Comparison of mesenchymal stem cells obtained by suspended culture of synovium from patients with rheumatoid arthritis and osteoarthritis.

BACKGROUND: Mobilization of mesenchymal stem cells (MSCs) from the synovium was revealed using a "suspended synovium culture model" of osteoarthritis (OA). The pathology of rheumatoid arthritis (RA) differs from that of OA. We investigated whether mobilization of MSCs from the synovium also occurred in RA, and we compared the properties of synovial MSCs collected from suspended synovium culture models of RA and OA. METHODS: Human synovium was harvested during total knee arthroplasty from the knee joints of patients with RA (n = 8) and OA (n = 6). The synovium was suspended in a bottle containing culture medium and a culture dish at the bottom. Cells were harvested from the dish and analyzed. RESULTS: No significant difference was observed between RA and OA in the harvested cell numbers per g of synovium. However, the variation in the number of cells harvested from each donor was greater for RA than for OA. The harvested cells were multipotent and no difference was observed in the cartilage pellet weight between RA and OA. The surface epitopes of the cells in RA and OA were similar to those of MSCs. CONCLUSION: Mobilization of MSCs from the synovium was demonstrated using a suspended synovium culture model for RA. The harvested cell numbers, chondrogenic potentials, and surface epitope profiles were comparable between the RA and OA models.

The Baba classification focused on implant designs is useful in setting the therapeutic strategy for interprosthetic femoral fracture.

PURPOSE: The purpose of this study was to investigate the clinical outcomes of femoral fracture with implants on the proximal and distal sides to verify whether actual fracture morphologies follow the fracture types of Baba classification focusing on implant designs useful for periprosthetic femoral fracture. METHODS: Prosthesis was present in 85 with periprosthetic femoral fractures. Excluding 73 patients with fracture around the femoral stem or fracture of the TKA femoral component alone, 12 patients with 14 legs with both implants were investigated. All patients were radiographically assessed for implant stability according to the Baba classification. For clinical evaluation, intra- and postoperative complications, the operation time, and intra-operative blood loss were investigated. RESULTS: The Baba classification fracture type showed the implant as unstable and stable types in 3 and 11 legs, respectively. The consistency rate between the Baba classification-based judgment of plain radiograms acquired at the time of injury and actual surgical findings was 100%. As a result of treatment according to the Baba classification, bone union was achieved in all patients. There were no intra- or postoperative complications. CONCLUSIONS: Applying the Baba classification, implant stability could be sufficiently evaluated in not only periprosthetic femoral fractures following hip arthroplasty, but also interprosthetic femoral fractures, thereby verifying its usefulness in setting the treatment strategy.

In total hip arthroplasty via the direct anterior approach, a dual-mobility cup prevents dislocation as effectively in hip fracture as in osteoarthritis.

PURPOSE: The main purpose of this study was to compare the outcome of total hip arthroplasty (THA) via the direct anterior approach (DAA) using a dual-mobility cup (DMC) in patients with femoral neck fracture to those in patients undergoing elective THA for osteoarthritis. PATIENTS AND METHODS: We retrospectively investigated 40 hips with femoral neck fracture (group A), and 81 hips with osteoarthritis (group B). THA via the DAA using the DMC was performed in both groups. A primary/secondary outcome variable were the presence of dislocation/operative time, intra- and/or peri-operative complication, and mortality. RESULTS: Dislocation did not occur in either group. The complication rate was slightly higher in group A than in group B, but not statistically significant. CONCLUSION: THA with the DMC using the DAA was as effective for femoral neck facture as it was for elective THA in patients with osteoarthritis.

Long-term results of rotational acetabular osteotomy for osteonecrosis with collapse of the femoral head in young patients.

