The placement of the patellar component during TKA differs from one patella to another. Thus, by defining the OCPP on a patient-by-patient basis, the surgeon should be able to reproduce the functional anatomy of the native patella.
The patella remains one of the main sources of post-operative complication following total knee arthroplasty surgery. Optimal positioning of the patellar component is still a controversy with no clear-cut guidelines. Instead of choosing an empirical position, we described a novel surgical technique to better locate the patellar button based on the individual patellar anatomy of each patient.
Introduction: Osteonecrosis of the femoral head (ONFH) remains a therapeutic challenge for patients undergoing total hip arthroplasty (THA). The majority of these patients are young with high functional demand, and show an increased risk of dislocation following surgery than patients with osteoarthritis. The use of double mobility cup (DMC) has been linked with lower rates of complications when compared to conservative cups; however, the literature is scarce over DMC results in patients with ONFH. The aim of the study is to report the early outcomes of patients with ONFH treated with THA-DMC. Materials: A retrospective analysis of patients suffering from ONFH who underwent THA using DMC (THA-DMC) from 2006 to 2015 were evaluated for functional status and risk of post-operative complications. Thirty THA-DMC in 26 patients with a mean follow-up of 51 months were evaluated clinically (modified Hip Harris Score) and radiologically. Results: The mean age of the included patients was 54.9 years. At final follow-up, the mean modified Hip Harris score was 98.7 ± 2.7 and no dislocation episodes or revision surgeries were recorded. The radiological assessment revealed no signs of migration/tilting, radiolucent lines, periprosthetic osteolysis or heterotopic ossification over the DMC component and the femoral stem. The survival rate over 51 months of follow-up was 100%. Discussion: The use of the new generation of dual mobility cup in patients with ONFH showed excellent functional early results with no major complications such as dislocation.
Objective: The aim was to investigate the clinical relevance of preoperative caudal adjacent segment degeneration (ASD) in patients undergoing isolated L4-5 fusion to determine a threshold of degeneration at which a primary L4-S1 fusion would be warranted.Summary of Background Data: Increased motion and biomechanical forces across the adjacent caudal segment in isolated L4-L5 fusion leads to concerns regarding the increased incidence of revision surgery because of the development of ASD.Methods: Patients who underwent isolated L4-L5 fusion between 2014 and 2019 were reviewed. Pfirrmann grading and the disc heights of the caudal level relative to the rostral level were used to quantify preoperative adjacent degenerative disc disease. To assess the influence of preoperative caudal degenerative disc disease, preoperative disc height ratios (DHRs) were compared for patients who reported minimal, moderate, and severe Oswestry disability index (ODI) sores on postoperative assessment. For each patient-reported outcome measure (PROM), adjacent DDD was compared for those who did and did not meet MCID. An area under curve analysis was used to identify a threshold of degeneration impacting outcomes from the preoperative DHR.Results: A total of 123 patients were studied with an average follow-up of 2.11 years. All patients demonstrated a significant improvement in all PROMs after surgery. When categorizing patients based on the severity of postoperative ODI scores, there were no preoperative differences in the L5-S1 Pfirrmann grading or DHRs. There was a significant association between greater preoperative anterior DHR and an increased number patients who met MCID for visual analog scale back. There were no radiographic differences in preoperative L5-S1 Pfirrmann grade or DHR for ODI, visual analog scale leg, MCS-12, or PCS-12. area under curve analysis was not able to identify a preoperative DHR threshold that reflected worse MCID for any PROM.
Conclusion:No preoperative radiographic indicators of caudal ASD were predictive of worse clinical outcomes after isolated L4-5 fusion.
Objective
Medial patellofemoral ligament (MPFL) injury occurs in the majority of the cases of acute patellar dislocation. The role of concomitant lateral retinaculum release with MPFL reconstruction is not clearly understood. Even though the lateral retinaculum plays a role in both medial and lateral patellofemoral joint stability in MPFL intact knees, studies have shown mixed clinical outcomes following its release during MPFL reconstruction surgery. Better understanding of the biomechanical effects of the release of the lateral retinaculum during MPFL reconstruction is warranted. We hypothesize that performing a lateral release concurrent with MPFL reconstruction will disrupt the patellofemoral joint biomechanics and result in lateral patellar instability.
Methods
A previously developed and validated finite element (FE) model of the patellofemoral joint was used to understand the effect of lateral retinaculum release following MPFL reconstruction. Contact pressure (CP), contact area (CA) and lateral patellar displacement were recorded. abstract.
Results
FE modeling and analysis demonstrated that lateral retinacular release following MPFL reconstruction with tibial tuberosity-tibial groove distance (TT-TG) of 12 mm resulted in a 39% decrease in CP, 44% decrease in CA and a 20% increase in lateral patellar displacement when compared to a knee with an intact MPFL. In addition, there was a 45% decrease in CP, 44% decrease in CA and a 21% increase in lateral displacement when compared to a knee that only had an MPFL reconstruction.
Conclusion
This FE-based analysis exhibits that concomitant lateral retinaculum release with MPFL reconstruction results in decreased PF CA, CP and increased lateral patellar displacement with increased knee flexion, which may increase the risk of patellar instability.
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