Uncemented trabecular metal high-flex posterior-stabilized monoblock total knee arthroplasty in patients aged 60 years or younger.

BACKGROUND: Uncemented trabecular metal (TM) monoblock tibial components in total knee arthroplasty (TKA) have shown excellent clinical results for up to 10 years. However, these studies were performed in highly specialized units, with few surgeons and often excluding knees with secondary osteoarthritis (OA), severe malalignments and previous surgery. The purpose of this study was to investigate implant survivorship and clinical and radiological outcome of the uncemented TM high-flex posterior stabilized (PS) monoblock tibial component in routine clinical practice. METHODS: A retrospective study of 339 knees (282 patients) operated with the implant in routine clinical practice at two hospitals on patients aged 60 years or younger between 2007 and 2015. The operations were performed by 12 surgeons and there were no specific contraindications for use of the implant. Follow up ended in 2020. The status of the implant of deceased patients at death and those not attending follow up was checked with the Swedish Knee Arthroplasty Register. Clinical follow up consisted of clinical investigation, PROMs, and knee X-ray. RESULTS: Follow up was mean (range) 8.5 (5-13.8) years, and the 8-year survival rate was 0.98 (standard error 0.007). Five patients five knees) were deceased, five knees were revised (none due to aseptic loosening), and 16 patients did not attend the clinical follow up. Forty-four percent of the knees had secondary OA and 45% had had previous operations. 93% were satisfied or very satisfied with the operation and forgotten joint score (FJS) was median (interquartile range) 81 (44-94). Radiographic analysis revealed bone in close contact with the tibial tray and pegs in most cases, and in only 2% of the knees were potential radiolucent lines found. CONCLUSION: The results indicate that this uncemented implant performs excellently in routine clinical practice and also in younger patients with secondary OA or previous knee operations.

Uncemented monoblock trabecular metal posterior stabilized high-flex total knee arthroplasty: similar pattern of migration to the cruciate-retaining design - a prospective radiostereometric analysis (RSA) and clinical evaluation of 40 patients (49 knees) 60 years or younger with 9 years' follow-up.

Background and purpose - Uncemented monoblock cruciate retaining (CR) trabecular metal (TM) tibial components in total knee arthroplasty (TKA) work well in the long-term perspective in patients ≤ 60 years. Younger persons expect nearly normal knee flexion after TKA, but CR implants generally achieve less knee flexion compared with posterior stabilized (PS) implants. Cemented PS implants have higher revision rate than CR implants. Can an uncemented monoblock PS TM implant be used safely in younger patients? Patients and methods - 40 patients (49 knees) age ≤ 60 years with primary (20 knees) or posttraumatic osteoarthritis (OA) were operated with a high-flex TKA using an uncemented monoblock PS TM tibial component. Knees were evaluated with radiostereometric analysis (RSA) a mean 3 days (1-5) postoperatively, and thereafter at 6 weeks, 3 months, 1, 2, 5, and 9 years. Clinical outcome was measured with patient-related outcome measures (PROMs). Results - The implants showed a pattern of migration with initial large migration followed by early stabilization lasting up to 9 years, a pattern known to be compatible with good long-term results. Clinical and radiological outcome was excellent with 38 of the 40 patients being satisfied or very satisfied with the procedure and bone apposition to the entire implant surface in 46 of 49 knees. Mean knee flexion was 130°. 1 knee was revised at 3 months due to medial tibial condyle collapse. Interpretation - The uncemented monoblock PS TM implant works well in younger persons operated with TKA due to primary or secondary OA.

5'-Esters of 2'-deoxyadenosine and 2-chloro-2'-deoxyadenosine with cell differentiation-provoking agents.

Phenylacetic and retinoic acids are carboxyacidic cell differentiating agents displaying anticancer activities. We report on a new class of compounds including the 5'-esters of 2'-deoxyadenosine (dA) or 2-chloro-2'-deoxyadenosine (cladribine, 2CdA) and the aforementioned acids. The rationale behind the synthesis of these esters was that if they are hydrolyzed inside the lymphoid cells, either dA will be removed from the intracellular environment by deamination, or 2CdA will be phosphorylated and accumulated. In either case targetted delivery of the differentiating agent to the lymphoid cells may be envisaged. The said compounds were synthesized by the Mitsunobu procedure employing triphenylphosphine and azadicarboxylic acid esters, and their stability was tested against various esterases. Esters of dA and 2CdA with phenylacetic acids were found to be resistant to enzymatic hydrolysis, whereas those with retinoic acids were efficiently hydrolyzed by commercially available hepatic esterase as well as by esterases present in the blood plasma and in diluted human lymphocyte lysate. Susceptibility to enzymatic hydrolysis was found to be a prerequisite of cytotoxic and/or differentiating activity of these esters in leukemic cell lines.