Greater medial proximal tibial slope is associated with bone marrow lesions in middle-aged women with early knee osteoarthritis.

BACKGROUND: Bone marrow lesion (BML) is an important magnetic resonance finding (MRI) finding that predicts knee osteoarthritis. The purpose of this study was to investigate the influence of proximal tibial morphology on BML, including the spreading root sign (SRS), in women without radiographic knee osteoarthritis (OA). It was hypothesized that varus alignment and a greater posterior tibial slopes (PTS) are associated with BML. MATERIALS AND METHODS: A total of 359 female volunteers without knee OA who were participants in the Iwaki Health Promotion Project in 2017 or 2019 were enrolled. Participants were divided into the non-OA and early knee OA (EKOA) groups based on the Luyten's classification criteria. The presence of pathological cartilage lesions, BMLs, attritions, meniscal lesions and effusions was scored on T2-weighted fat-suppressed magnetic resonance imaging (MRI) according to the Whole-Organ MRI Scoring system. The medial proximal tibial angle (MPTA) and medial and lateral PTS (MPTS and LPTS, respectively) were measured. Regression and receiver operating characteristic (ROC) analyses were performed to reveal the relationship between BMLs and proximal tibial morphological parameters. RESULTS: Of the 359 participants, 54 (15%) were classified as having EKOA. The prevalence of cartilage lesions, BMLs, attritions, meniscal lesions and effusions was higher in the EKOA group than in the non-OA group. The two groups had no significant difference in the proximal tibial parameters. Regression analysis revealed that age and a smaller MPTA were associated with BML in both groups. Attrition (p = 0.029) and the MPTS (p = 0.025) were positively associated with BML in the EKOA group. CONCLUSION: The prevalence of BMLs was higher in women with EKOA and correlated with the varus and greater posterior slopes in those without radiographic knee OA. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

TiNbSn stems with gradient changes of Young's modulus and stiffness reduce stress shielding compared to the standard fit-and-fill stems.

BACKGROUND: The difference between Young's moduli of the femur and the stem causes stress shielding (SS). TiNbSn (TNS) stem has a low Young's modulus and strength with gradient functional properties during the change in elastic modulus with heat treatment. The aim of this study was to investigate the inhibitory effect of TNS stems on SS and their clinical outcomes compared to conventional stems. METHODS: This study was a clinical trial. Primary THA was performed using a TNS stem from April 2016 to September 2017 for patients in the TNS group. Unilateral THA was performed using a Ti6Al4V alloy stem from January 2007 to February 2011 for patients in the control group. The TNS and Ti6Al4V stems were matched in shape. Radiographs were obtained at the 1- and 3-year follow-ups. Two surgeons independently checked the SS grade and appearance of cortical hypertrophy (CH). The Japanese Orthopaedic Association (JOA) scores before and 1 year after surgery were assessed as clinical scores. RESULTS: None of the patients in the TNS group had grade 3 or 4 SS. In contrast, in the control group, 24% and 40% of patients had grade 3 and 4 SS at the 1- and 3-year follow-ups, respectively. The SS grade was lower in the TNS group than in the control group at the 1- and 3-year follow-ups (p < 0.001). The frequencies of CH in both groups were no significant difference at the 1- and 3-year follow-ups. The JOA scores of the TNS group significantly improved at 1 year after surgery and were comparable to control group. CONCLUSION: The TNS stem reduced SS at 1 and 3 years after THA compared to the proximal-engaging cementless stem, although the shapes of the stems matched. The TNS stem could reduce SS, stem loosening, and periprosthetic fractures. TRIAL REGISTRATION: Current Controlled Trials. ISRCTN21241251. https://www.isrctn.com/search?q=21241251 . The date of registration was October 26, 2021. Retrospectively registered.

Two-stage revision knee arthroplasty for metallosis in a patient with rheumatoid arthritis: A case report.

We report a successful case of two-stage revision total knee arthroplasty performed for treating painless metallosis after total knee arthroplasty with a metal-backed patella. A 63-year-old woman diagnosed with rheumatoid arthritis underwent left total knee arthroplasty with a metal-backed patella at 32 years of age. The patient did not have knee pain; however, knee joint swelling, a strange noise, and pigmentation were reported 4 years ago. Radiographs showed cloud and metal-line signs anteriorly and posteriorly at the femoral condyle. Therefore, a two-stage surgery was performed for infection prevention and ease of performing posterior synovectomy. The patient underwent initial synovectomy via a posterior approach, followed by anterior synovectomy and revision total knee arthroplasty. Synovectomy was performed well without perioperative infection or failure of wound healing. In cases with metallosis after total knee arthroplasty, the two-stage revision total knee arthroplasty should be considered, depending on the degree of synovial proliferation and the risk of complications.

