Perioperative bleeding control in total hip arthroplasty: hemostatic powder vs. tranexamic acid-a prospective randomized controlled trial.

BACKGROUND: Perioperative bleeding in total hip arthroplasty (THA) can lead to various problems, so effective management of blood loss is needed. This prospective, single-blind, randomized controlled trial aimed to compare the efficacy of topical administration of SURGICEL® (a hemostatic agent of oxidized regenerated cellulose) powder (SP) and tranexamic acid (TXA) in controlling perioperative bleeding during THA. MATERIALS AND METHODS: In total, 114 patients undergoing THA for osteoarthritis were randomized to either group S (THA with SP) or group T (THA with TXA). Data including patient demographics, laboratory data (C-reactive protein [CRP], hemoglobin, and hematocrit), operative time, and intraoperative blood loss were analyzed. Clinical outcomes were assessed using WOMAC, JOA, FJS scores, and visual analog scale (VAS) scores. Primary outcomes were estimated total and postoperative blood loss, while secondary outcomes included hematological test results and various clinical scores. RESULTS: 57 patients were allocated to each group, with 55 in group S and 56 in group T were finally included in the analysis. There was no significant difference (p = 0.141) in estimated total blood loss between group S (788.2 ± 350.1 ml) and group T (714.1 ± 318.4 ml). Hemoglobin and hematocrit levels and WOMAC, and FJS scores were not significantly different between the two groups at any time point. CRP levels were significantly different on postoperative days 4 and 7, and JOA score was significantly different on preoperative and postoperative period. However, the differences in CRP and JOA score values themselves were relatively small and not clinically different. CONCLUSIONS: Topical administration of SP is as effective as TXA in reducing perioperative bleeding in patients undergoing THA. Additionally, no significant difference was observed in early postoperative clinical outcomes between SP and TXA. LEVEL OF EVIDENCE: Therapeutic Level I. TRIAL REGISTRATION: The University Hospital Medical Information Network (UMIN) registration number UMIN000047607.

Stem Alignment With the Tapered Wedge Cementless Stem "Accolade II" Does Not Affect Bone Mineral Density Over 5 Years After Total Hip Arthroplasty.

Background: This study aimed to investigate the relationship between 3-dimensional (3D) alignment and postoperative bone mineral density (BMD) changes with Accolade II tapered wedge stems, which have a different proximal shape from other tapered wedge stems, up to 5 years after primary total hip arthroplasty. Methods: We retrospectively analyzed the hips of 89 patients who underwent total hip arthroplasty using the second-generation proximally coated cementless stem (Accolade II; Stryker Orthopedics, Mahwah, NJ) at our institution from 2014 to 2018 over a 5-year follow-up. We evaluated the relationship between stem alignment, measured using 3D-templating software, and BMD changes in the 7 Gruen zones and compared the data with those from a former study using other short taper-wedge stems. Results: BMDs in zones 1 and 7 continued to decrease gradually every year after surgery, and BMD in zone 7 showed the largest decrease (21%) from baseline over 5 years. No correlation was found between stem alignment (varus/valgus, flexion/extension, and anteversion/retroversion) and changes in BMD in each zone over 5 years. Conclusions: Our data showed no correlation between 3D stem alignment and changes in BMD in each Gruen zone over 5 years. This suggests that the Accolade II stem may fit better into any shape of the proximal medullary canal because of its unique characteristics.

Highly Porous Titanium Cups Frequently Presenting with Radiolucent Lines in Cementless Primary Total Hip Arthroplasty: A Retrospective Cohort Study.

Background/Objectives: A highly porous titanium cup with a three-dimensional metal interface was recently introduced to improve biological fixation and survival. However, radiography has revealed concerns regarding these cups, despite their excellent short- and mid-term clinical outcomes. This study compared the clinical and radiographic results of a highly porous titanium cup with those of a hydroxyapatite-coated porous titanium cup after primary total hip arthroplasty (THA). Methods: Fifty-one primary THAs were investigated. A highly porous titanium cup was used in 17 hips, and a hydroxyapatite-coated porous titanium cup was used in 34 hips. No significant differences in preoperative patient demographic characteristics were observed between the two groups. The 2-year postoperative clinical and radiographic results were compared. Results: Radiolucent lines were observed in 13 (76%) of 17 hips with highly porous titanium cups and in none (0%) of 34 hips with hydroxyapatite-coated porous titanium cups (p < 0.001). In the highly porous titanium cup group, radiolucent lines were observed in five hips (29%) in one zone, two hips (11%) in two zones, and six hips (35%) in three zones. No cup loosening was observed in either group. Conclusions: Radiolucent lines were significantly more frequent in highly porous titanium cups. This study suggests that, compared to the three-dimensional structure of porous titanium, the hydroxyapatite coating of porous titanium had a greater influence on bone ingrowth in the short term. The meaning of these findings in the long-term is unclear yet.

