformities.The surgical outcome of medial compartment OA depends on the severity of the tibiofibular joint OA and shows a linear correlation with the BMI of patients,the inclination of proximal tibiofibular articulation and pre-op knee function.In general,a greater distal displacement generated by a fibular head,suggesting a better ROM of the tibiofibular joint,results in more obvious improvements in post-op symptoms.Part two Bone marrow edema changes after proximal fibular osteotomy to treat medial compartment knee osteoarthritis-prospective MRI studyObjective: Bone marrow edema is a important indicators in evaluating the severity of osteoarthritis.The prospective study aims to evaluate the bone marrow edema volume changes after the proximal fibular osteotomy for treating the knee osteoarthritis.By analyzing the reason of the reduction of bone marrow edema,the effect of the proximal fibular osteotomy to the knee osteoarthritis is evaluated.Methods: Eighteen cases(14 females and 4 males,mean age 61.5±6.4 years)with medial compartment OA complicated with knee varus deformities were selected randomly between March 2014 and May 2014.The VAS(visual analog scale,VAS)>5,and the Kellgren/Lawrence score≥2,mean BMI was 27.38±4.24 kg/m2.A total of 27 knees were available for proximal fibulectomy.The mean disease duration was 6.92±4.1 years.None of the patients had received an intra-articular injection or surgery within six months prior to enrollment in the study.By MR imaging the proximal tibia,subchondral bone marrow edema was evaluated using Whole-Organ MRI Score(WORMS).Linear regression analysis was performed to analyze the HSS score improvement and the bone marrow edema.Results: Of the 27 affected limbs,3 knees showed a WORMS score of 0(11.2%);9 knees showed a score of 1(33.3%);6 knees showed a score of 2(22.2%);and 9 knees showed a score >3(33.3%)in the femoral condyle.In the proximal tibial,5 knees showed a WORMS score of 0(18.6%);6 knees showed a score of 1(22.2%);9 knees showed a score of 2(33.3%);and 7 knees showed a score >3(25.9%).After linear regression analysis,2 univariate linear regression equation were as follows:1)VY1(improvement of HSS)=-5.434-0.432 medial femoral condylar subchondral bone marrow edema(X1)2)Y2(improvement of HSS)=-5.228-0.389 medial center plateau subchondral bone marrow edema of tibia(X2)Conclusions: By using the MR imaging,we found that the subchondral bone marrow edema reduced significantly after the surgery.Proximal fibular osteotomy can make decompression of the medial compartment knee osteoarthritis.The bone marrow edema in special area had linear regression relationship with HSS improvement.Part three Bone mineral density changes after proximal fibular osteotomy to treat medial compartment knee osteoarthritis-prospective QCT studyObjective: Bone mineral density is a important indicators in evaluating the compression force on the trabecular bone.The prospective study aims to evaluate the bone mineral density volume changes after the proximal fibular osteotomy for treating the knee osteoarthritis.By analyzing the reason of the reduction or increase of bone mineral density,the effect of the proximal fibular osteotomy to the knee osteoarthritis is evaluated.Methods: Fifteen cases(14 females and 1 males,mean age 64.0±5.4 years)with medial compartment OA complicated with knee varus deformities were selected randomly between March 2014 and May 2014.The VAS(visual analog scale,VAS)>5,and the Kellgren/Lawrence score≥2.A total of 17 knees were available for proximal fibulectomy.The mean disease duration was 7.24±5.1 years.None of the patients had received an intra-articular injection or surgery within six months prior to enrollment in the study.By QCT imaging the proximal tibia,subchondral bone mineral density was evaluated.Linear regression analysis and compaired t test was performed.Results: Of the 17 affected limbs,bone mineral density in the medial central and medial aterioral area of proximal tibial plateau pre-op.After the proximal fibular osteotomy,the bone mineral density in the both area mentioned decrease significantly.By the reduction of the stress shelter effect on the medial compartment,the trabecular bone in epiphyseal may have more bone mineral density.Around the proximal tibiofibular joint,the mineral density was increased after removal of part of the proximal fibular.Conclusions: By using the QCT imaging,we found that the subchondral bone mineral density reduced significantly in the medial tibial plateau after the surgery.Proximal fibular osteotomy may make decompression of the medial compartment knee osteoarthritis.Conclusions:1.Proximal fibula osteotomy is a simple and effective procedure to reduce knee pain and varus deformity in medial compartment knee OA.After the surgery,a free proximal fibula head was present,generating a biomechanical structure on the lateral knee similar to a “patella” to counteract knee varus deformities.The surgical outcome of medial compartment OA depends on the severity of the tibiofibular joint OA and shows a linear correlation with the BMI of patients,the inclination of proximal tibiofibular articulation and pre-op knee function.In general,a greater distal displacement generated by a fibular head,suggesting a better ROM of the tibiofibular joint,results in more obvious improvements in post-op symptoms.2.By using the MR imaging,we found that the subchondral bone marrow edema reduced significantly after the surgery.Proximal fibular osteotomy can make decompression of the medial compartment knee osteoarthritis.The bone marrow edema in special area had linear regression relationship with HSS improvement.3.By using the QCT imaging,we found that the subchondral bone mineral density reduced significantly in the medial tibial plateau after the surgery.Proximal fibular osteotomy may make decompression of the medial compartment knee osteoarthritis.