Long-term results of Chiari pelvic osteotomy on the preservation of hip function with mean follow-up of more than 30 years and its prognostic factors.

BACKGROUND: Clinical outcomes of Chiari pelvic osteotomy for acetabular dysplasia, including conversion to total hip arthroplasty (THA), have not been adequately explored. The purpose of this study was to examine the long-term results and clinical outcomes of Chiari pelvic osteotomy as the primary outcome and to analyze its prognostic factors as the second outcome. METHODS: This study was a multicenter, retrospective cohort study. Ninety-seven patients underwent Chiari pelvic osteotomy at three hospitals between March 1975 and October 1997. The long-term clinical outcomes of Chiari pelvic osteotomy, including conversion to THA and hip pain, were analyzed using the Kaplan-Meier method. In addition, the prognostic factors for conversion to THA after Chiari pelvic osteotomy were evaluated with clinical variables and radiographic parameters. RESULTS: The study included 51 hips in 45 patients (4 men and 41 women) with long-term follow-up. The survival rates assessed by Kaplan-Meier analysis with conversion to THA as an endpoint, were 90.2% (95% confidence interval (CI) 82.0-98.4%) at 20 years and 73.5% (95% CI 61.1-86.0%) at 30 years. In contrast, the Kaplan-Meier survival rates with the Japanese Orthopaedic Association hip score for pain ≤20 as an endpoint, were 86.3% (95% CI 76.8-95.7%) at 20 years and 65.6% (95% CI 52.3-79.0%) at 30 years. Only older age at osteotomy was the significantly poor prognostic factor for conversion to THA, with a hazard ratio of 1.11/year, 95% CI 1.06 to 1.18, (p < 0.01). CONCLUSION: Chiari pelvic osteotomy may still be a good alternative to bony reconstructive surgery for acetabular dysplasia especially in young patients. Only older age at the osteotomy was related to the poor prognosis of preserving hip function.

Spectroscopic Quantitative Measurement of the Cartilage Surface using Arthroscopy Correlates with a Conventional Macroscopic Grading System.

Purpose: To quantify the cartilage surface profile visualized during arthroscopic surgery and examine its clinical utility by comparing the results of quantitative measurements with a conventional grading system. Methods: Fifty consecutive patients diagnosed with knee osteoarthritis and who underwent arthroscopic surgery were included in this study. A 4 K camera system was used, and the cartilage surface profile was visualized using the augmented reality imaging program. The highlighted image was displayed in 2 colors: black (the worn cartilage area) and green (the part where the cartilage thickness was maintained). The percentage of the green area was calculated using ImageJ and used as an index of cartilage degeneration. The quantitative value was statistically compared with the International Cartilage Repair Society (ICRS) grade as a conventional macroscopic evaluation. Results: In the quantitative measurement, the median percentage of the green area was 60.7 at ICRS grades 0 and 1 (interquartile range [IQR], 67.3-51.0), 47.2 at grade 2 (IQR, 54.1-39.2), 36.5 at grade 3 (IQR, 43.2-30.4), and 34.0 at grade 4 (IQR, 38.5-29.3). There was a significant difference between the macroscopic grades, except for Grades 3 and 4. There was a significant negative correlation between macroscopic evaluation and quantitative measurement (r = -0.672, P < .001). Conclusions: The quantitative measurement of the cartilage surface profile using the spectroscopic absorption technique was significantly correlated with the conventional macroscopic grading system and demonstrated fair to good inter-rater and intra-rater reliabilities. Level of Evidence: Level II, diagnostic (prospective cohort study).

Genome-Wide Association Study and Transcriptome of Japanese Patients with Developmental Dysplasia of the Hip Demonstrates an Association with the Ferroptosis Signaling Pathway.