A novel imageless accelerometer-based navigation system improves acetabular cup placement accuracy during total hip arthroplasty in the lateral decubitus position.

INTRODUCTION: The accuracy of acetabular cup placement using conventional portable imageless navigation systems in total hip arthroplasty (THA) in the lateral decubitus position remains challenging. Several novel portable imageless navigation systems have been developed recently to improve cup placement accuracy in THA. This study compared the accuracy of acetabular cup placement using a conventional accelerometer-based portable navigation (c-APN) system and a novel accelerometer-based portable navigation (n-APN) system during THA in the lateral decubitus position. MATERIALS AND METHODS: This retrospective cohort study compared 45 THAs using the c-APN and 45 THAs using the n-APN system. The primary outcomes were the absolute errors between the intraoperative and postoperative values of acetabular cup radiographic inclination and anteversion angles and the percentage of cases with absolute errors within 5°. Intraoperative values were shown on navigation systems, and postoperative measurements were conducted using computed tomography images. RESULTS: The median absolute errors of the cup inclination angles were significantly smaller in the n-APN group than in the c-APN group (3.9° [interquartile range 2.2°-6.0°] versus 2.2° [interquartile range 1.0°-3.3°]; P = 0.002). Additionally, the median absolute errors of the cup anteversion angles were significantly smaller in the n-APN group than in the c-APN group (4.4° [interquartile range 2.4°-6.5°] versus 1.9° [interquartile range 0.8°-2.7°]; P < 0.001). Significant differences were observed in the percentage of cases with absolute errors within 5° of inclination (c-APN group 67% versus n-APN group 84%; P = 0.049) and anteversion angles (c-APN group 62% versus n-APN group 91%; P = 0.001). CONCLUSIONS: The n-APN system improved the accuracy of the cup placement compared to the c-APN system for THA in the lateral decubitus position.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan.

OBJECTIVES: This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity. DESIGN: Retrospective observational study of a nationwide database. SETTING: The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint. PARTICIPANTS: This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018. MAIN OUTCOME MEASURE: The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis. RESULTS: The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years. CONCLUSION: ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact. TRIAL REGISTRATION NUMBER: Chiba University ID1049.

Is bone remodelling around fully hydroxyapatite-coated and tapered-wedge stems related to the stem fixation pattern?

PURPOSE: This study aimed to compare bone mineral density (BMD) changes around the femoral component after total hip arthroplasty (THA) in a fully hydroxyapatite-coated stem (CORAIL) and in a tapered-wedge stem (Taperloc complete) and identify predictors of BMD changes. METHODS: This retrospective study compared 43 hips in the CORAIL group and 40 hips in the Taperloc group. The relative changes in BMD at 2 years after THA measured using dual-energy X-ray absorptiometry and the three-dimensional quantified contact states of the stem with the femoral cortical bone were assessed. Predictors of the relative change in the BMD around the proximal part of the stem were examined using multiple regression analysis. RESULTS: The decrease in BMD in Gruen zone 7 was significantly less in the CORAIL group than in the Taperloc group (P = 0.02). In the CORAIL group, the contact area in any zone was not a significant predictor of the relative changes in BMD. The contact area between the Taperloc stem and the femoral cortical bone in zones 2 and 6 was a positive predictor of the relative changes in BMD in zones 1 (P = 0.02 and P = 0.04, respectively) and 2 (P = 0.008 and P = 0.004, respectively). CONCLUSION: The CORAIL stem suppressed the postoperative BMD loss around the stem, irrespective of the contact state. The Taperloc complete stem required contact with the proximal femoral metaphysis to suppress the postoperative BMD loss around the stem.

Stem alignment with short tapered-wedge cementless stems affects bone mineral density continuously for at least 5 years after primary total hip arthroplasty.

