Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction Decreases Passive Anterior Tibial Subluxation Compared With Isolated Anterior Cruciate Ligament Reconstruction Despite Similar Rotational Stability and Clinical Outcomes.

PURPOSE: To analyze the effect of augmenting a hamstring autograft anterior cruciate ligament reconstruction (ACLR) with an anterolateral ligament reconstruction (ALLR) on a primary outcome of passive anterior tibial subluxation (PATS) and a secondary outcome of the clinical outcomes. METHODS: ACL-injured patients who underwent primary ACLR between March 2014 and February 2020 at our center were enrolled. Patients who underwent combined procedures (ACLR + ALLR) were matched in a 1:1 propensity ratio to patients who underwent ACLR only. We evaluated PATS, knee stability (side-to-side laxity difference, pivot-shift test), and patient-reported outcome measures (PROMs) after the procedure and documented complications. RESULTS: From an initial cohort of 252 patients with a minimum follow-up period of 2 years (48.4 ± 16.6 months), 35 matched pairs were included, and 17 patients (48.6%) in each group underwent second-look arthroscopy. The combined ACLR + ALLR group showed significantly better improvement of PATS in the lateral compartments than the isolated ACLR group (P = .034). There were no significant differences between the groups regarding knee stability (side-to-side laxity difference, pivot-shift test), PROMs, complications, and second-look arthroscopic findings (all P > .05). Moreover, the proportions of patients who achieved the minimal clinically important difference in PROMs were not different between groups. CONCLUSIONS: The combined ACLR + ALLR procedure was associated with a mean improvement in anterior tibial subluxation for the lateral compartment that was 1.2 mm better than an isolated ACLR procedure, despite its lack of clinical significance. LEVEL OF EVIDENCE: Level III, cohort study.

Trend Shift in the Cause of Revision Total Knee Arthroplasty over 17 Years.

Background: The number of revision total knee arthroplasty (TKA) has been increasing. Although many studies have analyzed the causes of revision TKA in Western countries, a limited number of studies have analyzed changes in causes of or trends in revision TKA in Asia. This study analyzed and determined the frequency and causes of failures after TKA in our hospital. We also analyzed the differences and trends over the past 17 years. Methods: A total of 296 revision TKAs performed in a single institution from 2003 to 2019 were analyzed. During the 17-year study period, patients who had undergone primary TKA between 2003 and 2011 were classified into a past group, while those who had undergone primary TKA from 2012 to 2019 were classified into a recent group. A revision performed within 2 years after primary TKA was defined as early revision. Further, differences in causes of revision TKA according to the interval from primary TKA to revision TKA were determined. The causes of revision TKA were analyzed through a comprehensive analysis of patients' medical records. Results: Overall, infection was the most common cause of failure (151/296 cases, 51.0%). Compared to the past group, the recent group had a relatively higher proportion of patients undergoing revision TKA for mechanical loosening (past group, 19.1% vs. recent group, 31.9%) and instability (11.2% vs. 13.5%) and a relatively lower proportion of patients undergoing revision TKA for infection (56.2% vs. 48.8%), polyethylene (PE) wear (9.0% vs. 2.9%), osteolysis (2.2% vs. 1.9%), and malalignment (2.2% vs. 1.0%). On comparison according to the interval from primary TKA to revision TKA, the rate of infection relatively decreased, whereas the rate of mechanical loosening and instability relatively increased in the late revision TKA compared to the early revision TKA. Conclusions: Infection and aseptic loosening were the most common reasons of revision TKA in both past and recent groups. Compared to the past, revision TKA due to PE wear has decreased significantly and revision TKA due to mechanical loosening has relatively increased recently. Orthopedic surgeons need to be aware of recent trends in mechanisms of failure and should try to recognize and address the probable causes in TKA.

No Difference in Clinical Outcomes and Survivorship for Robotic, Navigational, and Conventional Primary Total Knee Arthroplasty with a Minimum Follow-up of 10 Years.

