Implantation of mesenchymal stem cells in combination with allogenic cartilage improves cartilage regeneration and clinical outcomes in patients with concomitant high tibial osteotomy.

PURPOSE: This study aimed to compare the clinical, radiological, and second-look arthroscopic outcomes of implanting mesenchymal stem cells (MSCs) alone and together with allogenic cartilage in patients treated with concomitant high tibial oteotomy (HTO) for varus knee osteoarthritis. METHODS: Eighty patients treated with cartilage repair procedures and concomitant HTO were prospectively randomized into two groups: MSC implantation (MSC group), and MSC implantation with allogenic cartilage (MSC-AC group). Clinical outcomes were evaluated using the Lysholm Score and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at preoperative and every follow-up visit. Radiological outcomes were evaluated by measuring the femorotibial angle and posterior tibial slope. During second-look arthroscopy, cartilage regeneration was evaluated according to the Kanamiya grade. RESULTS: Clinical outcomes at the second-look arthroscopy (mean 12.5 months [MSC group] and 12.4 months [MSC-AC group]) improved significantly in both groups (P < 0.001 for all). Clinical outcomes from the second-look arthroscopy to the final follow-up (mean 27.3 months [MSC group] and 27.8 months [MSC-AC group]) improved further only in the MSC-AC group (P < 0.05 for all). Overall, the Kanamiya grades, which were significantly correlated with clinical outcomes, were significantly higher in the MSC-AC group than in the MSC group. Radiological outcomes at final follow-up revealed improved knee joint alignments relative to preoperative conditions but without significant correlation between clinical outcomes and Kanamiya grade in either group (n.s. for all). CONCLUSION: Implantation of MSCs with allogenic cartilage is superior to implantation of MSCs alone in cartilage regeneration accompanied with better clinical outcomes. LEVEL OF EVIDENCE: Therapeutic study, level II.

Comparative Matched-Pair Analysis of Keyhole Bone-Plug Technique Versus Arthroscopic-Assisted Pullout Suture Technique for Lateral Meniscal Allograft Transplantation.

PURPOSE: To compare the clinical outcomes and meniscal extrusion measured by magnetic resonance imaging (MRI) between the keyhole bone-plug technique and arthroscopic-assisted pullout suture technique in lateral meniscal allograft transplantation (MAT). METHODS: Between October 2009 and February 2015, patients who underwent lateral MAT were retrospectively reviewed. The inclusion criteria were patients with symptomatic knees that had undergone total or subtotal meniscectomy who were treated with lateral MAT with a minimum follow-up period of 2 years. We excluded 13 patients with anterior cruciate ligament injury to the ipsilateral knee and 6 patients with combined cartilage procedures. In addition, we excluded 19 patients because they did not undergo follow-up MRI and 13 patients who did not undergo more than 2 years of follow-up. Thirty-seven patients who underwent lateral MAT with the keyhole bone-plug technique were identified and assigned to group A. Forty-five patients who underwent lateral MAT with the arthroscopic-assisted pullout suture technique (group B) were then matched by age, body mass index, and time from previous meniscectomy to lateral MAT. Clinical outcome assessments included preoperative and postoperative subjective International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores and the visual analog scale (VAS) score for pain evaluation. MRI was used to assess meniscal extrusion. RESULTS: The mean follow-up period was 35.8 ± 6.5 months (range, 24-65 months) in group A and 34.6 ± 6.2 months (range, 24-55 months) in group B. Significant improvements in the VAS pain score, subjective IKDC score, Tegner score, and Lysholm score after lateral MAT were found (P < .001), and there were no significant differences between the 2 groups at final follow-up (VAS score, 1.4 ± 0.8 in group A and 1.2 ± 1.0 in group B [P = .164]; subjective IKDC score, 72.9 ± 8.1 in group A and 74.2 ± 7.3 in group B [P = .427]; Tegner activity score, 4.0 ± 0.9 in group A and 4.1 ± 0.8 in group B [P = .374]; and Lysholm score, 75.5 ± 10.6 in group A and 76.2 ± 11.8 in group B [P = .786]). On MRI, the meniscal extrusion extent was 3.1 ± 0.9 mm in group A and 2.9 ± 0.8 mm in group B (P = .223), and the relative percentages of extrusion were 27.0% ± 3.9% and 26.1% ± 4.2%, respectively (P = .273). CONCLUSIONS: Compared with the keyhole bone-plug technique, the arthroscopic-assisted pullout suture technique in lateral MAT showed comparable clinical and MRI results at short-term follow-up. LEVEL OF EVIDENCE: Level IV, case series with intragroup comparisons.

The Effect of Patient-Specific Instrumentation Incorporating an Extramedullary Tibial Guide on Operative Efficiency for Total Knee Arthroplasty.