AIM: This study aimed to assess the relationship between the three-dimensional (3D) alignment of short tapered-wedge cementless stems and bone mineral density (BMD) changes in patients followed up for 5 years after total hip arthroplasty (THA). METHODS: We retrospectively analysed the hips of 52 patients who underwent THA using short tapered-wedge cementless stems at our institution from 2013 to 2016 with complete 5-year follow-up data. We evaluated the relationship between stem alignment, measured using a 3D-templating software, and BMD changes in the 7 Gruen zones. RESULTS: After 1 year, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD in zones 3 and 4 were noted. After 5 years, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD zones 2, 3, and 4 were observed. With increased amounts of varus/flexion stem alignment, the amount of BMD loss decreased. There was no correlation between anteverted stem insertion and changes in BMD levels. CONCLUSIONS: Our data showed that stem alignment affects BMD based on 5-year follow-up data after surgery. Careful observation is necessary, especially when using short tapered-wedge cementless stems, as stem alignment may affect changes in BMD levels more than 5 years after surgery.

Mobile-bearing prosthesis suppresses the postoperative rotational mismatch and improves patient-reported outcome measurements better than fixed-bearing prosthesis: rotational analysis by 3D measurement in total knee arthroplasty.

INTRODUCTION: It is preferable to reduce postoperative excessive rotational mismatch between the femur and tibia that causes poor clinical results following total knee arthroplasty (TKA). The aim of this study is to compare postoperative rotational mismatches and clinical outcomes with mobile- and fixed-bearing prostheses. MATERIALS AND METHODS: This study classified 190 TKAs into two groups equally by propensity score matching: mobile-bearing group (n = 95) and fixed-bearing group (n = 95). Computed tomography images of the whole leg were taken at 2 weeks postoperatively. The component alignments, rotational mismatches between the femur and tibia, and rotations among components were measured three-dimensionally. The knee range of motion, New Knee Society Score (KSS) subjective sores, and Forgotten Joint Score (FJS-12) were assessed at the final follow-up. RESULTS: Rotational mismatch between the femur and tibia was significantly less in the mobile- (- 0.8° ± 7.3°) than in the fixed-bearing (3.3° ± 8.5°, p < 0.001) group. New KSS functional activity score was significantly poorer in patients with excessive rotational mismatch (61.3 ± 21.4) than in those without it (49.5 ± 20.6, p = 0.02). Comparing mobile-bearing prosthesis, the use of fixed-bearing prosthesis was a risk factor for postoperative excessive rotational mismatch (odds ratio: 2.32, p = 0.03). CONCLUSION: When compared to a fixed-bearing prosthesis, TKA using a mobile-bearing prosthesis could suppress the postoperative rotational mismatch between the femur and tibia that causes poor subjective functional activity score. However, since this study was conducted for PS-TKA, the results might not be applicable to other models.

The modification of bone cut angle and joint line obliquity did not change the tibiofemoral kinematics and stability of knee joint after total knee arthroplasty.

INTRODUCTION: Previous reports using cadaveric knees and musculoskeletal computer simulation have shown that kinematically aligned (KA) total knee arthroplasty (TKA) provides more natural and physiological tibiofemoral kinematic patterns than mechanically aligned (MA) TKA. These reports suggested that the modification of joint line obliquity improve the knee kinematics. This study aimed to determine whether joint line obliquity change the intraoperative tibiofemoral kinematics in TKA candidates with knee osteoarthritis. METHODS: Thirty consecutive knees with varus osteoarthritis that underwent TKA using a navigation system were evaluated. Two types of trial components were prepared: (1) MA TKA model: component trial in which articulating surface was parallel to the bone cut surface (2) KA TKA model: the femoral component trial, which mimicked the KA TKA method of Dossett et al. was designed 3° valgus and 3° internal rotation to the femoral bone cut surface, and the tibial component trial was designed 3° varus to the tibial bone cut surface. These two trials were set on the same knees during the operation, and the tibiofemoral rotational kinematics and varus-valgus laxity were measured from 0° to 120° of knee flexion using a navigation system. RESULTS: The joint gap was 20 ± 2 mm and 3° ± 1° varus in extension and 20 ± 2 mm and 3° ± 1°varus in flexion. The differences in femoral component rotation between KA TKA and MA TKA were not statistically significant for any knee flexion angle. The differences in varus-valgus laxity between KA TKA and MA TKA were also not statistically significant for any knee flexion angle. CONCLUSION: Although the degree of joint line obliquity varies widely in various KA TKA methods, this study, which mimicked the method of Dossett et al. showed that the modification of joint line obliquity did not change the tibiofemoral kinematics and stability of the knee joint in TKA candidates with knee osteoarthritis.

