Background: The coronal plane alignment of the knee (CPAK) classification system divides coronal knee anatomy into 9 phenotypes, suggesting different soft tissue balancing is needed for optimal outcomes. We investigated the interplay between CPAK phenotypes and gap stress curves throughout the knee's range of motion, aiming to understand their impact on total knee arthroplasty balancing.
Methods: There were 1,112 total knee arthroplasty cases from 2 imageless robotic assisted navigation systems using posterior stabilized implants that were classified into CPAK phenotypes. Medial and lateral initial gap values were measured throughout the knee flexion-extension arc, gap curve morphologies were generated, and mediolateral (ML) gap balance was calculated for each phenotype. The most common phenotypes were included in this study, CPAK I to VI.
Results: Each phenotype exhibited a distinct gap curve morphology. Type I maintained the largest ML gap difference (-3.6 to -2.1), with the medial compartment tightest in extension. Type II showed relative laxity in the lateral compartment compared to the medial gap (-1.0 to -1.9), with the medial compartment tightening through flexion. Type III had a looser medial and tighter lateral compartment in extension that inverts to a tighter medial compartment in deep flexion (2.1 to -0.8), while Type IV showed a decreasing compartment difference with increased flexion (-3.7 to 0.6). Type V had fluctuating tightness (-0.6 to 1.8), and Type VI had the medial compartment tightening more with flexion (0.6 to 1.8).
Conclusions: The distinct stress curves and ML gap behavior provide a "fingerprint" for each corresponding CPAK phenotype. Investigating these morphologies can help determine the best phenotype-specific treatments, including alignment strategy, implant selection, and gap balance, for optimal functional and patient outcomes.
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http://dx.doi.org/10.1016/j.arth.2024.06.011 | DOI Listing |
J Arthroplasty
January 2025
Orthopedic Surgery Artificial Intelligence Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA. Electronic address:
Background: Minimum joint space width (mJSW) is an important continuous quantitative metric of osteoarthritis progression in the knee. The purpose of this study was to develop an automated measurement algorithm for mJSW in the medial and lateral compartments of the knee that can flexibly handle native knees as well as knees after arthroplasty.
Methods: We developed an end-to-end algorithm consisting of a deep learning segmentation model plus a computer vision algorithm to measure mJSW in the medial and lateral compartments of the knee.
Am J Sports Med
January 2025
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Background: A larger joint line convergence angle (JLCA) increases the stress load on the medial compartment. Few reports, however, have discussed the effect of the JLCA on the cartilage status and clinical outcomes after opening-wedge high tibial osteotomy (OWHTO).
Purpose/hypothesis: To reveal the effect of the JLCA on clinical results after OWHTO.
Cell Transplant
January 2025
Division of Rheumatology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
To assess the impact of a single intra-articular (IA) injection of bone marrow-derived mesenchymal stem cells (BM-MSCs) in patients with knee osteoarthritis (OA), a randomized, double-blind, placebo-controlled study was conducted. The study included 24 patients with knee OA who were randomly assigned to receive either a single IA injection of BM-MSCs or normal saline. Changes in the visual analog scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Injury and Osteoarthritis Outcome Score (KOOS) after IA injection were assessed at 3, 6, 9, and 12 months.
View Article and Find Full Text PDFJ Orthop
September 2025
Department of Orthopaedic Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
Introduction: Total knee replacements are becoming more prevalent. There is still a lot of controversy regarding patellar resurfacing. Surgeons advocating for resurfacing state reduced risk for anterior knee pain and need for future revision surgery.
View Article and Find Full Text PDFJ Orthop Translat
January 2025
Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, 6F Biomedical Technology Building, No. 301, Yuantong Rd., Zhonghe Dist., New Taipei City, 23564, Taiwan.
Background And Objective: Osteoarthritis is a widespread and debilitating condition, particularly affecting the medial compartment of knee joint due to varus knee deformities. Medial opening wedge high tibial osteotomy (MOWHTO) has emerged as an effective treatment, but it comes with challenges like fractures, correction loss, and nonunion, leading to unsatisfactory results in up to 26 % of patients. In response, our study explores the potential of a bioabsorbable magnesium-based bulk metallic glass composite (MgZnCa BMGC) enriched with molybdenum particles as an innovative solution for MOWHTO.
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