Background: Computer-assisted surgery, including robotic and navigational total knee arthroplasty (TKA), has been proposed as a technique used to improve alignment of implants. The purpose of this study was to compare the clinical and radiological outcomes during a minimum follow-up period of 10 years among robotic, navigational, and conventional TKA. Methods: A total of 855 knees (robotic group, 194; conventional group, 270; and navigational group, 391) were available for physical and radiological examinations over a mean follow-up period of 10 years. The survival rate was analyzed using the Kaplan-Meier method based on the survival endpoint. The Hospital for Special Surgery score, Western Ontario and McMaster Universities Osteoarthritis Index, Knee Society Score, and range of motion were used for clinical evaluation. The hip-knee-ankle (HKA) axis angle, the coronal inclination of femoral and tibial components, and the presence of radiolucent lines were also assessed at the final follow-up. Results: All clinical assessments at the final follow-up revealed improvements in the three groups without any significant difference among the groups (p > 0.05). The cumulative 10-year survival rate was 97.4% in the robotic group, 96.6% in the conventional group, and 98.2% in the navigational group, with no significant difference (p = 0.447). The rates of complication-associated surgery were not significantly different among the groups (p = 0.907). Only the proportion of outliers in the HKA axis angle showed a significant difference (p = 0.001), but other radiological outcomes were not significantly different among the three groups. Conclusions: Our study demonstrated satisfactory survival rates for robotic, navigational, and conventional TKAs and similar clinical outcomes during the long-term follow-up. Larger studies with continuous serial data are needed to confirm these findings.

Preoperative Bone Marrow Edema Negatively Impacts 10-Year Outcomes After Unicompartmental Knee Arthroplasty.

BACKGROUND: The purpose of this study was to investigate the association between the extent of subchondral bone marrow edema (BME), as classified by magnetic resonance imaging, and intermediate to long-term outcomes after unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis. METHODS: We enrolled 150 knees (144 patients) that underwent fixed-bearing UKA between April 2003 and December 2014 with a minimum follow-up of 5 years; the mean overall follow-up duration was 10 years (range, 5-18 years). We divided the patients into 2 groups based on the presence or absence of preoperative BME. Patients were also subdivided into 4 groups according to their BME scores determined by the magnetic resonance imaging Osteoarthritis Knee Score method. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Forgotten Joint Score. Furthermore, survival rates and relevant risk factors that affect joint survivorship were analyzed. RESULTS: The groups with BME demonstrated significantly worse postoperative WOMAC pain and Forgotten Joint Scores at the final follow-up than the group without BME (all P < .05). We also found significant differences among the scores of groups with different BME grades (all P < .05). Post hoc analysis demonstrated differences between groups 1 and 2, 1 and 3, 1 and 4, and 2 and 4 (all P < .05) with a significant correlation between postoperative clinical outcomes and the extent of BME (r = 0.430 [WOMAC pain], r = -0.342 [Forgotten Joint Score]; P < .05). The survival rate was 95.4% for a mean period of 10 years for the UKAs, and the UKA survival was not associated with the presence of BME (P = .232; log-rank test). CONCLUSION: At a mean of 10 years, preoperative BME negatively impacted the clinical outcomes, especially pain, after UKA. However, UKA contributed to excellent survival rates for the same duration of follow-up, regardless of BME severity. Although this study does not provide any evidence that preoperative BME should be identified as a contraindication, evaluation of BME can provide crucial information about the expected outcomes.

Allogenic umbilical cord blood-derived mesenchymal stromal cell implantation was superior to bone marrow aspirate concentrate augmentation for cartilage regeneration despite similar clinical outcomes.

PURPOSE: The aim of this study was to compare clinical and second-look arthroscopic outcomes between bone marrow aspirate concentrate (BMAC) augmentation and human umbilical cord blood-derived mesenchymal stromal cell (hUCB-MSC) implantation in high tibial osteotomy (HTO) for medial compartmental knee osteoarthritis and identify the relationship between articular cartilage regeneration and HTO outcomes. METHODS: A total of 176 patients who underwent HTO combined with a BMAC or hUCB-MSC procedure for medial compartment osteoarthritis (Kellgren-Lawrence grade 3) between June 2014 and September 2018 with a minimum follow-up of 2 years were reviewed. After HTO, multiple holes were drilled at cartilage defect sites of the medial femoral condyle (MFC), and then prepared BMAC or hUCB-MSCs in combination with scaffolds were implanted in the MFC lesions. After propensity score matching based on sex, age, body mass index, and lesion size, 55 patients in each of the BMAC and hUCB-MSC groups were successfully matched. Second-look arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system and Koshino staging system. Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), Short-Form 36 (SF-36), and Tegner activity scores. RESULTS: At a mean follow-up of 33 months, clinical outcomes including IKDC, KOOS, SF-36, and Tegner activity scores were significantly improved in both groups (p < 0.001); however, there were no differences between the two groups. Second-look arthroscopy showed better healing of regenerated cartilage in the hUCB-MSC group (Grade I [4 cases, 9.1%]; Grade II [30 cases, 68.2%]; Grade III [11 cases, 22.7%]) than in the BMAC group (Grade I [1 case, 2.7%]; Grade II [20 cases, 54.1%]; Grade III [11 cases, 29.7%]; Grade IV [5 cases, 13.5%]) according to the ICRS CRA grading system (p = 0.040). There was no significant intergroup difference in terms of defect coverage based on the Koshino staging system (p = 0.057). Moreover, ICRS CRA grades at second-look arthroscopy were significantly correlated with clinical outcomes (r = - 0.337; p = 0.002). CONCLUSION: There were no significant differences in the clinical outcomes between the two groups. Both treatments provided similar, reliable outcomes in terms of pain relief, functional scores, and quality of life at a mean follow-up of 33 months. However, hUCB-MSC implantation was more effective than BMAC augmentation for articular cartilage regeneration.

