J Bone Joint Surg Am. 2025 Dec 10. doi: 10.2106/JBJS.25.00641. Online ahead of print.

ABSTRACT

BACKGROUND: Anterior cruciate ligament (ACL) injuries may lead to long-term neuromuscular and structural adaptations in thigh muscles. Although quadriceps dysfunction is well reported, chronic changes in other muscle groups, especially in nonoperatively managed ACL-deficient individuals, remain poorly understood.

METHODS: The present cohort study utilized Osteoarthritis Initiative data to assess longitudinal thigh muscle changes in individuals with ACL tears confirmed on magnetic resonance imaging (MRI) and no history of reconstruction. A validated deep-learning model segmented muscle cross-sectional area and quantified intra-muscular adipose tissue and contractile percentage. Quantitative MRI data were obtained at baseline and at 4-year follow-up. Propensity score matching (1:2 to 1:3) controlled for baseline covariates. Strength was assessed with use of standardized Osteoarthritis Initiative protocols. Linear mixed-effects models compared longitudinal changes between ACL-deficient and ACL-intact thighs.

RESULTS: A total of 1,207 thighs were analyzed, including 92 with ACL tears and 1,115 controls, with a mean patient age of 61 ± 9 years. Over 4 years, ACL-deficient thighs exhibited progressive hamstring atrophy (-28.18 mm2/year; 95% confidence interval, -42.43 to -13.92; p < 0.001) and sartorius atrophy (-3.02 mm2/year; 95% confidence interval, -5.15 to -0.89; p = 0.006). No significant differences were observed in quadriceps or adductor cross-sectional area. Hamstring force decreased significantly (-3.49 N/year; 95% confidence interval, -6.62 to -0.36; p = 0.029), whereas quadriceps force and specific force showed no significant changes. Intra-muscular adipose tissue and contractile percentage did not significantly differ between groups. Findings had been similar in unmatched patients.

CONCLUSIONS: The present findings highlight selective muscle deterioration in the posterior thigh muscles following ACL injury, with minimal changes in quadriceps morphology, over time. These results underscore the importance of long-term, targeted rehabilitation strategies focusing on hamstring preservation. This study represents the first longitudinal matched-cohort analysis of muscle morphology and fat infiltration in unreconstructed ACL-deficient knees.

LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

PMID:41370366 | DOI:10.2106/JBJS.25.00641

J Bone Joint Surg Am. 2025 Dec 10. doi: 10.2106/JBJS.25.00797. Online ahead of print.

ABSTRACT

Hospital technology approval remains a formidable barrier to the adoption of surgical innovations. Despite compelling clinical evidence, technology requests frequently face rejection based on flawed economic models that emphasize the pricing of incumbent technology and time savings in the operating room over genuine value creation. This article provides a strategic framework for winning hospital approval by applying Economic Value to the Customer (EVC) principles and strategies to address managerial agency problems. This approach transforms technology evaluation from frustrating cost-focused rejection to value-centric approval that benefits surgeons and patients seeking access to innovation and vendors requiring market penetration.

PMID:41370365 | DOI:10.2106/JBJS.25.00797

J Bone Joint Surg Am. 2025 Dec 9. doi: 10.2106/JBJS.24.01377. Online ahead of print.

ABSTRACT

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

PMID:41364773 | DOI:10.2106/JBJS.24.01377

J Bone Joint Surg Am. 2025 Dec 9. doi: 10.2106/JBJS.25.00485. Online ahead of print.

ABSTRACT

BACKGROUND: The goals of this study were to develop an artificial intelligence (AI)-driven automated preoperative planning system for anterior cruciate ligament (ACL) reconstruction by integrating deep learning with computed tomography (CT)-magnetic resonance imaging (MRI) image fusion and segmentation, and to evaluate its accuracy.

METHODS: Structures on CT and MRI scans of 200 knee joints from patients with an intact ACL (aged 18 to 50 years, 81.0% male, all ethnic Chinese) were manually annotated. Fusion of the CT and MRI images was performed using a Dual-UNet registration architecture incorporating multiscale information fusion, enabling dynamic 3D reconstruction of the fused images for ACL insertion site identification and isometry assessment. A deep-learning framework was trained to analyze the fused image to precisely optimize ACL tunnel positioning, including identifying the entrances and exits of the femoral and tibial tunnels. Criteria in the automated planning included proximity to the ideal point, coverage of the anatomical footprint area, and isometric length variation of <2 mm. The accuracy of the AI system was then validated in 36 ACL reconstructions performed in bone models by comparing the drilled femoral and tibial tunnel lengths and graft length between the tunnels with the planned values. Finally, clinical feasibility was tested in 36 patients undergoing ACL reconstruction surgery using 3D-printed patient-specific guides derived from the AI planning, with 36 conventional surgeries as controls. Deviation of tunnel positions from the planned positions was compared between the 2 groups.

RESULTS: CT-MRI image fusion was able to generate an individualized 3D model with high segmentation accuracy (Dice coefficient = 0.864). The AI planning required 192 ± 90.2 seconds per case. In the bone model validation, the mean deviation between the planned and executed values was <1 mm for the femoral and tibial tunnel lengths and graft length between the tunnels (all p > 0.05). In the clinical testing, the AI-guided group demonstrated significantly smaller deviations from the ideal point compared with the conventional group in the deep-to-shallow (D-S), high-to-low (H-L), medial-to-lateral (M-L), and anterior-to-posterior (A-P) directions (all p < 0.05).

