Objective: To evaluate availability of dual-source computed tomography (CT) for representative joint pathologies and to document the findings of each.
Methods: We used dual-source CT to evaluate representative joint diseases. Dual-source CT has two X-ray tubes and can produce two different X-ray energies (80 KV and 140 KV) at the same time. We analyzed CT values of each structure obtained by dual-source CT, and distinguished one from the others using the three-material decomposition theory.
Results: Dual-Energy Imaging produced virtual non-contrast (VNC) images, which detected several clinically important joint pathologies such as articular cartilage defect of the knee joint, labral tear of the hip, and triangular ligament tear of the wrist.
Conclusion: VNC imaging obtained by dual-source CT is considered to be valuable in the evaluation of joint pathologies.

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Objective: In joint replacement surgery for young patients, it is important to preserve the bone stock for future revision surgery. We performed 118 total hip arthroplasties (THAs), using the Mayo conservative hip prosthesis since March 2003. The purpose of this study was to evaluate the short-term results of THAs using the Mayo conservative hip prosthesis for young patients with osteonecrosis of the femoral head who were aged less than 40 years old?
Methods: From March 2003 to September 2008 inclusive, we performed 29 THAs on 25 patients under 40 years old. The average age at surgery was 33 years and the average observation period was 38.5 months. Clinical and radiographic evaluations were performed for all the cases.
Results: Japanese Orthopedic Association (JOA) score improved from 50 to 95 points, respectively There were no loosening or dislocations identified. In one patient with alcoholism, stem subsidence of 2 mm was observed, but it was not progressive. In 93% of the cases, spot welds were found until 8 months after surgery in such a high proportion of patients.
Conclusion: From the results of this study, it appeared that short-term results, when using the Mayo conservative hip prosthesis for young patients with osteonecrosis of the femoral head, were satisfactory.

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Objective: To review medium-term outcomes of 34 patients who underwent total hip arthroplasty (THA) or bipolar hip prosthesis (BHP) using the Mayo conservative prosthesis (Mayo stem) in young patients.
Methods: Records of 40 hips in 7 men and 27 women aged 30 to 65 (mean, 52.7) years who underwent THA for osteoarthritis secondary to dysplastic hips or BHP for idiopathic osteonecrosis of the femoral head or femoral neck fracture, and had been followed up for a mean of 7.2 (range, 5-9.7) years, were retrospectively reviewed. The outcomes of Mayo stem were evaluated in size, alignment, contact point, bone reaction (stress-shielding, radiolucent line, increased bone density, and neocortex), and complications (loosening, intraoperative fracture, subsidence and thigh pain).
Results: Four hip procedures used overly small sized stems, and 2 hip procedures used overly large sized stems. Alignment was evaluated by measuring the angle between the tail line of the stem and the lateral cortex of the femur in the anteroposterior view. The mean angle was 0.6 degrees. Multi contact points were identified in the intraoperative radiographic images. Grade 2 stress-shielding (Engh classification) were identified in 18% of the hips. Radiolucent lines were demonstrated in zones 1 (37%), 2 (8%), and 7 (5%), respectively. All of the hips showed increased density (zone 2) and neocortex (zone 6). In 8 patients, intraoperative femoral fracture at the site of the implantation was found, but there were no differences in clinical outcomes. There was no subsidence of more than 2 mm, implant loosening, or thigh pain.
Conclusion: In this study, we demonstrated satisfactory medium-term outcomes of Mayo stem in young patients.

