Adjustable-Loop Cortical Suspensory Fixation Results in Greater Tibial Tunnel Widening Compared to Interference Screw Fixation in Primary Anterior Cruciate Ligament Reconstruction.

Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.

A Hierarchical Metal Nanowire Network Structure for Durable, Cost-Effective, Stretchable, and Breathable Electronics.

Polymer nanofiber-based porous structures ("breathable devices") have been developed for breathable epidermal electrodes, piezoelectric nanogenerators, temperature sensors, and strain sensors, but their applications are limited because increasing the porosity reduces device robustness. Herein, we report an approach to produce ultradurable, cost-effective breathable electronics using a hierarchical metal nanowire network and an optimized photonic sintering process. Photonic sintering significantly reduces the sheet resistance (16.25 to 6.32 Ω sq-1) and is 40% more effective than conventional thermal annealing (sheet resistance: 12.99 Ω sq-1). The mechanical durability of the sintered (648.9 Ω sq-1) sample is notably improved compared to that of the untreated (disconnected) and annealed (19.1 kΩ sq-1) samples after 10,000 deformation cycles at 40% tensile strain. The sintered sample exhibits ∼29 times less change in electrical performance compared to the thermally annealed sample. This approach will lead to the development of affordable and ultradurable commercial breathable electronics.

Intra-Articular Injection of a Novel DVS Cross-Linked Hyaluronic Acid Manufactured by Biological Fermentation (YYD302) in Patients With Knee Osteoarthritis: A Double-Blind, Randomized, Multicenter, Noninferiority Study.

PURPOSE: This double-blind, randomized, Phase III clinical trial was conducted to assess the efficacy and safety of the novel divinyl sulfone cross-linked hyaluronate (YYD302) compared with the 1,4-butanediol diglycidyl ether cross-linked hyaluronate (Synovian) in patients with knee osteoarthritis. METHODS: A total of 184 patients with osteoarthritis (Kellgren-Lawrence grade I-III) were randomized to 1 of 2 study groups (YYD302 group, n = 95; Synovian group, n = 89). A single injection of YYD302 or Synovian was given to both groups, and 182 participants completed the study (YYD302 group, n = 95; Synovian group, n = 87). The primary end point was the change in weight-bearing pain (WBP) at 12 weeks after the primary single injection. Secondary end points included the Knee Injury and Osteoarthritis Outcome Score; the Western Ontario and McMaster Universities Osteoarthritis Index score; the Patient Global Assessment and Investigator Global Assessment; the range of motion, swelling, and tenderness of the target knee; OMERACT-OARSI responder rate; WBP responder rate (the proportion of patients achieving at least 20 mm or 40% decrease in WBP); and rate of rescue medicine use and its total consumption at weeks 2, 4, and 12. Based on the efficacy results at week 12, the responders were administered an additional single injection of the same study drug at week 24, and safety and efficacy were additionally assessed at week 36. FINDINGS: Mean changes of WBP at 12 weeks after the primary injection were -31.76 mm with YYD302 and -29.74 mm with Synovian, proving noninferiority of the YYD302 group to the Synovian group as the lower bound of the 95% CI (-4.3 to 8.3) was well above the predefined margin (-10 mm). At week 2, the Knee Injury and Osteoarthritis Outcome Score (total, pain, activities of daily living, and sports/recreation) and Western Ontario and McMaster Universities Osteoarthritis Index scores (total, stiffness) were significantly better in the YYD302 group than in the Synovian group. There were no significant differences between the groups in all other end points. Local overall adverse events (pain, heat, erythema, or swelling) at the injection site were observed in 48.4% of the YYD302 group and in 47.7% of the Synovian group. No serious reactions were reported. There was no statistically significant difference between the 2 groups regarding re-injected patients (YYD302 group, n = 54; Synovian group, n = 46) in any of the efficacy outcomes at week 36. IMPLICATIONS: The results of this study support that YYD302 is comparable to Synovian in terms of the efficacy and safety of the intra-articular injection treatment for osteoarthritis of the knee joint. Furthermore, YYD302 provided faster improvements in some efficacy assessments compared with Synovian. ClinicalTrials.gov identifier: NCT03561779.

