Association Between MRI Signal Intensity of the Repaired Lateral Meniscus and Residual Anterolateral Knee Laxity After ACL Reconstruction.

Background: Anterolateral knee laxity (ALLx) has been linked to tears of the lateral meniscus (LM) and anterior cruciate ligament (ACL) injury. Purpose: To investigate the longitudinal relationship between the signal intensity (SI) of the repaired LM on magnetic resonance imaging (MRI) and residual ALLx after ACL reconstruction (ACLR). Study Design: Cohort study; Level of evidence, 3. Methods: Included were 87 patients who underwent double-bundle ACLR and lateral meniscal repair (mean age, 23.5 years; body mass index, 23.7 kg/m2; 56 women) at a single institution between 2010 and 2019. Proton density-weighted (PDW) and T2-weighted (T2W) MRI was performed at 3, 6, and 12 months postoperatively, and the SI ratio (SIR) was calculated as (SI of the repaired LM)/(SI of the posterior cruciate ligament). At the 12-month follow-up, ALLx was evaluated using the pivot-shift test; an International Knee Documentation Committee grade ≥1 indicated residual ALLx. Results: Overall, 12 patients (13.8%) exhibited ALLx at 12 months postoperatively. At 3 months postoperatively, the SIR on PDW images (SIR-PDW) was significantly higher in patients with ALLx versus those without ALLx (1.98 ± 0.77 vs 1.49 ± 0.52, respectively; P = .007); there was no difference in the SIR on T2W images between the groups. SIR-PDW at 3 months postoperatively was correlated negatively with patient age (r = -0.308, P = .004). When patients were stratified into a younger (≤22 years; n = 53; ALLx = 7 [13.2%]) and an older (>22 years; n = 34; ALLx = 5 [14.7%]) group, the area under the receiver operating characteristic curves (AUCs) for SIR-PDW in the younger group were statistically significant for predicting the prevalence of ALLx at all follow-up times (AUCs, 0.733-0.788) with optimal cutoff values of 2.00 at 3 months, 1.50 at 6 months, and 1.50 at 12 months. Logistic regression analysis revealed that if younger patients consistently had higher SIR-PDW values than the cutoff values, they were more likely to have residual ALLx (odds ratios, 10.24-23.57). Conclusion: For younger patients who underwent both ACLR and lateral meniscal repair, higher MRI SI of the repaired LM was associated with a higher prevalence of residual ALLx.

A new neural network model that detects graft ruptures and contralateral anterior cruciate ligament injuries.

PURPOSE: The purpose of this study was to develop a neural network model for predicting second anterior cruciate ligament (ACL) injury risk following ACL reconstruction using patient features from medical records. METHODS: Of 486 consecutive patients who underwent primary unilateral ACL reconstruction, 386 patients (198 women, 188 men) with a mean age of 25.1 ± 11.6 years were included in this study. Fifty-eight features, including demographic data, surgical, preoperative and postoperative data, were retrospectively collected from medical records, and features with an incidence of less than 5% were excluded. Finally, 14 features were used for the analysis. The multilayer perceptron was composed of four hidden layers with a rectified linear unit as activation and was trained to maximise the area under the receiver-operating characteristic curve (auROC). Subsequently, validation was carried out through a rigorous threefold cross-validation process. To ascertain the most efficacious combination of features with the highest auROC, a single feature with the least impact on auROC maximisation was systematically eliminated from the comprehensive variable set, ultimately resulting in the retention of a mere two variables. RESULTS: The median follow-up period was 50.5 (24-142) months. Fifty-seven knees had a second ACL injury, with a graft rupture rate of 7.7% and a contralateral injury rate of 6.9%. The maximum auROC for predicting graft rupture was 0.81 with two features: young age and hamstring graft. Meanwhile, the maximum auROC for predicting contralateral ACL injury was 0.74 with seven features, including young age, presence of medial meniscus tear, small body mass index, hamstring graft, female sex and medial meniscus repair or treatment. CONCLUSION: A neural network model with patient features from medical records detected graft ruptures and contralateral ACL injuries with acceptable accuracy. This model can serve as a new, useful tool in clinical practice to inform decisions about ACL reconstruction and retuning to sports postoperatively. LEVEL OF EVIDENCE: Level IV.