This study examined the association between developmental dysplasia of the hip (DDH) and disease-associated loci in a Japanese cohort. A genome-wide association study (GWAS) of 238 Japanese patients with DDH and 2044 healthy individuals was performed. As a replicate, GWAS was also conducted on the UK Biobank data with 3315 cases and matched 74,038 controls. Gene set enrichment analyses (GSEAs) of both the genetics and transcriptome of DDH were performed. Transcriptome analysis of cartilage specimens from DDH-associated osteoarthritis and femoral neck fractures was performed as a control. Most of the lead variants were very low-frequency ones in the UK, and variants in the Japanese GWAS could not be replicated with the UK GWAS. We assigned DDH-related candidate variants to 42 and 81 genes from the Japanese and UK GWASs, respectively, using functional mapping and annotation. GSEA of gene ontology, disease ontology, and canonical pathways identified the most enriched pathway to be the ferroptosis signaling pathway, both in the Japanese gene set as well as the Japanese and UK merged set. Transcriptome GSEA also identified significant downregulation of genes in the ferroptosis signaling pathway. Thus, the ferroptosis signaling pathway may be associated with the pathogenic mechanism of DDH.

Concomitant Lateral Meniscus Tear is Associated with Residual Rotatory Knee Instability 1 Year after Anterior Cruciate Ligament Reconstruction: Case-cohort Study.

Lateral meniscus tear (LMT) accompanied by anterior cruciate ligament (ACL) injuries has been reported to provoke rotatory instability of the affected knee joint. Unfortunately, these previous papers did not determine whether LMT-derived rotatory knee instability is residual because only preoperative or time zero data exists. This study aimed to longitudinally investigate how the prevalence of comorbid LMT is associated with residual rotatory knee instability (RKI) 1 year after ACL reconstruction (ACLR). A total of 327 patients who underwent double-bundle ACLR (average age: 23.4 years, body mass index: 23.5 kg/m2, 215 females). The patients were divided into three groups based on arthroscopy: 1) intact lateral meniscus (LM); 2) unrepaired LMT; 3) repaired LMT. At the 1-year follow-up, the pivot-shift test was performed. The prevalence of RKI, determined according to IKDC grades (grade ≥1 denoted RKI), was compared with chi-square or Fisher's exact tests. Thirty-eight patients (11.6%) had RKI; 203 subjects (62.1%) showed LMT, and 124 patients were diagnosed with an intact LM. Out of the 203 patients, 79 (38.9%) underwent LM repair. RKI was more prevalent in the LMT group than in the intact group (13.8% versus 8.1%, p = 0.117; Odds ratio: 1.499 [95%CI: 0.864 - 2.600]). In addition, the prevalence of RKI was significantly higher in the LM-repair group than in the intact-LM group (17.7% versus 8.1%, p = 0.038; Odds Ratio: 2.455 [95%CI: 1.032 - 5.842]). Medial meniscus tear (MMT) was detected in 113 patients (34.6%); RKI prevalence was not statistically different between the intact-MM group and the MMT group (12.2% versus 10.6%, p = 0.681). The current cohort study clarified that LMT comorbid with ACL injury was longitudinally associated with increased RKI prevalence 1 year after ACLR. Therefore, patients who underwent both ACLR and LM repair demonstrated a significantly higher prevalence of residual RKI.

Preoperative quantitative pivot shift does not correlate with in vivo kinematics following ACL reconstruction with or without lateral extraarticular tenodesis.

PURPOSE: Quantitative pivot shift (QPS) testing using PIVOT technology can detect high- and low-grade rotatory knee instability following anterior cruciate ligament injury or reconstruction (ACLR). The aim of this project was to determine if preoperative QPS correlates with postoperative knee kinematics in the operative and contralateral, healthy extremity following ACLR with or without lateral extraarticular tenodesis (LET) using a highly precise in vivo analysis system. A positive correlation between preoperative QPS and postoperative tibial translation and rotation following ACLR with or without LET in the operative and healthy, contralateral extremity was hypothesized. METHODS: Twenty patients with ACL injury and high-grade rotatory knee instability were randomized to undergo anatomic ACLR with or without LET as part of a prospective randomized trial. At 6 and 12 months postoperatively, in vivo kinematic data were collected using dynamic biplanar radiography superimposed with high-resolution computed tomography scans of patients' knees during downhill running. Total anterior-posterior (AP) tibial translation and internal-external tibial rotation were measured during the gait cycle. Spearman's rho was calculated for preoperative QPS and postoperative kinematics. RESULTS: In the contralateral, healthy extremity, a significant positive correlation was seen between preoperative QPS and total AP tibial translation at 12 months postoperatively (rs = 0.6, p < 0.05). There were no additional significant correlations observed between preoperative QPS and postoperative knee kinematics at 6 and 12 months postoperatively in the operative and contralateral, healthy extremity for combined isolated ACLR and ACLR with LET patients as well as isolated ACLR patients or ACLR with LET patients analyzed separately. DISCUSSION: The main finding of this study was that there was a significant positive correlation between preoperative QPS and total AP tibial translation at 12 months postoperatively in the contralateral, healthy extremity. There were no significant correlations between preoperative QPS and postoperative in vivo kinematics at 6 and 12 months following ACLR with or without LET. This suggests that QPS as measured with PIVOT technology does correlate with healthy in vivo knee kinematics, but QPS does not correlate with in vivo kinematics following ACLR with or without LET.

