Validity of a preoperative scoring system for surgical management of periprosthetic hip infection: one-stage vs. two-stage revision.

INTRODUCTION: There are no widely accepted algorithms for determining optimal treatment for periprosthetic joint infection (PJI). Our study aimed to confirm the validity of a previously published scoring system in a larger number of patients to support a rational surgical treatment strategy for periprosthetic hip infection. MATERIALS AND METHODS: Between February 2001 and December 2020, we performed 155 consecutive revision total hip arthroplasties (THAs) for PJI, with mean follow-up of 6 years. One-stage revision THA was performed in 56 hips and two-stage revision THA in 99 hips. Prosthesis survival from recurrent infection was determined by Kaplan-Meier analysis, using implant removal as the endpoint. The pre-operative scoring system (full score of 12 points), including 6 essential elements, was retrospectively evaluated. RESULTS: The 10-year survival rates were 98% for one-stage (95% confidence interval [CI], 94-100) and 87% (95% CI, 79-96) for two-stage revision THA. Multivariate Cox regression analysis provided a total preoperative score as an independent risk factor for implant removal (hazard ratio, 0.17; 95% CI, 0.06-0.49; p < 0.001). The sensitivity and specificity at the cut-off of 4 points on the scoring system were 80% and 91%, respectively. The average score for one-stage revision THA in successful and failed cases were 8.9 and 6.0, and for two-stage revision THA were 6.5 and 3.9, respectively. We found significant differences between successful cases in one- and two-stage revision THA (p < 0.05). CONCLUSIONS: The preoperative scoring system was useful for managing PJI. One-stage revision THA is recommended in patients scoring ≥ 9 points, and meticulously performed two-stage revision THA is encouraged for patients scoring ≥ 4 points.

Experimental periprosthetic fractures with collarless polished tapered cemented stems.

PURPOSE: After cemented total hip arthroplasty, the risk of periprosthetic fracture (PPF) of taper-slip stems is higher than that of composite-beam stems. We aimed to assess the conditions resulting in PPFs of taper-slip stems using a falling weight. METHODS: Taper-slip stems were fixed to five types of simulated bone models using bone cement, and the fractures were evaluated by dropping stainless-steel weights from a predetermined height onto the heads. The periprosthetic fracture height in 50% of the bone models (PPFH50) was calculated using the staircase method. RESULTS: For the fixation with 0° of flexion, the values for PPFH50 were 61 ± 11, 60 ± 13, above 110, 108 ± 49, and 78 ± 12 cm for the cobalt-chromium-molybdenum alloy, stainless steel alloy (SUS), titanium alloy (Ti), smooth surface, and thick cement mantle models, respectively; for the fixation with 10° of flexion (considering flexure), the PPFH50 values were 77 ± 5, 85 ± 9, 90 ± 2, 89 ± 5, and 81 ± 11 cm, respectively. The fracture rates of the polished-surface stems were 78.6 and 35.7% at the proximal and distal sites, respectively (p < 0.05); the fracture rates of the smooth-surface stems were 14.2 and 100%, respectively (p < 0.05). CONCLUSION: The impact tests demonstrated that the conditions that were less likely to cause PPFs were use of Ti, a smooth surface, a thick cement mantle, and probably, use of SUS.

The modified Spitzy shelf acetabuloplasty for the dysplastic hip.

Aims: Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty. Methods: Between November 2000 and December 2016, we retrospectively evaluated 144 consecutive hip procedures in 122 patients a minimum of five years after undergoing modified Spitzy shelf acetabuloplasty for acetabular dysplasia including osteoarthritis (OA). Our follow-up rate was 92%. The mean age at time of surgery was 37 years (13 to 58), with a mean follow-up of 11 years (5 to 21). Advanced OA (Tönnis grade ≥ 2) was present preoperatively in 16 hips (11%). The preoperative lateral centre-edge angle ranged from -28° to 25°. Survival was determined by Kaplan-Meier analysis, using conversions to total hip arthroplasty as the endpoint. Risk factors for joint space narrowing less than 2 mm were analyzed using a Cox proportional hazards model. Results: The mean Merle d'Aubigné clinical score improved from 11.6 points (6 to 17) preoperatively to 15.9 points (12 to 18) at the last follow-up. The survival rates were 95% (95% confidence interval (CI) 91 to 99) and 86% (95% CI 50 to 97) at ten and 15 years. Multivariate Cox regression identified three factors associated with radiological OA progression: age (hazard ratio (HR) 2.85, 95% CI 1.05 to 7.76; p = 0.0398), preoperative joint space (HR 2.41, 95% CI 1.35 to 4.29; p = 0.0029), and preoperative OA (HR 8.34, 95% CI 0.94 to 73.77; p = 0.0466). Conclusion: Modified Spitzy shelf acetabuloplasty is an effective joint-preserving surgery with a wide range of potential indications.

