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Background The purpose of this study was to evaluate true change in leg length after open-wedge high tibial osteotomy (OWHTO) using three-dimensional (3D) assessments, examine the factors that influence leg lengthening and verify their validity in clinical practice. Methods Study 1: a retrospective case series simulation study, included 46 patients (55 knees) that underwent knee arthroplasty or HTO. OWHTO was simulated from preoperative computed tomography using 3D preoperative planning software. Uni- and multivariate regression analyses were conducted to identify predictors related to change in leg length. Study 2: a retrospective case series study, included 53 patients (55 knees) that underwent OWHTO in another institution. Change in leg length was measured preoperatively and 1 year postoperatively and was compared with the predicted change in leg length calculated using the formula obtained from Study 1. Results Study 1: the true change in leg length significantly increased and showed a strong correlation with the opening width. The change in leg length was predicted using the formula “change in leg length = opening width × 0.75–1.5.” Study 2: the predicted change in leg length showed no significant difference from the change in leg length 1 year postoperatively and a strong correlation with the measured change. Conclusions The true change in leg length after OWHTO was predicted using the formula obtained from the 3D model. Predicting the change in leg length preoperatively can be a basis to consider other HTOs.

BACKGROUND Postoperative gait speed, especially comfortable gait speed, is an important factor for predicting function after total hip arthroplasty (THA). In this study, we examined factors related to gait speed, including preoperative lower and upper-limb functional parameters and postoperative lower-limb alignment. In addition, we examined factors related to postoperative good comfortable gait speed (≥1.34 m/s: one indicator of a good clinical outcome). The purpose of this study was to determine if better preoperative functional parameters had a positive effect on postoperative gait speed. METHODS This prospective case-control study included 91 patients with hip osteoarthritis who underwent unilateral THA. Patients who had undergone a prior hip surgical procedure or had Crowe type-3 and 4 hips, complications after THA, knee osteoarthritis-related pain, and severe lumbar conditions were excluded. The 1-leg standing time (OLST) and knee extensor strength of the operatively treated side and the contralateral side and the functional reach test were examined preoperatively and at 1 year postoperatively. The leg-length discrepancy and global offset compared with the contralateral side and leg lengthening were examined using 3-dimensional models captured through computed tomographic scans. RESULTS The preoperative contralateral side OLST was a significant factor (p < 0.001) for postoperative comfortable gait speed, and the preoperative contralateral-side knee extensor strength was a significant factor (p = 0.018) for postoperative maximum gait speed. Leg-length discrepancy and differences in global offset after THA were not significant factors for postoperative gait speed. The preoperative comfortable gait speed with a cutoff value of 1.115 m/s (area under the receiver operating characteristic curve, 0.690 [95% confidence interval, 0.569 to 0.810]; p = 0.003; sensitivity of 65.5% and specificity of 74.2%) was an independent factor associated with a good postoperative comfortable gait speed. Preoperative contralateral-side OLST was a significant factor (p = 0.027) for preoperative comfortable gait speed. CONCLUSIONS The preoperative contralateral-side, lower-limb functional status is a significant factor for postoperative gait speed. Early surgical intervention before the contralateral-side function declines or a preoperative rehabilitation intervention on the contralateral side may improve THA outcome. LEVEL OF EVIDENCE Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Background A chronic expanding hematoma (CEH) is a rare complication caused by surgery or trauma; it mostly affects the soft tissues, such as those in the trunk or extremities. We present the first case of a large intraosseous CEH presenting with chronic disseminated intravascular coagulation (DIC), 22 years after total hip arthroplasty (THA); the CEH was treated with a single-stage excision and revision THA. Case presentation A 67-year-old man presented to our hospital with left thigh pain and an enlarging mass. He had no history of trauma, anticoagulant use, or a collagen vascular disorder. The patient initially declined surgery. Two years later, radiographs and computed tomography images revealed progressive osteolysis, marginal sclerosis, and calcification in the left femur, in addition to loosening of the femoral component. Laboratory data revealed anemia and chronic DIC of unknown causes. Magnetic resonance imaging revealed a “mosaic sign” on the mass, indicating a mix of low- and high-signal intensities on T2-weighted images. Needle biopsy prior to surgery revealed no infection or malignant findings. An intraosseous CEH was suspected due to extensive osteolysis and loosening of the femoral component. No other factors that could induce chronic DIC were identified, such as sepsis, leukemia, cancer, trauma, liver disease, aneurysms, or hemangiomas. Therefore, we speculated that the anemia and chronic DIC were caused by the large intraosseous CEH. A single-stage revision THA with surgical excision was performed to preserve the hip function and improve the chronic DIC. The postoperative histopathological findings were consistent with an intraosseous CEH. The anemia and chronic DIC improved after 7 days. There was no recurrence of intraosseous CEH or chronic DIC at the 6-month follow-up. The left thigh pain improved, and the patient could ambulate with the assistance of a walking frame. Conclusions The loosening of the femoral component caused persistent movement, which may have caused intraosseous CEH growth, anemia, and chronic DIC. It is important to differentiate CEHs from malignant tumors with hematomas. Furthermore, the “mosaic sign” noted in this case has also been observed on magnetic resonance images in other cases of CEH.

