Clinical outcomes and survival comparison between NexGen all-poly and its metal-backed equivalent in total knee arthroplasty.

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.

Biomechanical analysis of all-polyethylene total knee arthroplasty on periprosthetic tibia using the finite element method.

BACKGROUND AND OBJECTIVE: Total knee arthroplasty (TKA) with modern all-polyethylene tibial (APT) components has shown high long-term survival rates and comparable results to those with metal-backed tibial components. Nevertheless, APT components are primarily recommended for older and low-demand patients. There are no evidence-based biomechanical guidelines for orthopaedic surgeons to determine the appropriate lower age limit for implantation of APT components. A biomechanical analysis was assumed to be suitable to evaluate the clinical results in patients under 70 years. The scope of this study was to determine biomechanically the appropriate lower age limit for implantation of APT components. METHODS: To generate data of the highest possible quality, the geometry of the computational models was created based on computed tomography (CT) images of a representative patient. The cortical bone tissue model distinguishes the change in mechanical properties described in three parts from the tibial cut. The cancellous bone material model has a heterogeneous distribution of mechanical properties. The values used to determine the material properties of the tissues were obtained from measurements of a CT dataset comprising 45 patients. RESULTS: Computational modeling showed that in the majority of the periprosthetic volume, the von Mises strain equivalent ranges from 200 to 2700 µÎµ; these strain values induce bone modeling and remodeling. The highest measured deformation value was 2910 µÎµ. There was no significant difference in the induced mechanical response between bone models of the 60-year and 70-year age groups, and there was <3% difference from the 65-year age group. CONCLUSIONS: Considering in silico limitations, we suggest that APT components could be conveniently used on a bone with mechanical properties of the examined age categories. Under defined loading conditions, implantation of TKA with APT components is expected to induce modeling and remodeling of the periprosthetic tibia. Following clinical validation, the results of our study could modify the indication criteria of the procedure, and lead to more frequent implantation of all-polyethylene TKA in younger patients.

Advantages in Prognosis of Adult Patients with Ewing Sarcoma: 11-years Experiences and Current Treatment Management.

Ewing sarcoma (ES) is an exceptionally rare tumor in adults. Data regarding outcomes of adult patients with ES and experiences with age-adapted therapeutic strategies are very limited. The aim of this study was to evaluate prognostic factors and clinical outcome in a cohort of adult patients treated according to pediatric protocols in the Czech Republic. The records of 58 adult ES patients diagnosed between 2002 and 2013 were reviewed and factors relevant to prognosis and survival were analyzed. The median age of study cohort was 29 years (range, 18-59). The most frequent location was axial (36.2%), followed by involvement of extraskeletal tissues (34.5%) and bones of the extremities (29.3%). Twenty-eight (48.3%) patients had metastatic disease. In cases with localized ES, the 5-year overall survival (OS) was 76.5%. Using the log-rank test, the presence of metastasis at diagnosis, local treatment without surgery and a failure to achieve complete remission were associated with significantly shorter survival. In a multivariate Cox proportional hazard analysis, the achievement of complete remission was an independent predictor of patients's survival time. Outcomes of adults with localized ES treated according to multimodal pediatric protocols are similar to children. The achievement of complete remission is an independent predictor of survival time in ES patients. Severe hematological toxicity is foreseeable and manageable. Prognosis of patients with metastases or progression remains dismal.

Severe cobalt intoxication following hip replacement revision: clinical features and outcome.

CONTEXT: Cobalt intoxication has become more frequent due to the wide use of metal hip implants. CASE DETAILS: A 56-year-old male patient underwent total hip prosthesis, with a ceramics-on-ceramics implant. Almost 3 years later, it was replaced by metal implant containing cobalt, chromium, and titanium. He developed weight loss, heart, thyroid, and neurological toxicity, with severe hearing loss. He was treated with 2,3-dimercaptopropane-1-sulfonate (DMPS), and cobalt excretion increased. Clinical symptoms apart from deafness gradually resolved. CONCLUSION: We report significant cobalt poisoning from a damaged hip replacement with cobalt containing implant and a slow abrasion of the metal by residual ceramic particles. Chelation therapy resulted in apparent benefit.

Use of the harmonic system in total hip arthroplasty: a prospective, comparative, observational study.

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 7th day (83.3 mg 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 75 mg/l vs. 96 mg/l at the third day (P<0.05) and 26 mg /l vs. 54 mg /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 3rd day (P<0.01), respectively 1.1 ukat/l compared to 1.8 ukat/l at the 7th 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.

Total hip replacement with the CLS expansion shell and a structural femoral head autograft for patients with congenital hip disease.

BACKGROUND: Reconstruction of a dysplastic acetabulum in a patient with osteoarthritis of the hip may be accomplished with a variety of surgical techniques. The aim of our study was to assess the outcomes of total hip replacement with the uncemented CLS expansion shell and a structural femoral head autograft to augment the deficient acetabulum in patients with osteoarthritis secondary to congenital hip disease. METHODS: Between 1990 and 1994, we used a CLS expansion shell with a structural femoral head autograft in forty-three consecutive patients (forty-three hips) with osteoarthritis secondary to congenital hip disease. The ratio of male to female patients was 5:38, and the mean age of the patients was forty-eight years. According to the preoperative radiographic assessment, the dysplasia was categorized as Crowe type I in six patients, Crowe type II in thirty-one patients, and Crowe type III and type IV in three patients each. No patient was lost to follow-up. The mean duration of follow-up was 120 months. Plain radiographs were made immediately after surgery and at the latest follow-up evaluation. Clinical outcomes were determined with use of the Harris hip score and the Merle d'Aubigné and Postel score, and a radiographic analysis was performed. RESULTS: Postoperatively, the mean Harris hip score had improved 58 points for patients with Crowe type-I and II dysplasia, 47 points for patients with Crowe type-III dysplasia, and 46 points for patients with Crowe type-IV dysplasia (p < 0.05 for all). At the latest follow-up examination, the mean Harris hip score for all patients was 92.6 points. The mean Merle d'Aubigne and Postel score was 8.3 points preoperatively and 15.8 points at the time of the latest follow-up. The mean coverage of the shell by the graft immediately after surgery was 32.2%. Osteointegration of the CLS expansion shell was evident radiographically in all forty-three hips at the latest follow-up evaluation. There were no failures of the bone grafts. Clinical survival of the CLS expansion shell with a structural femoral head autograft was 100% at a mean of ten years after surgery. The rate of survival of the shell, with radiographic signs of loosening as the end point, was 88.2% at ten years. CONCLUSIONS: The CLS uncemented expansion shell, when used with a structural femoral head autograft, provides a reliable reconstruction, augments deficient acetabular bone stock, and allows placement of the socket at or close to the anatomic center of hip rotation in patients undergoing total hip arthroplasty to treat the sequelae of congenital hip disease.