This retrospective study was to determine if patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) leads to shortened surgical time through increased operating room efficiency according to different tibial PSI designs. 166 patients underwent primary TKA and were categorized into three groups as follows: PSI without extramedullary (EM) tibial guide (group 1, n = 48), PSI with EM tibial guide (group 2, n = 68), and conventional instrumentation (CI) group (group 3, n = 50). Four factors were compared between groups, namely, operative room time, thickness of bone resection, tibial slope, and rotation of the component. The mean surgical time was significantly shorter in the PSI with EM tibial guide group (group 2, 63.9 ± 13.6 min) compared to the CI group (group 3, 82.8 ± 24.9 min) (P < 0.001). However, there was no significant difference in the PSI without EM tibial guide group (group 1, 75.3 ± 18.8 min). This study suggests that PSI incorporating an EM tibial guide may lead to high operative efficiency in TKA compared to CI. This trial is registered with KCT0002384.

Patient-specific instrumentation development in TKA: 1st and 2nd generation designs in comparison with conventional instrumentation.

INTRODUCTION: This study was conducted to determine if the difference in magnetic resonance imaging (MRI)-based 2nd generation patient-specific instrumentation (PSI) design affects post-operative restoration of neutral mechanical alignment in total knee arthroplasty (TKA) compared with the 1st generation PSI design and conventional surgical techniques. In addition, it is aimed at elucidating whether PSI improves surgical efficiency with respect to operating room time, estimated blood loss and the number of instrument trays used intra-operatively. MATERIALS AND METHODS: We report our experience in TKA using PSI techniques in 234 patients from August 2012 to March 2015. The patients were divided into 1st (n = 64) and 2nd (n = 70) generation PSI design. The control group (n = 100) underwent TKA with the conventional instrument technique. RESULTS: The mean surgical time was significantly shorter in the 2nd generation PSI design (62.1 ± 12.1 min) than in the control group (80.6 ± 21.7 min; P < 0.001). A mechanical axis malalignment of >3° of the lower limb was observed in 5.7% of the patients in 2nd generation PSI design compared with 26.0% of the control group (P = 0.006). No significant difference in mechanical alignment on post-operative long alignment radiography was found between 20.3% of the patients in 1st generation PSI design and the control group (P = 0.584). CONCLUSION: The 1st generation PSI design did not have a shorter surgical time or improved alignment compared with conventional instrumentation (CI). However, the use of the perfectly fitted 2nd generation PSI design was associated with improvements in both of these measurements. This study emphasizes the importance of PSI design in intra-operative and post-operative outcomes of TKA.

Effects of measurement methods for tibial rotation axis on the morphometry in Korean populations by gender.

BACKGROUND: There have been arguments for methodology in tibial rotation axis measurement, which accordingly determines the morphometry of the proximal tibia in total knee arthroplasty. The morphometry of the proximal tibia for the Korean population is determined by gender, based on the anatomical tibial axis and reliable rotational orientation in knee replacements, to evaluate the size suitability of the currently available prostheses in Korea. METHODS: This study reconstructed the MRI images in three-dimensions for identification and measurement of the mediolateral (ML) and anteroposterior (AP) lengths of the proximal tibia and the tibial aspect ratio (ML/AP) using proximal tibial anthropometric data for 700 osteoarthritic knees (587 females and 113 males). The ML and AP lengths were measured using tibial rotation axis techniques based on the medial one-third tibial tubercle and Cobb's method. RESULTS: Significant differences (P<0.05) in ML, medial anteroposterior (MAP), lateral anteroposterior (LAP) lengths, and aspect ratio (ML/LAP) were observed for males and females with respect to different measurement techniques for the tibial rotation axis. However, the measured aspect ratio (ML/MAP) of tibiae for the Korean population did not show significance. The measured aspect ratio (ML/AP) ratio of tibiae for the Korean population was higher than that of currently available tibial components. CONCLUSIONS: Results from this study can guide development of gender-specific tibial prosthesis designs with different ML and AP aspect ratios based on the tibial anatomical rotation axis for the Korean population.

Morphometry of femoral rotation for total knee prosthesis according to gender in a Korean population using three-dimensional magnetic resonance imaging.

BACKGROUND: We aimed to evaluate differences in femoral arthometric data for 700 osteoarthritic knees (587 females and 113 males) with respect to gender in a Korean population. METHODS: We identified and measured the mediolateral (ML) and anteroposterior (AP) lengths, femoral aspect ratio (ML/AP), surgical epicondylar axis (SEA), and Whiteside's line (WL). In addition, the anterior, posterior, and distal bone resections of the implanted femurs were evaluated using SEA and WL as references using a three-dimensional analysis method. RESULTS: ML and AP lengths significantly differed according to gender. ML dimension and aspect ratio were greater in males than in females for a given AP dimension in the femur. No statistically significant differences in femoral rotation with SEA as a reference were observed between male and female knees; however, a significant difference was shown using WL as a reference and both affected the amount of bone resection irrespective of gender. CONCLUSION: This study provides important guidelines for gender-specific femoral prosthesis design with different ML and AP aspect ratios and femoral rotation based on SEA and WL for Korean populations.