Background A few previous studies have investigated patient satisfaction after total hip arthroplasty (THA) according to the degree of pelvic deformity. This study compared patient-reported outcomes after primary THA for Crowe types III, IV and I dysplasia. Methods This retrospective, single-center, single-surgeon case-control study included patients who underwent primary THA between 2008 and 2016. We sent postal questionnaires to 38 patients with Crowe type III and IV dysplasia. Among the questionnaire respondents, 23 patients, excluding those with a follow-up period of Results The H and control groups were not significantly different in the postoperative JOA scores and SF-36. In the H group, VAS at the final follow-up was significantly higher, and significantly more patients felt that postoperative rehabilitation was serious, expressing that they underwent THA for LLD correction. In addition, the VAS scores in the FO group was higher than those in the N-FO group. Postoperative LLD was significantly greater in the H group than in the control group. Each group had an NPS of > 50. Conclusion The postoperative VAS score was higher in Crowe type III and IV dysplasia than in Crowe type I dysplasia, but no significant differences were detected in the postoperative satisfaction, JOA score, and SF-36 score. These findings may help explain the effects of THA preoperatively to patients with Crowe type III and IV dysplasia. Level of evidence Therapeutic Level 3b.

Background:In total hip arthroplasty with computer navigation assistance, cup orientation is generally determined according to the coordinate system relative to the functional pelvic plane (FPP). However, there is a large difference in the cup anteversion between a posterior pelvic tilt relative to the computed tomography (CT) table in the sagittal plane and anterior pelvic tilt, even when the cup is set at the same orientation angle according to each FPP. The present study analysed this difference from the viewpoint of 3-dimensional (3D) coverage of the acetabular component (3D coverage) to determine how the 3D acetabular coverage is altered with changes in pelvic sagittal tilt.Methods:We analysed 3D-simulated acetabular coverage measured in 3D pelvic models reconstructed from the preoperative CT data of 50 patients. In each patient, we created 5 pelvic models with a sagittal tilt of 10° increments between 20° anterior tilt and 20° posterior tilt relative to the CT table.Results:We found that 3D coverage decreased as the pelvis tilted posteriorly. Particularly, there were significant differences between the pelvis with 20° anterior tilt and that with neutral tilt ( p < 0.001). There was also a difference between the pelvis with neutral tilt and that with a 20° posterior tilt ( p < 0.01). The mean decrease in 3D coverage between the pelvis with neutral tilt and that with 20° posterior tilt was 7.2 ± 1.6%.Conclusions:We found that 3D coverage differed among pelvis with different sagittal tilts when the cup orientation angle was determined according to FPP.

This report is the first study to compare the clinical outcomes between cementless and cemented femoral prostheses in total hip arthroplasty (THA) with subtrochanteric femoral shortening osteotomy for Crowe type IV hips. We identified 26 hips in 20 patients who had undergone cemented (n = 13) or cementless (n = 13) THA with subtrochanteric femoral shortening osteotomy for Crowe type IV hips with a minimum follow-up period of 2 years. The mean follow-up period was 60.8 ± 33.9 months (24–120 months). We compared radiological findings, postoperative clinical recoveries, postoperative complications, and implant survival rates. In both groups, there were no cases of aseptic loosening for the acetabular and femoral implant. In terms of bone union at the osteotomy site, the mean duration was significantly longer in the cemented group (9.8 ± 4.2 months) than in the cementless group (5.0 ± 1.9 months). The clinical hip score in gait and pain at 3 months postoperatively was significantly higher in the cemented group than in the cementless group, while there were no significant changes at other timepoints between two groups. The number of postoperative complications was not significantly different between the two groups. The implant survival rate was 92% in the cementless group and 100% in the cemented group at 5 years postoperatively (P = 0.31). The cemented femoral prosthesis is superior to the cementless femoral prosthesis for early clinical recovery, while the duration required to achieve bone union at the osteotomy site is longer in the cemented femoral prostheses. It is possible for surgeons to perform successful hip reconstructions, regardless of the fixation method used for THA with shortening femoral osteotomy.