Extent of Preoperative Medial Meniscal Extrusion Influences Intermediate-Term Outcomes After Medial Opening-Wedge High Tibial Osteotomy.

BACKGROUND: The purpose of the present study was to determine the relationship between preoperative medial meniscal extrusion, as classified according to magnetic resonance imaging (MRI), and medial opening-wedge high tibial osteotomy outcomes at intermediate-term follow-up. METHODS: We reviewed the records for 212 patients who had undergone medial opening-wedge high tibial osteotomy for the treatment of medial compartment osteoarthritis between January 2009 and September 2014, with a minimum duration of follow-up of 5 years. Patients were divided into 2 groups according to the presence of pathologic medial meniscal extrusion (>3 mm). Moreover, patients were divided into 4 groups according to MRI Osteoarthritis Knee Score (MOAKS) criteria and relative medial meniscal extrusion values. Associations between the extent of preoperative medial meniscal extrusion and clinical outcomes over a mean duration of follow-up of 8.1 years were evaluated with use of Spearman rank correlation analysis. Regression analyses were performed to determine preoperative characteristics relevant to medial meniscal extrusion. Clinical outcomes were assessed with use of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Tegner activity scale score. RESULTS: Postoperative KOOS pain scores were significantly different in the pathologic and non-pathologic medial meniscal extrusion groups (69.9 ± 18.0 versus 79.2 ± 11.4, respectively; p < 0.001). Additionally, the degree of preoperative medial meniscal extrusion based on both classification methods and the postoperative KOOS pain score were significantly correlated (r = -0.404 and -0.364; p < 0.001). Despite the inferior clinical outcomes associated with greater preoperative medial meniscal extrusion, medial opening-wedge high tibial osteotomy was associated with significant improvement in all outcome measures between the preoperative and latest follow-up assessments (p < 0.001). Preoperative meniscal patterns, including horizontal flap, complex, and root tears (p = 0.001), and increased Kellgren-Lawrence grade (p < 0.001) were related to the severity of medial meniscal extrusion. The survival rate was 94.8% at a mean of 8.1 years, and survival was not associated with the grade of medial meniscal extrusion as assessed with either classification scheme. CONCLUSIONS: At intermediate-term follow-up, greater preoperative medial meniscal extrusion was related to inferior postoperative clinical outcomes, specifically pain, after medial opening-wedge high tibial osteotomy. Despite the inferior results associated with preoperative medial meniscal extrusion, medial opening-wedge high tibial osteotomy was associated with a satisfactory survival rate after a mean of 8.1 years, regardless of the extent of medial meniscal extrusion. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Older age increases the risk of revision and perioperative complications after high tibial osteotomy for unicompartmental knee osteoarthritis.

Among various patient risk factors affecting survival after high tibial osteotomy (HTO), the ideal age limit for HTO is unclear. This study was performed to evaluate the effect of age on survival rate and complications after HTO for medial unicompartmental osteoarthritis. Among of 61,145 HTO patients from Korean National Health Insurance database, 41,112 patients underwent the procedure before the age of 60 years (Group A), 13,895 patients between the age of 60 and 65 years (Group B), and 6138 patients after the age of 65 years (Group C). We compared the survival rate in person-years among the three groups from the date of primary surgery until subsequent total knee arthroplasty. Perioperative complications were also recorded. The adjusted hazard ratio (HR) were calculated using the multivariable Cox proportional hazard regression model, adjusting for the potential confounders: age, sex, type of medical insurance, region of residence, hospital type, comorbidities, and Charlson comorbidity index score. The total number of HTO increased 6.5-fold, especially in patients aged > 65 years (by 8.2-fold) from 2008 to 2018. The overall revision rate was 4.2% in Group A, 6.4% in Group B, and 7.3% in Group C. The 5- and 10-year revision rate was significantly lower in Group A (p < 0.001), but no difference between Groups B and C. After adjusting for potential confounders, multivariable regression analysis revealed that revision rate was significantly lower in Group A than Group B (HR: 0.57; p < 0.0001), but no difference between Groups B and C. The incidence of complications was also significantly lower in Group A than in other groups. The inferior survival rate and more perioperative complications after HTO was found in old patients (aged ≥ 60 years) than in young patients. Therefore, the patient age is one of the predicting factors for a high risk of failure after HTO.

