Large bone defects resulting from trauma, tumor resection, infection, or degenerative diseases pose a major clinical challenge in orthopedic surgery and regenerative medicine. Despite advances in biomaterials and surgical techniques, successful outcomes are often compromised by poor vascularization, limited osteoinduction, and donor-site morbidity associated with autografts or allografts. However, conventional delivery systems suffer from burst release, rapid clearance, off-target effects, and supraphysiologic dosing, which can lead to undesirable complications such as ectopic ossification and inflammation, with some reports raising concerns about the long-term tumorigenic risk. Heparin, a naturally highly sulfated glycosaminoglycan structurally related to heparan sulfate, has emerged as a particularly attractive candidate for affinity-based biomaterial systems. It naturally binds over 300 growth factors, including bone morphogenetic proteins. By protecting these proteins from enzymatic degradation, enhancing their bioavailability, and mediating receptor clustering, heparin provides both biochemical stability and biofunctional modulation. This review provides a comprehensive overview of heparin-based delivery strategies in bone tissue engineering. We begin by describing the biological functions of heparin in modulating growth factor activity. We then discuss in detail the different heparin-based biomaterials designed to sustain the release of growth factors for bone tissue engineering, including the heparin-polycation coacervate system; heparin-based supramolecules; and heparin-based hydrogels, nanoparticles, and microspheres for sustained release of bone morphogenic proteins and other growth factors for bone tissue engineering. Finally, we assess the clinical and translational relevance of heparin-based systems, identify key challenges, and outline future perspectives, highlighting the potential of these biomaterials for providing safer and more effective therapies for bone regeneration.
Background:Although the posterior tibial slope (PTS) has been identified as a key factor influencing anterior cruciate ligament (ACL) graft biomechanics and clinical outcomes, little is known regarding which plateau has the greater effect on mechanics of the ACL-reconstructed knee. There are differences in slopes of the medial and lateral tibial plateaus, but this difference has yet to be biomechanically investigated in an ACL-reconstructed setting. Purpose:To investigate the individual effects of medial and lateral PTS differential modifications on ACL graft force, anterior tibial translation (ATT), and internal tibial rotation in a cadaveric model. Study Design:Controlled laboratory study. Methods:Twelve fresh-frozen human cadaveric knees (mean age, 61.6 years) were tested. Native PTS was measured using computed tomography. ACL reconstruction was performed, followed by individual anterior closing-wedge osteotomies of the medial and lateral compartments to achieve a 0° slope. Each compartment was then adjusted in 5° increments with 3-dimensional printed wedges and secured with an external fixator. Biomechanical testing consisted of a 500-N axial load and a 1-N⋅m axial torque across 8 medial-lateral PTS states: native/native, 5°/10°, 5°/5°, 10°/5°, 10°/10°, 10°/15°, 15°/15°, and 15°/10°. ACL graft force, ATT, and internal tibial rotation at full extension were recorded. Linear mixed modeling was used to evaluate the effect of medial and lateral slopes on the outcome variables. Results:The lateral tibial slope contribution had a greater effect on ACL graft force and ATT than the medial tibial slope contribution. Each 1° increase in lateral slope was associated with a 4.9-N (11.1%) increase in graft force and a 0.63-mm (25.2%) increase in ATT (P < .001). Each 1° increase in medial slope was associated with a 1.9-N (4.3%) increase in graft force and a 0.48-mm (19.2%) increase in ATT (P < .001). Internal tibial rotation was not significantly affected by either lateral or medial PTS. Conclusion:Although both slopes significantly affected ACL graft force and ATT, lateral PTS had a greater effect on ACL graft force and ATT compared with the medial PTS and may warrant primary consideration for a slope-correcting osteotomy. Clinical Relevance:While correction of both medial and lateral slopes is important, the lateral PTS contributes more significantly to ACL graft forces and ATT.
Background: The patient-specific instrumentation (PSI) used during corrective high tibial osteotomies and distal femoral osteotomies is based on 3-dimensional computed tomography (3D CT). Plain radiographs are typically used preoperatively to determine the need for an osteotomy; however, it is unclear how well measurements on plain radiographs correlate with 3D CT.Purpose/Hypothesis: The purpose of this study was to evaluate the correlation between coronal and sagittal alignment measurements on plain radiographs and 3D CT. It was hypothesized that there would be high agreement in the measurement of the mechanical medial tibial width ratio (mMTWr) and the medial posterior tibial slope (PTS) between both modalities.Study Design: Cohort study (diagnosis); Level of evidence, 3.Methods: Patients who underwent hip-to-ankle CT as part of the preoperative workup before a corrective osteotomy from October 2020 to November 2023 were reviewed. Coronal (mMTWr) and sagittal alignment (medial PTS) were evaluated preoperatively by 2 raters on standing whole-leg radiographs and a lateral radiograph of the knee, respectively, and by semi-automated PSI software on 3D CT. Intraclass correlation coefficients (ICC) were calculated to assess interrater reliability for each measurement and to evaluate agreement between raters and the PSI software.Results: Complete data sets were obtained for 91 cases. The ICC between raters for preoperative mMTWR was 0.99. The ICC between the raters' measurements and the PSI software measurements of mMTWr was 0.99. The ICC between raters for preoperative PTS was 0.82. The ICC between the raters' measurements and the PSI software's PTS measurements was 0.63.Conclusion: This study found that coronal measurements performed on whole-leg radiographs and 3D CT were highly correlated, with near-perfect agreement, and that medial PTS measurements showed moderate agreement between modalities. These data suggest that measurements on plain radiographs are reproducible and accurate for evaluating coronal alignment and PTS preoperatively. Surgeons can confidently use plain radiographs to assess whether or not a patient is a candidate for a knee osteotomy.
Abstract Purpose To establish updated international consensus statements on reverse total shoulder arthroplasty, revision surgery, and rehabilitation, return to play, and follow‐up for rotator cuff tears, reflecting new evidence, evolving techniques, and ongoing areas of controversy. Methods A consensus process on the treatment of rotator cuff tears was conducted, with 97 shoulder/sports surgeons from 15 countries participating. There were 9 specific subtopics (1) Diagnosis, (2) Nonoperative Management, (3) Repair of Posterosuperior Tears, (4) Subscapularis Repair, (5) Graft/Patch Augmentation and Superior Capsular Reconstruction, (6) Tendon Transfers, (7) Reverse Total Shoulder Arthroplasty, (8) Revision Surgery, and (9) Rehabilitation, Return to Play, and Follow‐up. Consensus was defined as achieving 80% to 89% agreement, whereas strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. Results Of the 47 consensus statements, 1 achieved unanimous consensus, 33 achieved strong consensus, 10 achieved consensus, and 3 did not achieve any level of consensus. Conclusions There was consensus that reverse shoulder arthroplasty is indicated for patients with irreparable tears, pseudoparalysis, or failed prior repairs with pain and dysfunction, whereas contraindications include inadequate deltoid or axillary nerve function and active infection. In the revision setting, consensus supported a structured approach emphasizing careful assessment of tissue quality, bone stock, stiffness, and expectations, with agreement on the prognostic relevance of prior surgeries in determining the optimal reconstructive strategy. For rehabilitation and return to play, the panel agreed that no universal timeline exists; instead, clearance should be based on restoration of strength, range of motion, proprioception, pain resolution, and psychological readiness. There was variability in recommended follow‐up schedules and the role of routine imaging, with no agreement on the ideal surveillance protocol. Level of Evidence Level V, expert opinion.