Purpose:The mechanisms underlying thigh pain in patients with well-fixed cementless femoral components after total hip arthroplasty (THA) remains unclear. We hypothesized that the thigh pain is correlated with the initial contact state of the stem and aimed to investigate the relation between thigh pain and the initial contact state.Materials and methods:A total of 209 hips of 184 patients were analysed in this retrospective case–control study. The patients were divided into a thigh pain group ( n = 13 hips) and a control group (without thigh pain, n = 196). Post-operative stem contact images were three-dimensionally visualized by a density mapping function using computed tomography data, which quantified the stem contact area according to Gruen zones. Thigh pain was defined as anterior or anterolateral pain upon loading at 3-month post-operatively.Results:Thirteen hips (6.2%) had thigh pain; however, all the hips demonstrated stable bony ingrowth radiographically. The thigh pain group had a significantly lower contact area in zone 2 ( p = 0.014). The multivariate logistic regression analysis showed that the contact area of zone 2 was negatively correlated with thigh pain [odds ratio (OR): 0.858, p = 0.018], and the canal flare index was negatively correlated with the development of thigh pain (OR: 0.336, p = 0.026).Conclusions:We identified an association between the initial contact state and post-operative thigh pain. Our data demonstrated that proper lateral contact prevents the occurrence of thigh pain in THA using a tapered wedge stem.

A computed tomography (CT)-based hip navigation system is a useful tool for achieving precise implant alignment angle. However, it has the disadvantage of prolonged procedure duration. A prolonged procedure duration may increase the incidence of postoperative surgical site infection (SSI) or periprosthetic joint infection (PJI) following primary THA. Studies identifying whether CT-based hip navigation system increases the incidence of SSI and PJI compared to the free-hand technique for total hip arthroplasty (THA) are rare. The study aimed to assess whether the CT-based hip navigation system can cause SSI and PJI compared to the free-hand technique. We investigated 366 patients with osteoarthritis who completed the minimum 2-year follow-up and underwent primary THAs (n = 435), including 70 hips in 62 patients of the non-navigation group and 365 hips in 304 patients of the navigation group. We compared the incidence rate of SSI and PJI between the non-navigation group and navigation group. Only three patients in the navigation group (0.8%) developed SSI or PJI, while no patient developed SSI or PJI in the non-navigation group. There was no significant difference in the incidence rate of SSI or PJI between the two groups (P = 1.0), although the mean operation time in the navigation group was about 20 min longer. CT-based hip navigation system may not be associated with SSI or PJI after primary THA, although it prolongs the operation time.

In THA, using a larger femoral head can increase the oscillation angle and jumping distance. However, there have been no reports which indicate precisely how increasing the jumping distance leads to an increase in the angle from impingement to dislocation (jumping angle). In this study, we clarified the jumping angle of various head diameters and its relationship with pelvic morphology. Using a three-dimensional templating system, virtual THA and ROM simulations were performed in 82 patients. We investigated the distance between bony and prosthetic impingement points and the head centre and calculated the jumping angle for various head diameters. We measured various pelvic shapes and length to clarify the relationship between pelvic morphology and impingement distance. Jumping angles were 7.7° ± 3.2°, 12.1° ± 1.6°, 15.4° ± 2.5° and 10.0° ± 3.0° with flexion, internal rotation with 90° flexion (IR), extension and external rotation (ER), respectively, when we used a 22-mm head diameter. Bony jumping angle increased about 0.5°, 0.8°, 1.0° and 0.7° per 2-mm increase in head diameter with flexion, IR, extension and ER. On the other hand, prosthetic jumping angle remained almost stable at about 31°. Impingement distance was related to pelvic morphology in all directions. Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. On the other hand, bony jumping angle was less than prosthetic jumping angle in all cases. Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. Prosthetic impingement angles were stable. In addition, the bony jumping angle was less than the prosthetic jumping angle in all cases.

Past reports showed good mid-term results of RHA for Japanese patients. However, few reports have compared the mid- to long-term results for RHA in Japanese patients with and without osteoarthritis. Therefore, this study investigated the mid- to long-term results of RHA in Japanese patients with osteoarthritis compared to those without. We conducted a retrospective review of a consecutive series of 92 hips in 80 patients (59 men and 21 women). The minimum follow-up period was 5 years. The JOA hip scoring system was used to clinically evaluate hip function. In the radiological assessment, stem-shaft angle, inclination of the acetabular component, postoperative complications, and adverse reactions around RHA were evaluated. The 10-year survival rate using the Kaplan-Meier method was investigated to compare patients with and without osteoarthritis. A significant difference was observed between the preoperative and postoperative JOA hip scores of either group. Also, the radiological assessment revealed no significant changes in either group. All three revision THAs were performed on patients in the only non-osteoarthritis group. In the osteoarthritis group, the 10-year survival rate was 94% (95% CI 81.8-100) in males and 100% (95% CI 100) for females; in the non-osteoarthritis group, the rate was 80% (95% CI 55.1-100) in males and 66.7% (95% CI 13.3-100) for females. In conclusion, this study showed good mid- to long-term clinical results for young Japanese osteoarthritis patients, with less satisfactory mid- to long-term results in patients without osteoarthritis.