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).

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.

Bilateral Sleeve Fracture of the Patella in a Healthy 11-Year-Old Male: A Case Report.

Bilateral sleeve fracture of the patella (SFP) in skeletally immature children is a rare injury. We report the case of a healthy 11-year-old male who suffered bilateral SFP while playing tag. The avulsed fragments of his left patella were highly comminuted. Open reduction and internal fixation (ORIF) were performed using suture anchors, and the knees were immobilized using a cylinder cast for three weeks. At the one-year follow-up assessment, both knees were found to have regained full strength with no extension lag. However, we observed malunion due to lateral shift of the avulsed fragment, cystic lesions, and clicking in the patella, and the patient experienced residual pain in the left knee. Based on this, we conclude that the sleeve fracture of the patella with comminuted cartilaginous fragments was difficult to treat and might have led to poor clinical results if anatomical reduction and fixation had not been performed.

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.

Influence of hamstring tendon and bone-patellar tendon-bone autografts on worsened patient reported outcome measurements in revision anterior cruciate ligament reconstruction: Comparing outcomes between primary and revision reconstructions.

Background: This study aimed to compare the clinical outcomes and patient reported outcome measurement scales (PROMs) between hamstring tendon (HT) or bone-patellar tendon-bone (BTB) grafts in each primary and revision anterior cruciate ligament (ACL) reconstruction. Additionally, the clinical outcomes and PROMs between primary and revision surgeries were compared. Methods: A total of 150 patients (109 primary and 41 revision ACL reconstructions) were enrolled and followed up for an average of 3.9 years (2 years minimum). Knee injury and osteoarthritis outcome scores (KOOS) were examined as PROMs. Side-to-side differences of anterior knee laxity were assessed using KT-1000 and were recorded at the final follow-up. After categorizing patients into HT and BTB reconstruction groups, regression analysis was performed to determine the relationship between revision surgery and changes in KOOS. Results: In patients who underwent primary surgery, there was no significant difference in side-to-side differences of anterior laxity and KOOS between HT and BTB grafts. In those who underwent revision surgery, BTB grafts had a higher KOOS for activities of daily living (ADL) than HT grafts (p = 0.032). Comparing primary and revision surgeries, postoperative side-to-side differences of anterior laxity in the revision group were significantly larger than those in the primary group (p = 0.001). The KOOS for sports after overall revision reconstruction was significantly lower than that after primary reconstruction (p = 0.026). Comparing the KOOS after dividing all patients into HT and BTB reconstruction groups, in the HT reconstruction group, postoperative KOOS results were not different in any subscale from BTB grafts. In contrast, the KOOS for sports (p = 0.008) and QOL (p = 0.039) were significantly lower in revision surgery than in primary surgery. Furthermore, regression analysis including multiple confounders in the HT reconstruction group showed revision surgery using HT graft was correlated with worsened KOOS for symptoms (p = 0.012) and sports (p = 0.010). Revision surgery using BTB graft was not correlated with decreased KOOS. Conclusions: There were no differences between the clinical outcome and KOOS in primary and revision surgery, except for ADL scores following revision ACL reconstruction using BTB graft. Side-to-side difference of anterior laxity and KOOS for sports following revision ACL reconstruction were inferior to those following primary ACL reconstruction.Furthermore, revision ACL reconstruction using HT grafts were correlated with low scores in KOOS for symptoms and sports, while there was no difference of anterior laxity between BTB and HT grafts in revision surgery.

Clinical outcomes of medial patellofemoral ligament reconstruction using FiberTape and knotless SwiveLock anchors.