Low Rate of Return to Preinjury Tegner Activity Level Among Recreational Athletes: Results at 1 Year After Primary ACL Reconstruction.

BACKGROUND: There is limited information about the functional recovery and rate of return to preinjury levels of sports among recreational athletes after anterior cruciate ligament reconstruction (ACLR). PURPOSE: To investigate the recovery of quadriceps or hamstring strength, assess functional performance, and determine the rate of return to preinjury sports levels among recreational athletes at 1 year after ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 91 recreational-level athletes who underwent anatomic single-bundle ACLR were enrolled. We evaluated the limb symmetry index (LSI) of the quadriceps and hamstring peak torque strength at 60°, in addition to hop test performance (single-leg, triple, crossover, and 6-m timed), patient-reported outcomes, and pre- versus postoperative Tegner activity levels. Outcomes were compared between younger (age <25 years) and older patients (age ≥25 years). RESULTS: There were 48 patients in the younger group and 43 patients in the older group. At 1-year follow-up, the overall LSIs for quadriceps strength and hamstring strength were 77% and 86%, respectively, and the LSIs of the hop tests were 79% for single-leg, 81% for triple, 84% for crossover, and 85% for 6-m timed hop. Overall, only 24% patients returned to their preinjury Tegner level, and only 8% of patients met the criteria for return to pivoting, cutting, and jumping sports. At 1-year follow-up, the younger group showed significantly more quadriceps strength than the older group (85% vs 64%; P = .0001), better single, triple, crossover, and 6-m timed hop test results (85% vs 69%, P = .003; 84% vs 75%, P = .046; 91% vs. 74%, P < .001; and 91% vs 76%, P = .003, respectively), higher Lysholm score (87 vs 74; P < 0.001) and International Knee Document Committee score (82 vs 66; P < .001), and a higher rate of return to preinjury Tegner level (35% vs 12%; P = .009). CONCLUSION: Only 24% of patients returned to the preinjury Tegner level at 1 year after ACLR (35% younger group vs 12% older group; P = .009). This information might be helpful in setting realistic expectations for recreational athletes after surgery.

All-Organic, Solution-Processed, Extremely Conformal, Mechanically Biocompatible, and Breathable Epidermal Electrodes.

Conformal integration of an epidermal device with the skin, as well as sweat and air permeability, are crucial to reduce stress on biological tissues. Nanofiber-based porous mesh structures (breathable devices) are commonly utilized to prevent skin problems. Noble metals are normally deposited on nanomesh substrates to form breathable electrodes. However, these are expensive and require high-vacuum processes involving time-consuming multistep procedures. Organic materials are suitable alternatives that can be simply processed in solution. We report a simple, cost-effective, mechanically biocompatible, and breathable organic epidermal electrode for biometric devices. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is sprayed on a nanofiber-mesh structure, treated using only heat and water to enhance its biocompatibility and conductivity, and used as the electrode. The treatment is accomplished using an autoclave, simultaneously reducing the electrical resistance and sterilizing the electrode for practical use. This research can lead to affordable and biocompatible epidermal electrodes with improved suitability for various biomedical applications.

Intra-articular Administration of Tranexamic Acid Has No Effect in Reducing Intra-articular Hemarthrosis and Postoperative Pain After Primary ACL Reconstruction Using a Quadruple Hamstring Graft: A Randomized Controlled Trial.

BACKGROUND: Insufficient data are available to support the routine use of tranexamic acid (TXA) in anterior cruciate ligament (ACL) surgeries with respect to administration method and frequency, exposure duration, dose, and adverse effects. PURPOSE: To investigate whether intra-articular (IA) administration of TXA could reduce hemarthrosis and postoperative pain in patients after ACL reconstruction. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 47 patients were included in this study, which was performed between July 2017 and May 2019. Single-bundle reconstructions using autologous hamstring tendon grafts were performed in all patients. The patients were randomized into 2 groups: the TXA group (received the index procedure with 100-mL IA injection of TXA [30 mg/mL]) and a control group (did not receive IA injection of TXA). No patients received a drain. Blood loss was calculated on the basis of hemoglobin balance at postoperative day (PD) 2. The visual analog scale (VAS) for pain score was assessed at PD 3. The midpatellar circumference was measured at PD 2 and PD 5. Knee range of motion (ROM) was evaluated 6 weeks after surgery. RESULTS: The mean ± SD blood loss was 467 ± 242 mL in the TXA group and 558 ± 236 mL in the control group. No significant differences were found for blood loss (P = .20), VAS pain scores (P = .28), ROM at postoperative week 6 (P = .61), or patellar circumference at PD 2 (P = .75) and PD 5 (P = .84). CONCLUSION: This study showed that IA administration of 3.0 g of TXA had no effect in reducing blood loss and postoperative pain after primary anatomic single-bundle ACL reconstruction using quadruple hamstring autografts. REGISTRATION: NCT04042688 (ClinicalTrials.gov identifier).