PURPOSE: The surgical treatment of osteonecrosis with collapse of the femoral head is still controversial. The purpose of this study was to investigate the clinical outcome of rotational acetabular osteotomy by Ninomiya and Tagawa for osteonecrosis of the femoral head in young patients. PATIENTS AND METHODS: Rotational acetabular osteotomy was performed in 202 consecutive patients between 1995 and 2003. Among them, rotational acetabular osteotomy with osteonecrosis of the femoral head was performed in 31 patients (42 hips). The mean age at the time of surgery was 31.2 years (range 16-45). The mean duration of follow-up was 16.1 years (range 13.1-21 years). RESULTS: The mean preoperative Japanese Orthopedic Association hip score of 56.8 points improved to a mean of 72.4 points at the final follow-up. The 10-year survival rate with conversion to total hip arthroplasty as an end-point was 91.9%, and the 15-year survival rate was 75.5%, the 20-year survival rate was 67.9%. The conversion to total hip arthroplasty was performed in nine hips. The average time to the conversion to total hip arthroplasty was 12.1 years. CONCLUSIONS: Even though the necrotized range is wide, if normal cartilage remains on the lateral side of the femoral head, it can be utilized for the weight-bearing region by laterally rotating the acetabulum. Since the outcome was favorable, we believe that this is a valuable treatment option for this disease.

Influence of the contralateral hip state after total hip arthroplasty on patient-reported outcomes measured with the Forgotten Joint Score-12.

PURPOSE: The purpose of this study was to examine the influence of the contralateral hip state on postoperative assessment using the Forgotten Joint Score-12 (FJS-12) in comparison with the McMaster Universities Osteoarthritis Index (WOMAC) and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ). METHODS: One hundred and thirty-four hips underwent total hip arthroplasty (THA) between 2014 and 2015. Of these, the subjects were 106 hips with degenerative hip arthrosis as a primary disease for whom initial THA was performed on the affected side. The WOMAC and JHEQ were investigated before surgery and 1 month, 6 months, and 1 year after surgery. The FJS-12 was examined 1 month, 6 months, and 1 year after surgery. RESULTS: We divided the subjects into three groups based on the state of the contralateral hip, which was not surgically treated in this study: healthy (n = 43), THA (n = 31), and OA (n = 31) groups. One year after surgery, the mean FJS-12 scores in the healthy, THA, and OA groups were 69.1, 52.8, and 68.0 points, respectively. In the THA group, the score was significantly lower than in the healthy and OA group. There were no significant differences in WOMAC and JHEQ scores among the three groups. CONCLUSIONS: The FJS-12 score in the presence of an arthroplasty on the contralateral side was more markedly influenced by the contralateral hip state compared with that in the presence of contralateral painful OA. This result suggests that it is necessary to understand the characteristics of PROs and utilize them for post-THA assessment.

Importance of the spinopelvic factors on the pelvic inclination from standing to sitting before total hip arthroplasty.

PURPOSE: Dislocation after total hip arthroplasty (THA) is a major postoperative complication. Even if the cup is in the safe zone, dislocation caused by implant impingement may occur during postural changes. The aim of the present study was to investigate the spinopelvic factors that influence pelvic inclination changes from standing to sitting in patients with hip diseases who were candidates for THA. METHODS: 74 patients who underwent primary THA were included according to our criteria. The analysis of the sagittal balance of the spinopelvic complex was performed on standing and sitting lateral radiographs. Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis angle (LLA), thoracic kyphosis angle (TK), and sagittal vertical axis (SVA) were measured. The differences between the standing and sitting positions regarding the spinal and pelvic parameters were analyzed. Correlations between the variables of the spinopelvic parameters were examined using Spearman's rank correlation coefficient. RESULTS: The changes in SVA, TK, LLA, SS, PT, and PI from the standing to sitting positions, respectively, were -3.9 ± 48.2 mm, -0.1° ± 6.4°, 21.4° ± 17.7°, 22.2° ± 12.2°, -22.3° ± 13.2°, and 0.4° ± 6.9°. The lumbar lordosis was reduced and pelvic rotation was extended from the standing to the sitting position. The correlation coefficient between the change in the SS and that in the LLA was 0.72 (p < 0.0001). The correlation coefficient between the change in PT and that in the LLA was -0.68 (p < 0.0001). CONCLUSIONS: The change in pelvic inclination from standing to sitting is strongly related to the mobility of the lumbar spine in patients with hip diseases.

