Journal of Experimental Orthopaedics最新文献

Purpose

To develop a machine learning model capable of predicting the bony risk of non-contact anterior cruciate ligament injury, thereby enabling the identification of factors that contribute to such injuries.

Methods

Data were collected from 400 cases of non-contact ACL-injured and 200 ACL-intact control subjects using Computed Tomography between March 2022 and June 2025. Thirteen features, encompassing demographic, clinical, and radiomic data, as well as six different algorithms, were utilised to develop predictive machine learning models. Shapley Additive Explanations (SHAP) analysis was subsequently performed on the optimal model.

Results

The Maximum 2D Diameter Column values for the non-contact ACL injury group and the intact ACL group were 31.12 ± 2.92 mm (95% confidence interval [CI]: 30.83–31.40, p < 0.05) and 32.37 ± 3.07 mm (95% CI: 31.94–32.80, p < 0.05). The Extreme Gradient Boosting classifier was identified as the optimal predictive model, achieving an area under the precision–recall curve of 0.94, the highest among all models evaluated. SHAP analysis revealed that the most predictive feature was the Maximum 2D Diameter Column of the notch, defined as the largest pairwise Euclidean distance between tumour surface mesh vertices in the row-slice plane, followed by the lateral and medial posterior tibial slope.

Conclusion

The machine learning model developed in this study demonstrated excellent predictive performance for non-contact ACL injuries. The Maximum 2D Diameter Column was the most important predictor, followed by the lateral and medial posterior tibial slope.

Level of Evidence

Level III.

Purpose

To provide a comprehensive overview of the surgical techniques for medial patellofemoral ligament (MPFL) reconstruction, with a focus on their technical aspects, indications and the advantages and disadvantages of each approach. These techniques vary significantly based on patient-specific factors, such as skeletal maturity and anatomical complexity.

Methods

A systematic review of PubMed, Scopus and Embase databases was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify studies on MPFL reconstruction techniques published within the last 20 years. Studies focusing on technical descriptions of surgical methods were included, while those lacking sufficient detail or reporting only clinical outcomes were excluded. A total of 45 studies met the inclusion criteria and were analysed.

Results

Autografts, particularly semitendinosus and gracilis tendons, were the most commonly utilized, while allografts and synthetic grafts were less frequently reported. Femoral fixation methods predominantly included interference screws, whereas patellar fixation methods were evenly distributed between bony tunnels and anchors. Dynamic and quasi-anatomic techniques were commonly employed in patients with open physes to prevent damage to growth plates. Intraoperative fluoroscopy was frequently used to ensure accurate graft placement in anatomical techniques. Open surgical approaches were the most commonly reported, with minimally invasive and arthroscopic methods being less prevalent.

Conclusions

MPFL reconstruction techniques exhibit considerable variability in graft selection, fixation methods and surgical approaches. Anatomical-static techniques provide excellent biomechanical stability but may not be suitable for skeletally immature patients. In contrast, quasi-anatomical and dynamic techniques offer greater flexibility and are particularly advantageous for paediatric populations, though they may compromise long-term stability. Standardized protocols and further research are needed to optimize outcomes, particularly in complex patient scenarios.

Level of Evidence

Level III, systematic review.

Purpose

Chronic patellofemoral instability (PFI) and pain are influenced by axial malalignment of the patellofemoral joint. Tibiofemoral rotation, defined as the rotation between femur and tibia knee, has shown to be correlated to PFI. This study aimed to determine whether tibiofemoral rotation is associated with anatomical risk factors for patellofemoral maltracking in patients with PFI. It was hypothesised that greater tibiofemoral rotation correlates with other predisposing factors for PFI.

Methods

Eighty-five consecutive patients (mean age 22.6 ± 8.9 years; 58 female) with PFI underwent standardised bilateral knee MRI in 0° extension for rotational analysis. Tibiofemoral rotation was measured as the angle between the posterior femoral condylar tangent and posterior tibial plateau tangent on axial images. Ipsilateral and contralateral values along other anatomical patellofemoral risk factors were recorded. One-sample t-tests compared to the healthy contralateral side. Pearson correlations assessed associations between tibiofemoral rotation and anatomic risk factors for patellofemoral maltracking.