Trochanteric Claw Plate Fixation for Greater Trochanteric Fracture or Osteotomy in Total Hip Arthroplasty.

This study retrospectively evaluated 41 consecutive open reductions and internal fixations following primary or revision total hip arthroplasty, which required trochanteric claw plate fixation for greater trochanteric fracture or osteotomy between January 2008 and December 2020. The mean duration of clinical follow-up was 4.2 years (range, 1-13 years). The patients included 13 men and 28 women, with a mean age of 68 years (range, 32-87 years). The indications for intervention included trochanteric osteotomy, intraoperative fracture, and non-union including postoperative fracture in 6, 9, and 26 cases, respectively. The mean Merle d'Aubigné Clinical Score improved from 9.4 points (range, 5-15 points) pre-operatively, to 14.3 points (range, 9-18 points) at the last follow-up. Bone union occurred in 35 cases (85%), while implant breakage occurred in four cases. At the last follow-up, the mean Merle d'Aubigné Clinical Scores of bone union and non-union were 15.3 and 14.1, respectively (p=0.48). The Kaplan-Meier survival rate, with the endpoint being revision surgery for pain, non-union, dislocation, or implant breakage, at 10 years was 80.0% (95% confidence interval: 62.6-97.4%). Greater trochanteric fixation using a trochanteric claw plate yielded successful results.

Can serum C-reactive protein determine the timing of reimplantation in two-stage revised arthroplasty for periprosthetic hip infection?

BACKGROUND: There are no definitive guides to determine the timing of reimplantation in two-stage revision total hip arthroplasties (THA) for periprosthetic joint infection (PJI). This study was to design to support a rational strategy of surgical treatment using serum C-reactive protein (CRP). METHODS: We analyzed a total of 75 hips for PJI in the process of performing two-stage and multiple-stage revision THAs. CRP level was retrospectively evaluated every week and transformed to log2 (CRP) using a logistic regression model. Prosthesis survival from recurrent infection was determined by Kaplan-Meier analysis, using implant removal as the endpoint. Receiver operating characteristic curves were calculated using each log2 (CRP) to assess predictions of recurrent infection. RESULTS: The 10-year survival rates were 85% (95% confidence interval, 76-95) and 100% for two-stage and multiple-stage revision THAs, respectively. Preoperatively, at 1, 2, 3, and 5 weeks, log2 (CRP) was not associated with recurrent infection. In failed two-stage revision THAs, log2 (CRP) at 3 weeks divided by that at 2 weeks showed a significant difference. Failure was associated with a ratio of >4.0 for the CRP level between 3 and 2 weeks. CONCLUSION: In two-stage revision THA for PJI, patients with CRP elevation from 2 weeks to 3 weeks, especially 4-fold elevation, suggests the need for further debridement and postponement of second-staged reimplantation.

Treatment strategies for recurrent dislocation following total hip arthroplasty: relationship between cause of dislocation and type of revision surgery.

BACKGROUND: There are many therapeutic options for dislocation following total hip arthroplasty (THA). The aim of this study was to evaluate the results of revision surgery for dislocated hips. METHODS: Between November 2001 and December 2020, 71 consecutive revision hip surgeries were performed at our institution for recurrent dislocation following THA. We conducted a retrospective study of all 65 patients (71 hips), who were followed for a mean of 4.7 ± 3.2 years (range, 1-14). The cohort included 48 women and 17 men, with a mean age of 71 ± 12.3 years (range, 34-92). The mean number of previous surgeries was 1.6 ± 1.1 (range, 1-5). From intraoperative findings, we created six categories of revision hip surgery for recurrent dislocation following THA: open reduction and internal fixation (2 hips); head change or liner change only (6 hips); cup change with increased head size only (14 hips); stem change only (7 hips); cup and stem change (24 hips); and conversion to constrained cup (18 hips). Prosthesis survival was analyzed by the Kaplan-Meier method, with repeat revision surgery for re-dislocation or implant failure as the endpoint. A cox proportional hazards model was used for risk factors of re-revision surgery. RESULTS: Re-dislocation occurred in 5 hips (7.0%) and implant failure in 1 hip (1.4%). The 10-year survival rate was 81.1% (95% confidence interval, 65.5-96.8). A Dorr classification of "positional" was a risk factor for re-revision surgery due to re-dislocation. CONCLUSION: Clear understanding of the cause of dislocation is essential for optimizing revision procedures and improving the rate of successful outcomes.

