Medialized Dome and Anatomic Onlay Patella Designs in the Modern Posterior Stabilized Rotating Platform Total Knee Arthroplasty Demonstrate No Clinical or Radiological Differences at One Year.

BACKGROUND: A successful outcome after total knee arthroplasty (TKA) includes the restoration of patellofemoral function. Modern patella component designs in TKA include a medialized dome and more recently, an anatomic design. There is a paucity of literature comparing these 2 implants. METHODS: This prospective nonrandomized study examined 544 consecutive TKAs with patella resurfacing using a posterior-stabilized, rotating platform knee prothesis performed by a single surgeon. A medialized dome patella design was used in the first 323 cases and an anatomic design in the subsequent 221 cases. Patients were assessed preoperatively, at 4 weeks and 1-year post-TKA for Oxford Knee Score (OKS) (total, pain, and kneeling components) and range of movement (ROM). Radiolucent lines (RLLs), patellar tilts and displacements, as well as reoperations were assessed at 1-year post-TKA. RESULTS: At 1-year post-TKA, both groups demonstrated similar improvements in ROM, OKS, pain, and kneeling scores, and had a similar incidence of fixed-flexion deformity (all P > .05). Radiographically, there was no clinically significant difference in the incidence of RLLs, patellar tilts, and displacements. The prevalence of reoperations (1.8 versus 3.2%, P = .526) was similar between the designs with no patella-related complications. CONCLUSION: Both medialized dome and anatomic patella designs result in improved ROM and OKS with no patella-related complications. However, our study showed no differences between the designs at 1 year.

Application of bone cement directly to the implant in primary total knee arthroplasty. Short-term radiological and clinical follow-up of two different cementing techniques.

PURPOSE: This study aimed to optimize cement application techniques in fully cemented primary total knee arthroplasty (TKA) by comparing the effects of two different approaches: cement on bone surface (CoB) versus cement on bone surface and implant surface (CoBaI) on the short-term presence of radiolucent lines (RLL) as indicators of potential complications. METHODS: In this monocentric study, a total of 379 fully cemented primary TKAs (318 patients) were included. The two study groups were differentiated by the technique of cement application: CoB group (cement applied only on bone surface) and CoBaI group (cement applied on both bone surface and implant surface). The presence of RLL or osteolysis was evaluated using the updated Knee Society Radiographic Evaluation System. RESULTS: In the whole study population, RLL were present in 4.7% of cases, with a significantly higher incidence in the CoBaI group (10.5%) at the 4-week follow-up. At the 12-month follow-up, RLL were observed in 29.8% of TKAs in the CoBaI group, while the incidence was lower in the CoB group (24.0%) (not statistically significant). There were two revisions in each group, none of which were due to aseptic loosening. CONCLUSION: The findings of this study suggest that the application of bone cement on bone surface only (CoB) may be more beneficial than applying it on both bone surface and implant surface (CoBaI) in terms of short-term presence of RLL in fully cemented primary TKA. Long-term results, especially with regard to aseptic loosening, will be of interest and may provide valuable guidance for future directions in bone cement applications in TKA.

Metal-on-Metal Hips: Ten-Year Clinical and Radiographic Outcomes of the ADEPT Metal-on-Metal Hip Resurfacing and Modular Total Hip Arthroplasty.

BACKGROUND: The aim of this study is to update the 10-year follow-up survivorship and metal ions levels of a cohort of metal-on-metal (MoM) hip resurfacing (HR) and large-diameter-head (LDH) total hip arthroplasty (THA). METHODS: The study is a retrospective analysis of prospectively collected data that compared the outcomes of 24 MoM HR (21 patients) and 15 (11 patients) modular LHD MoM THA at >10 years follow-up. Baseline characteristics as well as intraoperative and postoperative information were collected, including complications, revisions, clinical and radiographic outcomes, and serum metal ions level (Cobalt, Chromium). Metal ion levels were compared using a two-tailed unpaired t-test and Wilcoxon signed-rank test (jamovi v2.3.3.0, Sydney, NSW, AU). RESULTS: No significant differences were detected in gender, BMI, and ASA score between the two groups. Patients in the modular THA group were significantly older (57 years vs. 46 years; p < 0.05). The HR overall survivorship was 91.7% (22 of 24 hips) with survivorship from implant failure and/or aseptic loosening and/or metal debris related 100% of problems. The modular THA overall survivorship was 86.7% (13 of 15 hips) with survivorship from implant aseptic loosening and metal ions complications of 93.4% (14 of 15 hips). No significant difference was noted when comparing clinical outcomes. Metal ions were significantly lower in the HR group (Co 25.8 nmol/L vs. 89 nmol/L; p < 0.001-Cr 33.5 nmol/L vs. 55.2 nmol/L; p = 0.026). CONCLUSION: Both implants reported excellent and comparable clinical outcomes at >10 years follow-up. The Adept HR reported remarkable survivorship, in line with the registry data, proving once again its reliability in young active males. The modular LDH THA, despite being discontinued, presented higher reliability and a lower failure rate when compared with similar withdrawn MoM implants. Trunnionosis did not appear to be a significant problem in this particular modular design.

Popliteal tendon impingement as a cause of pain following total knee arthroplasty: a systematic review.

INTRODUCTION: Popliteal tendon impingement (PTI) is an under-recognized cause of persistent pain following total knee arthroplasty (TKA). The purpose of the systematic review was to summarize and outline successful strategies in the diagnosis and management of PTI. METHODS: A systematic review following the PRISMA guidelines was performed for four databases: MEDLINE (Pubmed), Ovid EMBASE, Web of Science, and Cochrane Database. It was registered in the International Prospective Register for Systematic Reviews and Meta-analysis (PROSPERO) under the registration number: CRD42023398723. The risk of bias assessment was performed using the criteria of the methodological index for non-randomized studies (MINORS). RESULTS: A total of 8 studies were included. There were 2 retrospective case series and 6 case reports. The follow-up ranged from 6 to 30 months. Two studies described PTI as an intraoperative phenomenon during TKA with "snapping"; whilst 6 studies described indications and outcomes for arthroscopic tenotomy for PTI following TKA. In making the diagnosis, there was concurrence that the posterolateral pain should be focal and that dynamic ultrasonography and diagnostic injection play an important role. Two specific clinical tests have been described. There was no consistency regarding the need for imaging. There were no reports of instability following popliteal tendon tenotomy or other complications. CONCLUSION: PTI should be suspected as a cause for persistent focal pain at the posterolateral knee following TKA. The diagnosis can be suspected on imaging and should be confirmed with dynamic ultrasonography and an ultrasound-guided diagnostic injection. An arthroscopic complete tenotomy of the tendon can reliably alleviate pain and relies on correct diagnosis. There is no evidence for clinically relevant negative biomechanical consequences following tenotomy. LEVEL OF EVIDENCE: Systematic Review of Level IV and V studies.