How much force is acting on the shoulder joint to create a Hill-Sachs Lesion or reverse Hill-Sachs Lesion?

BACKGROUND: It has not been clarified yet how much force is acting on the shoulder joint to create Hill-Sachs/reverse Hill-Sachs lesions which are commonly observed in patients with anterior or posterior shoulder instability. The purpose of this study was to determine the magnitude of force to create these bony lesions using cadaveric shoulders. METHODS: Fourteen fresh-frozen cadaveric shoulders were used. Compression tests were performed using the universal testing machine. The specimens were randomly divided into two groups. In group A, the posterior humeral head (the bare area and articular cartilage) was first compressed against the anterior glenoid rim to simulate a Hill-Sachs lesion, followed by the anterior humeral head being compressed against the posterior glenoid rim. In group B, the same procedure was repeated in the reverse order. X-ray microcomputed tomography (microCT) was also performed. RESULTS: The maximum compression force to create a Hill-Sachs lesion was 771 ± 214 N (mean ± SD) on the articular cartilage of the posterior humeral head, which was significantly greater than the force of 447 ± 215 N to create it on the bare area (P = 0.0086). Regarding the reverse Hill-Sachs lesions, the maximum compression force was 840 ± 198 N when it was created on the articular cartilage of the anterior humeral head, which was significantly greater than the force of 471 ± 100 N when it was created at the footprint of the subscapularis tendon (P = 0.0238). MicroCT showed multiple breakage of the trabecular bone. CONCLUSION: A force to create a Hill-Sachs lesion or a reverse Hill-Sachs lesion was significantly greater when it was created on the humeral articular cartilage than at the non-cartilage area. Also, the force to create a reverse Hill-Sachs lesion was significantly greater than the one to create a Hill-Sachs lesion.

Lower bone mineral density can be a risk for an enlarging bone marrow lesion: A longitudinal cohort study of Japanese women without radiographic knee osteoarthritis.

OBJECTIVES: The aim is to elucidate the relationship between bone mineral density (BMD) at baseline and the change of bone marrow lesion (BML) during a 2-year follow-up (2YFU) period. METHODS: Seventy-eight female participants (mean age: 54.9 ± 9.6 years) without radiographic knee osteoarthritis were eligible. Based on right-knee magnetic resonance imaging, maximum BML area (BMLa) was calculated by tracing the BML border. The change in BMLa was defined using the following formula: [2YFU] - [Baseline] = ΔBMLa. Positive ΔBMLa was defined as enlarged; negative ΔBMLa was defined as regressed. Dual-energy X-ray absorptiometry was performed to measure the BMD of distal radius. Young adult mean [YAM (%)] of the BMD was used for statistical analysis. Linear regression analysis was conducted with ΔBMLa as the dependent variable and YAM as the independent variable. Receiver operating characteristic curve and logistic regression analyses were conducted for YAM to predict the prevalence of BML enlargement or regression. RESULTS: Twenty-six (33.3%) patients had enlarged BMLa, 12 (15.4%) participants showed regressing BMLa, and 40 (51.3%) patients remained stable. YAM was negatively associated with ΔBMLa (ß: - 0.375, P = 0.046). The best predictor of BML enlargement risk was 85% (odds ratio: 8.383, P = 0.025). CONCLUSIONS: Lower BMD could predict BML enlargement during a 2YFU period.

A modified minimally invasive surgery for thoracic pyogenic spondylitis: Percutaneous pedicle screw fixation in combination with a vertebral debridement in a separate posterolateral approach-A case report.

In this report, we present a successfully treated case of intractable thoracic pyogenic spondylitis using one-step curettage/bone grafting of spinal anterior segment and less-contaminated percutaneous spinal posterior fixation via separated posterior approaches, which was not compatible with conventional spinal instruments.