Limb lengthening after total knee arthroplasty (TKA) has been reported in some cases, all of which were evaluated using two-dimensional images. To our knowledge, no case has been evaluated using three-dimensional (3D) images. We investigated 3D limb lengthening after TKA.We simulated 100 varus knees using 3D templating software. Virtual TKA was performed to maintain the original joint line by conducting a measured-resection technique. We examined the relationships of 3D distance between the femoral head center and ankle center before and after TKA, degree of hip-knee-ankle angle (HKA) improvement, and degree of flexion contracture angle improvement.All cases showed limb lengthening (average, 9.4 ± 6.0 mm). The coefficients of correlation with limb lengthening and the degree of HKA improvement and the degree of flexion contracture angle improvement were good (0.730 and 0.751, respectively). The correlation between the degree of total improvement (the degree of HKA improvement + the degree of flexion contracture angle improvement) and limb lengthening was strong (r = 0.896).The expected limb lengthening when performing measured-resection TKA is expressed as 0.58 × (the degree of HKA improvement + the degree of flexion contracture angle improvement) mm and is a useful index.

Past reports have shown the tendency of posterior pelvic tilt to increase over time after total hip arthroplasty (THA). We have hypothesized that the volume and extent of released joint capsule may influence the change in postoperative pelvic tilt. This study was conducted to ascertain whether surgical approach during THA (posterior or anterior) has an effect on postoperative changes in pelvic tilt. We conducted a retrospective review of 81 hips in 60 patients. Patients classified as Crowe group 2, 3, and 4, those who had multiple previous compression fractures, and those with spinal fusion due to spinal arthrosis were excluded. Also, those who had previously undergone THA or total hip resurfacing also were excluded. Patients were divided into two groups, those with preoperative anterior pelvic tilt and those with posterior tilt. Preoperative and postoperative X-rays and CT scans for each group were assessed to determine the chronological change in pelvic tilt, and the data were statistically analyzed for patients who had experienced both the posterior and anterior approaches. Regardless of surgical approach, there was no significant difference in the mean change in postoperative APP angle over time in either the bilateral or unilateral cases or in the groups of preoperative anterior or posterior pelvic tilt. Our results showed that surgical approach does not influence postoperative pelvic tilt after THA. In preoperative planning for THA, therefore, surgeons may need not to consider the difference of surgical approach with regard to postoperative changes in pelvic tilt.

This study investigated the influence of the rotation of innominate bone on anterior pelvic plane (APP) tilt, the angle formed by the APP, and coronal plane of the body to determine whether the provision of proper information about the sagittal balance of the body by the value of the APP tilt (APPT). In total, 244 patients (171 females, 73 males) who were candidates for total hip or knee arthroplasty, periacetabular osteotomy, or shelf arthroplasty were included. The rotational angle of the innominate bone was quantified using computed tomography images at the level of the anterior superior, and anterior inferior iliac spine, and ischiopubic portion. Clustering analysis was performed to identify subtypes of innominate bone rotation. High, intermediate, and low internal rotational alignment groups were identified in females, characterized by rotational angles. Males were treated as one group, and no intergroup differences were observed in sacral slope (SS) and pelvic incidence. However, intergroup differences in APPT were found, indicating a variation in APPT irrespective of sagittal body balance. A negligible relationship between SS and APPT was observed in the high-internal-rotation group, intermediate-internal-rotation group, and male group, whereas a moderate correlation found in the low-internal-rotation group (r = .59). The results could suggest surgeons that the value of the APPT provides no information on the sagittal balance; therefore, it may be ignored for acetabular component positioning during preoperative planning for total hip arthroplasty.

Background Implantation of Kerboull acetabular reinforcement cross-plates (Kerboull plate) carries a risk for injury to vascular structures and pelvic organs. To our knowledge, there is no study assessing anatomical assessment related to this risk with this specific design. Therefore, we performed a prospective study to answer the following four questions: 1) What is the minimum distance and angle between the plate and iliac vessels? 2) What is the distance between the plate and the inner cortex of the ilium? 3) What is the ratio of views with muscle tissue present on the inner surface of the ilium? 4) What are the boundaries of the safe zone for transacetabular screw fixation for a Kerboull plate? Hypothesis A safe zone for fixation screws would be defined by a narrow range of insertion angles. Materials and methods This is a CT-based 3D templating prospective study. Simulations were performed for 18 patients fitted with a Kerboull plate. An original Kerboull plate (Stryker, Mahwah, NJ, USA) was placed at a 45° abduction angle relative to the X-axis (alignment A) and the palette was placed vertically to the X-axis (alignment B). We measured the distance from the centre of the plate to the inner surface of the cortex of the ilium, the shortest distance to vessels and the angle of existing vessels, and the ratio of muscles on the inner surface of the ilium. Results The shortest distance to the vascular structures increased with increasing angle of insertion of the fixation screws, 85.8 ± 12.1 mm for A and 111.4 ± 12.0 mm for B at 45°. The distance to the inner cortex was further increased for screws inserted in posterior direction. At insertion angles ≥ 40°, the screws passed through muscle before invading the pelvis in most cases. However, at anterior-posterior angle (AP angles) ≤ −10°, the risk of direct insertion of screws into the sacroiliac joint increased. Discussion The safe zone for transacetabular screws would be insertion at an angle ≥ 40°, with an AP angle between 0° and −10° (slight posterior direction). Level of evidence Level IV prospective diagnostic study.