Second-look arthroscopic cartilage status is related to intermediate-term outcomes after medial opening-wedge high tibial osteotomy.

AIMS: To determine the relationship between articular cartilage status and clinical outcomes after medial opening-wedge high tibial osteotomy (MOHTO) for medial compartmental knee osteoarthritis at intermediate follow-up. METHODS: We reviewed 155 patients (155 knees) who underwent MOHTO from January 2008 to December 2016 followed by second-look arthroscopy with a mean 5.3-year follow-up (2.0 to 11.7). Arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system. Patients were divided into two groups based on the presence of normal or nearly normal quality cartilage in the medial femoral condyle: good (second-look arthroscopic) status (ICRS grade I or II; n = 70), and poor (second-look arthroscopic) status (ICRS grade III or IV; n = 85) groups at the time of second-look arthroscopy. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form survey. RESULTS: Significant improvements in all clinical outcome categories were found between the preoperative and second-look arthroscopic assessments in both groups (p < 0.001). At the latest follow-up, the mean IKDC and WOMAC scores in the good status group further improved compared with those at the time of second-look arthroscopic surgery (p < 0.001), which was not shown in the poor status group. The mean IKDC (good status, 72.8 (SD 12.5); poor status, 64.7 (SD 12.1); p = 0.002) and mean WOMAC scores (good status, 15.7 (SD 10.8); poor status, 21.8 (SD 13.6); p = 0.004) significantly differed between both groups at the latest follow-up. Moreover, significant correlations were observed between ICRS CRA grades and IKDC scores (negative correlation; p < 0.001) and WOMAC scores (positive correlation; p < 0.001) at the latest follow-up. Good cartilage status was found more frequently in knees with the desired range of 2° to 6° valgus correction than in those with corrections outside this range (p = 0.019). CONCLUSION: Second-look arthroscopic cartilage status correlated with clinical outcomes after MOHTO at intermediate-term follow-up, despite the relatively small clinical differences between groups. Cite this article: Bone Joint J 2021;103-B(11):1686-1694.

No difference of survival between cruciate retaining and substitution designs in high flexion total knee arthroplasty.

The aim of this study was to compare the long-term implant survival and outcomes in patients with high-flexion cruciate-retaining (CR) or high-flexion posterior cruciate-substituting (PS) knee implants. A total of 253 knees (CR group: 159 vs. PS group: 94) were available for examination over a mean follow-up of 10 years. Clinical outcomes were assessed including the Hospital for Special Surgery score, Knee Society score and Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up. Radiologic measurements were also assessed including the hip-knee-ankle angle and radiolucent lines according to the KSS system at the final follow-up. The survival rate was analyzed using the Kaplan-Meier method. At the final follow-up, the mean total HSS scores were similar between the two groups (p = 0.970). The mean hip-knee-ankle angle at the final follow-up was similar between groups (p = 0.601). The 10- and 15-year survival rates were 95.4% and 93.3% in the CR group and 92.7% and 90.9% in the PS group, respectively, with no significant difference. Similar clinical and radiographic outcomes could be achieved with both the high-flexion CR and high-flexion PS total knee designs without a difference in survival rate after a 10-year follow-up.

Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Are More Effective Than Bone Marrow Aspiration Concentrate for Cartilage Regeneration After High Tibial Osteotomy in Medial Unicompartmental Osteoarthritis of Knee.