Comparative analysis of glyceroglycolipids from Lactiplantibacillus pentosus and other Lactiplantibacillus species.

Cellular lipids of Lactiplantibacillus species were extracted and neutral glyceroglycolipids (GGLs) were purified, and analyzed by thin-layer chromatography (TLC). Four GGLs with known structures were detected in GGL preparation of L. plantarum, and the same GGL profiles of TLC were observed for all other strains of Lactiplantibacillus species examined, suggesting that the GGL profile could be one of the chemotaxonomic characters of the genus Lactiplantibacillus. On the other hand, the quantity of each GGL showed some variation among species, and L. pentosus was found to have higher proportion of disaccharide-type GGL, designated GGL-3 in this study, compared with other species including L. plantarum. The quantitative difference of GGL-3 found in this study could be regarded as the characteristics of L. pentosus. The carbohydrate structure of L. pentosus GGL-3 was precisely analyzed by 1H NMR and methylation analysis, and the structure was confirmed to be αGal-(1→2)-αGlc-diacylglycerol, with the carbohydrate structure identical to that of L. plantarum, although fatty acid composition of the two GGL-3 showed some difference.

Endofemoral Shooting Technique for Removing Well-fixed Cementless Stems.

Background: The removal of a well-fixed cementless stem poses technical challenges. The aim of this study was to evaluate the outcomes of our endofemoral extraction technique established in 2001. Methods: Between January 2001 and December 2016, 118 consecutive revisions following bipolar or total hip arthroplasty, which required cementless femoral stem removal, were performed at our institution. This retrospective study evaluated 106 patients (108 hips) who were followed up for a mean of 9.2 years (range, 5-20 years). The patients included 15 men and 91 women with a mean age of 65 years (range, 33-87 years). Endofemoral extracted stem removal was performed as follows. Multiple Kirschner wires were sequentially inserted into the interface between the implant and cortical bone, after which the implant was detached using a thin chisel. After the cementless stem was removed, it was replaced with a cemented stem using an autograft, as needed. Radiological loosening of the femoral stem was defined as definite or probable loosening, based on the criteria of Harris et al. Prosthesis survival was analyzed using the Kaplan-Meier method, with the endpoint set as repeat revision surgery for stem loosening or femoral fracture. Results: Re-revision surgery was performed in 7 hips. Stem loosening was observed in 4 hips, and the mean subsidence was 0.3 mm (0-3 mm). The 10-year survival rate was 97.7% (95% confidence interval, 93.2-100). Conclusions: Our technique for removing well-fixed cementless stems yielded successful results.

Daptomycin for the Treatment of Gram-Positive Periprosthetic Hip Infections: Can Daptomycin Prevent the Implant Removal?

Introduction Management of periprosthetic hip infections (PHIs) generally consists of implant removal and thorough debridement, accompanied by appropriate antibiotic therapy. Daptomycin (DAP) is a novel antibiotic, which allowed for implant retention in several patients after treating their infected joints. However, there is no consensus about implant retention or removal during the treatment of PHIs. The aim of this study was to examine the effect of DAP and to determine a surgical treatment strategy. Methods This study retrospectively evaluated 20 patients between August 2014 and December 2018, divided into implant retention (n=9) and implant removal groups (n=11). Infection control and risk of recurrent infection were evaluated. Infection control was defined as not requiring implant removal after the final treatment. Results Infection control rates in implant retention and implant removal groups were 67% and 90%, respectively. All late chronic infections resulted in failure cases within the implant retention group. In the implant retention group, mean preoperative risk scores for successful cases were significantly higher than those for failure cases (p<0.05). Conclusions Patients with low risk did not require implant removal, suggesting that DAP may be a breakthrough alternative to traditional PHI management.

Detection of 2-hydroxy-fatty acids and 2-hydroxy-fatty acid-containing ceramides in a gliding marine bacterium Aureispira marina.