Background There have been no studies on the differences in impingement-free angle that result from different combined anteversion (CA) patterns. The aim of this study was to find the optimal CA pattern for achieving a favorable impingement-free angle, including bony and prosthetic impingement, in total hip arthroplasty. Methods We evaluated 100 patients with no hip arthritis. We investigated the impingement-free angle (flexion, internal rotation with 90° flexion, extension, and external rotation) after changing the stem and cup anteversions to satisfy several CA patterns [cup anteversion + stem anteversion = 30°, 40°, 50°, and 60°; cup anteversion + 0.7 × stem anteversion = 37.3° (:Widmer's theory); and cup anteversion + 0.77 × stem anteversion = 43.3° (:Yoshimine's theory)] using 3-dimensional templating software. Results The impingement-free angle changed dramatically among the various CA patterns. The optimal CA was changed by various stem anteversion. Only CA: Widmer with stem anteversion of 20° satisfied daily-life range of motion (ROM) requirements (flexion ≥130°, internal rotation with 90° flexion ≥ 45°, extension ≥ 40°, external rotation ≥ 40°). Conclusion Good impingement-free angle cannot be obtained with single fixed CA. Different CA patterns should be used, depending on the differences in the stem anteversion. A CA of 30° with 0° ≤ stem anteversion ≤10°; a CA:Widmer with 20° of stem anteversion; a CA of 40° or Widmer with 30° of stem anteversion. When stem anteversion is ≥40°, CA should be decided by each patient's state. Among them, a stem anteversion of 20° with cup anteversion of 23.3° was found to be the best CA pattern.

The influence of stem sagittal alignment on clinical outcomes is unclear in total hip arthroplasty (THA). The purpose of this study is to assess the relationship between stem sagittal alignment and clinical and radiographic outcomes using 3D-CT. We performed 370 consecutive primary THAs between 2009 and 2013. After exclusion, 102 hips in 89 patients using single tapered-wedge stem were included. Mean follow-up was 4.7 years. Stem sagittal alignment was measured using CT, and patients were divided into flexion and neutral alignment groups. Clinical and radiographic outcomes were compared between two groups. Furthermore, we evaluated the anterior femoral offset and initial contact state. There were no significant differences in clinical or radiographic outcomes between two groups. CT data analysis and multiple regression analysis showed flexion alignment increased anterior femoral offset (AFO) and Gruen zone 4 contact area. There was no significant difference in clinical or radiographic outcomes between flexion and neutral alignment of the tapered-wedge stem at an average of 4.7 years of follow-up. The increase of AFO and distal contact area in flexion alignment could affect the improvement of impingement-free range of flexion and intraoperative fracture.

There is no documented maximum amount that an extremity can be safely lengthened in primary total hip arthroplasty (THA) without neurologic or soft tissue complications. We retrospectively reviewed patients who underwent primary THA with acute limb lengthening and investigated the safety range for acute limb lengthening in primary THA. This study included 61 hips in 52 patients who underwent primary THA with acute limb lengthening (more than 2.5 cm) without femoral shortening osteotomy. The amount of lengthening was measured from pre-operative and post-operative X-ray films using computer graphics software, then the ratios of the amount of lengthening to femoral length (L/F ratio = amount of lengthening / femoral shaft length × 100) were calculated. We investigated correlation with nerve and soft tissue complications at operation in regard to this index. The average amount of lengthening was 3.0 cm (2.5 to 4.8). The average L/F ratio was 7.9 (6.2 to 12.9). There were seven nerve complications and two soft tissue complications in the whole series. In all nine complications, eight indicated higher L/F ratios than 8.7. Altogether, 12 hips indicated a higher L/F ratio than 8.7; 66% of them showed neurological or soft tissue problems. ROC curve analysis indicated that the optimal cutoff value of the L/F ratio was 8.7, which predicted acute lengthening-related complications with a sensitivity of 88.9% and a specificity of 92.3% (AUC = 0.88). The patients who underwent THA with acute lengthening of more than 8.7% of femoral shaft length are at high risk of complications caused by acute limb lengthening in primary THA.

