Clinical Studies Of Postoperative Knee-related Parameters For Distal Femur Tumor Prosthesis

Background：The area surrounded of knee joint is the predilection sitesof bone tumors, especially osteosarcoma. There are reports that the incidenceof osteosarcoma in the distal femur maximum incidence located femur, tibia,humerus was4:2:1[1]. Dahlin[2]reported5116cases in the incidence of bonetumors which is1,362cases around the knee, accounting for26%. TumorKnee arthroplasty prosthesis has a unique advantage in numerous knee limbsalvage method, the treatment of malignant tumors around the knee isincreasingly being recognized by domestic and foreign medical experts,although not mentioned accurate statistics in China, but increasing in recentliterature of view presented. The advantage is that the prosthesis can calculatethe size of bone cut characterized by a combination of stress, or choose tocustomize existing models can be instantly restored after knee replacement gota faster recovery of limb function, does not affect the normal chemotherapy;especially for patients with poor prognosis, often youngsters can improvetheir quality of life in a limited lifetime; with the development of biologicalengineering and biological materials science, all forms of artificial prosthesisappears, the surgeon can choose different specifications prosthesis underspecific circumstances, to ensure the integrity and security of the border tumorresection.However, varying degrees of influence knee function complications alsoappeared after joint replacement, such as reduced range of motion, pain, gaitabnormalities, intra-articular friction flu. The study found that tumor-relatedparameters knee prosthesis in the clinical course of change, but the relevantliterature are rare.Purpose： study the relevant parameters were measured to analyze therelationship between changes in knee function and parameter changes related causes and countermeasures are discussed.Methods： from2012to2013in the Third Hospital of Hebei MedicalOncology Bone, admitted14cases of distal femur tumor type knee prosthesisin patients before and after surgery, were routinely taken straight-LateralX-ray and knee CT, then measuring relevant parameters:①patellar height:Insall-Salvati measurement, namely the patella to the tibial tuberosity than thedistance between the lower edge of the long axis of the patella,②lateralpatellofemoral angle: vertex and femoral condylar connect with patellararticular surface of the lateral femoral angulation,③tibiofemoral angle: thelong axis of the femur and the tibia long axis at an angle,④femur angle: theangle between the lateral femoral condyle and outside the long axis of thefemur into the vertex connectivity,⑤tibia upper corner: the long axis ofthe tibial articular surface of the tibia into the outer angle (see Figure1).Using SPSS statistical software, using paired t-test statistical analysis beforeand after surgery to change the circumstances relevant parameters (P <0.05both statistically significant). The mean follow-up of6months (5months to8months), functional assessment, using pre-Enneking limb musculoskeletalreconstruction after surgical treatment of tumors functional assessment criteria(MSTS score, see Table1) system, based on lower extremity pain, functionalactivities, feelings and brace use, walking ability, gait changes in six aspectsof knee function score (0-5points each out of30points), using paired t testanalysis before and after surgery knee function to change the situation.Spearman line will choose to do with changes in the correlation function of theknee statistically significant difference in the parameters analyzed.Results： Significantly differences in height of the patella before andafter the surgery which was next segment tumor type artificial joint femoralprosthesis replacement,patellar height was significantly lower (P <0.01, Table2); There was no significant difference (P>0.05, Table3-6) prior to analysisand after surgery of the statistical data in lateral patellofemoral angle,tibiofemoral angle, distal femur angle and tibia upper corner. Preoperativeevaluation and follow-up knee function, scores were significantly different (P <0.01, see Table7). The postoperative patellar height and postoperative kneefunction score do correlation analysis showed that there was a significantnegative correlation (P <0.01, Figure2). However,The difference of patellarheight between preoperative and postoperative compared with the follow-upknee function score showed no significant correlation (P>0.05).Conclusion： Relevant parameters of Distal femur tumor prosthesisartificial knee replacement surgery, the patellar position was significantlylower than the preoperative. The remaining parameters had no significantdifference Compared with the preoperative; Knee function was improvedafter the operative, tumor type prosthesis treatment of malignant tumorsaround the knee has benefits for knee function recovery; patellar position wasno significant correlation with knee function recovery, the more absolutepatellar height deviation from the normal range, the worse knee function, thebetter knee function approaching the normal range.