PURPOSE: The purpose of this study was to compare the outcome of cartilage regeneration between bone marrow aspirate concentrate (BMAC) augmentation and allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSCs) transplantation in high tibial osteotomy (HTO) with microfracture (MFX) for medial unicompartmental osteoarthritis (OA) of the knee in the young and active patient. METHODS: Between January 2015 and December 2019, the patients who underwent HTO and arthroscopy with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA with kissing lesion, which was shown full-thickness cartilage defect (≥ International Cartilage Repair Society [ICRS] grade 3B) in medial femoral cartilage and medial tibial cartilage, were include in this study. Retrospectively we compared clinical outcomes, including Hospital for Special Surgery score, Knee Society Score (KSS) pain and function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between BMAC and hUCB-MSCs group at minimum of 1-year follow-up. Also, second-look arthroscopy was performed simultaneously with removal of the plate after complete bone union. Cartilage regeneration was graded by the ICRS grading system at second-look arthroscopy. Radiological measurement including hip-knee-ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed. RESULTS: Of 150 cases that underwent HTO with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA, 123 cases underwent plate removal and second-look arthroscopy after a minimum of 1 year after the HTO surgery. Seventy-four cases were kissing lesion in medial femoral cartilage and medial tibial cartilage during initial HTO surgery. Finally, the BMAC group composed of 42 cases and hUCB-MSCs group composed of 32 cases were retrospectively identified in patients who had kissing lesions and second-look arthroscopies with a minimum of 1 year of follow-up. At the final follow-up of mean 18.7 months (standard deviation = 4.6 months), clinical outcomes in both groups had improved. However, there were no significant differences between the IKDC, WOMAC, or KSS pain and function scores in the 2 groups (P > .05). At second-look arthroscopy, the ICRS grade was significantly better in the hUCB-MSC group than in the BMAC group in both medial femoral and medial tibial cartilage (P = .001 for both). The average ICRS grade of the BMAC group improved from 3.9 before surgery to 2.8 after surgery. The average ICRS grade of the hUBC-MSC group improved from 3.9 before surgery to 2.0 after surgery. Radiological findings comparing postoperative HKA angle, posterior tibial slope angle, and correction angle showed no significant differences between the groups (P > .05). Therefore it was found that the postoperative correction amount did not affect the postoperative cartilage regeneration results. CONCLUSIONS: We found that the hUCB-MSC procedure was more effective than the BMAC procedure for cartilage regeneration in medial unicompartmental knee OA even though the clinical outcomes improved regardless of which treatment was administered. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Increased joint obliquity after open-wedge high tibial osteotomy induces pain in the lateral compartment: a comparative analysis of the minimum 4-year follow-up outcomes using propensity score matching.

PURPOSE: To analyze the effects of increased medial proximal tibial angle (MPTA) on the clinical outcomes and cartilage deterioration in the lateral compartment after a mean follow-up period of 4 years following open-wedge high tibial osteotomy (OWHTO) using propensity score matching (PSM) analysis. METHODS: Among 376 knees treated with OWHTO for medial unicompartmental osteoarthritis with varus deformity, 36 knees with MPTA increase of > 95° and 108 knees with MPTA increase of < 95° at the final follow-up were included. The baseline prognostic factors [age, sex, preoperative hip-knee-ankle (HKA) angle, body mass index, and preoperative knee range of motion] were equalized between the 2 groups using PSM; consequently, 31 pairs of patients were compared. The radiographic and clinical outcomes, including lateral compartment pain, were assessed. For 18 patients in each group, second-look arthroscopy and cartilage status assessment were performed. RESULTS: The preoperative demographics were similar between the groups. At the final follow-up, the HKA angle and joint line obliquity were significantly higher in the increased MPTA group. No significant differences were observed in the clinical outcomes between the groups. On second-look arthroscopy, significant cartilage deterioration of the lateral compartment was not observed in either group. Pain in the lateral compartment was experienced significantly more frequently in the increased MPTA group (p < 0.01). CONCLUSION: Although excessively increased MPTA after HTO had no significant effects on the clinical outcomes and cartilage deterioration in the lateral compartment at the minimum 4-year follow-up, lateral compartment pain was experienced significantly more frequently in the increased MPTA group.

Allogeneic umbilical cord blood-derived mesenchymal stem cells combined with high tibial osteotomy: a retrospective study on safety and early results.

BACKGROUND: Cartilage repair performed as a single-stage procedure is an important advancement in the treatment of full-thickness cartilage injury and has potential for widespread clinical use. PURPOSE: To investigate the short-term outcomes and cartilage regeneration after implantation of allogeneic human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in patients who received high tibial osteotomy (HTO) for symptomatic medial knee osteoarthritis. METHODS: Patients underwent treatment of full-thickness chondral injury in the osteoarthritic knee with HTO and implantation of hUCB-MSCs and were followed prospectively for a minimum of one year. Ninety-three patients were followed for a mean 1.7 years (range, 1.0-3.5). Median cartilage lesion size was 6.5 cm2 (range, 2.0-12.8). Clinical outcomes were examined with patient-reported scoring instruments that consisted of the International Knee Documentation Committee (IKDC) subjective score, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score, Knee Society Score (KSS), and Hospital for Special Surgery (HSS) score. Cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) cartilage repair assessment grading (CRA) system and the Koshino regeneration staging system in 49 patients who underwent second look arthroscopic assessment when their HTO plates were removed. RESULTS: At final follow-up, the median IKDC subjective score had significantly improved from 39.0 to 71.3; the WOMAC score from 44.5 to 11.0; the KSS pain and function scores from 29.8 to 43.2 and 61.0 to 81.2, respectively; and the HSS from 61.6 to 82.7 (p < 0.05). Pre-operative examination showed ICRS grade IV cartilage injury in all knees, and cartilage regeneration at 2nd look arthroscopy showed improvements (8.2% of patients improved to ICRS grade I, 69.3% to grade II, and 22.5% to grade III). Moreover, Koshino stage was B in 24.5% and C in 75.5% of patients (p < 0.05). CONCLUSION: Allogeneic hUCB-MSC implantation combined with HTO for medial knee osteoarthritis was safe and showed signs of cartilage status improvement. Furthermore, randomized controlled studies with a control group are necessary to determine the real effectiveness and indications of this new combined procedure for patients with osteoarthritis.

