How does corrective fusion surgery for adult spinal deformities affect pelvic inclination in the supine position as the reference plane for THA?

PURPOSE: To determine the changes in pelvic inclination in the supine and standing positions after spinal corrective surgery, and to identify the most predictive factor for changes in pelvic inclination with the supine position as the reference plane for total hip arthroplasty. METHODS: We retrospectively analysed the data of 124 patients who underwent spinal corrective fusion surgery for adult spinal deformity between 2012 and 2016 at our institution. Spinal parameters were assessed preoperatively and postoperatively using whole spine radiographs in the standing position. The sacral slope (SS) was measured using spine and pelvis computed tomography. Differences between the preoperative and postoperative SS values in each position were calculated as Δsupine SSpre post and Δstanding SSpre post, respectively. We statistically analysed the correlations between Δsupine SS pre post and preoperative spinal parameters to determine the most useful predictor of Δ supine SSpre post. RESULTS: The mean Δsupine SSpre post of 10.5°(-13°-50°) was significantly smaller than the mean Δstanding SSpre post of 13.2° (-19°-44°) (p = 0.02). Moreover, 21 patients (17%) had Δsupine SSpre post > 20°. The Δsupine SS pre post was correlated with preoperative LL (r = -0.34 p < 0.01), PT (r = 0.42 p < 0.01), and SVA (r = 0.37 p < 0.01). Preoperative supine SS (r = -0.54, p < 0.01) had the highest correlation with Δsupine SSpre post, whereas preoperative standing SS showed no correlation (r = -0.14 p = 0.12). CONCLUSION: Preoperative supine SS is the most useful predictive factor for changes in supine pelvic inclination, and low preoperative values should be noted. This information should be considered for the management of patients with hip-spine syndrome.

Macrocyclic peptide-based inhibition and imaging of hepatocyte growth factor.

Activation of hepatocyte growth factor (HGF) by proteolytic processing is triggered in cancer microenvironments, and subsequent signaling through the MET receptor is involved in cancer progression. However, the structure of HGF remains elusive, and few small/medium-sized molecules can modulate HGF. Here, we identified HiP-8, a macrocyclic peptide consisting of 12 amino acids, which selectively recognizes active HGF. Biochemical analysis and real-time single-molecule imaging by high-speed atomic force microscopy demonstrated that HiP-8 restricted the dynamic domains of HGF into static closed conformations, resulting in allosteric inhibition. Positron emission tomography using HiP-8 as a radiotracer enabled noninvasive visualization and simultaneous inhibition of HGF-MET activation status in tumors in a mouse model. Our results illustrate the conformational change in proteolytic activation of HGF and its detection and inhibition by a macrocyclic peptide, which may be useful for diagnosis and treatment of cancers.

Deviation of the centre of rotation of the femoral head in dysplastic hip joints.

OBJECTIVE: Hip instability may be based not only on some mismatch between the size of the femoral head and acetabulum but also on the deviation of the centre of rotation of the femoral head. The aim of this study was to compare the differences between the centre of rotation of the femoral head and that of the acetabulum in normal and dysplastic hips. MATERIALS AND METHODS: Thirty dysplastic hips and 30 control hips without dysplastic hip were included in this study. Computed tomography data were imported into three-dimensional analysis software. The sphere radius of the acetabulum, the sphere radius of the femoral head, and the deviation of the centre of rotation of the femoral head from that of the acetabulum were analysed. RESULTS: The sphere radii of the acetabulum and femoral head were significantly larger in dysplastic hips. Distances between the centre of rotation of the acetabulum and that of the femoral head were significantly larger in dysplastic group than in control group. The centre of rotation of the femoral head was significantly deviated anterosuperiorly in dysplastic hips. We found significant negative correlations between centre-edge angle and the distance between the centre of rotation of the acetabulum and that of the femoral head in all subjects. CONCLUSION: In dysplastic hip joints, the centre of rotation of the femoral head was more deviated anterosuperiorly from that of the acetabulum than in normal hip joints even in static condition, which might be clinically associated with the micro-instability in dysplastic hips.

