Journal of Experimental Orthopaedics最新文献

Purpose: To evaluate whether a high lateral distal femoral angle (LDFA) contributes to undercorrection of lower-limb alignment following medial open wedge high tibial osteotomy (MOWHTO), and to determine the LDFA threshold above which tibial correction alone may be insufficient.

Methods: This retrospective study analysed 68 patients who underwent MOWHTO at our hospital between 2020 and 2022. Based on their postoperative mechanical axis (MA), patients were categorised into two groups: the acceptable correction group (A-group; MA 57%-67%) and the undercorrection group (U-group; MA ≤ 56%). Radiographic parameters before and after surgery were compared between the two groups. Simple and multiple regression analyses were used to identify factors affecting postoperative MA. A receiver operating characteristic (ROC) curve was utilised to identify the LDFA cut-off value associated with undercorrection.

Results: A total of 54 patients met the inclusion criteria (A-group, n = 35; U-group, n = 19). The U-group demonstrated a significantly higher preoperative mechanical LDFA (89.5° vs. 87.6°, p = 0.001) and a lower medial proximal tibial angle (mMPTA) (84° vs. 86°, p = 0.014) than that in the A-group. Both mLDFA (p = 0.006) and mMPTA (p = 0.010) were independent predictors of postoperative MA in multiple regression analysis. The ROC analysis identified an LDFA cut-off of 89.2° for predicting undercorrection (area under the curve = 0.78; sensitivity, 36.8%; specificity, 88.6%). Patients with an LDFA ≥ 89.2° had significantly higher body mass index, joint line convergence angle, varus stress angle, percentage condylar tibial translation and preoperative knee joint line obliquity.

Conclusions: A high LDFA (≥89.2°) is associated with an increased risk of undercorrection after MOWHTO, despite accurate tibial correction. These findings suggest that in cases with significant distal femoral varus, isolated tibial osteotomy may be insufficient. Double-level osteotomy, including femoral correction, should be considered in such cases to achieve optimal alignment.

Level of evidence: Level Ⅳ, retrospective comparative study.

Purpose: The primary aim was to study the impact of joint line obliquity (JLO) on clinical outcomes and survivorship in patients undergoing total knee arthroplasty (TKA) after a previous high tibial osteotomy (HTO). The secondary aim was to study how maintaining neutral JLO at both HTO and TKA affected clinical outcomes of TKA.

Methods: A retrospective review of patients undergoing TKA following valgus-producing HTO, having a minimum 1-year follow-up, was performed. Using the coronal plane alignment of the knee (CPAK) classification, three groups of JLO were formed: distal JLO (<177°), neutral JLO (177-183°) and proximal JLO (>183°). Clinical outcomes were assessed using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The level of significance was 0.05.

Results: The study included 110 TKA (mean follow-up: 5.8 years). Prevalence of a proximal JLO post-TKA was higher (p < 0.05) in those with a proximal JLO pre-TKA (40%) as compared to those with a neutral JLO pre-TKA (13%). The odds ratio of having a proximal JLO post-TKA was 4 (95% confidence interval: 1.4-11.1, p < 0.05) in those having a proximal JLO pre-TKA. Revision rate in the proximal JLO post-TKA, neutral JLO post-TKA and distal JLO post-TKA groups was 20%, 8% and 4% respectively, with no statistical difference (p > 0.05). Post-TKA, the stiffness, function and total WOMAC were significantly better (p < 0.05) in patients with a neutral JLO pre-TKA and neutral JLO post-TKA as compared to those with a proximal JLO pre-TKA and proximal JLO post-TKA or a proximal JLO pre-TKA and neutral JLO post-TKA.

Conclusion: While a proximal JLO after conversion TKA did not show a statistically higher revision rate, maintaining a neutral JLO during HTO and at the time of subsequent TKA was associated with higher post-operative clinical scores. However, further research in different and larger populations is needed to confirm these findings.

Level of evidence: Level IV.

Purpose: To assess the mid- to long-term clinical and functional outcomes and return to sports following derotational distal femoral osteotomy (DDFO) for the treatment of recurrent patellofemoral instability and associated increased femoral antetorsion.

