Giant-cell tumor of bone (GCTB) is an intermediate type of primary bone tumor characterized by locally aggressive growth with metastatic potential. The aim of this study was to identify new druggable targets among the cell signaling molecules involved in GCTB tumorigenesis. Profiles of activated signaling proteins in fresh-frozen tumor samples and tumor-derived cell lines were determined using phosphoprotein arrays. Analysis of the obtained data revealed epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor beta (PDGFRβ) as potential targets, but only the PDGFR inhibitor sunitinib caused a considerable decrease in stromal cell viability in vitro. Furthermore, in the case of a 17-year-old patient suffering from GCTB, we showed that the addition of sunitinib to the standard treatment of GCTB with the monoclonal antibody denosumab resulted in the complete depletion of multinucleated giant cells and mononuclear stromal cells in the tumor tissue. To summarize, the obtained data showed that a specific receptor tyrosine kinase (RTK) signaling pattern is activated in GCTB cells and plays an important role in the regulation of cell proliferation. Thus, activated RTKs and their downstream signaling pathways represent useful targets for precision treatment with low-molecular-weight inhibitors or with other types of modern biological therapy.

We compared technical issues, postoperative outcomes and surgical complications of total hip arthroplasty when using the harmonic scalpel (HS) when compared with conventional techniques (CT) in a prospective, comparative observational study. Thirty patients undergoing total hip arthroplasty were assessed. Operative time, blood loss in drains, postoperative pain, soft tissue injury and complications were recorded. We found no significant differences between the HS and CT groups at baseline. Mean operative time was longer in the HS group compared with the CT of total hip arthroplasty (61 minutes vs. 54 minutes; P<0.05). We found no difference in postoperative pain using a visual analogue scale score, or use of paracetamol. The use of tramadol was reduced in the HS group compared to CT group at the 7^th day (83.3mg vs. 113.3 mg; P<0.05). Drainage volume was significantly lower in the HS group at 24 hours (332 ml vs. 429 ml; P<0.05) and at 48 hours (429 vs. 537 ml; P<0.05). C-reactive protein blood levels were significantly lower in the HS group 75mg/l vs. 96mg/l at the third day (P<0.05) and 26mg /l vs. 54mg /l at the seventh day (P<0.01). Creatine kinase blood levels were significantly lower in the HS group at 3 and 7 days (2.4 ukat/l compared to 5.3 ukat/l at the 3^rd day (P<0.01), respectively 1.1 ukat/l compared to 1.8 ukat/l at the 7^th day (P<0.01). We found no significant differences in blood myoglobin levels between the two groups. The use of the HS may reduce postoperative pain, drainage volume, and soft tissue injury in patients undergoing total hip arthroplasty, which may justify the cost of the technique. The use of HS may have further applications in revision hip arthroplasty and tumour surgery.

Background: The purpose of this study was to evaluate the implant survival, functional score and complications of intercalary endoprostheses implanted for metastatic involvement of the femoral and humeral diaphysis. Methods: The selected group covered patients with bone metastasis who were surgically treated with an intercalary endoprosthesis between 2012 and 2021. The functional outcome was evaluated with the Musculoskeletal Tumor Society (MSTS) scoring system, and complications were evaluated by using the failure classification for prosthetics designed by Henderson. Results: The mean follow-up was 29.8 months. In our group of 25 patients with 27 intercalary endoprostheses (18 femurs, 9 humeri), there were 7 implant-related complications (25.9%), which were more common on the humerus (4 cases, 44.4%) than on the femur (3 cases, 16.7%). Only type II failure—aseptic loosening (5 cases, 18.5%)—and type III failure—structural failure (2 cases, 7.4%)—occurred. There was a significantly higher risk of aseptic loosening of the endoprosthesis in the humerus compared with that in the femur (odds ratio 13.79, 95% confidence interval 1.22–151.05, p = 0.0297). The overall cumulative implant survival was 92% 1 year after surgery and 72% 5 years after surgery. The average MSTS score was 82%. The MSTS score was significantly lower (p = 0.008) in the humerus (75.9%) than in the femur (84.8%). Conclusions: The resection of bone metastases and replacement with intercalary endoprosthesis has excellent immediate functional results with an acceptable level of complications in prognostically favourable patients.