Does the Canal Fill Ratio and Femoral Morphology of Asian Females Influence Early Radiographic Outcomes of Total Hip Arthroplasty With an Uncemented Proximally Coated, Tapered-Wedge Stem?

BACKGROUND: Noncement femoral fixation in total hip arthroplasty (THA) has been gaining popularity. However, owing to the numerous varieties of uncemented stems and differing types of femoral stem morphology, it is unclear whether the clinical outcomes of all uncemented stems are equal. The aim of this study was to investigate the relationships between canal fill ratio and femoral morphology and early radiologic outcomes in Japanese patients who underwent THA with an uncemented proximally hydroxyapatite-coated, tapered-wedge stem. METHODS: We retrospectively reviewed 103 patients who had undergone THA using a single proximally coated tapered-wedge stem. The relationships between canal fill ratio and femoral morphology and early radiologic outcomes after THA with those stem were investigated. RESULTS: Eighty-one hips were analyzed after inclusion and exclusion criteria were applied. Failed osteointegration proximally was observed in 4 hips (4.9%). Canal flare index was significantly greater in hips with failed osteointegration than in those with successful osteointegration (P = .009). Distal hypertrophy was observed in 14 hips (17.3%). Proximal-distal matching ratio was significantly lower in hips with distal hypertrophy than in those without (P = .01). Canal fill ratio at 2 cm above the lesser trochanter was smaller in hips with failed osteointegration and distal hypertrophy than in those without (P = .02). CONCLUSION: Suboptimal radiologic changes were seen with greater distal fill with smaller proximal fill and with a narrow femoral canal. It is important to select the stem that can achieve the original concept of intended primary and secondary fixation areas.

Lateral femoral cutaneous nerve injury with the direct anterior approach for total hip arthroplasty.

PURPOSE: Although injury of the lateral femoral cutaneous nerve (LFCN) is a known complication after total hip arthroplasty (THA) via the direct anterior approach (DAA), the impact of this complication on postoperative quality of life (QOL) is unclear. This study aims to investigate the incidence of LFCN injury after DAA for THA, and to determine the impact of LFCN injury on QOL and hip function. METHODS: We prospectively investigated 122 hips operated upon using the DAA regarding the incidence of LFCN injury using self-reported questionnaires, hip functional scores such as the Harris Hip Score (HHS) and the Japanese Orthopaedic Association (JOA) score, and patient-reported outcomes such as the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS). RESULTS: LFCN injury was seen in 39 hips (31.9 %). In affected hips, the leading symptom was hypo-aesthesia (46.2 %), followed by tingling or jolt-like sensation (28.2 %). There was no difference in the HHS and JOA score between those with LFCN injury and those without. There was a significant difference in the FJS-12 between the two groups (50.9 ± 25.3 for hips with LFCN injury vs 64.3 ± 25.7 without, p = 0.01). There was a non-significant tendency for patients with LFCN injury to have a lower JHEQ than those without (63.6 ± 19.6 for hips with LFCN injury vs 70.8 ± 22.9 without, p = 0.13). CONCLUSIONS: The incidence of LFCN injury decreased QOL but not hip function after DAA for THA.

Surgeons changing the approach for total hip arthroplasty from posterior to direct anterior with fluoroscopy should consider potential excessive cup anteversion and flexion implantation of the stem in their early experience.

PURPOSE: Many reports outline the benefits derived from using the direct anterior approach (DAA) in primary total hip arthroplasty (THA); however, the learning curve for the DAA has not been well documented, and the complications associated with the DAA during this learning curve seem relatively high. The aim of this study was to investigate implant positioning in primary THA, when the surgeon was a novice at the DAA, and had previously used the standard posterior approach (PA). PATIENTS AND METHODS: We investigated implant positioning in the first 80 consecutive THA cases performed by two senior surgeons using the DAA (with fluoroscopic assistance), and compared them to the same two surgeons' previous 80 respective THA cases performed using their previous standard posterior approach. RESULTS: Cup positioning accuracy was higher for the DAA (p < 0.001) but greater cup anteversion (19.3° ± 11.0 using the PA vs 27.6° ± 6.3 using DAA, p < 0.0001) was also demonstrated. A total of 69.3 % of cups in the DAA group were positioned with an anteversion angle greater than their target angle. In the DAA group the stem was more frequently positioned in flexion and less frequently in neutral than for the PA group. CONCLUSIONS: Although fluoroscopic assistance seemed to decrease complications such as femoral fracture, surgeons changing from PA to DAA for THA should consider potential excessive cup anteversion and flexion implantation of the stem in their early experience with DAA.