Densely Distilled Flow-Based Knowledge Transfer in Teacher-Student Framework for Image Classification.

We propose a new teacherstudent framework (TSF)-based knowledge transfer method, in which knowledge in the form of dense flow across layers is distilled from a pre-trained "teacher" deep neural network (DNN) and transferred to another "student" DNN. In the case of distilled knowledge, multiple overlapped flow-based items of information from the pre-trained teacher DNN are densely extracted across layers. Transference of the densely extracted teacher information is then achieved in the TSF using repetitive sequential training from bottom to top between the teacher and student DNN models. In other words, to efficiently transmit extracted useful teacher information to the student DNN, we perform bottom-up step-by-step transfer of densely distilled knowledge. The performance of the proposed method in terms of image classification accuracy and fast optimization is compared with those of existing TSF-based knowledge transfer methods for application to reliable image datasets, including CIFAR-10, CIFAR-100, MNIST, and SVHN. When the dense flow-based sequential knowledge transfer scheme is employed in the TSF, the trained student ResNet more accurately reflects the rich information of the pre-trained teacher ResNet and exhibits superior accuracy to the existing TSF-based knowledge transfer methods for all benchmark datasets considered in this study.

Epidemiology of Bearing Dislocations After Mobile-Bearing Unicompartmental Knee Arthroplasty: Multicenter Analysis of 67 Bearing Dislocations.

BACKGROUND: This study investigated the epidemiology and causes of bearing dislocations following mobile-bearing unicompartmental knee arthroplasty (MUKA) and determined whether the incidence of primary bearing dislocations decreases as surgeon experience increases. METHODS: We retrospectively reviewed the bearing dislocations following MUKAs performed by 14 surgeons with variable experience levels. Causes of bearing dislocations were determined based on the surgical records, radiographs, and operator's suggestion. Using a chi-squared test, the incidence of bearing dislocation was compared between the first 50, the second 50, and the next 100 unicompartmental knee arthroplasties (UKAs) of each surgeon's cohort. RESULTS: There were 67 (3.6%) bearing dislocations from 1853 MUKAs. The mean time to bearing dislocations after index MUKAs was 33 months (range, 1-144 months); 55% of the bearing dislocations occurred within 2 years after the index MUKAs. Primary bearing dislocations (n = 58) were the most common, followed by secondary (n = 6) and traumatic dislocations (n = 3). There was no significant difference in the incidence of bearing dislocation between the first 50 and second 50 UKAs for each surgeon. Two surgeons showed a significant decrease in bearing dislocations in their second 100 UKAs, while the other surgeons did not show a difference between their first 100 and second 100 UKAs. CONCLUSION: Most bearing dislocations after MUKAs were related to technical errors such as component malposition or gap imbalance. This study did not confirm that the incidence of bearing dislocations decreases as the number of cases increases. LEVEL OF EVIDENCE: IV, Case series.

Breathable Nanomesh Humidity Sensor for Real-Time Skin Humidity Monitoring.

The importance of monitoring the condition of skin is increasing as its relevance to health is becoming more well understood. Inappropriate humidity levels can cause atopic dermatitis or hair loss. However, conventional film substrates used in electronic skin monitoring devices cause accumulation of sweat or gas between the device and biological tissue, leading to negative effects in long-term humidity measurements. Thus, real-time measurements of skin humidity over long periods are difficult using conventional film devices. Here, a breathable nanomesh humidity sensor that can monitor skin humidity for a long time is developed by using biocompatible materials such as gold, poly(vinyl alcohol), and Parylene C. The sensor presents excellent gas and sweat permeability and precisely detects the humidity level of an object for a long time. This study demonstrates the successful real-time detection of the humidity level from human skin and also detects the relative humidity of a plant surface over a prolonged period. This sensor is expected to have wide applicability for cultivating delicate plants as well as to reveal correlations between skin humidity and disease for biomedical applications.