Human adipose-derived mesenchymal stem cell-based medical microrobot system for knee cartilage regeneration in vivo.

Targeted cell delivery by a magnetically actuated microrobot with a porous structure is a promising technique to enhance the low targeting efficiency of mesenchymal stem cell (MSC) in tissue regeneration. However, the relevant research performed to date is only in its proof-of-concept stage. To use the microrobot in a clinical stage, biocompatibility and biodegradation materials should be considered in the microrobot, and its efficacy needs to be verified using an in vivo model. In this study, we propose a human adipose-derived MSC-based medical microrobot system for knee cartilage regeneration and present an in vivo trial to verify the efficacy of the microrobot using the cartilage defect model. The microrobot system consists of a microrobot body capable of supporting MSCs, an electromagnetic actuation system for three-dimensional targeting of the microrobot, and a magnet for fixation of the microrobot to the damaged cartilage. Each component was designed and fabricated considering the accessibility of the patient and medical staff, as well as clinical safety. The efficacy of the microrobot system was then assessed in the cartilage defect model of rabbit knee with the aim to obtain clinical trial approval.

The Influence of Preoperative Tibial Bone Marrow Edema on Outcomes After Medial Opening-Wedge High Tibial Osteotomy.

BACKGROUND: The relationship between preoperative subchondral bone marrow edema (BME) in the osteoarthritic knee and pain has been established. However, little is known about the influence of preoperative BME on outcomes after medial opening-wedge high tibial osteotomy (MOHTO). The purpose of this study was to clarify the association between preoperative BME severity and clinical outcomes after MOHTO at intermediate follow-up. METHODS: We reviewed the cases of 105 consecutive patients who underwent MOHTO for osteoarthritis of the knee with preoperative subchondral BME in the medial aspect of the tibia between January 2005 and December 2015. BME was evaluated using magnetic resonance imaging (MRI). The sizes of the BME lesions were determined on the basis of the maximum diameter and were classified as small (<1 cm), medium (<2 cm), large (<4 cm), or very large (diffuse; >4 cm). Associations between preoperative BME severity and postoperative outcomes at a mean follow-up of 6.2 years (range, 2.0 to 14.3 years) were evaluated according to a Spearman correlation matrix with each reviewer's grades. Functional outcomes were assessed using the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS), and Short Form-12 (SF-12) questionnaire. Survival rate and complications were also evaluated. RESULTS: The degree of preoperative BME was not significantly correlated with postoperative outcomes (p > 0.05). There were significant improvements between the preoperative and latest follow-up assessments in all functional outcome categories (p < 0.001). Patients demonstrated marked improvements with respect to pain, function, and quality of life. The overall survival rate was 95.2%, with a mean follow-up of 6.2 years. Six major complications were identified in 5.7% of the patients, and these resulted in 5 patients (4.8%) who had conversion to total knee arthroplasty. CONCLUSIONS: We did not find any correlation between preoperative subchondral BME severity and postoperative outcomes. MOHTO showed good functional outcomes, a low major complication rate, and an excellent survival rate with a mean follow-up of 6.2 years, regardless of the degree of preoperative BME. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Survival and Risk Factor Analysis of Medial Open Wedge High Tibial Osteotomy for Unicompartment Knee Osteoarthritis.