Association Between Early Postoperative Graft Signal Intensity and Residual Knee Laxity After Anterior Cruciate Ligament Reconstruction.

Background: Magnetic resonance imaging (MRI) graft signal intensity is associated with graft damage after anterior cruciate ligament reconstruction (ACLR). However, little is known about the relationship between graft signal intensity and residual laxity of the reconstructed knee based on patient age. Purpose/Hypothesis: To evaluate the relationship between graft signal intensity and residual laxity in younger and older patients who underwent ACLR. We hypothesized that higher graft signal intensity would be associated with reduced postoperative knee stability. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 192 patients who underwent double-bundle ACLR were recruited. Proton density-weighted and T2-weighted MRI was performed at 3, 6, and 12 months after surgery, and the signal intensity ratio (SIR) of the anteromedial and posterolateral bundles was measured as the graft signal intensity reference values. At 12 months after surgery, if the KT-1000 arthrometer measurement exhibited a side-to-side difference of ≥2 mm, the patient was determined as having anterior knee laxity. Rotatory knee laxity was defined as a positive pivot shift with International Knee Documentation Committee grade ≥1. The Mann-Whitney U test was used to compare the SIR in patients with and without residual laxity. The Spearman correlation coefficient was used to evaluate the relationship between demographic parameters and the SIR. Based on receiver operating characteristic curves, the optimal SIR cutoff values to predict residual laxity were calculated, and logistic regression analysis was conducted. Results: Of 192 patients, 26 (13.5%) had anterior knee laxity, and 20 (10.4%) had rotatory knee laxity. The SIR was negatively correlated with age. In younger patients (<30 years; n = 135), those with residual laxity had a significantly higher SIR than those without laxity; this relationship was not significant in older patients (≥30 years; n = 57). Based on receiver operating characteristic curves and logistic regression analysis, the cutoff values that were determined for the SIR were significantly associated with a higher odds ratio of residual laxity. Conclusion: Graft signal intensity decreased with patient age. Patients with higher graft signal intensity in the early postoperative phase after ACLR exhibited a higher prevalence of residual laxity, particularly in younger patients.

Central Sensitization and Postoperative Improvement of Quality of Life in Total Knee and Total Hip Arthroplasty: A Prospective Observational Study.

Background: While total knee arthroplasty (TKA) and total hip arthroplasty (THA) lead to excellent clinical outcomes, some patients experience residual surgical site pain and reduced satisfaction. This prospective observational study investigated the prevalence of preoperative and postoperative residual central sensitization (CS) after TKA and THA. The influence of residual CS on the improvement in quality of life (QOL) was also investigated. Methods: The participants were 40 patients who underwent TKA and 47 patients who underwent THA. CS was measured using the central sensitization inventory (CSI) questionnaire. Knee symptoms were evaluated using the Knee Injury and Osteoarthritis Outcome Scales (KOOS), and hip symptoms were evaluated using the Japanese Orthopedic Association Hip-disease Evaluation Questionnaires (JHEQ). General QOL was evaluated using EuroQOL (EQ-5D-5l). Regression analysis was performed to estimate factors related to low QOL after surgery. Results: Preoperatively, 47.5% of TKA patients and 66.0% of THA patients were CS positive (P=0.083), which reduced to 10.0% (P=0.042) and 25.5% (P=0.202), respectively, 3 months after surgery. Although the improvements in KOOS subscales and EQ-5D-5l scores in TKA patients with residual CS were significantly lower than in those without residual CS, residual CS status had no effect on JHEQ subscales and EQ-5D-5l scores in THA patients. Regression analysis indicated that EQ-5D-5l was negatively correlated with CSI in the TKA group (P=0.017). In contrast, CSI was not correlated with EQ-5D-5l in the THA group (P=0.206). Conclusion: Postoperative QOL improvement was achieved 3 months after THA regardless of residual CS status. In contrast, preoperative CS was negatively associated with the improvement in QOL after TKA.

Greater medial meniscus extrusion seen on ultrasonography indicates the risk of MRI-detected complete medial meniscus posterior root tear in a Japanese population with knee pain.