Safety in early experience with a direct anterior approach using fluoroscopic guidance with manual leg control for primary total hip arthroplasty: a consecutive one hundred and twenty case series.

BACKGROUND AND PURPOSE: An encouraging result with direct anterior approach (DAA) is attractive for both patients and surgeons. However, the risks associated with beginning to use DAA require further analysis of the learning curve and better countermeasures to ensure safety. We ask whether the complication rate in the DAA by the inexperienced surgeon could be decreased with specific countermeasures. Our hypothesis was that the complication rate would be low even in early phase of the learning curve using the DAA with these particular countermeasures. PATIENTS AND METHODS: We investigated a consecutive series of 120 primary THA using the DAA with four specific countermeasures; 1) defined exclusion criteria for DAA; 2) no positioning table; 3) use of fluoroscopy as much as required; and 4) having an experienced assistant for DAA (one who has performed the procedure in more than 100 cases). The operative time, the time of fluoroscopic use during the operation, intra and post-operative complications, re-operation for any reason, and cup and stem alignment were investigated. RESULTS: Although the operation times were similar, the duration of fluoroscopy decreased with surgeons' experience. There were no intra-operative complications and no re-operations for any reason. One anterior dislocation was observed in one patient. The mean cup inclination and anteversion angle was 39.7° ± 7.6° and 30.3° ± 7.6°; 43.3 % of stems were positioned in flexion, 55.8 % in the neutral position on the lateral view. CONCLUSION: We demonstrated a lower complication rate during our early experience with the DAA using four countermeasures. Using these countermeasures for the first 40 cases may be useful for surgeons who are considering DAA.

Benefit and risk in short term after total hip arthroplasty by direct anterior approach combined with dual mobility cup.

PURPOSE: No previous reports have described the benefits and risks associated with the dual mobility cup (DMC) in primary THA via direct anterior approach (DAA). The aim of this study was to compare the safety and rate of early postoperative complication of the DAA with the DMC for THA with those of the DAA with a single standard cup, and to investigate the influence of the learning curve of the use of DMC on intra- and perioperative outcomes. METHODS: We retrospectively investigated 60 hips treated in the single-DAA group and 60 hips treated in the dual-DAA group. A primary/secondary outcome variable was the presence of any intra- or perioperative complication within the first 6 months/the operative time and hip function at 6 months postoperatively. We also analyzed influence of the learning curve of the use of DMC on intra- and perioperative outcomes. RESULTS: No intraoperative complications were observed in either group. One anterior dislocation and one periprosthetic hip fracture were occurred in the single-DAA group. The surgical times in the single-DAA and dual-DAA groups were 112.0 ± 20.9 and 121.0 ± 26.9 min (p < 0.001). There was no significant difference in the 6-month postoperative hip function scores between the two groups. There was no influence of the learning curve of the use of DMC on intra- and perioperative outcomes. CONCLUSION: We have demonstrated the short-term safety and lack of inferiority of using the DMC in the DAA compared with the standard single mobility cup.

Greater trochanter chip fractures in the direct anterior approach for total hip arthroplasty.