Dislocation rate and its risk factors in total hip arthroplasty with concurrent extensive spinal corrective fusion with pelvic fixation for adult spinal deformity.

BACKGROUND: Though there are several reports on the high dislocation rates following total hip arthroplasty (THA) before or after spinal surgery, the literature specific to extensive spinal corrective fusion with pelvic fixation for adult spinal deformity is limited. This study determined the rate and risk of hip dislocation after THA and extensive spinal corrective fusion. METHODS: We retrospectively analyzed the data of 23 adults (27 hips) who underwent both extensive spinal corrective fusion with pelvic fixation and THA between 2010 and 2018. Surgery-related characteristics were investigated from medical records, while standing anteroposterior pelvic radiographs and lateral spinal radiographs were used to measure spinal alignment parameters and THA acetabular orientation. Patients were grouped based on the occurrence of dislocation, and the rate and risk of dislocation were compared. RESULTS: The rate of THA dislocations was extremely high-22% (6 of 27 hips) of patients. All dislocations occurred posteriorly in patients with prior THAs that were performed using the posterior approach. The pelvic tilt was significantly greater in patients with THA dislocations (p = 0.02) than in those without. Cup radiographic anteversion in the supine (p = 0.02) and standing (p = 0.05) positions was significantly smaller in patients with dislocations than in those without. CONCLUSION: Total hip arthroplasty concurrent with extensive spinal corrective fusion with pelvic fixation for adult spinal deformity has an extremely high rate of posterior hip dislocation. The posterior surgical approach and prior THA were high risk factors for dislocation. Hip and spine surgeons need focused pre-surgical planning to account for this risk.

Sagittal plane deformity after temporary epiphysiodesis of the distal femur for correcting limb length discrepancy.

BACKGROUND: Outcome of the temporary epiphysiodesis procedure for limb length discrepancy (LLD) is commonly evaluated in the coronal plane. The purpose of this study was to investigate implant position and complications of the distal femur and patella in the sagittal plane after the temporary epiphysiodesis. METHODS: We retrospectively reviewed 27 patients with LLD who underwent temporary epiphysiodesis of the distal femur using staples (11 patients) or eight-plates (16 patients) between 2007 and 2015. The mean age was 9.7 years (range, 6.3-13.8) at the time of epiphysiodesis. The implants were removed after a mean period of 2.6 years (range, 0.8-4.8) from the epiphysiodesis. Correction amount of LLD was measured on anteroposterior long leg standing radiographs. Implant position, extension deformity of the distal femur (>5° from epiphysiodesis to removal of implant) and patella baja (the epiphyseal line midpoint method < 1.0) were evaluated using lateral knee radiographs. RESULTS: The average correction amount of LLD was 17.4 mm (range, 2-34). The average implant position was 43.1% (range, 35-55) from the anterior edge of the distal femoral epiphysis. At removal surgery, 16 patients (59%) had extension deformity of the distal femur and 14 patients (52%) showed patella baja. There were significant correlations between implant position and extension deformity (r = -0.51, p < 0.01) and as well as between correction amount of LLD and patella baja (r = -0.64, p < 0.01). CONCLUSION: After temporary epiphysiodesis for the treatment of LLD, extension deformity of the distal femur and patella baja occurred frequently. Anterior placement of the implants is associated with extension deformity of the distal femur. The implant should be placed in the center of distal femoral physis, not the center of femoral shaft. Excessive correction of LLD should be avoided due to a risk of patella baja.

Intraoperative bacterial contamination in total hip and knee arthroplasty is associated with operative duration and peeling of the iodine-containing drape from skin.