Methods: Patients who underwent DDFO as well as concomitant procedures between 2007 and 2016 were eligible for inclusion. Recurrent instability, complications, revision surgery and return to sports rates were evaluated after a minimum follow-up of 5 years. Kaplan-Meier survival analysis was performed for the risk of recurrent instability or undergoing further surgery other than hardware removal. Patient-reported outcome measures (PROMs; Visual Analog Scale [VAS] for pain, Tegner Activity Scale [TAS], Kujala score, Banff Patellofemoral Instability Instrument [BPII] 2.0 and Patellofemoral Instability-Return to Sport after Injury [PFI-RSI] scale) were recorded.

Results: Of 44 knees in 42 patients eligible for inclusion, 25 knees in 24 patients (64% female) with a mean age of 27.3 ± 9.0 years at the time of surgery were available for follow-up at a mean of 8.7 ± 2.7 years (follow-up: 57%). Two patients (5%) underwent early revision surgery due to loss of osteosynthesis at the distal femur. Three patients (12%) reported subjective recurrent instability at a median of 3.9 (3.5-7.0) years post-operatively. The Kaplan-Meier estimator showed a survival probability free of recurrent instability and revision (except hardware removal) of 87% (95%-confidence interval 76%-100%) at 5 years. At final follow-up, patients reported good knee function (Kujala score: 78.5 ± 16.6), knee-related quality of life (BPII: 68.3 ± 22.3), psychological readiness to return to sport (PFI-RSI: 73.3 [43.8-90.0]), and moderate activity levels (TAS: 4.0 [3.0-4.0]). The majority of patients returned to sports (84%).

Conclusion: DDFO provided effective treatment for recurrent patellofemoral instability associated with increased femoral antetorsion. Favourable clinical and functional outcomes as well as high return to sport rates were observed at a mid- to long-term follow-up.

Level of evidence: Level IV, retrospective case series.

Purpose: This study introduces the posterior tibial plateau offset (PTO). It was hypothesised that (1) the PTO is reliably quantifiable and (2) correlates with the posterior tibial slope (PTS).

Methods: The study involved lateral radiographs of patients who sustained an anterior cruciate ligament (ACL) graft failure and a control group. Exclusion criteria were skeletal immaturity, osteoarthritis (Kellgren and Lawrence grade > I), lateral radiographs with <15 cm of tibial shaft, or malrotated radiographs. The PTS was measured in both groups. The PTO was defined as the relative distance from the posterior tibial plateau to the tibial shaft axis in relation to the sagittal diameter of the tibial plateau (in%). Linear correlation assessed the PTS to PTO association.

Results: A total of 146 patients (ACL graft failure, n = 103; control group, n = 43; 45% female, 60% left knees) were included. Mean overall PTO was 82% ± 7% (1%-35%), and mean PTS was 12° ± 3 (7-20). The PTS and PTO showed a moderate positive correlation in the overall collective (r = 0.5; p < 0.001), ACL graft failure group (r = 0.49; p < 0.001), and control group (r = 0.69; p < 0.001), indicating a higher slope corresponded to a greater PTO. There was no statistical difference in PTO between the ACL failure and the control group (82% vs. 83%, p < 0.05). ICC between three raters was (0.8-0.9; p < 0.05).

Conclusion: The PTO is a simple and repeatable measurement. A higher PTS is associated with a greater PTO, and the variability of the PTO across the patients with ACL graft failure and the control group was high. When planning osteotomy levels in the highly sloped proximal tibia, the PTO may be considered to optimise individualised planning for patients with failed ACL reconstruction.

Level of evidence: Level V.

Purpose: Robotic-assisted total knee arthroplasty (TKA) has emerged as a reliable strategy to improve surgical accuracy and enable functional alignment (FA), also referred to as functional knee positioning (FKP). However, its application in patients with major coronal plane deformities remains under-investigated. This study aimed to evaluate complication rates, implant survival, radiographic outcomes and patient-reported measures in patients with severe deformities undergoing robotic-assisted TKA with FA/FKP principles compared to matched controls.

Methods: A retrospective comparative study was conducted on patients who underwent robotic-assisted TKA between March 2021 and February 2023 at a single high-volume centre. Patients with ≥15° varus or ≥10° valgus deformity were included in the study group and matched 1:1 with controls presenting neutral alignment. All procedures used the Mako robotic-arm-assisted system with standardised FA/FKP principles. Clinical outcomes included knee society score (KSS), forgotten joint score (FJS-12), Kujala anterior knee pain scale (AKPS) and range of motion. Radiographic measurements and robotic data were assessed. Complications, reoperations and revision rates were analysed.