BACKGROUND: We aimed to prospectively investigate the clinical outcomes of medial patellofemoral ligament (MPFL) reconstruction using polyester high-strength suture tape with knotless anchors. METHOD: Forty-three patients (65 knees) were followed for at least 1 year postoperatively, with 27 patients (43 knees) followed for 2 years postoperatively. All patients underwent MPFL reconstruction using polyester high-strength suture tape (FiberTape®; Arthrex) with knotless anchors (SwiveLock®; Arthrex). Repeated dislocation and residual patellar apprehension signs were recorded, and congruence and tilting angles were measured. Changes in Knee Injury and Osteoarthritis Outcome Scale (KOOS) scores and their associations with the preoperative tibial tubercle-trochlear groove (TT-TG) distance were analyzed. RESULTS: No repeat dislocations (0%) were observed. One (2.4%) residual positive patellar apprehension sign was noted. The mean tilting angle decreased from 24.8° to 10.7° (P < 0.001), and the mean congruence angle decreased from 24.9° to 4.3° (P < 0.001). At 2 years follow up, all KOOS subscales had improved: pain (92.0 ± 12.9), symptoms (90.2 ± 11.9), activities of daily living (95.7 ± 7.3), sports activity (85.7 ± 16.9), quality of life (87.7 ± 12.9), and patellofemoral (89.0 ± 9.6) outcomes. KOOS subscale scores improved regardless of the preoperative TT-TG distance (21.1 ± 3.5 mm; range, 13.8-29.9 mm). CONCLUSIONS: MPFL reconstruction using FiberTape and knotless SwiveLock anchors was performed without sacrificing autologous tissue. No recurrent patellar dislocation was observed during the 2-year follow up period. All KOOS subscale scores improved using FiberTape and SwiveLock anchors in MPFL reconstruction.

Metabolomics with severity of radiographic knee osteoarthritis and early phase synovitis in middle-aged women from the Iwaki Health Promotion Project: a cross-sectional study.

BACKGROUND: Osteoarthritis (OA) is one of the costliest and most disabling forms of arthritis, and it poses a major public health burden; however, its detailed etiology, pathophysiology, and metabolism remain unclear. Therefore, the purpose of this study was to investigate the key plasma metabolites and metabolic pathways, especially focusing on radiographic OA severity and synovitis, from a large sample cohort study. METHODS: We recruited 596 female volunteers who participated in the Iwaki Health Promotion Project in 2017. Standing anterior-posterior radiographs of the knee were classified by the Kellgren-Lawrence (KL) grade. Radiographic OA was defined as a KL grade of ≥ 2. Individual effusion-synovitis was scored according to the Whole-Organ Magnetic Resonance Imaging Scoring System. Blood samples were collected, and metabolites were extracted from the plasma. Metabolome analysis was performed using capillary electrophoresis time-of-flight mass spectrometry. To investigate the relationships among metabolites, the KL grade, and effusion-synovitis scores, partial least squares with rank order of groups (PLS-ROG) analyses were performed. RESULTS: Among the 82 metabolites examined in this assay, PLS-ROG analysis identified 42 metabolites that correlated with OA severity. A subsequent metabolite set enrichment analysis using the significant metabolites showed the urea cycle and tricarboxylic acid cycle as key metabolic pathways. Moreover, further PLS-ROG analysis identified cystine (p = 0.009), uric acid (p = 0.024), and tyrosine (p = 0.048) as common metabolites associated with both OA severity and effusion-synovitis. Receiver operating characteristic analyses showed that cystine levels were moderately associated with radiographic OA (p < 0.001, area under the curve 0.714, odds ratio 3.7). CONCLUSION: Large sample metabolome analyses revealed that cystine, an amino acid associated with antioxidant activity and glutamate homeostasis, might be a potential metabolic biomarker for radiographic osteoarthritis and early phase synovitis.

Biomechanical Analysis of Unstable Osteochondral Fragment Fixation Using Three Different Techniques: Osteochondral Plug, Bioabsorbable Pin, and Suture Anchor with Tape.