Periprosthetic fracture is one of the most serious complication of total knee arthroplasty. In our retrospective clinical study we designed our classification with rules for treatment of those fractures. During the last thirty years we treated 53 distal femoral periprosthetic fractures in our orthopaedic department. In our clinical study we reviewed our group of distal femoral periprosthetic fractures with on the basis of X-ray findings, the treatment method used and treatment outcomes. According to our findings we divided distal femoral periprosthetic fractures into six groups: Type I Nondisplaced fractures, 5.7%; treatment failure rate, 33%. Type II a Fractures with lateral comminution (the most often type of fractures), 37.7%; treatment failure rate, 20%. Type II b Fractures with medial comminution, 7.5%; treatment failure rate, 60%. Type II c Fractures above TKA (the second most often type), 34%; treatment failure rate, 18%. Type II d Comminuted fractures, 5.7%; treatment failure rate, 18%. Type IIIFractures with loosening of TKA, 9.4%; treatment failure rate, 20%. For the treatment of fractures we used various methods according to the type of fracture: Plate osteosynthesis in 32 cases, with failure in seven. Three failures in IIa group due to incorrect osteosynthesis with condylar plate, treated by reosteosteosynthesis with same implant. One in IIb group treated primarily with cement plomb, after second failure treated with revision total knee arthroplasty. Two failures in IIc group, treated by reosteosynthesis with spongioplasty using the same implant. One failure in III group solved with revision TKA. Intramedullary nail in nine cases , with failure in two. One failure in IIb group treated by reosteosynthesis with condylar plate and cement plombage. One in IIc group due to infection, solved with extraction of material and second stage revision TKA. Conservative treatment in three cases,with failure in two. One in I group treated with condylar plate. One in IId group solved with revision TKA. Miniosteosynthesis in three cases, with failure in two.One failure in IIa group treated with condylar plate, one in IIb group treated with intramedullary nail and additional hydroxyapatite plombage. Revision total knee arthroplasty in five cases with no failure. Extraction of TKA, external fixation, and arthrodesis in 1 case with no failure. The rules for treatment of distal femoral periprosthetic fractures are not definite yet. For fractures above TKA is recommended nail osteosynthesis; for fractures at the level of femoral component is preferable to use osteosynthetic material, condylar plate or LCP. Bone grafts, bone cement, and artificial bone are used to augment osteosynthesis in comminuted fractures. Fractures at the site of loosening are indicated for revision TKA. According to our results: Type I: Conservative treatment possible. Osteosynthesis with condylar plate is recommended. Type IIa: Indication for condylar plate osteosynthesis. Type IIb: The most problematic group. Osteosynthesis with condylar plate with augmentation or condylar plate placed from medial side. Type IIc: Plate osteosynthesis possible, intramedullary nail is recommended. Type IId: Osteosynthesis with augmentation is possible in some cases; revision TKA is recommended. Type III: Indication for revision TKA.

Purpose: This study aims to compare total knee replacement (TKA) with NexGen All-Poly (APT) and NexGen Metal-Backed (MBT) in terms of implant survivorship, reasons leading to implant failure and functional results of defined age categories. Methods: A single-centre, retrospective evaluation of 812 patients who underwent knee replacement with NexGen CR between 2005 and 2021, comparing a modern congruent APT component to a modular MBT equivalent component using a similar surgical technique at a notable mean follow-up duration. Implant survival, functional outcomes using the Knee Society Score and range of motion were evaluated and compared in different age categories. Results: Of the 812 NexGen CR TKAs performed at our institution, 410 (50.4%) used APT components and 402 (49.6%) MBT components. The survival rate of NexGen APT was 97.1% and that of NexGen MBT was 93.2% (p = 0.36). Removal of the implant occurred overall in 15 cases, for MBT in ten cases, and for APT in four cases. The FS was proved to be significantly higher when APT components were implanted in younger patients than for MBT (p = 0.005). A similar range of motion between the components was recorded (p = 0.1926). Conclusion: Under defined conditions, we measured the clinical results of implants from a single manufacturer implanted in a single department using a similar surgical technique. Considering the limitations, we suggest that all-polyethylene tibial components are equal or even superior to metal-backed ones across the examined age categories.