BACKGROUND: The direct anterior approach (DAA) for the treatment of total hip arthroplasty (THA) has gained popularity in recent years. Chip fractures of the greater trochanter are frequently seen, but the risk factors for such fractures are unknown. The study aimed to identify the risk factors for chip fractures in patients undergoing primary THA by the DAA during the surgeons' learning curve. MATERIALS AND METHODS: From November 2011 to April 2015, the first experiences of three surgeons who performed 120 THAs by the DAA (120 hips; 40 cases per beginner surgeon) were included. The incidence of chip fracture of the greater trochanter, the size of the greater trochanter as measured by computed tomography, and the patients' characteristics were retrospectively investigated. RESULTS: After exclusion of 11 hips, the remaining 109 hips were investigated. Chip fracture of the greater trochanter was identified in 32 hips (29.4 %). Univariate analysis with and without fractures showed that the width and depth of the greater trochanter were statistically significant risk factors (p = 0.02 and p < 0.001, respectively). Multivariate analysis using a logistic regression model demonstrated that the depth of the greater trochanter was an independent risk factor for chip fracture of the greater trochanter (OR 1.725; 95 % CI 1.367-2.177; p < 0.001). CONCLUSION: The size of the greater trochanter was identified as a risk factor for chip fracture of the greater trochanter. Novice surgeons should pay attention to the size of the greater trochanter when performing THA by the DAA.

Total hip arthroplasty using a Kerboull-type plate for rapidly destructive coxarthrosis: comparison with uncemented acetabular component.

INTRODUCTION: Clinical outcomes of total hip arthroplasty (THA) to treat rapidly destructive coxarthrosis (RDC) have been reported, but to our knowledge, there have been no studies comparing implants. The aim of this study was to examine the effectiveness of acetabular reconstruction for RDC by comparing the clinical results of THA using a Kerboull-type plate with an uncemented cup. PATIENTS AND METHODS: Among 921 primary THAs performed between 2006 and 2014, 27 were performed for the treatment for RDC using a Kerboull-type plate or a conventional uncemented cup. A Kerboull-type plate for acetabular reinforcement device was used in 13 hips and an uncemented cup in 14 hips. The mean follow-up period was 61.2 months. RESULTS: The duration of surgery was 156.8 ± 36.4 min in the Kerboull-type plate group and 103.3 ± 14.4 min in the uncemented cup group, being significantly longer in the former (P = 0.0002). In the Kerboull-type plate group and the uncemented cup group, the 5-year survival rates were 100 and 83.9 %, respectively. Recurrent dislocation was observed in two cases in which the posterior approach had been used. CONCLUSIONS: In our study, the loosening of the acetabular components was noted in 14.3 % of uncemented cup-applied cases, but no loosening was noted in any Kerboull-type plate-applied case. Therefore, for RDC, in which objective evaluation of fragile bone quality is difficult, the use of the Kerboull-type plate, which disperses weight-bearing of the acetabular, may be an effective means to achieve early functional recovery as well as a long-term favorable outcome.

Higher reliability and validity of Baba classification with computerised tomography imaging and implant information for periprosthetic femoral fractures.

PURPOSE: Baba classification for periprosthetic femoral fracture focuses on the positional relationship between the implant design and fracture site. The objective of this study was to investigate whether the addition of CT images and implant information to plain radiograms increases the reliability of Baba classification to a level higher than that of Vancouver classification. METHODS: Twenty patients were randomly selected from 61 patients with periprosthetic femoral fracture between 2009 and 2014. After Vancouver and Baba classifications were fully explained to six orthopedic surgeons (three experts and three non-experts), plain radiograms, CT imaging and implant information at the time of injury were presented, and the inter- and intra-observer reliability based on the Vancouver and Baba classifications and accuracy rates of stem stability were investigated. RESULTS: When interobserver reliability was made based on only radiograms, the mean κ value of Baba classification-based judgments made by the experts was 0.76, and those of Vancouver classification-based judgments made by the experts was 0.41. When interobserver reliability was made based on the radiograms and CT images and implant information, the mean κ value of Baba classification-based judgments made by the experts was 0.94, and those of Vancouver classification-based judgments were 0.48. Intra-observer reliability of Baba classification was 0.81 in the experts. Validity analysis showed 95.0% agreement within all subgroups. CONCLUSIONS: Reliability and validity of Baba classification was improved when additional information was given. We believe that this new classification is useful to establish a therapeutic strategy for femoral fractures around the stem.

New classification focusing on implant designs useful for setting therapeutic strategy for periprosthetic femoral fractures.