Where is the Target Point to Prevent Cortical Hinge Fracture in Medial Closing-Wedge Distal Femoral Varus Osteotomy?

The purpose of this study was to investigate whether the location of the hinge affects the incidence of hinge fracture during medial closing-wedge distal femoral varus osteotomy (DFVO). Twenty knees from 10 fresh-frozen human cadavers (mean age, 75 ± 17 years) were used to perform uniplanar medial closing-wedge DFVO with a 7-mm wedge. Each specimen was randomly assigned to either group A (supracondylar hinge) or group B (lateral condylar hinge). The incidence of hinge fracture and stability was compared between both groups after uniplanar medial closing-wedge DFVO. In group A, 8 of 10 knees had a lateral cortex fracture during closure of the osteotomy gap, and all fractured knees were unstable. Two knees with an intact lateral cortical hinge showed stability under manual valgus and varus forces. After intentional breakage of the lateral cortical hinge, both knees were found to be unstable under the same force. In group B, 2 of 10 knees had a lateral cortex fracture, and 8 knees had no fractures. All specimens were found to be stable under manual valgus and varus forces. After intentional breakage of the lateral cortical hinge in group B, 2 knees were unstable, while 8 knees remained stable. This study showed a significantly higher incidence of lateral cortical hinge fracture and instability in group A than in group B during closure of the osteotomy gap.

Evaluation parameters of graft maturation on second-look arthroscopy following anterior cruciate ligament reconstruction: a systematic review.

PURPOSE: The purpose of this systematic review was to investigate and summarize the evaluation methods of graft maturation on second-look arthroscopy following anterior cruciate ligament (ACL) reconstruction. METHODS: A literature search was performed on articles before December 2017 to identify the literature that has evaluated graft maturation on second-look arthroscopy following ACL reconstruction. Only studies using human grafts, evaluating graft maturation with two or more gross findings were included. Study design, grafts, surgical techniques, follow-up period, evaluation parameters, and categories were compiled. RESULTS: Twenty-eight studies were included in this study. All studies evaluated graft maturation with two or more of the following three findings: graft integrity, tension, and synovial coverage. Two to four categories were used for evaluating each parameter, but the criteria for classification were slightly different for each study. Several studies reported neo-vascularization of grafts and the total maturation score by summing up the scores assigned to each evaluation parameter. Three studies reported that there was no correlation between second-look findings and patient-reported outcomes. CONCLUSIONS: Graft integrity, tension, and synovial coverage were the most frequently evaluated for graft maturation on second-look arthroscopy. However, there is no uniform criterion for evaluation. Therefore, development of a valid, uinform criterion is required. LEVEL OF EVIDENCE: Level IV, systematic review of level I-IV investigations.

High incidence of subsequent re-operation following treatments for medial meniscus tears combined with anterior cruciate ligament reconstruction: second-look arthroscopic study.