Results: Eighty-eight patients (44 per group) were analysed, with a mean follow-up of 2.8 ± 0.9 years. Complication and revision rates were comparable between groups (revision: 2.3% vs. 0%, p = 0.987). Patients with major deformities achieved higher FJS-12 scores (83.9 ± 20.2 vs. 74.9 ± 19.0, p = 0.040), although the difference did not exceed the minimal clinically important difference (MCID = 9.9). Postoperative mHKA was less neutral in the deformity group (176.8° ± 4.7 vs. 180.0° ± 3.0, p = 0.002), without adverse impact on implant survival.

Conclusions: Robotic-assisted TKA performed with FA/FKP principles appears to be a feasible option for patients with severe varus or valgus deformities. Despite residual alignment variability, complication and revision rates remained comparable to standard cases, and patient-reported outcomes suggested greater perceived functional improvement.

Level of evidence: Level III.

Purpose: Unicompartmental knee arthroplasty (UKA) is a widely used treatment for isolated compartmental knee osteoarthritis, especially in younger and more active patients. Return to sport (RTS) has become a key postoperative outcome. While RTS after UKA is generally favourable, the influence of factors such as implant design, surgical technique, compartment treated and patient characteristics remains unclear. An updated and granular synthesis is needed, particularly to allow direct comparison with RTS outcomes after total knee arthroplasty (TKA).

Methods: A systematic review and meta-analysis was conducted following PRISMA guidelines and registered on PROSPERO. PubMed, Embase and Scopus were searched for studies from 2016 to April 2025 reporting RTS outcomes after UKA. Two reviewers independently screened articles, extracted data and assessed methodological quality using the modified Coleman Methodology Score. Weighted means and proportions were calculated, and correlation analyses explored associations between RTS and patient and surgical variables.

Results: Thirteen studies (n = 1675 patients) were included. The overall weighted mean RTS rate after UKA was 87.97% with a substantial proportion of patients resuming intermediate and high-impact sports. No significant differences in RTS were found between fixed-bearing and mobile-bearing implants, or between medial and lateral UKA. RTS was comparable between robotic-assisted and standard techniques. A moderate negative correlation between BMI and RTS was observed (r = -0.69, p = 0.019). Compared to TKA, UKA patients have a higher RTS rate (87.97% vs. 72%). UKA patients resumed a broader range of sports, with increased participation in intermediate- and high-impact activities.

Conclusions: UKA offers high RTS rates and supports participation in demanding physical activities. Neither implant design nor surgical technique substantially impacts RTS, whereas patient-related factors, especially BMI, are key predictors. Compared to TKA, UKA is associated with superior sport-related outcomes, underscoring its role in appropriately selected patients. These findings support shared decision-making and personalised postoperative planning.

Level of evidence: Level III.

Purpose: Surgical intervention for massive rotator cuff tear (MRCT) has been found to result in positive outcomes; however, a high retear rate has frequently been reported. The present study employed a chronic MRCT model to assess the impact of microdrilling, a bone marrow stimulation (BMS) technique and extracorporeal shockwave therapy (ESWT) on rotator cuff healing. We hypothesized that BMS would result in superior healing than ESWT, reflected by a more normal tendon-to-bone junction histomorphology.

Methods: A chronic rotator cuff tear model was created in the supraspinatus and infraspinatus tendons of 30 Sprague-Dawley rats. Four weeks later, the tendons were repaired using the transosseous technique. The animals were randomly assigned to three groups. In Group I, the intervention consisted exclusively of tendon repair. In Group II, ESWT was administered at various time points in conjunction with the repair process. In Group III, microdrilling was performed prior to the initiation of repairs. The animals were euthanized at 4 and 8 weeks post-repair. Repaired tendons, specifically the tendon-to-bone junction, were evaluated histomorphologically using the Bonar score and immunohistochemically for CD34, bone morphogenetic protein-2 (BMP-2), bone morphogenetic protein-7 (BMP-7) and transforming growth factor-β1 (TGF-β1).