Purpose: To compare the initial fixation strength of osteochondral fragment fixations using osteochondral plugs, bioabsorbable pins, and knotless suture anchors. Methods: Eighteen fresh-frozen immature (6 month old) porcine knees were used. An osteochondral fragment, cut from the articular surface of the medial femoral condyle to achieve a thickness of 5 mm, was used to mimic the unstable osteochondral fragment. It was fixed using three techniques, including two osteochondral plugs (osteochondral plug group), four full-threaded poly l-lactic acid pins (bioabsorbable pin group), and three suture anchors with a 2-0 tape (suture anchor group). Tensile loads at displacements of 1 and 2 mm and ultimate failure load were measured at a cross-head speed of 100 mm/min, and the variables of the three groups were compared statistically using a one-way ANOVA with Tukey's honestly significant difference test. Results: There was no significant difference in the tensile load to achieve 1-mm displacement. The load to achieve 2-mm displacement and the ultimate failure load were significantly greater in the suture anchor group than the osteochondral plug group and the bioabsorbable pin group. Conclusions: Single-pull destructive testing of a fixed articular osteochondral fragment with the force perpendicular to the articular surface, demonstrated no statistical difference in the tensile load to achieve 1-mm displacement, but the load to achieve 2-mm displacement was significantly greater for the three suture anchor-interlocking 2-0 tape constructs than the dual osteochondral plug fixation and the four bioabsorbable pin fixation constructs. Additionally, the three suture anchor-interlocking 2-0 tape construct's mean single-pull failure load was greater than other two fixation procedures. Clinical Relevance: To achieve osteochondral fragment union, sufficient fixation strength is critical. However, the initial fixation strength of osteochondral plugs, bioabsorbable pins, and knotless suture anchors for unstable osteochondral lesions remains unclear.

A Novel Quantitative Evaluation of Bone Formation After Opening Wedge High Tibial Osteotomy Using Tomosynthesis.

This study aimed to establish and validate a novel evaluation method using digital tomosynthesis to quantify bone formation in the gap after opening wedge high tibial osteotomy (OW-HTO). We retrospectively analyzed bone formation in the gap in 22 patients who underwent OW-HTO using digital tomosynthesis at 1, 2, 3, 6, 9, and 12 months postoperatively. Bone formation was semi-quantitatively assessed using the modified van Hemert's score and density measurements on digital tomosynthesis images. The gap filling value (GFV) was calculated as the ratio of the intensities of the opening gap and the tibial shaft. In addition, the relationship between the modified van Hemert's score and GFV was evaluated. The reproducibility of GFV had an interclass correlation coefficient (ICC [1,2]) of 0.958 for intraobserver reliability and an ICC (2,1) of 0.975 for interobserver reliability. The GFV increased in a time-dependent manner and was moderately correlated with the modified van Hemert's score (r = 0.630, p < 0.001). The GFV plateaued at 6 months postoperatively. In addition, the GFV was higher in patients with a modified van Hemert's score of 2 than in patients with a modified van Hemert's score of 3 (p = 0.008). The GFVs obtained using digital tomosynthesis can be used to assess postoperative bone formation in the opening gap after OW-HTO with high accuracy and reproducibility.

Prevalence of Segond fractures associated with anterior cruciate ligament injuries and their influence on knee joint stability; A case-control study.

BACKGROUND: The purpose of this study was to determine the prevalence of Segond fractures and to compare knee stability between patients undergoing primary anterior cruciate ligament (ACL) reconstruction with and without Segond fractures pre- and postoperatively. METHODS: A total of 712 patients who underwent primary ACL reconstruction between 2014 and 2019. Exclusion criteria included patients with multi-ligament knee injuries, skeletally immature patients, osteoarthritis in the knee, combined surgery of high tibial osteotomy, lack of data, and loss to follow-up for at least 2 years. Segond fractures were confirmed using plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Patients with Segond fractures were classified into Group S and without Segond fractures into Group N. Pre- and postoperative Lachman grades, pivot-shift grades, and assessment of side-to-side differences in anterior stability were evaluated. RESULTS: Five hundred and forty patients included in this study. There were 22 patients with Segond fractures. Of these, all 22 cases (4.1%) were identified on CT, but only 20 cases (3.7%) were identified on MRI and 18 cases (3.3%) on plain radiographs. There was no significant difference in preoperative Lachman grade or pivot-shift grade between Groups S and N (p = 0.662, p = 0.677, respectively). There was no significant difference in postoperative Lachman grade or pivot-shift grade between Groups S and N (p = 0.685, p = 0.390, respectively). There were no significant differences in preoperative (p = 0.398) or postoperative (p = 0.546) side-to-side differences of anterior stability between Groups S and N. CONCLUSIONS: Segond fractures were confirmed in 4.1% of the cases on CT scans among patients undergoing primary ACL reconstruction. Segond fractures did not affect preoperative or 2-year follow-up evaluations of knee stability. From these results, we concluded that Segond fractures did not affect the clinical outcomes of the primary ACL reconstruction and that it may not be necessary to treat Segond fractures.