To elucidate the association between medial meniscus extrusion measured on ultrasonography (MMEUS) and the prevalence of medial meniscus posterior root tear detected on magnetic resonance imaging (MMPRTMRI). We recruited 127 patients (135 knees; 90 females; mean age: 64.4 ± 8.7 years old; mean BMI: 25.5 ± 3.4 kg/m2) in this cross-sectional study. All participants had medial knee pain without a knee trauma or surgery history. Knee osteoarthritis (KOA) severity was evaluated using Kellgren-Lawrence grade (KLG) scores. Patients with KLG scores 0-1 and ≥ 2 were classified in non-radiographic (non-ROA) and radiographic KOA (ROA) groups, respectively. MMEUS was measured with patients in the supine position. Based on fat-suppressed T2-weighted images, MMPRTMRI was defined as the presence of "Ghost meniscus sign" and "Cleft/truncation sign", indicating an abnormal high signal intensity of a completely disrupted posterior root. MMEUS was compared between MMPRT+ and MMPRT- patients using a non-paired t-test. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off MMEUS to predict MMPRT+. The prevalence of MMPRT+ was 31.3% (25/80 knees) and 29.1% (16/55 knees) in the non-ROA and ROA groups. The MMEUS of MMPRT+ patients were significantly greater than that of MMPRT- patients in both the non-ROA (5.9 ± 1.4 mm vs. 4.4 ± 1.0 mm, P < 0.001) and ROA (7.8 ± 1.3 mm vs. 6.3 ± 1.3 mm, P < 0.001) groups. ROC curves demonstrated that 5-mm and 7-mm MMEUS were the optimal cut-off values in non-ROA (adjusted odds ratio: 6.280; area under the curve [AUC]: 0.809; P < 0.001) and ROA (adjusted odds ratio: 15.003; AUC: 0.797; P = 0.001) groups. In both early non-radiographic and established radiographic KOA stages, a greater MMEUS was associated with a higher MMPRTMRI prevalence.

Impacts of external rotators and the ischiofemoral ligament on preventing excessive internal hip rotation: a cadaveric study.

BACKGROUND: This study examined the biomechanics of preventing excessive internal hip joint rotation related to the hip flexion angle. METHOD: An intramedullary nail with a circular plate equipped with a protractor was installed in the femur of nine normal hips. The circular plate was pulled by 3.15 Nm of force in the internal rotation direction. The external rotators were individually resected, finally cutting the ischiofemoral ligament. The cutting order of the external rotators differed on each side to individually determine the internal rotation resistance. The external rotators were resected from the piriformis to the obturator externus in the right hips and the reverse order in the left hips. Traction was performed after excising each muscle and ischiofemoral ligament. Measurements were taken at 0°, 30°, and 60° of hip flexion, and the differences from baseline were calculated. RESULTS: For the right hip measurements, the piriformis and ischiofemoral ligament resection significantly differed at 0° of flexion (p = 0.02), each external rotator and the ischiofemoral ligament resections significantly differed at 30° of flexion (p < 0.01), and the ischiofemoral ligament and piriformis and inferior gemellus resections significantly differed at 60° of flexion (p = 0.04 and p = 0.02, respectively). In the left hips, the ischiofemoral ligament and obturator externus, inferior gemellus, and obturator internus resections significantly differed at 0° of flexion (p < 0.01, p < 0.01, and p = 0.01, respectively), as did each external rotator and the ischiofemoral ligament resections at 30° of flexion (p < 0.01). CONCLUSION: The ischiofemoral ligament primarily restricted the internal rotation of the hip joint. The piriformis and obturator internus may restrict internal rotation at 0° and 60° of flexion.

Anterior cruciate ligament reconstruction with lateral extraarticular tenodesis better restores native knee kinematics in combined ACL and meniscal injury.