Results

Mean ipsilateral tibiofemoral rotation was 6.9° ± 6.0° (range: −6.5° to 21.6°). Contralateral version averaged 6.4° ± 6.2° with no significant side difference. Absolute side-to-side difference was 3.7° ± 2.7°. Ipsilateral tibiofemoral rotation correlated with the tuberositas tibiae–trochlea groove (TT–TG) and medial posterior cruciate ligament distance (TT–PCL) (r = 0.37, p < 0.001, r = 0.43, p < 0.001), femoral torsion (r = −0.32, p = 0.003) and lateral trochlea inclination (r = −0.344, p = 0.001) whereas other patellofemoral risk factors showed no correlation.

Conclusion

Tibiofemoral rotation showed a significant correlation with anatomical risk factors associated with lateral patellar maltracking in patients with PFI. Moreover, patients with PFI demonstrated a wide variability in tibiofemoral rotation. Consideration of tibiofemoral rotation may enhance anatomical assessment and aid clinical decision-making in patients with PFI.

Level of Evidence

Level III.

Purpose

The uncemented posterior-stabilized total knee arthroplasty (PS-TKA) gained increasing acceptance as younger and active patients have higher requirements for the lifespan and functionality of prostheses, because their frequent gait and deep-flexion activities may amplify tibial implant–bone interface micromotion and increase the risk of early tibial loosening. The purpose of this study is to evaluate the biomechanical fixation effects of three different tibial tray backside designs, with the aim of informing surgeons in selecting the most appropriate fixation strategy for uncemented PS-TKA.

Methods

The finite element and micromotion models were developed to quantify the tibial von Mises stress and interface micromotion under the knee loading conditions. The effects of three common tibial tray backside designs, including a cylindrical stem with a triple flat keel (CS-TFK), a tapered stem with a double flat keel (TS-DFK) and a cylindrical stem with a double serrated keel (CS-DSK), on stress transfer and interface micromotion were compared.

Results

During walking, all designs exhibited similar stress and micromotion patterns, with minimal risk for prostheses instability. During squatting, the cylindrical stem with double serrated keel design exhibited the highest proximal tibial stress (124.03 MPa) and the lowest maximum micromotion (361.91 µm), resulting in the largest area suitable for bone ingrowth (42.53%). In contrast, the tapered stem with double flat keel design had the lowest stress (90.70 MPa), and its area at risk for poor osseointegration (micromotion >150 µm) increased by 44.70% compared with the cylindrical stem with double serrates keel design.

Discussion

The tibial tray backside design influenced its primary fixation. Among the evaluated designs, the CS-DSK balanced stress transfer and interface micromotion, suggesting it may be favored for uncemented PS-TKA in younger, active patients to lower the likelihood of early tibial aseptic loosening. CS-DSK favored early ingrowth but produced higher local stresses, so overload risk should be monitored in older patients with osteoporosis.

Level of Evidence

N/A.

Purpose

Kinesophobia is an important psychosocial construct to consider in rehabilitation of patients with patellar instability, in order to optimise their rehabilitation and ability to return to sport and an active lifestyle. Therefore, it is important to investigate the percentage of patients with kinesophobia before and 6 months after patella stabilising surgery. In addition to how it affects knee function and quality of life 6 months postoperatively.

Methods

A prospective cohort of 76 patients (mean age 22.8 years, 74% female) with patellar instability was included. Patients completed patient reported outcome measures (PROMs), including the Tampa scale of kinesophobia (TSK)-13, International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and Banff Patellofemoral Instability Instrument (BPII), preoperatively and 6 months postoperatively. Those with concomitant knee ligament injuries were excluded. Statistical analyses included paired sample t-tests for score changes and Pearson's correlation for associations between variables.