Comparative Matched-Pair Analysis of the Injection Versus Implantation of Mesenchymal Stem Cells for Knee Osteoarthritis.

BACKGROUND: The mesenchymal stem cell (MSC)-based tissue engineering approach has been developed to address the problem of articular cartilage repair in knee osteoarthritis (OA). However, the most effective method of MSC application has not yet been established. PURPOSE: To compare the injection and implantation of MSCs in patients with knee OA in terms of clinical and second-look arthroscopic outcomes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Among 182 patients treated with arthroscopic surgery using MSCs for knee OA from October 2010 to August 2012, patients treated with an injection of MSCs in combination with platelet-rich plasma (injection group; n = 20) were pair-matched with patients who underwent MSC implantation on a fibrin glue scaffold (implantation group; n = 20) based on sex, age, and lesion size. Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC) score and Tegner activity scale, and cartilage repair was assessed arthroscopically with the International Cartilage Repair Society (ICRS) grading system. RESULTS: The mean (±SD) IKDC and Tegner activity scores significantly improved from 38.5 ± 9.2 to 55.2 ± 15.0 and from 2.5 ± 1.2 to 3.5 ± 1.2, respectively, in the injection group and from 36.6 ± 4.9 to 62.7 ± 14.1 and from 2.3 ± 0.9 to 3.6 ± 1.1, respectively, in the implantation group at the time of second-look arthroscopic surgery (mean, 12.6 months postoperatively) (P < .001 in all cases). At final follow-up (mean, 28.6 months postoperatively), the mean IKDC and Tegner activity scores in the implantation group had improved further to 64.8 ± 13.4 and 3.9 ± 1.0, respectively (P < .001 and P = .035, respectively), while no significant improvements were found in the injection group (P = .130 and P = .655, respectively). At final follow-up, there was a significant difference in the mean IKDC score between groups (P = .049). Significant correlations between the number of administered MSCs and the postoperative clinical outcomes were found only in the injection group. Significant correlations between the clinical outcomes and the ICRS grades were found in both groups. The ICRS grades were significantly better in the implantation group (P = .041). In the injection group, 2 of the 20 lesions (10%) were grade I (normal), 5 (25%) were grade II (near normal), 8 (40%) were grade III (abnormal), and 5 (25%) were grade IV (severely abnormal). In the implantation group, 6 of the 20 lesions (30%) were grade I, 7 (35%) were grade II, 4 (20%) were grade III, and 3 (15%) were grade IV. CONCLUSION: Utilizing the described method, MSC implantation for knee OA resulted in better clinical and second-look arthroscopic outcomes than an MSC injection.

Mesenchymal stem cell implantation in osteoarthritic knees: is fibrin glue effective as a scaffold?

BACKGROUND: The cell-based tissue engineering approach that uses mesenchymal stem cells (MSCs) has addressed the issue of articular cartilage repair in osteoarthritic (OA) knees. However, to improve outcomes, an advanced surgical procedure with tissue-engineered scaffolds may be needed to treat patients with large cartilage lesions. PURPOSE: To investigate the clinical and second-look arthroscopic outcomes of the implantation of MSCs loaded in fibrin glue as a scaffold in patients with OA knees and to compare these outcomes with those of MSC implantation without a scaffold. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This study retrospectively evaluated 54 patients (56 knees) who were examined with second-look arthroscopy after MSC implantation for cartilage lesions in their OA knees. Patients were divided into 2 groups: 37 patients (39 knees) were treated with MSC implantation without a scaffold (group 1), and 17 patients (17 knees) underwent implantation of MSCs loaded in fibrin glue as a scaffold (group 2). Clinical outcomes were evaluated according to the International Knee Documentation Committee (IKDC) score and the Tegner activity scale, and cartilage repair was assessed with the International Cartilage Repair Society (ICRS) grade. Statistical analyses were performed to identify various prognostic factors associated with the clinical and second-look arthroscopic outcomes. RESULTS: At final follow-up (mean, 28.6 months; range, 24-34 months), the mean IKDC score and Tegner activity scale in each group significantly improved: group 1, from 38.1±7.7 to 62.0±11.7 (IKDC) and from 2.5±0.9 to 3.5±0.8 (Tegner); group 2, from 36.1±6.2 to 64.4±11.5 (IKDC) and from 2.2±0.8 to 3.8±0.8 (Tegner) (P<.001 for all). According to the overall ICRS cartilage repair grades, 9 of the 39 lesions (23%) in group 1 and 12 of the 17 lesions (58%) in group 2 achieved a grade of I or II. There was a significant difference in ICRS grades between the groups (P=.028). Overweight (body mass index≥27.5 kg/m2) and large lesion size (≥5.7 cm2) were significant predictors of poor clinical and arthroscopic outcomes in group 1 (P<.05 for both). There was a similar trend in group 2, but the differences were not significant, possibly owing to the smaller sample size. CONCLUSION: Clinical and arthroscopic outcomes of MSC implantation were encouraging for OA knees in both groups, although there were no significant differences in outcome scores between groups. However, at second-look arthroscopy, there were better ICRS grades in group 2.