BACKGROUND: The Multicenter Orthopaedic Outcomes Network (MOON) group recently reported that medial meniscus (MM) repairs are associated with more frequent re-operations when compared to lateral meniscus (LM) repairs. The purpose of this study was to compare the meniscal healing and the incidence of subsequent re-operation of medial and lateral meniscal tears that occurred concurrently with anterior cruciate ligament (ACL) injuries. METHODS: We retrospectively reviewed patients who underwent second-look arthroscopy after primary ACL reconstruction (ACLR) between June 2005 to December 2016. The healing of meniscal tears following repair or left in situ, and re-tear following partial meniscectomy, were evaluated via second-look arthroscopy and compared between medial and lateral meniscus. Moreover, the incidence of subsequent meniscal re-operation after the index ACLR were investigated and compared between medial and lateral meniscus. Subsequent meniscal re-operation was performed in cases of the following three symptomatic meniscus tears: re-tears at the meniscectomy site; new tears; and failed healing of repaired or left in situ meniscus. RESULTS: There were 148 meniscal tears in 121 patients at index ACLR. There were 62 MM tears, 38 LM tears, and 24 bilateral meniscus tears. At second-look arthroscopy, the "successful healing" rate for tears following repair was higher in LM tears (91.2%) compared to MM tears (80.0%), although it was not statistically significant (p > 0.05). No significant differences were observed in the healing of left in situ tears or re-tear of meniscectomy site between medial and lateral meniscus. Patients with MM tears combined with ACL injuries had a higher incidence of subsequent meniscal re-operation compared to patients with LM tears (25.6% vs 16.1%, p = 0.025). CONCLUSIONS: There was a trend for the successful healing rate to be higher in LM repairs than MM repairs. Subsequent meniscal re-operations after ACLR were more frequent in patients with medial meniscal tears concurrently with ACL injuries in comparison to patients with lateral meniscal tears. LEVEL OF STUDY: Level IV, retrospective case series.

Supine lateral radiographs at 90° of knee flexion have a similar diagnostic accuracy for chronic posterior cruciate ligament injuries as stress radiographs.

PURPOSE: This study aimed to evaluate whether supine lateral radiographs (SLRs) could replace stress radiographs for diagnosing chronic posterior cruciate ligament (PCL) injuries and identifying combined PCL injuries (defined as PCL injury with medial collateral ligament or posterolateral ligament complex injury). METHODS: In this retrospective study, both SLRs at 30° and 90° of knee flexion (30/90 SLRs) and Telos stress radiographs of patients with chronic PCL injuries (n = 38) and only 30/90 SLRs of healthy controls (n = 84) were taken. Injured-to-normal differences on 30/90 SLRs and stress radiographs were assessed. Correlation analysis was performed to evaluate injured-to-normal differences on 30/90 SLRs and stress radiographs in patients with chronic PCL injury. Subgroup analysis was performed to compare injured-to-normal differences on 30/90 SLRs and stress radiographs between the isolated and combined PCL injury groups. Receiver operating characteristic curves based on 30/90 SLRs were calculated to determine the cut-off value for diagnosing chronic PCL injury and identifying combined PCL injury. RESULTS: Injured-to-normal differences on both 30 SLRs (3.1 ± 3.6 vs 1.6 ± 1.2, P = 0.019) and 90 SLRs (7.5 ± 3.5 vs 1.2 ± 1.0, P < 0.001) were significantly greater in patients with chronic PCL injuries than in healthy controls. Further, 90 SLRs had a highly accurate diagnostic value for chronic PCL injuries (area under the curve 0.958). The cut-off value for diagnosing chronic PCL injuries based on 90 SLRs was 3.0 mm (sensitivity, 94.7%; specificity, 92.9%). Injured-to-normal differences on 30/90 SLRs were significantly correlated with those on stress radiographs. The correlation coefficients were 0.397 (P = 0.014) for 30 SLRs and 0.605 (P < 0.001) for 90 SLRs. The cut-off value for diagnosing combined PCL injuries based on 90 SLRs was 9.6 mm (area under the curve 0.72). CONCLUSIONS: The diagnostic accuracy of 90 SLRs for chronic PCL injuries was similar to that of stress radiographs. Therefore, the 90 SLRs are reliable alternative method to assess the posterior knee laxity when the stress radiographs are not available. LEVEL OF EVIDENCE: Level IV, case series.

Redislocation after Bearing Exchange for the Treatment of Mobile Bearing Dislocation in Medial Unicompartmental Knee Arthroplasty.