Results

Preoperative kinesophobia was reported in 47% of patients, decreasing to 18% at 6 months postsurgery. Significant improvements were noted in all PROMs, with the BPII showing the largest increase. Patients with preoperative kinesophobia reported worse knee function postoperatively. A strong negative correlation was found between changes in TSK-13 and BPII scores (r = −0.605), indicating that reductions in kinesophobia were associated with improvements in quality of life. In multiple regression analyse only preoperative TSK scores remained an independent significant 138 predictor of postoperative kinesophobia, with a shared explained variance of 16%.

Conclusion

This study highlights the prevalence of kinesophobia in patients undergoing surgery for patellar instability and its effect on postoperative outcomes. While surgery restored mechanical stability, many patients continued to exhibit kinesophobia after surgery.

Level of Evidence

Level III.

Purpose

To compare the thickness and magnetic resonance imaging (MRI) signal intensity at the patellar attachment of the quadriceps tendon (QT) and patellar tendon (PT) across age groups in order to evaluate age-related degenerative changes relevant to graft selection for anterior cruciate ligament (ACL) reconstruction. It was hypothesised that older groups would show increased signal intensity.

Methods

Patients aged 14–65 years who underwent knee MRI were retrospectively reviewed. Participants were categorised into the senior (50–65 years), middle (30–49 years), young (20–29 years) and teen (14–19 years) groups. After propensity score matching for sex, height and weight, 64 participants were included in each age group. T2* sagittal MR images of the ACL graft harvest area were used to measure the tendon thickness and signal intensity.

Results

QT was significantly thicker and had lower signal intensity than PT across all age groups. Thickness did not significantly differ between QT and PT across age groups. QT signal intensity was significantly higher in seniors than in young adults, whereas PT signal intensity was significantly higher in both middle-aged and senior groups than in the young group.

Conclusions

The QT was thicker than the PT and exhibited a lower signal intensity across all age groups. Compared to the 20–29-year age group, signal intensity was higher in the 50–65-year age group for the QT and in the 30–65-year age group for the PT. These MRI-based findings suggest that the QT may offer advantages as a graft source, particularly in patients aged >30 years.

Level of Evidence

Level III, cross-sectional study.

Purpose

To map the scientific literature on the use of dynamic ultrasound in the assessment of medial knee instability.

Methods

Primary (clinical or experimental) and secondary studies that used dynamic ultrasound to assess medial knee opening were included. There were no restrictions on language or date. Sources of information: The searches were conducted in the PubMed/MEDLINE, Scopus, Web of Science, Embase and CINAHL databases.

Data selection and extraction

The process of data selection and extraction was conducted by two independent reviewers. The information was organised into thematic tables and a conceptual matrix was developed based on the components of population, concept, and context.

Results

Ten studies were included: two biomechanical, six clinical, and two reviews. Ultrasound demonstrated good reliability in measuring medial opening and distinguishing between injured and normal knees. Heterogeneity was observed in the stress protocols, evaluation angles, units of measurement, and anatomical points.

Conclusions

Dynamic ultrasound presents consolidated clinical potential in the assessment of medial knee instability. Standardisation of methods and additional clinical validation are necessary.

Level of Evidence

Not applicable.

Purpose

To investigate the incidence and management of complications associated with all-inside technique (AIT) anterior cruciate ligament reconstruction (ACLR), and to compare postoperative outcomes between patients with successfully managed complications and complication-free controls.

Methods

A retrospective analysis was conducted on patients undergoing AIT-ACLR. AIT-related complications were documented, with a minimum 24-month follow-up. Propensity score matching (PSM, 1:2 ratio) was used to compare the complication and non-complication groups. Knee function was assessed using the Lysholm Knee Score, International Knee Documentation Committee Subjective Score, and Tegner Activity Scale. Stability was measured with the Ligs Digital Arthrometer.