PURPOSE: The purpose of this retrospective study was to evaluate the survival rates and analyze the factors that affect survival rate after primary treatment with medial open wedge high tibial osteotomy (MOWHTO) for medial unicompartmental knee osteoarthritis. METHODS: Clinical evaluation using Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index score and radiographic evaluation, including mechanical axis, were done before and after surgery. The main failure criteria for survival included the conversion to total knee arthroplasty or KSS of <60 points. Furthermore, risk factors that affected the survival after MOWHTO were analyzed. RESULTS: Three hundred thirty-nine knees were included after a minimum of 5 years' follow-up. Their mean age was 56 years, and mean follow-up duration was 9.6 years. The mean KSS and Western Ontario and McMaster Universities Osteoarthritis Index scores were significantly improved after surgery (87.3 and 18.5 points at 5 years and 81.7 and 23.6 points at 10 years). The mean hip-knee-ankle (HKA) angle was corrected from 7.2° varus to 3.4° valgus 1 year after surgery, which was maintained until 10 years after surgery (2.9° valgus at 5 years and 2.3° valgus at 10 years, P > .05). Using Kaplan-Meier survival estimates, the probability of survival for MOWHTO was 96.8% at 5 years, 87.1% at 10 years, and 85.3% at 13 years. The multivariate regression analysis revealed that age ≥65 years (hazard ratio [HR] = 2.34, P = .046), medial compartment cartilage damage International Cartilage Repair Society grade ≥4 (HR = 2.46, I = .045), lateral compartment cartilage damage International Cartilage Repair Society grade≥2 (HR = 3.38, P = .006), postoperative HKA angle <0° (HR = 4.69, P < .001) were associated with failure. CONCLUSION: MOWHTO seems to be a good treatment option for young and active patients with medial knee osteoarthrosis and varus alignment, with acceptable survival rates and satisfactory outcomes. Age ≥65 years, grade 4 cartilage damage in medial compartment, grade ≥2 cartilage damage in lateral compartment, and undercorrection of HKA angle appear to be significant risk factors associated with failure. LEVEL OF EVIDENCE: Level IV: retrospective case series.

Comparison of Posterior Cruciate-Retaining and High-Flexion Cruciate-Retaining Total Knee Arthroplasty Design.

BACKGROUND: High-flexion prostheses have been developed to achieve deep flexion after total knee arthroplasty. The purpose of this study is to compare standard NexGen (CR, cruciate-retaining) and high-flexion NexGen (CR-flex) total knee prostheses in terms of range of motion, clinical and radiologic outcomes, rates of complications, and survivorship in long-term follow-up. METHODS: From January 2000 to December 2008, 423 consecutive knees underwent total knee arthroplasty using standard CR or CR-flex prostheses. Fifty-three patients were lost to follow-up or declined to participate and 54 died, leaving 290 knees. The minimum duration of follow-up was 8 years (mean 10.1 years). Physical examination and knee scoring of patients were assessed preoperatively, at 6 months and 1 year after surgery, and annually thereafter. Supine anteroposterior and lateral radiographs and standing anteroposterior hip-to-ankle radiographs were obtained preoperatively and at each follow-up. RESULTS: Mean postoperative range of motions in the standard CR group and the CR-flex group were similar, showing no significant difference between the 2 groups (P = .853). At the time of the final follow-up, mean total Hospital for Special Surgery scores were similar between the 2 groups (P = .118). Mean Knee Society pain (P = .325) and function scores (P = .659) were also comparable between the 2 groups. Western Ontario and McMaster Universities Osteoarthritis Index score showed no intergroup difference either (P = .586). The mean hip-knee-ankle angle at the final follow-up was approximately the same (P = .940). Mean coronal angles of femoral and tibial component at final follow-up were also similar (P = .211 and P = .764, respectively). The prevalence of the radiolucent line was 0.6% in the standard CR group and 0.9% in the CR-flex group. Estimated survival rate according to Kaplan-Meier survival analysis was 97.2% in the standard CR group and 95.6% in the CR-flex group at mean follow-up of 10.1 years. CONCLUSION: This study suggests that excellent clinical and radiographic outcomes could be achieved with both standard and high-flexion CR total knee designs. High-flexion CR prosthesis did not show any advantages over the standard design.

Comparison of Clinical and Radiologic Outcomes and Second-Look Arthroscopic Findings After Anterior Cruciate Ligament Reconstruction Using Fixed and Adjustable Loop Cortical Suspension Devices.