PURPOSE: This study was conducted to investigate the outcomes of bearing exchange for the treatment of mobile bearing dislocation in medial unicompartmental knee arthroplasty (UKA). MATERIALS AND METHODS: We retrospectively reviewed 18 patients (15 females and 3 males, mean age of 65 years) treated with bearing exchange following mobile bearing dislocation in medial UKA. The occurrence of bearing redislocation, the Oxford Knee Score, and radiographic changes at the last follow-up were investigated. RESULTS: Bearing redislocation after bearing exchange occurred in 9 of 18 patients (50%). Of these 9 patients, 7 underwent conversion to total knee arthroplasty after bearing redislocation. The 9 patients without bearing redislocation showed good to excellent clinical outcomes at a mean follow-up of 55 months after bearing exchange. The non-redislocation group had a higher percentage of posterior dislocation of the bearing than the redislocation group (55.5% vs. 22.2%, p=0.040). Univariate logistic regression analysis showed no significant risk factors for bearing redislocation. CONCLUSIONS: This study showed a high rate of bearing redislocation after isolated, mobile bearing exchange for bearing dislocation following medial UKA. Therefore, bearing exchange as a sole treatment should be carefully considered in selected patients with correctable causes of bearing dislocation.

Attenuation of inflammation and cartilage degradation by sulfasalazine-containing hyaluronic acid on osteoarthritis rat model.

The aim of this study was to investigate the effects of a sulfasalazine-containing hyaluronic acid (SASP/HA) systems on in vitro anti-inflammation and the alleviation of cartilage degradation in both lipopolysaccharide (LPS)-stimulated synoviocytes and a rat model of monosodium iodoacetate (MIA)-induced osteoarthritis (OA). The SASP/HA resulted in long-term release of SASP from the SASP/HA for up to 60 days in a sustained manner. In vitro studies performed using real-time polymerase chain reaction (PCR) assay revealed that the SASP/HA was able to effectively and dose-dependently inhibit the mRNA expression levels of pro-inflammatory cytokines such as matrix metalloproteinases-3 (MMP-3), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in LPS-stimulated synoviocytes. In vivo studies showed that intra articular injection of SASP/HA greatly reduced the MIA-stimulated mRNA expression of MMP-3, COX-2, IL-6, and TNF-α in blood. Furthermore, these significant anti-inflammatory effects of SASP/HA contributed markedly to the alleviation of progression of MIA-induced OA and cartilage degradation, as demonstrated by X-ray, micro-computed tomography (micro-CT), gross findings, and histological evaluations. Therefore, our findings indicated that the long-term and sustained delivery of SASP using HA can play a therapeutic role in alleviating inflammation as well as protecting against cartilage damage in OA.

Posterior-stabilized inserts are preferable to cruciate-substituting ultracongruent inserts due to more favourable kinematics and stability.

PURPOSE: It is unknown whether the conforming superiority of ultracongruent (UC) inserts over posterior stabilized (PS) inserts, due to an increased anterior lip for prevention of anterior displacement of the condyles during knee flexion, leads to better knee scores or greater knee stability in arthroplasty patients. This meta-analysis compared clinical outcomes, intraoperative kinematics, sagittal stability, and range of motion (ROM) between groups with either UC or PS inserts in primary total knee arthroplasty (TKA). METHODS: Studies that recorded clinical outcomes, intraoperative kinematics, sagittal stability, and ROM in patients who underwent primary TKA with UC or PS inserts were included in the meta-analysis. Subgroup analyses based on differences in flexion angles were performed for intraoperative kinematics. RESULTS: Thirteen studies met the criteria for inclusion in the meta-analysis. The UC and PS insert groups reported similar pain scores (95% CI - 0.15 to 0.16; n.s.) and function scores (95% CI - 0.30 to 0.14; n.s.). In contrast, femoral rotation during flexion (95% CI - 0.06 to 6.35; p = 0.05), posterior femoral translation during flexion (95% CI - 2.74 to - 0.15; p = 0.03), tibial sagittal laxity at 90° (95% CI 2.91 to 7.72; p < 0.0001), and ROM (95% CI - 4.84 to - 1.53; p = 0.0002) differed significantly between the groups. Subgroup analyses revealed that the pooled data for femoral rotation were significantly different between groups: 60°, 4.09 (p < 0.00001); 90°, 7.94 (p < 0.00001); and 120°, 8.16 (p < 0.00001). Furthermore, pooled data for posterior femoral translation were significantly different between groups: 90°, - 3.70 (p < 0.00001); and 120°, - 3.96 (p < 0.00001). CONCLUSIONS: There were no significant differences in clinical outcomes between the groups with UC and PS inserts. However, the UC insert group showed significantly greater external femoral rotation, less posterior femoral translation, greater tibial laxity in the sagittal plane, and less ROM than the PS insert group. Based on the results of the current meta-analysis, in substituting the PCL, PS inserts are preferable to UC inserts due to more favourable kinematics and stability, even though both inserts have equivalent clinical outcomes. LEVEL OF EVIDENCE: Therapeutic study, Level II.