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Objective: Prevention of venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), is one of the most important clinical interventions after total hip arthroplasty (THA), which is a procedure associated with a high risk for VTE. We aimed to test the efficacy and safety of oral edoxaban, a factor Xa inbitor, for the prevention of VTE after THA in comparison to enoxaparin.
Methods: Following THA, 42 patients received either edoxaban or enoxaparin for VTE prophylaxis. There were a total of 8 males and 34 females, with an average age of 67.0 years old. This was a retrospective, non-randomised, and non-blinded study. The first 23 patients received subcutaneous enoxaparin 2000 IU every 12 hours for 10 days, starting 3 days after surgery. The following 19 patients received oral edoxaban 30 mg once daily for 7 days, starting 3 days after surgery. On days 1, 7, 14, and 28 following surgery, D-Dimer levels were compared. VTE events and bleeding events were recorded for up to 3 months.
Results: On day 1, D-Dimer level was 9.8±1.9 in patients given enoxaparin and 10.5±1.7 in patients given edoxaban (P = 0.8602). On day 7 following surgery, D-Dimer level was significantly lower in patients given edoxaban (7.0±0.7 vs 5.0±0.4), respectively, On day 14 following surgery, the difference still existed (7.2±0.7 vs 5.5±0.4, p < 0.05), but by day 28, there was no statistically significant difference between two groups (4.8±0.7 vs 3.8±0.5, P = 0.2627). No clinical VTE event or bleeding event occurred in this study.
Conclusion: Oral edoxaban 30 mg given once daily significantly suppressed the increase of D-Dimer levels in comparison with subcutaneous enoxaparin 2000 IU given every 12 hours. Bleeding was not observed in this study, and we therefore recommend that edoxaban is used for the prevention of VTE after THA.

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Objectives: We evaluated the efficacy of preoperative planning for implant placement with consideration of pelvic tilt in total hip arthroplasty (THA), and the accuracy of a computed tomography (CT)-based computer navigation system for implant positioning.
Methods: We examined 54 hips of 48 patients (38 females, 10 males; mean age 60.1 [range 38-89] years) who underwent THA and were followed-up for one year postoperatively. Preoperative planning included determination of cup inclination, cup anteversion, and stem antetorsion, using the anterior pelvic plane (APP) in the supine position as a reference. In the anterior tilt group (preoperative APP ≥10 degrees while standing), the standing APP value minus 10 degrees was the target reference, as the pelvis in such patients tends to tilt backward by up to 10 degrees after THA. For patients with lumbar-lordotic angles ≤30 degrees due to lumbar compression fractures, etc., in the posterior tilt group (preoperative APP ≤−10 degrees while standing), the midpoint between the supine and the standing APP values was the target reference, as the pelvis in such patients tends to tilt backward somewhat further after THA. Cup inclination, cup anteversion, and combined anteversion (CA) in the supine and the standing positions were examined one year after THA. The accuracy of the computer navigation system was also examined.
Results: The mean CA was 34.6±7.5 degrees in the supine position and 39.5±7.5 degrees in the standing position. CA did not differ among the three subgroups (anterior, intermediate, posterior tilt) in either the supine or the standing position, indicating that the implant placements were equally effective. The desired CA (37.3 degrees) was midway between those in the supine and the standing positions for each subgroup. The mean absolute errors between preoperative planning and postoperative CT measurement were 3.2±2.3, 3.6±3.1, 6.0±8.7, and 6.3±7.1 degrees for cup inclination, cup anteversion, stem antetorsion, and CA, respectively.
Conclusions: We obtained favorable THA results with preoperative planning for implant placement with pelvic tilt by demonstrating that supine and standing CA were unaffected by preoperative pelvic tilt at one year postoperatively. The mean absolute error of CA between preoperative planning and postoperative measurement was 6 degrees with the use of a CT-based navigation system for implant positioning.