The cellular fatty acid composition of Aureispira marina IAM 15389T (JCM 23197T), a gliding bacterium isolated from the coastline of Thailand, was re-examined by using a standard MIDI method based on alkaline hydrolysis, and two other methods. The direct transesterification using 5% HCl/methanol or 4 M HCl hydrolysis followed by methyl esterification revealed that 2-hydroxy-15-methyl-hexadecanoic acid (2-OH-iso-C17:0) and 2-hydroxy-15-methyl-hexadecenoic acid (2-OH-iso-C17:1), which were not reported in a previous paper, were found to be major cellular fatty acids of this bacterium, and the amount of 2-OH-iso-C17:1 was even higher than that of arachidonic acid (C20:4), a characteristic polyunsaturated fatty acid present in this bacterium. These 2-hydroxy-fatty acids were contained in two cellular lipids that were relatively stable against alkaline hydrolysis. One of them was analyzed by mass spectrometry, 1H-nuclear magnetic resonance, and other chemical methods, and identified as a ceramide composed of 2-hydroxy-fatty acid and sphingosine of 19 carbons with three double bonds. A minor ceramide containing 18 carbon sphingosine with three double bonds was also detected.

Aromatic Metamorphosis of Thiophenes by Means of Desulfurative Dilithiation.

A new mode of aromatic metamorphosis has been developed, which allows thiophenes and their benzo-fused derivatives to be converted to a variety of exotic heteroles. This transformation involves 1) the efficient generation of key 1,4-dianions by means of desulfurative dilithiation with lithium powder and 2) the subsequent trapping of the dianions with heteroatom electrophiles in a one-pot manner. Via the desulfurative dilithiation, the sulfur atoms of thiophenes are replaced also with a carbon-carbon double bond or a 1,2-phenylene for the construction of benzene rings.

A Possible Protective Effect of the 'Cam Deformity' on Femoral Neck Fracture: The Relationship between Hip Morphology and the Types of Hip Fracture.

We retrospectively evaluated the cases of 169 hip fracture patients, their previous fractures, and the contralateral hip joint's morphology. A history of contralateral hip fracture was present in 23 patients (Contra group). The other patients had a unilateral hip fracture: a trochanteric fracture (Troch group, n=73) or a femoral neck fracture (Neck group, n=73). In the Troch and Neck groups, we used anteroposterior and cross-table axialview radiographs of the contralateral hip to evaluate the proximal femur's anatomy. In the Contra group, the concordance rate between the first and second types of hip fracture was 65.2%, and the second hip fracture's morphology indicated that the trochanteric fracture had a cam deformity in terms of the femoral head-neck ratio. The average alpha angle and femoral head-neck offset in the Troch group were significantly larger than those in the Neck group. In the Neck group, pistol-grip deformities of Arbeitsgemeinschaft für Osteosynthesefragen types B1 (subcapital), B2 (transcervical), and B3 (displaced) were observed in 42.1%, 75%, and 6% of cases, respectively. There was a smaller alpha angle and a larger femoral head-neck offset in the contralateral hip of femoral neck fractures; thus, the "cam deformity" may protect against femoral neck fractures.

Linezolid versus daptomycin treatment for periprosthetic joint infections: a retrospective cohort study.

BACKGROUND: Linezolid (LZD) and daptomycin (DAP) are predominantly used to target gram-positive pathogens; however, treatment effectiveness and adverse reactions for periprosthetic joint infections (PJIs) remain unknown. The aim of this study was to compare the effectiveness and adverse reactions of LZD and DAP for PJIs. METHODS: This study retrospectively evaluated 82 patients between June 2009 and December 2017, to compare the effectiveness of LZD (group L, n = 39) and DAP (group D, n = 43) for treatment of PJIs harboring gram-positive microorganisms. Surgical options used with LZD or DAP therapy included implant retention, implant removal, and a shift to another appropriate antibiotic. Infection control was defined as not requiring implant removal after the final treatment. RESULTS: Gram-positive pathogens were isolated from 72% of group L and 70% of group D patients, respectively. Whole infection control rates against gram-positive pathogens in groups L and D were 79% and 77%, respectively. Furthermore, infection control rates were 94% and 58% in group L and 75% and 80% in group D, without and with implant removal, respectively. Significantly higher clinical success rates and lower adverse event rates were observed in group D, including higher red blood cell and platelet counts and lower C-reactive protein (CRP) levels. CONCLUSIONS: Although the effectiveness of LZD and DAP was equivalent in terms of infection control rates for refractory PJIs with gram-positive pathogens, DAP therapy significantly decreased CRP levels and caused fewer adverse events than LZD treatment.

Sonication of Extracted Implants Improves Microbial Detection in Patients With Orthopedic Implant-Associated Infections.