BACKGROUND: Surgical site infection (SSI) and periprosthetic joint infection are the most important problems after total hip arthroplasty (THA) and total knee arthroplasty (TKA). This study aimed to examine the risk factors for intraoperative bacterial contamination in THA and TKA. METHODS: One hundred and seven hips underwent THA, while 74 knees underwent TKA. After the implant was placed, a swab sample for bacterial culture was collected around the skin incision. At the time of specimen collection, patients were separated into two groups based on whether the iodine-containing drape remained adhered to the skin (group DR) or the iodine-containing drape was peeled off (group ND). Patient characteristics, including age, height, body weight, body mass index, operative duration, intraoperative blood loss, surgical procedures, and condition of the iodine-containing drape, were compared between patients with positive and negative bacterial cultures. RESULTS: In THA, which had a shorter operative duration than TKA (p < 0.001), there was one case of bacterial contamination. In TKA, there were ten cases of positive bacterial contamination, all in group ND. Postoperative SSI occurred in one case. The binomial logistic regression analyses confirmed that TKA [OR 16.562 (95% CI 2.071 to 132.430), p < 0.01] was a high risk factor of bacterial contamination compared to THA and the group ND [OR 0.000 (95% CI 0.000), p < 0.001] had a low risk of bacterial contamination compared to the group DR. In TKAs, operative duration was the risk factor of bacterial contamination [OR 1.026 (95% CI 1.000 to 1.054), p < 0.01]. CONCLUSIONS: Intraoperative bacterial contamination increases in procedures with long operating time and may be suppressed by proper use of an iodine-containing drape.

Intrawound vancomycin powder increases post-operative wound complications and does not decrease periprosthetic joint infection in primary total and unicompartmental knee arthroplasties.

PURPOSE: A frequent reason for revision surgery after total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is periprosthetic joint infection (PJI). The efficacy of intrawound VP in preventing PJI after primary TKA or UKA is rarely reported. The purpose of this study was to investigate the efficacy and side effects of local high-dose VP application to the joint to prevent PJI in TKA and UKA. METHODS: From 2010 to 2017, 166 consecutive patients that underwent primary TKA or UKA were enrolled. Seventy-five patients (92 knees) did not receive VP (control group), while 90 patients (110 knees, VP group) received VP (intrawound, 1 g) before capsule closure during TKA and UKA. Aseptic wound complications, such as skin erosion, wound dehiscence, and prolonged wound healing, were evaluated within 3 months post-operatively. PJI was assessed within a year post-operatively. RESULTS: Seven patients (7.6%) in the control group and five patients (4.5%) in the VP group had PJI. No significant differences existed in the PJI rates between the groups. Aseptic operative wound complications occurred in 4 patients (4.3%) and 13 patients (11.8%), whereas prolonged operative wound healing occurred in 3 patients (3.3%) and 14 patients (12.7%) of patients in the control and VP group, respectively. Operative wound complications were significantly frequent in the VP group. CONCLUSIONS: Intrawound VP administration does not decrease PJI occurrence in primary TKA and significantly causes aseptic wound complications. The use of intrawound VP for the prevention of PJI after primary TKA and UKA is not recommended. LEVEL OF EVIDENCE: Level II.

Investigation of the control of rotational alignment in the tibial component during total knee arthroplasty.

BACKGROUND: In this study, rotational errors that occur in relation to the tibial component of total knee arthroplasty (TKA) were investigated intraoperatively using a CT-free navigation system and postoperative CT images to confirm the correctness of the rotation. METHODS: Forty patients who underwent TKA using the navigation system were examined. These patients were split evenly into two groups, those whose rotational position was confirmed using a mark made manually on the tibia, and those whose rotation was confirmed using the navigation. All patients underwent postoperative CT scanning and were evaluated using the Knee Society Score. RESULTS: With navigation, a significant difference was found between the rotational positions for which we made a keel hole and those for which the tibial component was inserted unguided. After cementing, the rotational position in the group for which a manual mark was used to confirm the rotation differed significantly from the position for the group for which navigation during cementing was used. Although there were four outliers that had rotational errors over 3° after cementing in the manual mark group, there were no outliers in the navigation group. While there was significant difference in the rotational errors of the tibial component on postoperative CT between two groups, the Knee Society Score did not differ between two groups. CONCLUSION: The exact rotation of a tibial component cannot be maintained by simply creating a keel hole. The use of a manual mark resulted in rotational errors of the tibial component and the creation of the outliers. Therefore, it is suggested that the use of a navigation system can reduce the occurrence of such errors.