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Objective: Serum hyaluronan (sHA) is one of the leading biomarkers for knee osteoarthritis (OA). Although sHA levels increase in patients with knee OA, there has been little research regarding the association with knee symptoms related to OA. The purpose of this study was to investigate the relationship between sHA levels and changes of knee symptoms during a 3-year prospective cohort study.
Methods: There were 331 individuals (124 males and 207 females) from the general population who participated in an annual check-up project from 2008 to 2011, inclusive. Participants were stratified into three groups: low, middle and high, according to their sHA levels at entry into the study in 2008. Radiographic knee OA was graded according to the Kellgren-Lawrence (K-L) system, and grades 0 and 1 were defined as normal, grade 2 as moderate, and grades 3 and 4 as severe. Knee symptoms and function were evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS). Changes of KOOS among the three groups were compared statistically.
Results: Prevalence of OA was 86 out of 331 subjects. Cross-sectional analysis at baseline showed that sHA levels increased with the severity of radiographic knee OA and knee symptoms. All subscales of KOOS significantly decreased with increasing sHA levels,with their correlation coefficients ranging from −0.20 to −0.41. Longitudinal analysis showed that KOOS Pain and activities of daily living (ADL) in the high group decreased 1 year after, and KOOS Symptom decreased gradually, while the values of the middle and low groups were maintained. Also, those individuals with higher sHA levels had worsening KOOS pain, ADL and sports scores.
Conclusion: Higher sHA levels are associated with worsening of knee symptoms as well as the severity of radiographic knee OA. Our results show that sHA is a potential predictor for worsening of knee OA symptoms.

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Objective: It is known that high flexion in the normal knee is associated with internal rotation of tibia, but whether this rotation is reproduced in total knee arthroplasty (TKA) remains uncertain. It is assumed that different axial rotation magnitudes and patterns may occur after TKA. The purpose of this study was to intraoperatively evaluate the magnitudes and direction of axial tibiofemoral rotation in deep knee flexion.
Methods: One hundred and thirty-eight consecutive patients who underwent 156 primary mobile-bearing, posterior-stabilized TKAs were included. All the operations were performed by senior author (Y.K.) or under his supervision, using the gap balancing technique. After all the bone cut and soft tissue releases were completed, the flexion angle and tibiofemoral rotation were measured with specially designed trial components with the mobile-bearing mechanism in flexion under gravity and in manual passive maximum flexion. For the measurement of the flexion angle, the knees were photographed and the picture data was transferred to a personal computer. Because of the high conformity of the femoral component and tibial insert, no rotation could occur between the femoral component and the polyethylene insert.
Results: The mean flexion angle was 124.1°±9.5° (range, 99°-144°) under gravity and 136.7°±9.6° (range, 108°-156°) in passive maximum flexion. During this flexion arc (12.9°±3.5° range, 4°-23°), the average amount of the rotation was small measuring 1.3°±3.6° of internal rotation (range, external 12°-internal 12°). One hundred and eleven knees (71.2%) showed less than 3° of rotation and in 51 knees (32.7%) showed no rotation.
Conclusion: It has been reported that deep knee flexion in normal knees is always associated with significant internal rotation of the tibia. Intraoperative measurements in the current study have shown however, that the direction of tibial rotation in passive maximum flexion is unpredictable. In addition, the overall amount is negligible (approximately 1.3°) and absent in 32.7% of the knees. This information should be considered in the design of knee prostheses which aims to achieve deep knee flexion. The possible advantage for mobile-bearing TKA would be the ability to accommodate a wide and unpredictable range of axial rotation in deep flexion.

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Objective: We performed total knee arthroplasty (TKA) without patella resurfacing in patients with osteoarthritis of the knee. This study aimed to evaluate problems related to the patellofemoral (PF) joint postoperatively.
Methods: A total of 397 patients (347 affected knees) who had undergone Low Contact Stress mobile bearing knee arthroplasty (Depuy, Warsaw, Ind) six months or more before the study, were enrolled. Subjects included 46 males (36 affected knees) and 351 females (311 affected knees) respectively, with a mean age of 77.7±6.1 years (range, 59-94 years). The mean follow-up period was 72.3±2.4 months (range, 6-129 months). Clinical evaluation employed the Japanese Orthopaedic Association (JOA) scoring system for osteoarthritis of knees. We defined complications as including PF pain, crepitation, patellar clunk syndrome, spin-out, and reoperation. We also performed plain radiographic measurements.
Operations were performed by one surgeon, using the mid-vastus approach with cementless fixation. During the operation, the osteophyte around the patella was resected, and the osteophyte on the articular surface was shaped using a bone saw. Statistical analysis was performed using the Mann-Whitney's U test and a significance level of p<0.05 was adopted.
Results: The average JOA score improved significantly from 46.2±10.4 preoperatively to 82.6±6.1 postoperatively (P = 0.0002).
Postoperative PF pain was found in 37 patients (37 affected knees) at final evaluation. However, in these patients the pain was less severe than it had been preoperatively. Postoperative radiological evaluation was favorable in the majority of cases.
Conclusion: Clinical and radiological evaluation of patella non-resurfacing of mobile bearing total knee arthroplasty was generally favorable. Treatment of the patella in total knee arthroplasty remains controversial. We suggest that treatment of the patella must be determined on the basis of the shape of the sulcus on the femoral component.