A double tapered fully hydroxyapatite-coated stem has less contact area to femoral cortical bone than a tapered-wedge stem: a three-dimensional computed tomography-based density mapping analysis.

INTRODUCTION: It is clinically important to analyze the initial contact state between an implant and femoral cortical bone as it affects clinical outcomes, such as stress shielding, stem subsidence, thigh pain, and patient-reported outcomes after total hip arthroplasty. Whether the initial contact state of a double-tapered fully hydroxyapatite (HA)-coated stem is achieved with the preserved cancellous or cortical bone remains to be established. This study aimed to compare the contact area with the femoral cortical bone between a double-tapered fully HA-coated stem (HA group) and a tapered wedge cementless stem (TW group) using three-dimensional computed tomography (3DCT)-based templating software. MATERIALS AND METHODS: Forty-seven total hip arthroplasties in the HA and TW groups each were retrospectively analyzed. The contact area between the implant and femoral cortical bone in the whole stem and at each Gruen zone was measured using density mapping with 3DCT-based templating software. RESULTS: The demographic data were not significantly different between the two groups. The contact area in the whole stem area was lower in the HA group (HA 5.4 ± 1.8% vs. TW 9.0 ± 4.8%, p < 0.01). The HA group had a lower contact area in zone 2 (HA 6.7 ± 6.5% vs. TW 15.6 ± 10.8%, p < 0.01) and zone 6 (HA 1.8 ± 3.5% vs. TW 6.3 ± 3.6%, p < 0.01) than the TW group. The implant type (ß = 0.41, p < 0.01) and stem coronal alignment (ß = - 0.29, p < 0.01) were significant predictors of the contact area in the whole stem area in a multiple regression analysis (adjusted R2 = 0.27, p < 0.01). CONCLUSION: The contact area of the double-tapered fully HA-coated stem was significantly lower than that of the tapered wedge cementless stem.

A new accelerometer-based portable navigation system provides high accuracy of acetabular cup placement in total hip arthroplasty in both the lateral decubitus and supine positions.

INTRODUCTION: No studies have compared the accuracy of acetabular cup placement in total hip arthroplasty (THA) in the supine and lateral decubitus positions using the same portable navigation system. Thus, this study aimed to compare the accuracy of acetabular cup placement using a new accelerometer-based portable navigation system combined with an infrared stereo camera and inertial measurement unit between the supine and lateral decubitus positions. MATERIALS AND METHODS: This retrospective study compared 45 THAs performed in the supine position (supine group) and 44 THAs performed in the lateral decubitus position (lateral group) using the same portable navigation system. The primary outcome was the absolute errors of cup placement angles, defined as the absolute values of the differences between cup radiographic inclination and anteversion angles displayed on the navigation system and those measured on postoperative computed tomography images. RESULTS: No significant difference in the median absolute error of the cup inclination angle (supine group 1.7° [interquartile range 0.8°-3.1°] vs. lateral group 2.1° [interquartile range 1.0°-3.7°]; p = 0.07) was found between the two groups. Similarly, no significant difference in the median absolute error of the anteversion angle (supine group 1.9° [interquartile range 0.8°-3.4°] vs. lateral group 2.1° [interquartile range 0.9°-3.1°]; p = 0.42) was found. CONCLUSION: This new accelerometer-based portable navigation system may provide high accuracy of the cup placement in THA in the lateral decubitus and supine positions.

A comparison of accuracy and safety between stem-first and cup-first total hip arthroplasty: a prospective randomised controlled trial.