Repeated posterior dislocation of total hip arthroplasty after spinal corrective long fusion with pelvic fixation.

PURPOSE: Several reports have indicated that anterior dislocation of total hip arthroplasty (THA) can be caused by spinal degenerative changes with excessive pelvic retroversion. However, no reports have indicated that posterior dislocation can be caused by fixed pelvic anteversion after corrective spine surgery. We describe a rare case experiencing repeated posterior THA dislocation that occurred at 5 months after corrective spinal long fusion with pelvic fixation. METHODS: A 64-year-old woman had undergone bilateral THA at 13 years before presenting to our institution. She had been diagnosed with kyphoscoliosis and underwent three subsequent spinal surgeries after the THA. We finally performed spinal corrective long fusion from T5 to ilium with pelvic fixation (with iliac screws). Five months later, she experienced severe hip pain when she tried to stand up from the toilet, and was unable to move, due to posterior THA dislocation. Therefore, we performed closed reduction under sedation, and her left hip was easily reduced. After the reduction, she started to walk with a hip abduction brace. However, she had experienced 5 subsequent dislocations. RESULTS: Based on our findings and previous reports, we have hypothesized that posterior dislocation could be occurred after spinal corrective long fusion with pelvic fixation due to three mechanisms: (1) a change in the THA cup alignment before and after spinal corrective long fusion surgery, (2) decreased and fixed pelvic posterior tilt in the sitting position, or (3) the trunk's forward tilting during standing-up motion after spinopelvic fixation. CONCLUSIONS: Spinal long fusion with pelvic fixation could be a risk factor for posterior THA dislocation.

Comparison of hip muscle volume between fit-and-fill stem and tapered-wedge stem after total hip arthroplasty using the anterolateral approach.

BACKGROUND: In total hip arthroplasty (THA) surgery, hip muscle preservation is important in strengthening the stability of the hip and improving the activities of the patient. However, whether the type of femoral stem affects the recovery of the hip muscles remains unknown. The aim of this study was to compare the postoperative hip muscle recovery among femoral stem varieties after THA. METHODS: The computed tomography (CT) images of 44 patients (44 hips) who underwent THA using an anterolateral approach were reviewed. Twenty-two patients received a fit-and-fill (FF) stem and 22 received the tapered-wedge (TW) stem. The volumes of the gluteus maximus (GMA), gluteus medius (GME), and obturator internus (OI) were measured on three-dimensional models reconstructed using preoperative and 6-month postoperative CT images. Relationships between muscle volume changes and factors including the femoral stem length were evaluated. RESULTS: The GMA and GME volumes increased postoperatively by 8.2% and 8.3%, respectively, in the FF stem group and 7% and 6%, respectively, in the TW stem group, with no group differences. In contrast, the OI volume decreased postoperatively by 17.8% in the FF group and was preserved in TW group (p < 0.001). Moreover, OI volume was decreased in 19 patients (86%) in the FF group and in 11 patients (50%) in the TW group (p = 0.01). The normalized stem length was significantly associated with the postoperative change in OI volume (r = -0.45, p = 0.002). CONCLUSIONS: The TW stem showed a significant advantage over the FF stem in terms of OI preservation. Surgeons should pay close attention during surgery to avoid OI injury when using different femoral stem types. We suggest that a short and reduced lateral shoulder femoral stem is a better choice for the preservation of external rotation muscles.

Simulation of Implant Impingement After Spinal Corrective Fusion Surgery in Patients with Previous Total Hip Arthroplasty: A Retrospective Case Series.