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Background: It is important to understand the relative bone position of the hindfoot in order to understand pes planus (flat foot) pathologies as well as to make an accurate diagnosis. The three dimensional (3D) bone position is not yet completely understood. The aim of this study was to quantify and compare the relative bone positions that constitute the hindfoot in the neutral position of the ankle joint in patients with normal feet and pes planus, using 3D computed tomography (CT) reconstruction images.
Methods: CT images were taken of 22 patients with normal feet and 29 patients with pes planus deformity in the neutral position, from which 3D virtual models were made of each mid-hind foot bone. The center of the tibia, the talus, the calcaneus, the navicular bone, and the first metatarsal bone were calculated. The eigenvector of the talus, the calcaneus, and the navicular bone relative to the tibia was calculated. The eigenvector of the calcaneus, the navicular bone, and the first metatarsal bone relative to the talus was also calculated. We compared the 3D relative bone positions between normal feet and pes planus in the neutral position.
Results: The talus in pes planus was more dorsiflexed relative to the tibia as well as more adducted than in the normal foot. The calcaneus was more abducted relative to the tibia as well as more everted in pes planus compared to the normal foot. The first metatarsal bone in pes planus was more dorsiflexed relative to the talus as well as more abducted than in the normal foot. The calcaneus in pes planus was more dorsiflexed relative to the talus, more abducted as well as more everted in comparison to the normal foot. The navicular bone in pes planus was more dorsiflexed relative to the talus.
Conclusions: This study allows for more information to be provided in diagnosing pes planus and selecting more appropriate surgical procedures.

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Objectives: The main goal of rheumatoid arthritis treatment is to improve long-term quality of life by controlling symptoms and preventing progression of joint destruction. Thus, remission should be maintained via appropriate drug adherence. We studied background factors affecting the rate of drug adherence and long-term sustained remission derived from etanercept.
Methods: Patients treated with etanercept were stratified by background to compare the rate of drug adherence and sustained disease remission.
Results: The rate of drug adherence in 548 etanercept-treated patients who were initiated on treatment before July 2011 was calculated by the Kaplan-Meier method. The rate of overall 6-year drug adherence was 59.9%. Patients aged <55 years old, were associated with a greater drug adherence than those aged ≥55 years old, (68.0% vs 54.4%, p = 0.0013). Concomitant use of methotrexate was associated with greater adherence than those not using methotrexate (64.1% vs 54.9%, p = 0.0231). Sustained remission rates occurred in 114 patients achieving clinical remission at 1-year of etanercept treatment out of 249 patients eligible for ≥5-years of follow-up (remission rate: 45.8%). Remission was maintained up to 5 years in 55 out of 114 patients (48.2%). Patients with relapses (n = 39) had significantly longer disease duration than patients with sustained remission (p = 0.0288).
Conclusions: Etanercept is associated high rates of drug adherence and sustained remission. Data suggests that starting etanercept early and with methotrexate in younger patients is associated with greater drug adherence, and which enables sustained remission.