PURPOSE: To determine if anterior cruciate ligament (ACL) reconstruction (ACLR) with lateral extraarticular tenodesis (LET) is beneficial for restoring knee kinematics with concomitant meniscal pathology causing rotatory knee instability. METHODS: Twenty patients with an ACL tear were randomized to either isolated ACLR or ACLR with LET. Patients were divided into four groups based on the surgery performed and the presence of meniscal tear (MT): ACLR without MT, ACLR with MT, ACLR with LET without MT, and ACLR with LET with MT. Kinematic data normalized to the contralateral, healthy knee were collected using dynamic biplanar radiography superimposed with high-resolution computed tomography scans of patients' knees during downhill running. Anterior tibial translation (ATT) and tibial rotation (TR) as well as patient-reported outcome measures (PROMs) were analyzed at 6- and 12-months postoperatively. RESULTS: At 6 months, ACLR with LET resulted in significantly decreased ATT at heel strike compared to ACLR (ACLR without MT: 0.3 ± 0.8 mm and ACLR with MT: 1.4 ± 3.1 mm vs. ACLR with LET without MT: - 2.5 ± 3.4 mm and ACLR with LET with MT: - 1.5 ± 1.2 mm ATT, p = 0.02). At 6 months, at toe off ACLR with LET better restored ATT to that of the contralateral, healthy knee in patients with meniscal pathology, while in patients without meniscal pathology, ACLR with LET resulted in significantly decreased ATT (1.0 ± 2.6 mm ATT vs. - 2.6 ± 1.7 mm ATT, p = 0.04). There were no significant differences in kinematics or PROMs between groups at 12 months. CONCLUSION: For combined ACL and meniscus injury, ACLR with LET restores native knee kinematics at toe off but excessively decreases ATT at heel strike in the early post-operative period (6 months) without altering knee kinematics in the long term. Future large-scale clinical studies are needed to better understand the function of LET and ultimately improve patient outcomes. LEVEL OF EVIDENCE: III.

The effect of lateral extra-articular tenodesis on in vivo cartilage contact in combined anterior cruciate ligament reconstruction.

PURPOSE: Lateral extra-articular tenodesis (LET) may confer improved rotational stability after anterior cruciate ligament reconstruction (ACLR). Little is known about how LET affects in vivo cartilage contact after ACLR. The aim of this study was to investigate the effect of LET in combination with ACLR (ACLR + LET) on in vivo cartilage contact kinematics compared to isolated ACLR (ACLR) during downhill running. It was hypothesised that cartilage contact area in the lateral compartment would be larger in ACLR + LET compared with ACLR, and that the anterior-posterior (A-P) position of the contact center on the lateral tibia would be more anterior after ACLR + LET than after ACLR. METHODS: Twenty patients were randomly assigned into ACLR + LET or ACLR during surgery (ClinicalTrials.gov:NCT02913404). At 6 months and 12 months after surgery, participants were imaged during downhill running using biplane radiography. Tibiofemoral motion was tracked using a validated registration process. Patient-specific cartilage models, obtained from 3 T MRI, were registered to track bone models and used to calculate the dynamic cartilage contact area and center of cartilage contact in both the medial and lateral tibiofemoral compartments, respectively. The side-to-side differences (SSD) were compared between groups using a Mann-Whitney U test. RESULTS: At 6 months after surgery, the SSD in A-P cartilage contact center in ACLR + LET (3.9 ± 2.6 mm, 4.4 ± 3.1 mm) was larger than in ACLR (1.2 ± 1.6 mm, 1.5 ± 2.0 mm) at 10% and 20% of the gait cycle, respectively (p < 0.01, p < 0.05). There was no difference in the SSD in cartilage contact center at 12 months after surgery. There was no difference in SSD of cartilage contact area in the medial and lateral compartments at both 6 and 12 months after surgery. There were no adverse events during the trial. CONCLUSION: LET in combination with ACLR may affect the cartilage contact center during downhill running in the early post-operation phase, but this effect is lost in the longer term. This suggests that healing and neuromuscular adaptation occur over time and may also indicate a dampening of the effect of LET over time. (337 /350 words) LEVEL OF EVIDENCE: Level II.

Bone marrow lesion severity was associated with proximal tibial inclination in early knee osteoarthritis.