BACKGROUND: We assessed whether combining the conventional culture and implant sonicate fluid culture (SFC) methods increased the diagnostic accuracy of orthopedic implant-associated infection (OIAI). METHODS: Consecutive patients (n = 66) undergoing implant removal (OIAI, 17; non-OIAI, 49) were evaluated prospectively. We analyzed 493 samples (39 preoperative joint aspirates, 243 peri-implant tissue specimens, 124 implant sonication, 67 controls, and 20 water bath samples). OIAI was preoperatively evaluated based on clinical evidence of infection or aspirate culture (AC). Conventional methods required positive results in either preoperative ACs or intraoperative tissue cultures (TCs), whereas the combination method required at least 1 positive culture among 3 sources (AC, TC, or SFC). The application of SFC and the detection rate, sensitivity, and specificity of the diagnostic methods were assessed. RESULTS: No controls or water bath samples harbored bacteria. Three patients (18%) were detected by SFC only and Peptostreptococcus and Corynebacterium species were isolated by SFC only. The OIAI detection rate attributable to SFC was significantly higher than that of TC (61% vs 36%; P = .02). The sensitivities of AC, TC, and SFC at a cutoff point of 1 colony-forming unit/plate and 1 positive culture were 60%, 59%, and 71%, respectively. At a cutoff point of 2 positive cultures, the combination (vs conventional) method showed significantly greater sensitivity (71% vs 47%; P = .008). CONCLUSION: By incorporating SFCs into conventional culture methods, the diagnostic accuracy in the context of OIAI was significantly improved.

Reattachment of an osteotomized greater trochanter in total hip arthroplasty using an ultra-high molecular weight polyethylene fiber cable.

BACKGROUND: The optimum approach in total hip arthroplasty (THA) should reduce the risk of postoperative dislocation or limping, be applicable in every case, and be reusable in the future. The purpose of this study was to introduce our transgluteal approach for THA and to evaluate the type and frequency of complications around the greater trochanter. METHODS: This study retrospectively evaluated 892 THA cases between January 2010 and March 2015 performed using our transgluteal approach that osteotomized only the lateral anteroinferior greater trochanter. The trochanteric fragment was reattached using one of three different protocols: Group A, three non-absorbable polyester sutures; Group B, two non-absorbable polyester sutures and one ultra-high molecular weight polyethylene (UHMWPE) fiber cable; or Group C, two UHMWPE fiber cables. Postoperative complications were assessed and recorded, and univariate logistic regression analyses were performed to determine whether risk factors and radiological complications around the greater trochanter were correlated. RESULTS: None of the hips required revision for infection, dislocation, or limping. The rate of radiological complications around the greater trochanter at 1 year was 19.2% in Group A, 16.3% in Group B, and 7.9% in Group C (p < 0.001). Risk factors for radiological complications included the patient's disease or the surgeon's experience in Group A and the patient's age or the surgeon's experience in Group C. In the relationship between postoperative pain around the greater trochanter and radiological complications, there were no significant differences in all groups; no group interaction was observed (p= 0.3875). CONCLUSION: The UHMWPE fiber cable was effective to reduce complications of the reattached osteotomized greater trochanter in THA.

TGF-ß Signaling Accelerates Senescence of Human Bone-Derived CD271 and SSEA-4 Double-Positive Mesenchymal Stromal Cells.

It is generally thought that the proliferative capacity and differentiation potential of somatic stem cells, including mesenchymal stromal/stem cells (MSCs) and hematopoietic stem cells, decline with age. We investigated the effects of aging on human bone-derived MSCs expressing CD271 and SSEA-4 (double-positive MSCs [DPMSCs]). The percentages of DPMSCs in bone tissue decreased significantly with age. The DPMSCs from elderly patients (old DPMSCs) showed cellular senescence, which was evidenced by low growth potential, high senescence-associated ß-galactosidase activity, and elevated p16 and p21 CDK inhibitor levels. Moreover, old DPMSCs showed weak osteogenic differentiation potential and less hematopoiesis-supporting activity in comparison with young DPMSCs. Interestingly, the addition of transforming growth factor ß2 (TGF-ß2) induced cellular senescence in young DPMSCs. With the exception of the adipogenic differentiation potential, all of the aging phenomena observed in old DPMSCs were reversed by the addition of anti-TGF-ß antibodies. These results suggest that, in part, old DPMSCs accelerate cellular senescence through TGF-ß signaling.