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Purpose: In contemporary modular knee designs tibial insert locking mechanisms are intended to fix between the tibial insert and the tibial base-plate for preventing backside wear to limit interface micro motion. We describe two cases of failure of the locking mechanism of the tibial insert and tibial base-plate in one cruciate retaining (CR) type knee prosthesis (Maxim® CR knee system, Biomet Orthopaedics, Inc., Warsaw, IN, USA) over 10 years after primary total knee arthroplasty.
Cases: At 11 and 15 years postoperatively, both patients developed pain and a sudden instability with walking without any traumatic events. After the appearance of symptoms, there was locking mechanism failure evident on radiographs of both patients. Each patient underwent revision surgery, and the inserts were removed. The removed tibial inserts demonstrated significant wear in the anterior medial quarter and fracture of the locking bar was observed in each case. Clinical function for each patient after revision surgery was satisfactory.
Discussion: Some factors are described for failure of the tibial insert as follows. At first, during full knee flexion stress is concentrated on the anteriomedial side of the tibial insert which promotes wear, because the acceptable rotation range of the femorotibial component of the Maxim® total knee arthroplasty is markedly restricted. Additionally, wear may be accelerated by patient factors, such as a high activity level and high body mass index. It has been assumed that wear finally reaches the region around the deep groove for locking, which is a structural weak point, resulting in rupture of the locking system.
Conclusion: The failures in our two cases suggest that an alternative locking mechanism should be considered for this prosthesis.

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Purpose: Although rotator cuff tears are well documented in the literature, there have been relatively few reported cases of isolated subscapularis injuries without lesions of the long head of the biceps brachii. We highlight key points for the diagnosis and successful arthroscopic treatment.
Case: A healthy 32-year-old man sustained injury to his right shoulder when he tried to stop his leashed dog from chasing another animal. In his attempt to restrain the dog, his right shoulder was forced into extension and external rotation. He immediately experienced shoulder pain, which was later diagnosed as a contusion of the shoulder, and which was treated conservatively by his doctor. When we examined him 10 months after the injury, he had point tenderness of the anterior shoulder. There was limited movement to 150° of active forward flexion and 145° abduction associated with pain. The impingement sign of Hawkins and the belly press and lift-off tests were positive. There was no shoulder instability. Magnetic resonance imaging showed a partial-thickness articular-side tear of the subscapularis tendon. An arthroscopic view from the posterior portal showed that the middle portion of the articular-side of the subscapularis tendon (length 10 mm, depth < 5 mm) was detached from its humeral insertion site. Debridement of the partially torn tendon was then undertaken. No other rotator cuff abnormalities or lesions of the long head of the biceps brachii and its pulleys were detected intraoperatively. Three months postoperatively the patient had recovered full active range of motion. The impingement sign of Hawkins and the belly press and lift-off tests were negative and his Japanese Orthopaedic Association shoulder score improved from 66 to 100 points.

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We report two cases of glenoid fracture that were treated surgically.
Case 1: A 48-year-old man fell and injured his left shoulder. Radiological examination revealed a glenoid fracture with acromioclavicular dislocation, which was classified as type III by Ideberg classification, and multiple rib fractures with pulmonary contusion. Open reduction and internal fixation assisted by arthroscopy were performed and rehabilitation was started at two weeks postoperatively. Assisted shoulder motion was permitted after three weeks, and active shoulder motion was allowed at four weeks. The patient returned to his job three months after surgery. At 19 months after surgery, he was pain-free and his active flextion motion was 160 degrees. His Japan Orthopaedic Association (JOA) score was 100 points.
Case 2: A 59-year-old man injured his left shoulder in a traffic accident. Radiological examination revealed a glenoid fracture, which was classified as type V by Ideberg classification. Open reduction and internal fixation were performed and rehabilitation was started two weeks postoperatively. Assisted shoulder motion was permitted at three weeks, and active shoulder motion was allowed at four weeks. The patient returned to his job four months after surgery. At seven months after surgery, he was pain-free and active flexion was 130 degrees. His JOA score was 89 points.

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