CONCLUSIONS: The AI-driven segmentation of CT-MRI fusion images and automatic preoperative ACL reconstruction planning demonstrated the capability to automatically, precisely, and reproducibly generate plans for nearly ideal tunnel entry and exit points with isometric, anatomical, and individualization characteristics. This technology is expected to hold clinical potential for ACL reconstruction, including reduced complication and revision rates and enhanced postoperative function.

PMID:41364772 | DOI:10.2106/JBJS.25.00485

J Bone Joint Surg Am. 2025 Dec 9. doi: 10.2106/JBJS.25.00907. Online ahead of print.

ABSTRACT

BACKGROUND: Lateral extra-articular tenodesis (LET) is increasingly used to augment anterior cruciate ligament reconstruction (ACLR), particularly in patients with high-grade rotatory instability. Despite demonstrated biomechanical advantages, the long-term effect of LET on posttraumatic osteoarthritis (OA) remains unclear.

METHODS: We hypothesized that adding LET to ACLR reduces development of long-term moderate-to-severe radiographic OA, particularly after meniscectomy. We performed a PRISMA-compliant systematic review and meta-analysis, which was registered with PROSPERO. PubMed, Cochrane CENTRAL, and Scopus were searched through March 2025. Eligible randomized controlled trials (RCTs) or comparative cohort studies reported radiographic moderate-to-severe OA after ACLR with versus without LET, with a minimum follow-up of 5 years. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS: Six studies with 444 patients (mean follow-up, 13.1 years) were included. LET was associated with a significant reduction in moderate-to-severe OA in the lateral compartment. Subgroup analysis showed a significant reduction in lateral OA as measured using both the Kellgren-Lawrence (K-L) (OR, 2.87; 95% CI, 1.2 to 6.9; p = 0.02) and International Knee Documentation Committee (IKDC) classifications (OR, 4.38; 95% CI, 1.5 to 12.7; p = 0.01). In contrast, no significant difference was found in the medial compartment for either the K-L (OR, 1.26; 95% CI, 0.7 to 2.4; p = 0.49) or IKDC classification (OR, 2.06; 95% CI, 0.6 to 6.8; p = 0.24). In meniscectomized knees, LET significantly reduced OA risk, especially as measured with the IKDC (OR, 6.14; 95% CI, 1.7 to 22.6; p = 0.01) compared with the K-L classification (OR, 3.61; 95% CI, 1.1 to 12.3; p = 0.04). In contrast, although LET also reduced OA risk in non-meniscectomized knees, the difference was not significant. Compartment-specific OA data were unavailable within the meniscal subgroups.

CONCLUSIONS: This meta-analysis, the first to assess the long-term effect of LET on OA, indicated that LET significantly reduces moderate-to-severe OA risk, particularly in the lateral compartment and among meniscectomized knees. Findings support selective LET use during ACL reconstruction, especially in cases with compromised meniscal integrity, to help mitigate OA progression.

LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

PMID:41364753 | DOI:10.2106/JBJS.25.00907

J Bone Joint Surg Am. 2025 Dec 9. doi: 10.2106/JBJS.25.00499. Online ahead of print.

NO ABSTRACT

PMID:41364752 | DOI:10.2106/JBJS.25.00499

J Bone Joint Surg Am. 2025 Dec 9. doi: 10.2106/JBJS.25.00536. Online ahead of print.

ABSTRACT

BACKGROUND: The effect of tourniquet use on cement penetration in primary total knee arthroplasty (TKA) remains controversial. Current assessments rely primarily on radiograph-based 2D measurements, which limit the precision and comprehensiveness of analysis. Therefore, this study investigated the effect of tourniquet use on 3D cement penetration and the association of tourniquet use with mid-term implant stability.

METHODS: In this prospective randomized controlled trial, 141 Han Chinese (East Asian) patients (mean age, 68.3 years; 85% female) were allocated to 1 of 3 groups: tourniquet (Group A), no tourniquet (Group B), and tourniquet during cementation only (Group C). The primary outcomes were 3D cement penetration (thickness, volume, surface area) and mid-term implant stability assessed on the basis of radiolucent lines (RLLs) and survivorship. Cement penetration metrics across femoral and tibial components were systematically quantified through 3D morphological analysis of metal artifact reduction-computed tomography (MAR-CT) images reconstructed using Avizo software (Thermo Fisher Scientific). Secondary outcomes included blood loss, inflammatory and muscle-injury biomarkers, pain scores, functional scores, postoperative length of stay, and complication rates.

RESULTS: All participants were followed for 5 years. No significant intergroup differences in cement penetration (thickness, volume, surface area) around the tibial (p = 0.847, p = 0.473, and p = 0.395, respectively) and femoral (p = 0.203, 0.201, 0.399) components were observed. Cement thickness correlated with preoperative knee deformity but not with implant size. Additionally, Group B demonstrated superior clinical outcomes versus Groups A and C: lower levels of inflammatory and muscle-injury biomarkers, lower early pain scores, and a shorter hospital stay, with enhanced 3-month knee function demonstrated in Groups B and C versus Group A. Total blood loss, mid-term outcomes, and complication rates were comparable. No RLLs or revisions were observed, and the 5-year implant survival rate was 100%.

CONCLUSIONS: Tourniquet use showed no significant effect on cement penetration and mid-term implant stability in primary TKA, and omitting intraoperative tourniquet use was associated with better early postoperative functional recovery in patients undergoing TKA.

LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

PMID:41364748 | DOI:10.2106/JBJS.25.00536