Biomechanical analysis of bioabsorbable suture anchors for rotator cuff repair using osteoporotic and normal bone models.

BACKGROUND: This study aimed to compare the failure load of suture anchors used in rotator cuff repair between normal and osteoporotic bone models. METHODS: A total of 16 anchors made from metal (TwinFix Ti 5.0 or 6.5 mm, Corkscrew FT 4.5, 5.5, or 6.5 mm), polyether ether ketone (HEALICOIL PK [HC-PK] 4.5 or 5.5 mm, SwiveLock PK 4.75 or 5.5 mm), or bioabsorbable material (HEALICOIL RG [HC-RG] 4.75 or 5.5 mm, Corkscrew Bio 4.75, 5.5, or 6.5 mm, SwiveLock BC 4.75 or 5.5 mm) were included. Moreover, 10- and 5-pounds per cubic foot (pcf) Sawbone® models were set as normal and osteoporotic cancellous bone models, respectively. Pullout testing was performed in parallel to the insertion axis at a displacement rate of 12.5 mm/s using a universal testing machine. To evaluate the change in failure load between the two Sawbone® models with different densities, the remaining failure load ratio (RFLR) was defined as the ratio of the failure load in 10 pcf to that in 5 pcf. RESULTS: In the 10-pcf Sawbone®, TwinFix Ti 6.5 mm showed the highest mean failure load (304.0 ± 15.2 N). In the 5-pcf Sawbone® model, HC-PK 5.5 mm showed the highest failure load (146.3 ± 5.8 N). Among anchors with the same diameter, HC-PK and HC-RG showed a significantly higher failure load than other anchors in the 10- and 5-pcf Sawbone® models. HC-PK 5.5 mm (62.1%) and HC-PK 4.5 mm (51.1%) have the highest RFLR among anchors with the same diameter. CONCLUSIONS: HC-PK and HC-RG showed higher failure load than the other anchors in both normal and osteoporotic bone models, except for TwinFix Ti 6.5 mm in the 10-pcf Sawbone® model. Based on our results, bioabsorbable anchors had sufficient failure load for rotator cuff repair in addition to bioabsorbability.

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.

Early Return to Sports to Continue the Season after Anterior Cruciate Ligament Injury Is Not Recommended for Student Athletes.

OBJECTIVE: The objectives of this study were to investigate whether student athletes with anterior cruciate ligament (ACL) injuries who returned to sports (RTS) without reconstruction could continue their sporting activities until the end of the season and whether there was an increase in secondary damage associated with knee instability. METHODS: Altogether, 288 skeletally mature patients aged <25 years with new-onset isolated primary ACL injuries were included. Of these, 20 student athletes continued playing sports without ACL reconstruction to try to finish the season and were classified as the early return to sports (ERS) group; the remaining 268 patients, who immediately quit sports and underwent surgery, were classified as the non-ERS group. Knee symptoms and sporting performance for the rest of the season were assessed for the ERS group. The presence of secondary damage, e.g., meniscus injuries and chondral lesions, associated with instability were compared between the two groups. RESULTS: Fourteen ERS-group athletes (70%) indicated that their knees had given way during sporting activities, and seven athletes (35%) were unable to complete the season. In the ERS group, the mean self-estimated performance level after injury was 3.8 ± 2.5 (numeric rating scale 0-10). Despite the RTS period being relatively short, medial meniscus tears (P <0.001) significantly increased in the ERS group, and three patients experienced locking of the medial meniscus and required immediate surgery. CONCLUSIONS: Although ERS without reconstruction to complete the season may be a reasonable strategy for ACL injury, patients' self-estimated performance level was low and meniscal and cartilage injury rates significantly increased.