STUDY DESIGN: A retrospective case series. OBJECTIVE: The aim of this study was to introduce the prevention of total hip arthroplasty (THA) dislocation using an implant impingement simulation after spinal corrective fusion and to verify the outcomes. SUMMARY OF BACKGROUND DATA: A high dislocation rate was found among patients who underwent spinal deformity corrective fusion with previous THA. To avoid dislocation, an appropriate position of the stem and cup is important, but the pelvic inclination may change after corrective fusion for spinal deformity. METHODS: Twelve consecutive patients (two men, 10 women; average age, 72.1 [range, 55-81] years during spine surgery) with previous THA were included. Data were retrospectively retrieved from a single-center's prospectively collected database of adult spinal deformity operation. Before surgery, anterior implant impingement simulation in THA was performed using computed tomography-based software. The tolerable pelvic tilt (PT) in which the anterior implant impingement occurred in the hip at the 120° flexion position was measured. The lumbar lordosis angle was deliberately reduced during spinal surgery according to the tolerable PT. The effect of the implant impingement simulation was verified by comparison with patients who underwent surgery before simulation (before 2014). RESULTS: THA dislocation occurred in six patients: four of five (80%) in the non-simulation, and two of seven (28.6%) in the simulation group. The difference between the preoperative and tolerable PT angles was-25° to 33°, and three patients had negative angles. In these three patients, the risk of anterior impingement and THA dislocation significantly increased with correction of lumbar lordosis if the PT was anterior. Two patients experienced repeated THA dislocation with postoperative and tolerable PT angle differences of 2° and -23°. CONCLUSION: Our simulation of anterior implant impingement and subsequent adjustment of the degree of spinal correction was useful to prevent dislocation. However, this method did not prevent dislocation in some patients.Level of Evidence: 4.

Association of knee flexion angle after posterior-stabilized total knee arthroplasty with postoperative tibial external position relative to the femur and the extent of tibial internal rotation from knee extension to flexion.

BACKGROUND: This study evaluated the relationship between preoperative and postoperative knee kinematics, moreover, investigated tibial rotational position and the extent of tibial internal rotation from knee extension to flexion as factors to obtain significant knee flexion after total knee arthroplasty (TKA). METHODS: Fifty-four patients (60 knees total; 15 males, 16 knees; 39 females, 44 knees) who underwent posterior-stabilized TKA using a navigation system were included. Intraoperative knee kinematics involving tibial rotational position relative to the femur and the extent of tibial internal rotation were examined at two time points: 1) after landmarks registration (pre-TKA) and 2) after skin closure (post-TKA). The relationship between the knee flexion angle at one year postoperatively and intraoperative tibial rotational position, or the extent of tibial rotation among several knee flexion angles calculated with a navigation system were investigated. RESULTS: The postoperative knee flexion angle was positively associated with the preoperative flexion angle and intraoperative knee kinematics at post-TKA involving tibial external position relative to the femur at knee extension and the extent of tibial internal rotation from extension to 90° of flexion or to maximum flexion. There was a positive relationship between the extent of tibial internal rotation at pre-TKA and that at post-TKA. CONCLUSIONS: The intraoperative kinematics of the extent of tibial internal rotation at post-TKA was influenced by that at pre-TKA. The greater external position of the tibia relative to the femur at knee extension and the greater extent of tibial internal rotation at post-TKA might lead to good knee flexion angle.

Validation of a new 2.5D radiographic index evaluating acetabular coverage using ACX software.