Survival analysis of microfracture in the osteoarthritic knee-minimum 10-year follow-up.

PURPOSE: The aim of this study was to evaluate the survival of microfractures in patients with degenerative osteoarthritic knees and to analyze the factors affecting length of time before total knee arthroplasty (TKA) is performed. METHODS: This study reviewed 134 knees in 124 patients in whom microfracture was performed and for whom a minimum of 10 years of follow-up data were available. Mean follow-up was 11.2 years. The survival rate was evaluated. Failure was defined as the need for TKA. Another definition of failure was substantial symptoms in a patient whose pain score during follow-up was lower than the preoperative pain score or <60. We evaluated factors affecting survival, including size of the cartilage defect and severity of the preoperative varus deformity. The mechanical axis percentage (MA%) was defined as the percentage by which the mechanical axis bisected the total width of the tibia. RESULTS: The survival rate was 88.8% at 5 years and 67.9% at 10 years. Fifty-one patients proceeded to TKA a mean of 6.8 years after microfracture, and 6 knees were categorized as clinical failures. Age, gender, body mass index (BMI), and presence of meniscus lesions did not affect the survival of microfractures. Survival of microfractures in patients with a cartilage defect on the medial femoral condyle <2 cm(2) in size was better than that of microfractures in patients with larger defects. Survival of microfractures in patients with MA% >25% was better than that of patients with MA% <25%. CONCLUSIONS: Among 134 knees, 51 knees (38.1%) proceeded to TKA a mean of 6.8 years after microfracture in this study, and 6 knees were categorized as clinical failures. The survival rate was 88.8% at 5 years and decreased over time to 67.9% at 10 years. When considering microfracture, surgeons must consider factors affecting survival, such as size of the cartilage defect and severity of the preoperative varus deformity. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Does the severity of preoperative varus deformity influence postoperative alignment in both conventional and computer-assisted total knee arthroplasty?

PURPOSE: The postoperative alignment was compared according to the severity of preoperative varus deformity in computer-assisted and conventional total knee arthroplasty (CAS-TKA). METHODS: The study reviewed 127 consecutive CAS-TKA and 236 conventional TKA, retrospectively. In CAS-TKA, 77 knees with a varus deformity ≤15.0° were classified in group CAS-A and 50 knees with a varus deformity >15.0° were classified in group CAS-B. In conventional groups, 204 knees with a varus deformity ≤15.0 were classified in group Conventional-A and 32 knees with a varus deformity >15.0° were classified in group Conventional-B. The postoperative mechanical axis (MA) was compared among groups CAS-A, CAS-B, Conventional-A and Conventional-B. RESULTS: The average postoperative MA was 0.7° varus in group CAS-A, 2.8° varus in group CAS-B, 1.1° varus in group Conventional-A and 3.2° varus in group Conventional-B (p < 0.001). The postoperative MA was within 3° in 81.8, 62.0, 58.8 and 37.5 % of group CAS-A, CAS-B, Conventional-A and Conventional-B, respectively. CONCLUSIONS: The severity of preoperative varus deformity influences postoperative alignment despite using CAS. More careful correction of the alignment is required, especially in TKA performed on patients with a greater varus deformity. LEVEL OF EVIDENCE: III.

Long-term survival rate of implants and modes of failure after revision total knee arthroplasty by a single surgeon.

The purpose of the present study was to analyze the survival rate of implants and mode of failure after revision total knee arthroplasty (TKA) using one type of modular prosthesis by a single surgeon. From September 1990 to June 2009, 224 revision TKAs were performed in 194 patients. The 5-, 8-, and 10-year survival rates were 97.2%, 91.6%, and 86.1%, respectively. Re-revision TKAs were performed in 20 knees because of infection (seven knees), loosening (six knees), polyethylene wear (six knees), and periprosthetic fractures (one knee). The long-term survival rate of revision TKA was satisfactory, but careful attention is necessary to detect the late failure. The prevention of infection and the stable fixation of components are required at the time of revision TKA.