PURPOSE: To compare clinical and radiological outcomes, including tunnel widening, and to evaluate graft status by second-look arthroscopy after anterior cruciate ligament (ACL) reconstruction using 2 different femoral cortical suspension devices (fixed and adjustable loop). METHODS: Seventy-nine patients were included for this study. The patients were divided into 2 groups, 41 patients of fixed loop group (EndoButton) and 38 patients of adjustable loop group (TightRope). The Tegner activity, Lysholm knee score, Lachman test, and pivot-shift test were compared between the 2 groups. Anterior stress radiographs and femoral tunnel widening on plain radiographs were also compared. Twenty-seven patients (66%) in the EndoButton group and 21 patients (55%) in the TightRope group underwent the second-look arthroscopy. RESULTS: At the final follow-up, the mean Tegner activity, Lysholm, and International Knee Documentation Committee scores were improved in both groups and there were no statistically significant differences (5.1 ± 1.6 and 5.5 ± 2.1, P = .312; 90.4 ± 7.8 and 91.0 ± 6.5, P = .525; and 87.4 ± 6.7 and 88.7 ± 5.3, P = .127, respectively). There were no statistical significances in the both groups in terms of Lachman test and pivot-shift tests (P = .392, .559) as well as anterior stress radiographs (mean 3.2 ± 1.4 mm and 2.9 ± 1.1 mm, P = .343). Moreover, radiologic measurements comparing femoral tunnel widening at proximal and distal half also showed no significant differences (P = .540 and .412 on anteroposterior view; P = .254 and .437 on lateral view). In the second-look arthroscopy findings for graft tear and synovial coverage, there were no significant differences (P = .784 and .897). CONCLUSIONS: Both fixed loop and adjustable loop devices in ACL reconstruction provided good clinical and radiological outcomes. In patients with both devices, femoral tunnel widening at proximal and distal portion have no significant differences after ACL reconstruction. Moreover, second-look arthroscopy revealed no significant differences in terms of synovial coverage and rupture of the graft. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Correction to: No difference in outcomes and gait analysis between mechanical and kinematic knee alignment methods using robotic total knee arthroplasty.

The authors wish to acknowledge a confusion in alignment definition in the published paper.

No difference in outcomes and gait analysis between mechanical and kinematic knee alignment methods using robotic total knee arthroplasty.

PURPOSE: The purpose of this study was to compare clinical outcomes and perform gait analysis during walking to identify differences in kinematic and kinetic parameters between two alignment methods in robotic-assisted total knee arthroplasty (TKA). METHODS: Sixty patients were randomly assigned to undergo robotic-assisted TKA using either mechanical (30 patients) or kinematic (30 patients) alignment method. Clinical outcomes including varus and valgus laxities, range of motion (ROM), Hospital for Specific Surgery (HSS), Knee Society Score (KSS), and Western Ontario and McMaster Universities (WOMAC) scores and radiological outcomes were evaluated. Gait analysis of 3D spatiotemporal, kinetic, and kinematic parameters during walking was then performed for 10 age and gender matched patients of each group to determine differences between the two alignment methods. RESULTS: The median follow-up duration of the mechanical method group was 8.7 (range 8.1-9.4) years and that of the kinematic method group was 8.4 (range 8.0-9.1) years. Clinical outcomes between the two groups showed no significant difference in HSS, WOMAC, ROM, KS pain, or function score at the last follow-up. No significant difference in varus and valgus laxity assessment, mechanical alignment of the lower limb, or perioperative complications was shown between the two groups. In gait analysis, no significant difference in kinematic or kinetic parameters was found except for varus angle (p < 0.05) and mediolateral ground reaction force (p < 0.05). CONCLUSIONS: Results of this study show that mechanical and kinematic knee alignment methods provide comparable clinical and radiological outcomes after robotic total knee arthroplasty with an average follow-up of 8 years. There were no functional difference during walking between the two alignment methods either. LEVEL OF EVIDENCE: II.

Robotic versus conventional primary total knee arthroplasty: clinical and radiological long-term results with a minimum follow-up of ten years.

PURPOSE: The aim of this study was (1) to compare the clinical and radiological outcomes of robotic and conventional total knee arthroplasty with a minimum follow-up of ten years, (2) to evaluate the survival rate, (3) and to estimate the accuracy of the two techniques by analyzing the outliers of the total knee arthroplasty (TKA) patients. METHODS: We evaluated 351 patients (390 knees), 155 patients undergoing robotic TKA, and 196 patients treated with conventional TKA with a mean follow-up of 11.0 years. HSS, KSS, WOMAC, and SF-12 questionnaires were used for clinical evaluation. Mechanical alignment, implant radiological measurements, and outliers were analyzed for radiological results. Kaplan-Meier survival analysis was performed for survival rate. RESULTS: All clinical assessments showed excellent improvements in both groups (all p < 0.05), without any significant difference between the groups (p > 0.05). The conventional TKA group showed a significantly higher number of outliers compared with the robotic TKA group (0 < 0.05). The cumulative survival rate was 98.8% in the robotic TKA group and 98.5% in the conventional TKA group with excellent survival (p = 0.563). CONCLUSION: Our study showed excellent survival with both robotic and conventional TKA and similar clinical outcomes at long-term follow-up. And, in terms of radiological outcome, robotic TKA showed better accuracy and consistency with fewer outliers compared with conventional TKA. With longer follow-up and larger cohort, the accuracy and effectiveness of robotic TKA on implant survival rate can be elucidated in the future.