In vivo serum concentration of vancomycin in antibiotic-loaded acrylic cement for the treatment and prevention of periprosthetic hip infection.

BACKGROUND: Although antibiotic-loaded acrylic cement (ALAC) is used to prevent and treat periprosthetic hip infection, it is unknown how much antibiotic is deposited in the body in vivo, how high the serum concentration rises, or how long its effects last. The aim of this study was firstly to determine the amount of vancomycin (VCM) deposited as ALAC in the body, and secondly to assess the safety and drug elution profile of VCM in ALAC. METHODS: We administered VCM to prevent infection after total hip arthroplasty (THA) or to treat patients with methicillin-resistant Staphylococcus aureus. Patients were classified into two groups: a low-dose group (21 hips) that received primary THA for high-risk cases, revision THA without infection, or one-staged revision THA for infection; and a high-dose group (6 hips) that received cement beads during a two-staged revision THA. The amount of VCM placed as ALAC into the hip was calculated using the remaining ALAC. The serum concentrations of VCM and creatinine were evaluated at postoperative days 1, 4, 7, 14, and 28, and at 3 and 6 months. RESULTS: The mean amount of VCM placed as ALAC into the hip was 0.9 g and 3.4 g for cemented THA and cement beads, respectively (P < 0.0001). The mean serum concentration of VCM from ALAC in the high-dose group was significantly increased compared with that in the low-dose group on postoperative days 1, 4, 7, 14, and 28 (P < 0.0001), but it remained within a clinically safe range. No significant differences were observed between the preoperative and postoperative serum creatinine levels of either group. CONCLUSION: The average serum concentrations of VCM from ALAC were always less than the effective blood concentration, and were detectable until 6 months after surgery.

Bone Remodeling in Acetabular Reconstruction Using a Kerboull-Type Reinforcement Device and Structural Bone-Grafting in Total Hip Arthroplasty.

BACKGROUND: The purpose of this study was to identify the long-term durability of the Kerboull-type reinforcement device (KT plate) in acetabular reconstruction for massive bone defects, assessing the remodeling of structural bone grafts. METHODS: This study retrospectively evaluated 106 hips that underwent acetabular reconstruction using a KT plate between November 2000 and December 2010. Thirty-eight primary total hip arthoplasties (THAs) and 68 revised THAs were performed, and the mean duration of clinical follow-up was 8 years (5-14 years). Regarding reconstructing the acetabular bone defects, autografts were used in 37 hips, allografts in 68 hips, and A-W glass ceramics in 2 hips. RESULTS: One hip exhibited radiological migration and no revision for aseptic loosening. The mean Merle d'Aubigné Clinical Score improved from 7.5 points (4-12 points) preoperatively to 10.9 points (9-18 points) at the last follow-up. The Kaplan-Meier survival rate for radiological migration of primary and revised THAs at 10 years was 100% and 97% (95% confidence interval: 96%-100%), respectively. Bone remodeling was evaluated using the radiological demarcation at the bone-to-bone interface, and an improvement of 100% in primary THAs and 94% in revised THAs was observed. CONCLUSION: For massive bone defects, acetabular reconstruction using the KT plate with a structural bone grafting can yield successful results.

Midterm outcomes of high-flexion total knee arthroplasty on Japanese lifestyle.

OBJECTIVE: To evaluate the clinical outcomes after total knee arthroplasty (TKA) using the Genesis II posterior stabilized prosthesis with a high-flex insert during the mid-term follow-up and to assess its effect on the Japanese lifestyle. MATERIALS AND METHODS: Fifty-three consecutive patients (8 men and 45 women) underwent primary TKA. The mean follow-up time was 76 months (5-9 years). Clinical results were assessed with the Japanese Orthopedic Association osteoarthritis knee rating score (JOA knee score), range of motion, and lifestyle changes. RESULTS: The postoperative JOA knee score improved significantly compared to the preoperative JOA knee score. The mean preoperative flexion range improved from 112° to 123° postoperatively (p < 0.05). Additionally, our findings showed that 39% of patients enjoyed a floor-sitting life preoperatively, but only 30% of patients enjoyed floor-sitting life postoperatively. CONCLUSION: The postoperative range of knee motion and JOA knee score improved after TKA using the Genesis II posterior stabilized prosthesis with a high-flex insert, but the number of patients who enjoyed floor-sitting life decreased from 39% to 30% because of feelings of fear and discomfort. LEVEL OF EVIDENCE: Level IV, Therapeutic study.