PURPOSE: This study aimed to investigate the effect of tibial plateau (TP) inclination and serum bone metabolic markers on bone marrow lesion (BML) in the general Japanese population with early knee osteoarthritis (EKOA). METHODS: A total of 441 female volunteers who participated in the Iwaki Health Promotion Project in 2017 were enrolled. Participants without radiographic abnormalities were divided into normal and EKOA groups according to the Luyten's classification criteria for EKOA. The medial proximal tibial angle (MPTA), growth plate-TP angle, and growth plate-medial tibial plateau (MTP) angle were measured on standing anteroposterior radiographs of the knees. BML severity on T2-weighted fat-suppressed magnetic resonance imaging (MRI) was scored using the Whole-Organ MRI Score method. Serum levels of N-telopeptide of type I collagen, tartrate-resistant acid phosphatase-5b (TRACP-5b), bone-specific alkaline phosphatase, procollagen type I N-terminal propeptide, pentosidine, and homocysteine were assessed. Linear regression analysis was conducted to investigate the relationship between proximal tibial inclination, BML, and serum bone metabolic markers. RESULTS: The growth plate was observed in 309 (70%) participants, and 48 (16%) participants had EKOA. The mean MPTA, growth plate-TP angle, and growth plate-MTP angle were 86.1 ± 5.9°, 3.6 ± 1.1°, and 9.9 ± 2.6°, respectively. The MPTA was negatively correlated with the growth plate-TP and growth plate-MTP angles (p = 0.006, p < 0.001). Participants with EKOA who had BML exhibited greater growth plate-MTP angle than those who did not (p = 0.018). Regression analysis revealed that BML severity was positively associated with MPTA (p = 0.036) and a bone formation marker (p = 0.045). CONCLUSION: BML severity was positively associated with proximal tibial inclination and serum TRACP-5b level in participants with EKOA and normal knees, respectively. Assessment of proximal tibial inclination may provide insight into potential BML risk. Residual medial tibial inclination may potentially result in knee pain and symptoms in EKOA. LEVEL OF EVIDENCE: III.

Laterally shifted tibial tunnel can be the risk of residual knee laxity for double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To elucidate the relationship between graft tunnel position and knee laxity in the cases of double-bundle ACL reconstruction. METHODS: Total of 132 cases were included. Femoral and tibial tunnels were evaluated by quadrant method on 3D-CT. As additional reference of tibia, the distances from medial tibial spine to the tunnel center (DMS) and from Parsons' knob to the tunnel center (DPK) were evaluated; %DMS/ML and %DPK/AP were calculated (ML and AP: mediolateral and anteroposterior width of tibial plateau). Preoperative and postoperative (1 year from surgery) stabilities were evaluated by Lachman and pivot-shift procedures. If there was ≥ 2 mm side-to-side difference, the subject was defined as having anterior knee laxity (AKL); if the pivot-shift phenomenon was observed with IKDC grade ≥ 1, there was rotatory knee laxity (RKL). Multiple logistic regression analysis was conducted with the prevalence of AKL or RKL as the dependent variable and with tunnel positions as the independent variables. RESULTS: Overall, 21 subjects (15.9%) showed AKL, and 15 subjects (11.4%) showed RKL. Those with postoperative laxity showed higher %DMS/ML and higher femoral position than those without laxity. Regarding posterolateral bundle, logistic regression model estimated that %DMS/ML was associated with the prevalence of AKL (B = 0.608; p < 0.001) and RKL (B = 0.789; p < 0.001); %high-low femoral tunnel position (B = - 0.127; p = 0.023) was associated with that of RKL. CONCLUSION: There was the risk of residual knee laxity in ACL-reconstructed knee when tibial tunnel shifted more laterally or higher femoral tunnel was created with regard to posterolateral bundle. LEVEL OF EVIDENCE: III.

Mid-term results of a new femoral prosthesis using Ti-Nb-Sn alloy with low Young's modulus.

BACKGROUND: This study was performed to investigate the mid-term results of Ti-Nb-Sn (TNS) alloy stem with a low Young's modulus. METHODS: This study was a multicenter prospective cohort study. A total of 40 primary total hip arthroplasties performed between April 2016 and September 2017 was enrolled in this study. With the unique functional gradient properties by heating treatment, the strength of the proximal portion was enhanced, while the distal portion maintained a low Young's modulus. The surgeries were performed through the posterolateral approach using the TNS alloy stems. Radiographs were taken from immediately after surgeries until 3 years, and stress shielding and subsidence of the stems were evaluated. The incidences of the stem breakage were also assessed. Clinical assessments were performed using Japanese Orthopaedic Association (JOA) and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) scores. RESULTS: Among the 40 enrolled patients, 36 patients were female and 4 were male. At 3 years after surgery, there were no radiologic signs of loosening, subsidence, or breakage of the stem. Stress shielding was observed in 26 hips (65%). Of 26 hips, 16 hips (40%) were grade 1 and 10 hips (25%) were grade 2. There was no advanced stress shielding. The JOA and JHEQ scores significantly improved compared with the preoperative scores. CONCLUSION: The current study using a new TNS alloy femoral stem showed good clinical outcomes at 3-year follow-up. Radiologically, there was no loosening or subsidence of the stem. The mild stress shielding was observed in 65% of patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN21241251 . The date of registration was October 26, 2021. Retrospectively registered.