Hamstring autograft maturation is superior to tibialis allograft following anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: Using second-look arthroscopy, graft maturation was investigated and compared between hamstring (HA) autografts and tibialis anterior (TA) allografts after anatomic single-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: Fifty-six patients who underwent second-look arthroscopy after anatomic single-bundle ACLR with either HA autografts (26, HA group) or TA allografts (30, TA group) from 2007 to 2016 were retrospectively reviewed. Graft maturation on second-look arthroscopy was evaluated in terms of four parameters: graft integrity (tear), synovial coverage, graft tension, and graft vascularization. Each parameter received a maximum of two points, depending on the status of the reconstructed graft. The total graft maturation score was calculated as the sum of the parameter scores. The total graft maturation and individual parameter scores were compared between the two groups. RESULTS: The mean time from ACLR to second-look arthroscopy was 22.5 ± 7.8 months. The maturation scores in the HA group were significantly better in terms of graft integrity (p = 0.041), graft tension (p = 0.010), and graft vascularization (p = 0.024), whereas the graft synovial coverage score was not significantly different. The total graft maturation score of the HA group was significantly higher than that of the TA group (6.3 ± 0.4 vs. 4.9 ± 0.3, p = 0.013). CONCLUSIONS: This study shows the superior graft maturation of HA autografts compared with that of TA allografts at a mean follow-up of 22.5 ± 7.8 months after anatomic single-bundle ACLR. When anatomic ACLR using soft tissue graft is planned, HA autograft is recommended rather than soft tissue allograft, especially in young and active patients. LEVEL OF EVIDENCE: Retrospective cohort review, Level III.

Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. METHODS: We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. RESULTS: There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/µL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/µL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). CONCLUSION: Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

Does new instrumentation improve radiologic alignment of the Oxford® medial unicompartmental knee arthroplasty?

BACKGROUND: A new instrument system has been introduced to improve the accuracy and reproducibility of implant positioning in Oxford® unicompartmental knee arthroplasty (UKA). This study aimed to determine if the new instrumentation could improve postoperative implant positioning and limb alignment, and reduce the occurrence of outliers in Oxford® UKA. METHODS: A total of 77 cases of Oxford® UKA with the new instrumentation were included. Individual matching for the conventional instrument group was performed according to age, sex, and body mass index. Postoperative radiological variables, including the hip-knee-ankle angle and the varus/valgus and flexion/extension angles of the femoral and tibial implants, were measured and compared between the new instrumentation group and the conventional group. The outliers in implant positions and postoperative complications were also compared. RESULTS: No significant between-group differences were observed in terms of lower limb alignment and tibial implant alignment. However, statistically significant differences were identified in the varus/valgus and flexion/extension angles of the femoral implant (P=0.01 and P<0.001, respectively). More outliers were observed in the flexion/extension angles of the femoral and tibial implants in the new instrumentation group. Eight meniscal bearing dislocations and three lateral compartmental degenerative changes were found in the conventional group, while there were two meniscal bearing dislocations in the new instrumentation group during the study period. CONCLUSION: The present study did not confirm any benefit of the new instrument system in terms of postoperative limb alignment, positioning of the implant, or reducing outliers beyond the use of the conventional instruments.

What Factors Are Associated With Femoral Component Internal Rotation in TKA Using the Gap Balancing Technique?

BACKGROUND: When using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables. QUESTIONS/PURPOSES: (1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT? METHODS: Three hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson's correlation analysis, the postoperative TEA-PCA measured with postoperative CT was compared with theoretical TEA-PCA, which was calculated with preoperative TEA-PCA and actual femoral component rotation checked by the navigation system. RESULTS: After controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2-15]; Step 3: OR, 22, [95% CI, 7.8-62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA-PCA and the postoperative TEA-PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160). CONCLUSIONS: Extent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored. LEVEL OF EVIDENCE: Level III, therapeutic study.