BACKGROUND: The combined anteversion theory to prevent impingement in total hip arthroplasty (THA) has been proposed. However, because stem-anteversion is influenced by the native femoral anteversion and the stem flexion/extension angle, it is often difficult to adjust stem anteversion during surgery. Therefore, the stem-first (combined anteversion) technique may be useful to adjust and achieve appropriate cup anteversion during surgery with respect to the implanted stem anteversion angle. However, the technique may adversely affect cup or stem angle accuracy and result in intra-operative bleeding, post-operative adverse events, and prolonged operative time. It is inconclusive whether either the stem-first or cup-first technique is safe or accurate. Therefore, this study assessed the accuracy and safety of stem-first THA compared to those of cup-first THA. MATERIALS AND METHODS: This prospective randomised controlled trial analysed 114 patients who were randomly divided into 2 groups (stem-first group: n = 57, cup-first group (control group): n = 57). Primary outcomes included cup and stem angle, the discrepancies from the targeted angle and combined anteversion (evaluated via CT at 3 months postoperatively). Secondary outcomes included intraoperative blood loss, operative time, WOMAC, and adverse events. RESULTS: There were no significant differences in age, gender, BMI or in the primary and secondary outcomes between the 2 groups. CONCLUSIONS: Performing stem-first in THA did not adversely affect cup and stem angle accuracy, or result in intraoperative bleeding, prolongation of operative time, or postoperative adverse events. Thus, performing stem-first may be advantageous for achieving combined anteversion theory. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN) registration number UMIN000025189.

Successful en bloc resection for femoral head clear cell chondrosarcoma without biopsy: A case report.

Clear cell chondrosarcoma (CCCS) is a rare, low-grade, malignant chondrogenic bone tumour. This tumour commonly affects the epiphysis of long bones, particularly in the proximal femur. The present study reported on the case of a 58-year-old male with right hip pain of five months duration. Plain radiography, magnetic resonance imaging and computed tomography scan revealed the characteristic appearance of chondroid mineralisation in the right femoral head, suggesting typical CCCS. Although biopsy is the gold standard for definite diagnosis prior to treatment, wide resection with removal of the biopsy tract is thought to negatively affect the surgical margin and postoperative hip function. Therefore, en bloc resection without any biopsy and a hip hemiarthroplasty were performed. The pathological diagnosis was CCCS and an adequate surgical margin was obtained. No local recurrence or distant metastases were detected and postoperative function was excellent at the final follow-up. The femoral head is a typical location of CCCS. Wide resection with adequate margins is the main treatment strategy for CCCS and when radiological features are typical, en bloc resection without a biopsy is an acceptable treatment option to improve patient outcomes.

Is the Anterolateral or Posterolateral Approach More Effective for Early Postoperative Recovery after Minimally Invasive Total Hip Arthroplasty?

Currently, various minimally invasive surgical techniques are applied for total hip arthroplasty (THA). There are few studies comparing the early postoperative clinical outcomes of minimally invasive THA between anterolateral and posterolateral approaches. In this retrospective study, 62 patients underwent minimally invasive THA via either the anterolateral approach with an intermuscular exposure using the modified Watson-Jones approach (MIS-AL, 34 hips) or mini-incision THA with a posterolateral approach (MIS-PL, 28 hips). We analyzed intraoperative data, postoperative hematological data, postoperative radiographic findings, and the postoperative recovery of muscle strength. The mean surgical time was significantly longer in the MIS-PL than in the MIS-AL group. The mean postoperative serum C-reactive protein level was significantly higher in the MIS-PL group than in the MIS-AL group only on postoperative day 3. There were no significant between-group differences in the postoperative recovery rate of muscle strength during hip abduction. The recovery rate of muscle strength during hip extension was better in the MIS-AL group than in the MIS-PL group only on postoperative day 3. In conclusion, we found no obvious advantage in early postoperative recovery between the MIS-AL and MIS-PL approaches. Therefore, the benefit of rapid postoperative recovery was comparable between the MIS-AL and MIS-PL approaches.

Is medial pivot total knee arthroplasty suitable for patients with valgus knee osteoarthritis?

PURPOSE: Medial pivot total knee arthroplasty (MP-TKA) is characterized by the ball-in-socket medial tibiofemoral articulation to achieve low wear and to reproduce the medial pivot motion similar to that in the normal knee, and there have been reports of favorable long-term postsurgical outcomes. However, most of these cases concerned varus knees, and the outcomes of MP-TKA in valgus knees are unknown. The objective of this study was to investigate the postoperative outcomes in end-stage valgus knee OA patients who underwent MP-TKA, through comparisons with those who underwent TKA using the same prosthesis for varus deformity. METHODS: This retrospective, single-center, cohort study analyzed 171 knees of 121 patients who were divided into two groups (valgus knee group: 15 knees (13 patients), varus knee group: 156 knees (109 patients)). Primary outcome measures included the knee joint range of motion (evaluated preoperatively and at every year postoperatively). Secondary outcomes included operative time, laboratory data, estimated blood loss, clinical outcome measures and adverse events. RESULTS: There were no significant differences in age, sex and body mass index, as well as in the postoperative primary and secondary outcome measures between the two groups. CONCLUSION: The use of MP-TKA featuring ball-in-socket medial tibiofemoral articulation in patients with valgus knee OA showed equally favorable clinical outcomes more than 2 years after surgery, compared to patients with varus knees who received MP-TKA.