PURPOSE: In periprosthetic femoral fractures, our hypothesis was that when the bone and implant are stable, the fracture does not occur at the biologic or cement fixation regions but occurs at the no fixation region. The aim of this study was to investigate the validity of our new classification for periprosthetic femoral fractures and compare reliability of radiographic evaluation for implant stability between our classification and the Vancouver classification. PATIENTS AND METHODS: Sixty-six patients with periprosthetic femoral fracture were operatively treated by us between 2005 and 2013. We investigated the sensitivity and specificity of our new classification with actual implant stability. Twenty patients were randomly selected from 66 patients. After fully explaining the Vancouver and our new classification to four orthopaedic surgeons, plain radiographs acquired in two directions at the time of injury were presented, and the interobserver reliability based on the two classifications and accuracy rates of stem stability were investigated. RESULTS: The specificity of the new classification was 89%, and sensitivity was 94%. The positive and negative predictive values were 84% and 96%, respectively. Interobserver agreement was separately assessed among all possible pairs of orthopaedic surgeons. The κ values for the Vancouver and the new classification were 0.36 (0.19-0.49) and 0.76 (0.66-1.0), respectively. CONCLUSIONS: Our classification is based on a completely new concept and was prepared to overcome periprosthetic femoral fracture failures by objective evaluation. We believe this new classification is useful to establish a therapeutic strategy for femoral fractures around the stem.

Validation study of the Forgotten Joint Score-12 as a universal patient-reported outcome measure.

PURPOSE: The Forgotten Joint Score-12 (FJS-12) is for patients to forget their artificial joint and is reportedly a useful patient-reported outcome tool for artificial joints. The purpose of this study was to determine whether the FJS-12 is as useful as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) or the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) in Japan. METHODS: All patients who visited our hospital's hip joint specialists following unilateral THA from August 2013 to July 2014 were evaluated. Medical staff members other than physicians administered three questionnaires. Items evaluated were (1) the reliability of the FJS-12 and (2) correlations between the FJS-12 and the total and subscale scores of the WOMAC or JHEQ. RESULTS: Of 130 patients, 22 were excluded. Cronbach's α coefficient was 0.97 for the FJS-12. The FJS-12 showed a significantly lower score than the WOMAC or JHEQ (p < 0.01). The FJS-12 was moderately correlated with the total WOMAC score (r = 0.522) and its subscale scores for "stiffness" (r = 0.401) and "function" (r = 0.539) and was weakly correlated with the score for "pain" (r = 0.289). The FJS-12 was favorably correlated with the total JHEQ score (r = 0.686) and its subscale scores (r = 0.530-0.643). CONCLUSION: The FJS-12 was correlated with and showed reliability similar to that of the JHEQ and WOMAC. The FJS-12, which is not affected by culture or lifestyle, may be useful in Japan.

Is urinary incontinence the hidden secret complications after total hip arthroplasty?

INTRODUCTION: We hypothesized that posterior approach (PA) dissecting the short external rotators and anterior approach (AA) not dissecting these have different influences on the pelvic floor muscles and subsequently affect urinary incontinence. The objective of this study was to investigate whether AA advantageously influences symptoms of urinary incontinence. PATIENTS AND METHODS: The subjects were 76 female patients who underwent their primary total hip arthroplasty. The presence or absence of urinary incontinence before and after surgery was surveyed by a direct interview at the time of outpatient examination within a period from 1.5 year after surgery using the international consultation on incontinence questionnaire-short form. RESULTS: Urinary incontinence improved after surgery in eight patients (22.2%), slightly improved in one (2.8%), remained unchanged in 26 (72.2%), slightly aggravated in one (2.8%) in the AA group. In the PA group, urinary incontinence improved after surgery in one (2.5%), remained unchanged in 30 (75%), slightly aggravated in four (10%), and aggravated in five (12.5%). Symptoms of urinary incontinence were significantly improved in the AA group and aggravated in the PA group (Mann-Whitney U test, P = 0.0057). CONCLUSIONS: As the anatomical characteristic of the short external rotators, the root of the internal obturator muscle is connected to the levator ani muscle. Among the pelvic floor muscles, this levator ani muscle is closely involved in supporting the pelvic organs. Since the short external rotators may have been atrophied due to hip joint dysfunction before surgery, if the strength of this muscle group recovers, support of the pelvic organs and urinary incontinence may be improved. It was assumed that surgery through AA improved external rotation contracture of the hip joint and leg length, which increased tension of the internal obturator muscle, with which tension of the pelvic floor muscle also increased and improved urinary incontinence.