Purpose During total knee arthroplasty, few rotating reference axes can be reliably used after tibial resection. We speculated that a line that passes through the lateral edge of the posterior cruciate ligament (PCL) at its tibial attachment after resection and the most prominent point of the tibial tubercle [after-tibial resection (ATR) line] will provide a good reference axis. In this study, we aimed to evaluate the association between ATR and Akagi’s lines. Materials and methods In this case–control simulation study, we retrospectively evaluated 38 patients with varus knee and 28 patients with valgus knee. We defined the reference cutting plane as 10 mm distal from the lateral articular surface of the tibia in varus group and as 7 mm distal from the medial articular surface in the valgus group. We measured angles between Akagi’s line and the ATR line (ATR line angle) as well as between Akagi’s line and 1/3 Akagi’s line (1/3 Akagi’s line angle), which passes through the midpoint of PCL and the medial third of the patellar tendon. We used paired t-tests to determine the significance of differences between these angles, with p < 0.05 indicating statistical significance. Intra- and interclass correlation coefficients for the reproducibility of 1/3 Akagi’s line angle and ATR line angle were analyzed by two surgeons. Results We found that 1/3 Akagi’s line angle was 10.2° ± 1.3° in the varus group and 10.9° ± 1.3° in the valgus group (p = 0.017). The ATR line was positioned externally compared with Akagi’s line in all patients. Mean ATR line angles at 0°, 3° and 7° posterior slopes were 6.1° ± 1.9°, 5.8° ± 2.0° and 6.0° ± 1.7° in the varus group and 6.3° ± 2.3°, 6.2° ± 2.3° and 5.4° ± 2.1° in the valgus group, respectively. There were no significant differences in the ATR line angle between the varus and valgus groups. (p = 0.34–0.67) Intra- and interclass correlation coefficients for the reproducibility of 1/3 Akagi’s line angle were 0.936 and 0.986 and those for the reproducibility of ATR line angle were 0.811 and 0.839. Conclusions The ATR line was positioned between Akagi’s line and 1/3 Akagi’s line in all patients and was a valid option for evaluating rotational tibial alignment after tibial resection.

Medial collateral ligament (MCL) pie-crusting technique in total knee arthroplasty (TKA) is one of the methods of medial release. The effects and risks of blade pie-crusting have been reported in previous studies. However, only a few have reported the safety and efficacy of needle pie-crusting. In this cadaveric study, we quantitatively evaluated the amount of gap change by MCL needle pie-crusting. We investigated five knees of four fresh human cadavers and performed posterior-stabilized TKA. Only deep MCL release as the medial release was conducted. We punctured the MCL from the deep layer to the superficial layer using a 18 G needle in a 90-degree flexion position for 0, 10, 20, 50, 75, and 100 times. Medial and lateral gaps were measured accurately with a balancer at determined times in 0 and 90-degree flexion positions. Changes in medial and lateral gaps were not significant differences in flexion and extension position. However, in 90-degree flexion, medial gap changes were tended to be larger than lateral gap changes. A 0.6 mm additional medial release and a 0.2 mm additional lateral release were found per 10 times pie crust in flexion position (100 times, p: 0.08). However, large differences existed among the cases. Needle pie-crusting is safer than blade pie-crusting because of the small efficacy of one-time pie crust. MCL needle pie-crusting showed varied effects for each case. This result indicates the risk of relaxation of an unexpected gap. Caution should be taken when choosing between needle pie-crusting and blade pie-crusting.

The "grand-piano sign" is a well-known indicator of proper rotational femoral alignment. We investigated changes in the shape of the femoral anterior cutting plane by changing the rotational alignment, anterior portion depth, and cutting plane flexion angle.We simulated various cutting planes after cutting the anterior portion of the femur next to the distal femoral osteotomy in 50 patients with varus knee and also a femoral anterior osteotomy with four degree (S group) and seven degree (T group) flexion angles regarding the mechanical axis. We defined the final cutting plane as the farthest position that we could reach without making a notch and the precutting plane as two millimeters anterior from the final cutting plane. The simulated resection plane was rotated to produce external and internal rotation angles of 0°, three degrees, and five degrees relative to the surgical transepicondylar axis (SEA). We investigated medial and lateral portions of the femoral anterior cutting plane length ratio (M/L).When we cut parallel to SEA, M/L was 0.67±0.09 and 0.62±0.12 in the T and S groups, respectively. M/L was approximately 0.8 and 0.5 with five degree internal and external rotations, respectively (P0.01). On comparing final cutting and precutting planes, there were no significant differences in M/L without five degree external rotation in the T group and no significant difference in any case in the S group (P0.01).The ideal M/L of the femoral anterior cutting plane was 0.62-0.67. M/L did not change with a precutting plane in almost all rotational patterns.