Differences in the setting of acetabular component alignment guides between the supine and lateral positions for total hip arthroplasty.

The acetabular component orientation in total hip arthroplasty is of critical importance to clinical results. Although navigation systems and surgical robots have been introduced, most surgeons still use acetabular component alignment guides. This study aimed to compare the accuracy between modern acetabular component alignment guides for the lateral position and those for the supine position. Thirteen alignment guides for the lateral position and 10 for the supine position were investigated. All the lateral position alignment guides indicated cup alignment in operative definition, and the supine position alignment guides indicated cup alignment in radiographic definition. For lateral position alignment guides, the anteversion actually indicated by the alignment guide itself was smaller than that indicated by the manufacturer by a mean of 6° (maximum, 9°), and the inclination actually indicated by alignment guides themselves was larger than that by the manufacturer (p < 0.01) by a mean of 2° (maximum, 4°). For supine position alignment guides, the inclination and anteversion indicated by the alignment guide itself were identical with those indicated by the manufacturer. The current study showed that the angles actually indicated and those stated by manufacturers were not identical for lateral position alignment guides.

Changes in patient-perceived leg length discrepancy following total hip arthroplasty.

PURPOSE: Leg length discrepancy (LLD) after total hip arthroplasty (THA) prevents functional recovery and reduces patient satisfaction. We investigated impact of changes in patient-perceived LLD on patient satisfaction and walking ability. METHODS: one hundred and forty-nine patients with unilateral hip osteoarthritis undergoing THA from 2014 to 2017, (125 women, 24 men; average age, 68.5 years) with an objective LLD < 1 cm were included. Outcome measures included the patient-perceived LLD, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, 10-m walking speed, and affected leg loading rate, assessed preoperatively and at 3 weeks, 3 months, and 1 year postoperatively. RESULTS: The absolute patient-perceived LLD (mean ± SD) (the number of patients with perceived LLD > 5 mm) were 6.4 ± 9.6 mm [88 patients (59%)] preoperatively; and 2.2 ± 4.0 mm [48 (32%); p < 0.001], 0.7 ± 2.3 mm [17 (11%); p < 0.001], and 0.4 ± 1.6 mm [10 (7%); p = 0.095] at 3 weeks, 3 months, and 1 year postoperatively, respectively. All outcome measures improved over time. One year postoperatively, a weak positive correlation between the patient-perceived LLD and WOMAC or 10-m walking speed (r = 0.24, 0.23, respectively) was found. The risk of patient-perceived LLD persisting > 1 year postoperatively was 5.5-fold higher in patients who exhibited it at 3 months and those with a WOMAC score > 10 at 3 months postoperatively, using multivariate logistic regression. CONCLUSION: Achieving a post-THA objective LLD < 1 cm significantly reduced the patient-perceived LLD up to 3 months postoperatively. The residual patient-perceived LLD at 1 year postoperatively was predicted from the WOMAC score or the presence of patient-perceived LLD at 3 months after THA. LEVEL OF EVIDENCE: Therapeutic level IV.

Topical co-administration of zoledronate with recombinant human bone morphogenetic protein-2 can induce and maintain bone formation in the bone marrow environment.