Recent advances in the direct anterior approach to total hip arthroplasty: a surgeon's perspective.

INTRODUCTION: The direct anterior approach (DAA) has its origins in the first and oldest approach for hip replacement in the literature, but at the same time it would not be fanciful to suggest its increasing popularity as the latest approach for hip replacement procedures, especially among younger surgeons. However, in a geographical context, the DAA is not considered the major approach in most countries. Moreover, the term DAA encompasses numerous variations in terms of technique. AREAS COVERED: In this narrative review, we describe our recent experience of advances in the DAA in terms of improved techniques and devices, along with some of its disadvantages. Also, we express our perspective on its future application. EXPERT OPINIONS: The DAA is established as one of exemplary approaches to THA. The use of fluoroscopy, the traction table, and appropriate soft tissue management has become essential in the DAA for a safe and trouble-free procedure with adequate patient comfort. With the combination of recent technologies such as robotics, three-dimensional preoperative planning, and artificial intelligence (AI)-based surgeon assist systems, we can look forward to the DAA being performed more efficiently in the future.

Yields of mesenchymal stromal cells from synovial fluid reflect those from synovium in patients with rheumatoid arthritis.

The yield of primary synovial mesenchymal stromal cells (MSCs) from synovium of patients with rheumatoid arthritis (RA) is highly variable, but cell transplantation therapy with autologous synovial MSCs requires accurate prediction of the synovial MSC yield per synovium weight. Here, we determined whether the yield of synovial fluid MSCs might predict the ultimate yield of primary MSCs from the synovium of RA knees. Synovial fluid and synovium were harvested during total knee arthroplasty from the knee joints of 10 patients with RA. Synovial fluid (1.5 mL) was diluted fourfold and plated equally into six 60 cm2 dishes. Nucleated cells from digested synovium were similarly plated at 1 × 104 cells in 6 dishes. All dishes were cultured for 14 days and analyzed for MSC yields and properties, including in vitro chondrogenesis. The cultured synovial cell number was correlated with the cultured synovial fluid cell number (n = 10, R2 = 0.64, p < 0.01). Synovial fluid cells formed cell colonies and showed MSC-like surface epitopes and multi-differentiation potential. However, the cartilage pellet weight indicated a greater chondrogenic potential of the synovial MSCs (n = 8). The primary MSC yields from synovial fluid and synovium were correlated, indicating that the synovial fluid MSC yield can predict the ultimate synovial MSC yield.

Does total hip arthroplasty via the direct anterior approach using dual mobility increase leg length discrepancy compared with single mobility?

BACKGROUND: Total hip arthroplasty (THA) via the direct anterior approach (DAA) using dual mobility cup (DMC) is considered to effectively prevent postoperative dislocation. However, the dislocation and reduction procedure using a trial implant during the surgery is difficult because of high soft tissue tension. Thereby, leg length discrepancy (LLD) is difficult to assess when using DM via the DAA. PURPOSE: To compare the LLD between cases using conventional SM and those using DMC in THA via the DAA with fluoroscopy. PATIENTS AND METHODS: We retrospectively investigated 34 hips treated with DMC (DMC-DAA group) and 31 hips treated with SM (SM-DAA group). The LLD was defined as the difference in the distance from the teardrop to the medial-most point of the lesser trochanter between the operative and nonoperative sides at immediate postoperative X-ray. RESULTS: The mean LLD in the DMC-DAA group and SM-DAA group was 0.68 ± 7.7 mm and 0.80 ± 5.5, respectively, with no significant difference. The absolute value of the LLD in the DMC-DAA group and SM-DAA group was 6.3 ± 4.4 mm and 5.9 ± 5.5, respectively, with no significant difference. CONCLUSION: Despite the difficulty in assessment of the LLD during THA via the DAA using DMC, this technique does not increase the LLD compared with the use of SM. LEVEL OF EVIDENCE: III, matched case-control study.