BACKGROUND: Several radiographic signs have been described to assess acetabular coverage. However, plain radiographs only have 2 dimensions (2D) and cannot accurately show acetabular coverage. QUESTIONS/PURPOSES: We developed the ACX Dynamics software to calculate the radial centre-edge angle (RCEA), which represents the acetabular coverage of the femoral head at each acetabular edge point on the radial plane. This study validated the accuracy of the RCEA, as calculated by ACX Dynamics, as a quantitative parameter for acetabular coverage. PATIENTS AND METHODS: We reviewed the anteroposterior (AP) pelvic radiographs and computed tomography (CT) of 650 hips from 325 patients who presented with chief complaint of symptoms at the hip joint. Of 109 hip radiographs (68 patients) that satisfied the criteria, 50 randomised, blinded AP pelvic radiographs were chosen. We determined the absolute RCEA difference (°) [= RCEA ACX (°) - RCEA CT (°)], determined the correlation between RCEA ACX (°) and RCEA CT (°), and examined the RCEA's intra-observer and inter-observer reliability in 50 hips. RESULTS: The absolute RCEA difference from A45° to P75° was 1.9-3.1°. The correlation between the RCEA ACX (°) and RCEA CT (°) was > 0.7 in all lesions (p < 0.001). Using the intraclass correlation coefficient, the intra-observer reliability of the RCEA was 0.83-0.97 in the whole range, which is a highly reproducible and reasonable parameter, and the inter-observer reliability was > 0.80 in A45°-P0°. CONCLUSIONS: The RCEA ACX (°) can be used as a simple quantitative parameter for assessing acetabular coverage using AP pelvic radiograph.

Arthroscopic capsular repair using proximal advancement for instability following hip arthroscopic surgery: a case report.

Arthroscopic capsular reconstruction has been reported for joint capsule tear and joint instability after hip arthroscopic surgery. However, the procedure is complicated and requires proficiency. Herein, we present a case of mild dysplasia and instability following arthroscopic surgery performed against pain due to synovitis and labral injury. The patient refused osteotomy of the hip joint, so we performed hip arthroscopic surgery using a new method of arthroscopic capsular repair using proximal advancement. A 37-year-old woman underwent hip arthroscopic surgery two times at the right side and periacetabular osteotomy at the left side. She noticed instability of the right hip joint after the second hip arthroscopic surgery. For the joint capsular management at the second surgery, which was not suitable for capsular plication, arthroscopic capsular repair using proximal advancement was performed by lifting the distal capsule to the acetabular margin. This method is less technically demanding compared with capsular reconstruction, and it can securely achieve joint stability by retensioning the joint capsule and iliofemoral ligament. Patient-reported outcomes were assessed by modified Harris hip score (mHHS), non-arthritic hip score (NAHS) and visual analog scale (VAS). The patient reported an increase in the mHHS from 35.2 pre-operatively to 90.1, the NAHS increased from 50 pre-operatively to 88.7, and the VAS score improved from 9 points pre-operatively to 1 point at 2 years post-operatively. To our knowledge, this is the first report on arthroscopic capsular repair using proximal advancement in a patient with hip instability following hip arthroscopic surgery.

Dynamic solvophobic effect and its cooperativity in the hydrogen-bonding liquids studied by dielectric and nuclear magnetic resonance relaxation.

The reorientational relaxation of solvent molecules in the mixture of nonpolar solutes and hydrogen-bonding liquids including water, alcohols, and amides are studied by dielectric and 2H-nuclear magnetic resonance (NMR) spin-lattice relaxations. The retardation of the reorientational motion of the solvent by weak solute-solvent interaction is observed in all the solvent systems. On the other hand, no clear correlation between the strength of the solute-solvent interaction and the slowing down of the solvent motion is found in N,N-dimethylacetamide, which suggests the importance of the hydrogen bonding in the dynamic solvophobic effect. The cooperativity of the reorientational relaxation is investigated by the comparison between the collective relaxation measured by the dielectric spectroscopy and the single-molecular reorientation determined by NMR. The modification of the dielectric relaxation time caused by the dissolution of the solute is larger than that of the single-molecular reorientational relaxation time in all the solvents studied here. The effect of the static correlation between the dipole moments of different molecules is calculated from the static dielectric constant, and the effect of the dynamic correlation is estimated. The difference in the effects of the solutes on the collective and single-molecular reorientational relaxation is mainly ascribed to the dynamic cooperativity in the cases of water and alcohols, which is consistent with the picture on the dynamic solvophobicity derived by our previous theoretical analysis (Yamaguchi, T.; Matsuoka, T.; Koda, S. J. Chem. Phys. 2004, 120, 7590). On the other hand, the static correlation plays the principal role in the case of N-methylformamide.

