Outcome Analysis of En-bloc Excision and Endoprosthetic Replacement among the Cases Operated for Distal Femoral and Proximal Tibial Giant Cell Tumour around the Knee: A Retrospective Study

Introduction: Giant Cell Tumour (GCT) around the knee joint is the most common site for this locally malignant bone tumour and, in advanced stages, requires excision of the tumour mass. Current recommendations promote joint salvage procedures in allograft or mega prosthetic replacement. Patients undergoing this surgery need massive changes in their lifestyle to cope with their activities of daily living. The psychological and social impact following these procedures has not been extensively studied. Aim: To observe the long term functional results as well as the impact on quality of life in patients undergoing endoprosthetic replacements in GCT around the knee with emphasis on any difference in results among the cases operated for distal femoral and proximal tibial GCT. Materials and Methods: This retrospective study was conducted at Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow from June 2015 to June 2019 with a total sample size of 21 cases. The two groups formed were; one having GCT of distal end femur and the other group with GCT of proximal end tibia. The evaluation was done for outcome measures by Oxford Knee Score (OKS) and Musculo Skeletal Tumour Society score (MSTS) for their functional outcome and Short Form Health Survey (SF12) for their quality of life effect at two years postoperatively. Students unpaired t-test was performed for intergroup analysis and Analysis of Variance (ANOVA) was done for within the group analysis for subsequent follow-up visits. Data was analysed using Statistical Package for Social Sciences (SPSS) version 21. Results: The mean age of study population was 33.67±8.674 years. The male-female distribution was insignificant (p=0.673), providing us with a homogenous study group. Recurrent GCT was found significantly more commonly in the proximal tibia group than in the distal femur group (p=0.031). Comparison of OKS and MSTS preoperatively, at six months, at one year, and two years showed statistically significant improvement in successive follow-ups in both the distal femur and proximal tibia groups (p<0.001 in both groups). Intergroup analysis also showed significantly better scores in the distal femur group compared to the proximal tibia group in the preoperative period and all successive follow-ups. On intergroup analysis at 2 years, both the OKS (p=0.020*) and MSTS score (p<0.0001) were found to be statistically significant. SF-12 mental and physical scores preoperatively also showed statistically significant improvement in all cases (p<0.001 for mental and physical components. Conclusion: Early functional outcomes of en-bloc excision and reconstruction with modular endoprosthesis are good in terms of joint function and the patient’s overall mental and physical well-being.