Results: A lower Bonar scale score in Group III more closely resembled normal tissue with respect to tenocyte morphology, extracellular matrix composition and vascularity, although statistical significance was limited to vascularity and extracellular matrix composition. By contrast, Group II showed a significant time-dependent deterioration in tenocyte morphology. Group III exhibited elevated BMP-2 and BMP-7 expression levels, and an increase in CD34 at the tendon-to-bone junction was observed in Group II; however, these did not reach statistical significance. TGF-β1 expression remained comparable among all groups.

Conclusions: Both biological augmentation with BMS and ESWT demonstrated beneficial effects on tendon-to-bone healing in a rat model of chronic MRCT; however, these effects were not statistically significant. Although increased BMP-2, BMP-7 and CD34 expressions were noted in Group III, significant improvements were noted in vascularity according to the Bonar scale score, along with early enhancements in ground substance and overall histological structure. The deterioration of tenocyte morphology in the ESWT group highlights the need for optimized energy parameters.

Level of evidence: N/A.

Purpose: Medial meniscus posterior root tears (MMPRTs) disrupt the hoop stress mechanism, leading to increased meniscal extrusion and early osteoarthritis. This systematic review aims to evaluate current surgical techniques for MMPRT repair, including their biomechanical principles, technical aspects and clinical outcomes, with special attention to strategies addressing meniscal extrusion.

Methods: A systematic search was conducted across PubMed, Scopus and Cochrane Library using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Inclusion criteria encompassed studies describing surgical techniques for MMPRT repair published in the last 20 years. Techniques were categorized into pull-out transtibial repair, suture anchor repair and all-inside repair. Augmentation procedures were also evaluated. Quality assessment was performed using the Risk of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool for comparative studies.

Results: Forty-two studies were included. Thirty studies reported on pull-out transtibial techniques, eight on suture anchor repairs and four on all-inside repair. Various fixation strategies, suture configurations and devices were described. Biomechanical evidence supports the use of suture anchors for improved cyclic loading performance. Augmentation techniques such as gracilis autografts or centralization sutures were described in select cases to reduce extrusion. Comparative studies suggest that while no single technique guarantees superior healing, suture anchor repair may offer biomechanical advantages over pull-out repairs.

Conclusion: Multiple surgical options exist for MMPRT repair, each with specific advantages and limitations. The choice of technique should consider biomechanical integrity, tissue quality and the presence of extrusion. Augmentation strategies may enhance outcomes in selected cases. Further high-quality comparative studies are needed to define the optimal surgical approach.

Level of evidence: Level III, systematic review and meta-analysis.

Purpose: No consensus exists on the optimal sterilization method for contaminated grafts during anterior cruciate ligament (ACL) reconstruction surgery. This study evaluated the efficacy of single and multiple sequential disinfectants in sterilizing the contaminated graft.

Methods: Thirty ACLs were harvested from 30 knees during total knee arthroplasty and sectioned into 10 semi-identical pieces (n = 300). All grafts were dropped simultaneously on the operating room floor and left for 60 s. Then, the grafts were assigned to the 10 study groups. (1) The control group used no sterilizing method, and in the other nine groups were used different sterilizing solutions: (2) 1% povidone-iodine (PI), (3) 4% chlorhexidine (CH), (4) antibiotics including vancomycin and colistin (AB), (5) thrice washings with PI, CH and AB, (6) twice washing with PI and CH, (7) twice washing with PI and AB, (8) twice washing with CH and AB, (9) once washing with normal saline, and (10) thrice washings with normal saline. A wet swab was also rubbed on the operating room floor. The researchers responsible for cultivation and culture analysis were blinded to the graft tags in the various groups.

Results: Statistical comparisons of contamination rates between groups were performed using chi-square tests for categorical data, with Fisher's exact tests for pairwise comparisons. A p value of <0.05 was considered statistically significant for individual comparisons. Twenty-nine of the 30 control grafts were positive for bacterial culture, primarily for Staphylococcus epidermidis (n = 28) and Micrococcus luteus (n = 13). Eight samples in the PI group were positive for bacteria. No bacterium was isolated in the CH group. Grafts washed once and thrice with normal saline were positive for bacteria in 13 and 8 samples, respectively.

Conclusion: This study found the 4% CH solution to be the most effective method for sterilizing autografts accidentally dropped on the operating room floor.

Level of evidence: NA (cadaveric, animal and basic science studies).

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.