Hip arthroscopic Surgery after a Diagnosis of Premature Osteoarthritis of the Hip in Three Unicyclists: A Case Series.

INTRODUCTION: Although an association between femoroacetabular impingement (FAI) and sports has been reported, there are no reports regarding arthroscopic findings of osteoarthritis due to FAI in adolescent unicyclists. CASE REPORT: We present three cases of experienced unicyclists with coxarthrosis at puberty (three girls aged 17, 15, and 12 years). All three girls had bone morphology characteristics of FAI (two unicyclists with cam-type FAI and one with mixed-type FAI). None of them had a history of trauma or abnormal blood test result. The patients underwent hip arthroscopic surgery and intra-articular evaluation/treatment (acetabular labral repair, synovectomy, bone marrow stimulation [microfracture], and capsular closure). Arthroscopic findings included severe and extensive cartilage and acetabular labrum damages. After surgery, only two patients were able to return to competition. The characteristics of the unicycle competition may have led to puberty coxarthrosis due to FAI. CONCLUSION: Hip joint symptoms in adolescent unicyclists have a risk for causing severe and extensive damages to the labrum and articular cartilages at an early stage, thereby requiring preventive and attention-seeking measures.

Elevated erythrocyte sedimentation rate and high-sensitivity C-reactive protein in osteoarthritis of the knee: relationship with clinical findings and radiographic severity.

PURPOSE: We assessed erythrocyte sedimentation rate and high-sensitivity C-reactive protein concentration in knee osteoarthritis and non-knee osteoarthritis. In addition, we investigated potential relationship between the levels of erythrocyte sedimentation rate and high-sensitivity C-reactive protein with clinical findings and radiographic severity. METHODS: We compared erythrocyte sedimentation rate and high-sensitivity C-reactive protein concentration between 104 patients with knee osteoarthritis (knee osteoarthritis group; 25 males, 79 females; mean age, 73 y) and 50 patients without knee osteoarthritis (non-knee osteoarthritis group; 16 males, 34 females; mean age, 64 y) excluding any patients with comorbid joint osteoarthritis, rheumatoid arthritis, malignant tumours or inflammatory diseases. In the knee osteoarthritis group, we assessed whether erythrocyte sedimentation rate and high-sensitivity C-reactive protein concentration differed in clinical features and Kellgren-Lawrence (KL) grades. RESULTS: Erythrocyte sedimentation rate and high-sensitivity C-reactive protein were significantly higher in the knee osteoarthritis group than in the non-knee osteoarthritis group (P = 0.0013 and 0.00010, respectively). In the knee osteoarthritis group, erythrocyte sedimentation rate was significantly elevated in patients with tenderness and patellar ballottement (P = 0.032 and 0.038, respectively), and high-sensitivity C-reactive protein concentration was significantly elevated in patients with tenderness, swelling and patellar ballottement (P = 0.0042, 0.00030 and 0.019, respectively). Erythrocyte sedimentation rate in KL-I was lower than erythrocyte sedimentation rate in KL-III and -IV (P = 0.012 and 0.037, respectively). Erythrocyte sedimentation rate in KL-II did not significantly differ from erythrocyte sedimentation rate in the other groups. High-sensitivity C-reactive protein concentration was lower in grade I than in KL-II, -III and -IV (P = 0.044, 0.0085 and 0.049, respectively). CONCLUSIONS: Erythrocyte sedimentation rate and high-sensitivity C-reactive protein concentration were higher in patients with knee osteoarthritis and were related to clinical features. In knee osteoarthritis, high-sensitivity C-reactive protein concentration may increase in early-stage KL-II.