BACKGROUND: Bone morphogenetic proteins (BMPs) induce osteogenesis in various environments. However, when BMPs are used alone in the bone marrow environment, the maintenance of new bone formation is difficult owing to vigorous bone resorption. This is because BMPs stimulate the differentiation of not only osteoblast precursor cells but also osteoclast precursor cells. The present study aimed to induce and maintain new bone formation using the topical co-administration of recombinant human BMP-2 (rh-BMP-2) and zoledronate (ZOL) on beta-tricalcium phosphate (ß-TCP) composite. METHODS: ß-TCP columns were impregnated with both rh-BMP-2 (30 µg) and ZOL (5 µg), rh-BMP-2 alone, or ZOL alone, and implanted into the left femur canal of New Zealand white rabbits (n = 56). The implanted ß-TCP columns were harvested and evaluated at 3 and 6 weeks after implantation. These harvested ß-TCP columns were evaluated radiologically using plane radiograph, and histologically using haematoxylin/eosin (H&E) and Masson's trichrome (MT) staining. In addition, micro-computed tomography (CT) was performed for qualitative analysis of bone formation in each group (n = 7). RESULTS: Tissue sections stained with H&E and MT dyes revealed that new bone formation inside the ß-TCP composite was significantly greater in those impregnated with both rh-BMP-2 and ZOL than in those from the other experimental groups at 3 and 6 weeks after implantations (p < 0.05). Micro-CT data also demonstrated that the bone volume and the bone mineral density inside the ß-TCP columns were significantly greater in those impregnated with both rh-BMP-2 and ZOL than in those from the other experimental groups at 3 and 6 weeks after implantations (p < 0.05). CONCLUSIONS: The topical co-administration of both rh-BMP-2 and ZOL on ß-TCP composite promoted and maintained newly formed bone structure in the bone marrow environment.

Initiating range of motion exercises within 24 hours following total knee arthroplasty affects the reduction of postoperative pain: A randomized controlled trial.

BACKGROUND: Postoperative limitations in the range of motion (ROM) after TKA may occur occasionally and restrict a patient's ADL. Although ROM exercise is a means of increasing the ROM after TKA, the optimal time of initiating ROM exercise is still unclear. The purpose of this study is to examine different initiation timings of postoperative ROM exercises after TKA and to compare the results in terms of postoperative pain, swelling, and ROM improvement to determine the optimal time of initiating ROM exercises following TKA. METHODS: This was a prospective, single-center, single-blinded randomized controlled trial involving 109 patients scheduled for unilateral TKA. All patients underwent the physiotherapist assisted passive and active same rehabilitation program that only differed in the starting time of ROM exercise on postoperative day 1 or day 7. Postoperative assessment was performed with all attending personnel blinded to group assignment. Visual analog scale (VAS) of pain, ROM, thigh swelling, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and adverse outcomes were compared between groups on postoperative days within 2 years after surgery. RESULTS: VAS scores during the postoperative period from 18 to 72 h were significantly lower in the group with starting time of ROM exercise on postoperative day 1. The ROM, laboratory data, thigh girth, WOMAC and the incidence of complications did not differ between the two groups at any postoperative time-point. CONCLUSIONS: The results of this study suggested that ROM exercises beginning in the early postoperative stage are advantageous in reducing the postoperative pain after TKA.

Malrotation of the fixed-bearing posterior stabilized total knee prosthesis causes a postoperative rotational mismatch between the femur and tibia.

PURPOSE: This study aimed to identify factors associated with rotational mismatch after total knee arthroplasty (TKA) using fixed-bearing posterior stabilized prosthesis and to evaluate the impact of the rotational mismatch on clinical outcomes. METHODS: This retrospective cohort study included 159 cases that underwent TKA. Whole-leg computed tomography images were obtained 2 weeks after TKA, with three-dimensional measures of alignment. Rotational alignment of the femoral and tibial components and rotational mismatch between components and between the femur and tibia bones were evaluated. The new Knee Society Score (KSS) was obtained at the final outpatient visit, which was defined as the final follow-up timepoint. Predictive factors were identified for rotational mismatch of the lower extremity and poor new KSS. RESULTS: The mean follow-up period was 42 ± 16 months. Rotational mismatch ≥ 10° between bones was identified in 56 cases (35%), with a mean mismatch angle of 5.0° ± 9.1° of external rotation of the tibia relative to the femur. Rotational mismatch ≥ 10° between components was identified in three cases (2%; mean 0.3° ± 3.6° of internal tibial rotation). A multivariate regression analysis showed that component malrotation was predictive of post-operative rotational mismatch between bones (p < 0.01) and rotational mismatch ≥ 10° associated with poor new KSS (odds ratio 4.22; p < 0.01). CONCLUSION: Malrotation of the fixed-bearing posterior stabilized TKA causes a rotational mismatch between the femur and tibia bones. Excessive rotational mismatch between bones greater than 10° is a risk factor for poor postoperative functional outcome. Precise component positioning is essential for improving TKA outcomes. LEVEL OF EVIDENCE: III.