Clinical Outcomes and Postoperative Complications After All-Epiphyseal Double-Bundle ACL Reconstruction for Skeletally Immature Patients.

BACKGROUND: The treatment strategy for pediatric anterior cruciate ligament (ACL) tears, especially in patients with open physes, remains controversial. PURPOSE: To assess clinical outcomes and postoperative complications after all-epiphyseal double-bundle ACL (DB-ACL) reconstruction for patients with open physes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Included were 102 patients aged ≤15 years who underwent ACL reconstruction at a single institution and had a minimum of 2 years of follow-up. Of these patients, 18 had undergone all-epiphyseal DB-ACL reconstruction (mean age, 12.4 ± 1.2 year) and 84 had undergone conventional DB-ACL reconstruction (mean age, 14.1 ± 0.9 year). The outcomes of the all-epiphyseal group were compared with those of the conventional group. Objective clinical outcomes included KT-1000 arthrometer measurements of side-to-side difference in anterior tibial translation, Lachman test grade, and pivot-shift test grade. Radiographic angular deformity (defined as >3° of the side-to-side difference in femorotibial angle) and incidence of second ACL injury were also compared. RESULTS: The postoperative side-to-side difference in laxity significantly improved from 6.1 ± 2.4 to 0.6 ± 0.9 mm in the all-epiphyseal group (P = .001), and postoperative laxity was similar to that of the conventional group (0.4 ± 0.8 mm; P = .518). A Lachman grade 1 positive result was observed in 20% of the all-epiphyseal group and 3% of the conventional group (P = .042), and a pivot-shift grade 1 positive result was observed in 22% of the all-epiphyseal group and 4% of the conventional group (P = .074). A total of 4 patients (26.7%) in the all-epiphyseal group and 4 (6.1%) in the conventional group demonstrated angular deformity (P = .035). The incidence of postoperative ipsilateral ACL tear was 16.7% in the all-epiphyseal group and 23.8% in the conventional group (P = .757). The incidence of contralateral ACL tear was 11.1% in the all-epiphyseal group and 14.3% in the conventional group (P ≥ .999). CONCLUSION: All-epiphyseal DB-ACL reconstruction for skeletally immature patients achieved satisfactory clinical outcomes compared with conventional DB-ACL reconstruction. The incidence of ipsilateral graft rupture was relatively high in both groups. The all-epiphyseal group had a significantly higher incidence of angular deformity.

Failure load of the femoral insertion site of the anterior cruciate ligament in a porcine model: comparison of different portions and knee flexion angles.

BACKGROUND: This study compared the failure load of the femoral insertion site of the anterior cruciate ligament between different portions and knee flexion angles. METHODS: In total, 87 fresh-frozen, porcine knees were used in this study. Three knees were used for histological evaluation; the remaining 84 knees were randomly divided into 4 groups: anterior anteromedial bundle, posterior anteromedial bundle, anterior posterolateral bundle, and posterior posterolateral bundle groups (n=21 per group). The anterior cruciate ligament femoral insertion site was divided into these four areas and excised, leaving a 3-mm square attachment in the center of each bundle. Tibia-anterior cruciate ligament-femur complexes were placed in a material testing machine at 30°, 120°, and 150° of knee flexion (n=7), and the failure load for each portion was measured under anterior tibial loading (0.33 mm/s). RESULTS: Histological study showed that the anterior cruciate ligament femoral insertion site consisted of direct and indirect insertions. Comparison of the failure load between the knee flexion angles revealed that all the failure loads decreased with knee flexion; significant decreases were observed in the failure load between 30 and 150° knee flexion in the posterior anteromedial bundle and posterior posterolateral bundle groups. Comparison of the failure load according to different portions revealed a significant difference between the anteromedial and posterolateral bundle groups at 150° of knee flexion, but no significant difference among the groups at 30° of flexion. CONCLUSIONS: Although the failure load of the posterior portion decreased significantly in the knee flexion position, it (mainly consisting of indirect insertion) plays a significant role against anterior tibial load in the knee extension position; this appears to be related to the characteristics of the insertion site. Reflecting the complex structure and function of the ACL, this study showed that the failure load of the femoral insertion site varies with differences in positions and knee flexion angles.