We investigated the various impingement angles (including both bony and prosthetic impingement) and impingement types that can occur after THA, even when the same combined anteversion parameter is used. We also investigated the relationship between impingement angle and acetabular morphology or femoral anteversion. We evaluated 83 patients with no hip arthritis. We divided them into six groups according to acetabular CE angle (≤15°, >15–≤25°, and >25°) and femoral anteversion (≤20° and >20°). Using three-dimensional templating software, we changed stem and cup anteversion to satisfy a combined anteversion (CA) of 50° in each hip (stem anteversion + cup anteversion = 50°) and investigated the resulting impingement angles. Even with the same CA, differences in impingement angle occurred: 18.3° ± 7.2° with flexion, 30.2° ± 9.7° with internal rotation at 90° flexion, 20.2° ± 12.5° with extension, and 26.2° ± 7.8° with external rotation. As stem anteversion increased, the impingement type changed from prosthetic impingement to bony impingement in flexion and internal rotation and from bony impingement to prosthetic impingement in extension and external rotation. The flexion angle and internal rotation angle at 90° flexion increased (p

In TKA, we have used the "projected SEA", which is obtained by projecting the "true SEA" on the distal femoral cutting plane in clinical practice to determine the femoral component rotation. There are no reports examining the accuracy of the "projected SEA". In this study, we investigated the difference between the "true SEA" and "projected SEA".The present study was a CT-based computer-simulated case series. We evaluated 34 knees without osteoarthritis changes. These patients were selected from the operative schedule prior to THA. We defined the "true SEA" on the 3D model and the "projected SEA" on the cutting plane parallel to the distal femoral axis obtained based on the "true SEA". We changed the cutting angles from 20° flexion to 20° extension, and from five degrees varus to five degrees valgus. We measured the "true SEA angle" and "projected SEA angle" regarding the posterior condylar axis (PCA).The mean "true SEA angle" was 3.04°±1.34° (0.6-5.0°). The mean "projected SEA angle" was 3.43°±1.58° at 20° flexion, 3.42°±1.56° at 0° flexion, 3.43°±1.52° at 20° extension, 3.39°±1.59° at five degrees valgus, and 3.39°±1.50° at five degrees varus. At each cutting angle, the "projected SEA angle" was significantly larger than the "true SEA angle" (p0.001). There was no significant difference between any of the "projected SEA angles" (p0.001).We found that the true SEA and projected SEA do not differ significantly (0.39°±0.29° [range 0-1.0°]).

Background The surgical depths of approaches for total hip arthroplasty (THA) have not been reported previously. In this study, we investigate the relationships between the distances to the centre of the femoral head in different approaches and body mass index (BMI). Methods The study included patients with normal hip joints who presented to our hospital. We used the pelvic coordinate system relative to the anterior pelvic plane and the femur coordinate system relative to the posterior condylar plane. We assessed the anterior, anterolateral, lateral and posterior approaches, and defined each approach line. We evaluated each distance in terms of BMI and gender. Results 164 hips were assessed. The distance to the centre of the femoral head was the longest in the posterior approach, followed by the lateral, anterolateral, and anterior approaches (pConclusions The distance to the centre of the femoral head is the shortest in the anterior approach, regardless of BMI and gender. The distance in each approach might increase with an increase in BMI. BMI has similar effects in all approaches.

Initial fixation is a key factor in the success of cementless THA using a tapered wedge stem. The purpose of this study was to use three-dimensional templating software to examine the correlation between quantitative contact state and important clinical radiological outcomes, specifically stem subsidence, stress shielding, and cortical hypertrophy. We conducted a retrospective consecutive review of 75 hips in 70 patients over a minimum 3-year follow-up period. X-rays and CT scans were investigated to assess preoperative planning, quantify the contact state of implant and femur, and assess stem alignment, stem subsidence, stress shielding, and cortical hypertrophy. We evaluated the correlation between radiological outcomes and three-dimensional quantitative contact state according to Gruen Zone in each Dorr classification. Density mapping indicated that stem subsidence increased postoperatively if the stem had less cortical contact in the middle to distal portion of the implant in terms of initial fixation. Cases having too much cortical contact in the distal portion of the implant tended to have increased stress shielding. We found no correlation between cortical hypertrophy and the contact state of implant and femur. Density mapping with three-dimensional templating software can be useful in predicting stem subsidence and stress shielding following cementless THA with a tapered wedge stem. Further analysis is required to accurately depict the correlation between cortical hypertrophy and the contact state.

Background Groin pain and functional limitations may occur after total hip arthroplasty (THA) due to iliopsoas impingement (IPI). We aimed to determine the risk factors and thresholds of cup protrusion for symptomatic IPI. Methods This retrospective case-control study evaluated 569 primary THAs performed by a single surgeon in a single center. In all THAs, the cup was inserted with the assistance of the computed tomography–based navigation system. Twenty-two THAs (3.9%) were identified to have symptoms of IPI and included in the IPI group. Control group 1 comprised 547 THAs. Control group 2 (66 THAs) was formed by recruiting 3 data-matched controls per patient in control group 1. Risk factors for IPI were assessed in the IPI group and control group 1. Further analysis was performed in the IPI group and control group 2 to evaluate cup protrusion parameters measured on computed tomography images and radiographs. Results Multivariate logistic regression analysis confirmed that the anterolateral approach was associated with a higher risk of IPI (odds ratio [OR], 4.20); however, its goodness of fit was low. Axial protrusion length ≥12 mm (OR, 23.29; sensitivity = 72.7; specificity = 91.0) and sagittal protrusion length ≥4 mm (OR, 61.60; sensitivity = 86.4; specificity = 78.8) were determined as independent predictors of symptomatic IPI. In the linear regression analyses, higher native acetabular version and lower cup anteversion and inclination were related to cup protrusion. Conclusions This study determined the thresholds of cup protrusion length for IPI and identified associated factors increasing cup protrusion, which are useful for surgeons in determining cup position and alignment.