Results

A total of 274 patients were included, with 45 patients (16.4%) experiencing AIT-related complications. Complications comprised tibial lateral subluxation (21 cases, 7.7%; mean displacement: 2.3 mm, range 2.0–2.5 mm), which resolved spontaneously in 4 patients (19.1%) by 1 month postoperatively and in the remaining cases by 3 months. Femoral suspensory button malposition occurred in 12 patients (4.4%), with only one case (8.3%) requiring immediate revision due to a 7.6 mm displacement. The others (mean displacement: 2.5 mm, range 2.1–3.0 mm) were managed conservatively. Cortical breach at the tibial tunnel exit (7 cases, 2.6%) and flip drill bit breakage (5 cases, 1.8%) were addressed intraoperatively. Following PSM (complication group: n = 45 vs. non-complication group: n = 87), baseline demographics demonstrated no significant differences except for operative time (p = 0.035). There were no statistically significant differences in knee function and stability between the matched groups at 3, 6, 12, and 24 months postoperatively (p > 0.05 for all).

Conclusion

Postoperative knee function and stability demonstrated improvement following AIT-ACLR. Although appropriately managed complications did not substantially compromise clinical outcomes, the findings emphasize the importance of technical vigilance, intraoperative complication management, and preventive strategies to optimize surgical outcomes.

Level of Evidence

Level III, case-control study.

Femoral and/or tibial torsional abnormalities are highly prevalent in female patients with anterior knee pain (AKP) who are recalcitrant to appropriate conservative treatment. In this paper, we focus on increased internal femoral torsion, which sometimes is an under-recognised factor contributing to AKP. Two experts in patellofemoral pathology participated in conducting a review on the rationale and outcomes of rotational femoral osteotomy in female AKP patients and femoral maltorsion. Pathological femoral anteversion (FAV) is recognised as a cause of anterior knee pain. FAV is a problem because it changes the direction of the quadriceps and thereby the force acting on the patellofemoral joint. One of the key challenges in planning a rotational osteotomy is determining the precise degree of correction required. Murphy´s CT method is the closest to showing the anatomical reality when FAV is evaluated. Currently, there is no universally accepted cut-off point at which rotational femoral osteotomy should be performed. Moreover, limited evidence exists regarding the optimal level at which the osteotomy must be done. In appropriately selected cases, intertrochanteric rotational femoral osteotomy represents a reliable treatment option for symptomatic excessive FAV, offering favourable outcomes with minimal complications.

Level of Evidence

Level V.

Purpose

To develop and characterise a modification of the preparation protocol of a commercial leucocyte-rich platelet-rich plasma (LR-PRP) preparation device (the GPS® III Platelet Concentration System, Biomet, USA) that allows for consistent leucocyte-poor platelet-rich plasma (LP-PRP) extraction using the same components.

Methods

The study included two stages. In the first, the blood of eight healthy adults was processed using the GPS® III Platelet Concentration System (Biomet, USA). Samples were obtained to characterise platelet and leucocyte distribution in the system during the procedure per the manufacturer′s guidelines. In the second, based on the initial results, the standard preparation protocol that yields LR-PRP was modified to establish a new protocol for obtaining LP-PRP. To conclude, the newly proposed procedure was validated in 20 individuals, using both the traditional and modified protocols simultaneously.

Results

The characterisation of the commercial system suggested a specific distribution of blood components within the device: most leucocytes were found in the plasma collected through side port #3 (red cap) without waving or shaking the tube, whereas platelets in the sediment between the buoys were released when the tube was waved or shaken. When comparing to the standard protocol, the modified technique consistently yielded significantly lower platelet (MD −205 ×10³ platelets/µL, 95% confidence interval [CI], 92.1–317 ×10³ platelets/µL, <0.0001) and leucocyte concentrations (MD −19.0 ×10³ leucocytes/µL, 95% CI, 14.1–23.9 ×10³ leucocytes/µL, p < 0.0001) but the obtained LP-PRP had only 18.1% lower platelet concentration (95% CI, 6.71%–29.4%, p < 0.0001) and a relevant 75.3% lower leucocyte concentration (95% CI, 69.6%–81%, p < 0.0001).

Conclusions

The proposed modified PRP extraction protocol greatly reduced leucocyte concentrations with a minimal reduction in the platelet concentrations, enabling LP-PRP preparation with the same commercial device without the need for additional supplies.

Level of Evidence

Level III.