Association Between Central Sensitization and Increasing Prevalence of Nocturnal Knee Pain in the General Population with Osteoarthritis from the Iwaki Cohort Study.

PURPOSE: Knee pain is associated with osteoarthritis (OA) and increases during this condition; however, its correlation with central sensitization (CS) in arthritis patients requires greater understanding. The present cross-sectional cohort study to explore the prevalence of knee OA, nocturnal knee pain and disability in general population and to examine the association of CS with sleep quality in Japanese general population. PATIENTS AND METHODS: From among 1056 community-dowelling volunteers, 942 were enrolled as participants in this study. Bilateral weight-bearing anterior-posterior knee radiographs were classified by the Kellgren-Lawrence grade. Nocturnal knee pain and disability were assessed with self-reported questionnaires. Using the CS inventory with nine items (CSI-9), CS was defined as 10 points or higher. Sleep quality was scored using the Pittsburgh Sleep Quality Index (PSQI). Linear regression analysis, adjusted by age, sex, body mass index, Kellgren-Lawrence grade, nocturnal knee pain, and lifestyle habits, was performed to investigate the association of CS with PSQI. RESULTS: The prevalence of OA, nocturnal knee pain, and disability was 37.9%, 7.6%, and 6.2%, respectively. The mean CSI-9 score was 4.9 ± 4.4, with a CS prevalence of 14.0%. The mean PSQI score was 3.9 ± 2.4, which was correlated with the CSI-9 value. CS was not correlated with OA severity; however, nocturnal knee pain prevalence increased from 13.3% to 25.5% in knee OA patients with CS. The CSI-9 value correlated with PSQI total score and subscales. CONCLUSION: Knee OA severity correlated with nocturnal pain and disability; however, its association with CS was unproven. The combined effect of knee OA and CS elevated nocturnal pain and disability, resulting in diminished sleep quality.

Treatment Efficacy of Single Topical NSAID (S-Flurbiprofen Plaster) for Knee Symptoms and Locomotive Dysfunction in Knee Osteoarthritis Patients.

OBJECTIVE: The aim of this study was to demonstrate the non-inferiority of S-flurbiprofen plaster (SFPP) monotherapy for treating knee osteoarthritis compared with the combination of conventional oral and topical non-steroidal anti-inflammatory drugs (NSAIDs). METHODS: A total of 222 participants (114, SFPP group; 108, control group) were treated for 4 weeks. The primary endpoint was the change in the degree of pain felt while rising from a chair after 2 and 4 weeks of treatment as determined using the visual analog scale (VAS) . The secondary endpoint was the change in functional scores and test results. Safety was evaluated in terms of the adverse effects. RESULTS: The VAS score significantly decreased in both groups after 2 and 4 weeks of treatment. Non-inferiority in the VAS score was established only at 2 weeks. There were no significant differences in the secondary endpoints between the groups. Skin disorders were more frequent in the SFPP group; however, there was no difference in gastrointestinal (GI) adverse effects. CONCLUSIONS: The therapeutic efficacy of SFPP monotherapy for knee OA, with respect to changes in the VAS, was not shown to be non-inferior to conventional treatment at 4 weeks; however, non-inferiority was established at 2 weeks. The functional improvement in the SFPP group was comparable to that of the control group. No severe GI adverse effects associated with SFPP administration were observed; however, it is necessary to pay more attention to the occurrence of skin disorders with SFPP than with conventional topical NSAIDs.