A case of primary seminal vesicle carcinoma is reported. The tumor was a CA125-producing adenocarcinoma consisting of fine papillary-tubular, intricate branching or anastomosing glandular structures and was composed of small cuboidal, but occasionally hobnailed, cells with mostly clear, but occasionally granular, cytoplasm. Some tumor cells showed evidence of secretion of seromucinous materials into the interpapillary and cystic space. Immunohistochemically, almost half of the tumor cells expressed a positive reaction with anti-CA125, a common serological marker for ovarian epithelial carcinomas; however, no tumor cells expressed any other serological tumor markers such as carcinoembryonic antigen, alpha-fetoprotein, human chorionic gonadotropin, prostatic specific acid phosphatase, or prostatic specific antigen. The patient showed a high level of serological CA125, which fluctuated parallel with the growth, removal and recurrence of the tumor. The morphological and immunohistochemical findings suggested a close relationship between the present tumor and clear cell carcinoma of the ovary, which is thought to be of a Müllerian-Wolfian duct origin.

We developed a new povidone iodine coating technology for titanium hip implants and performed a clinical trial to assess its usefulness in suppressing postoperative infection. Results indicate that iodine-supported titanium has favorable antibacterial activity, biocompatibility, and no cytotoxicity. Thirty joints in 28 patients were treated using iodine-supported implants. Fourteen joints were revision total hip arthroplasty (THA) after periprosthetic infection, 13 were primary THA for immunosuppressive conditions or pyogenic arthritis, and 3 were conversions from hemiarthroplasty to THA for immunosuppressive conditions. Two examinations were conducted sequentially until final follow-up: white blood cell (WBC) and C-reactive protein (CRP) were measured pre- and postoperatively and thyroid hormone levels in the blood were examined. The mean follow-up period was 33 months (14–78). There were no signs of infection in any patient at the last follow-up. WBC and CRP levels returned to normal within several weeks. No abnormalities of thyroid gland function were detected. Loosening of the implants did not occur in any patient. Excellent bone ingrowth and ongrowth were found around prostheses. No cytotoxicity or adverse effects were detected. These results suggest that iodine-supported THA implants can be highly effective in preventing and treating postoperative infections.

This is a report of a post-mortem histological, histochemical, and immunohistochemical examination of a rare case of sclerosing encapsulating peritonitis (SEP) and non-occlusive mesenteric infarction (NOMI), two serious complications of continuous ambulatory peritoneal dialysis (CAPD), with which a man suffering hepatitis C virus (HCV)-induced liver cirrhosis for 7 years and trauma-induced paraplegia for 50 years had been treated for 1 year. The direct cause of death was encephalopathy caused by extreme hyperammonemia (11 250 microg/dL in serum). The autopsy revealed that the SEP had drastically reduced the length of the small intestine to 210 cm, 180 cm of which presented acute ischemic enteritis with Gram-negative bacterial infection. Histological examination of the SEP revealed that the exterior was composed of normal serosal elastic lamina, but with a cocoon-like appearance remarkably thickened by fibrosis to 3-8 times that of the normal subserosal layer and consisting of spindle cells and blood vessels, with some infiltration of mast cells and lymphocytes. The immunohistochemical examination of the spindle cells revealed few AE1/AE3(+) cells, HHF35(+) cells, and CD34(+) cells, many CD117(+) cells with slight proliferative activity based on MIB-1 positivity (proliferation index

An extremely rare case of malignant mesothelioma of the pericardium is reported. The tumor appeared to be the biphasic type of diffuse malignant mesothelioma which present many small to fine lipid droplets in the cytoplasm, particularly that of the epithelial cell, and a positive immunohistochemical reaction with antibodies to low molecular weight cytokeratin (45-50 kDa) in all of the tumor cells. The literature is also reviewed and the presence of lipid droplets and the importance of the immunohistochemical positivity to low molecular weight cytokeratin for differential diagnosis from other malignant tumors, such as invasive adenocarcinoma or primary sarcoma of the pleura, or soft tissue sarcoma involving the pleura is discussed.

Nickel sarcomatogenesis induced by a single intramuscular injection of 10 mg of nickel subsulfide (NiSS) into the soft tissue of two different colonies of Wistar rats was studied. In spontaneously hypertensive rats (SHR), a specific inbred colony of rats derived from a certain Wistar strain, the sarcoma induction rate was lower than that in common closed colony rats of the same strain (CWR). Sarcomas were induced in only 7 of the 30 rats (23.3%) in the SHR group (15 female and 15 male) but in 21 of the 31 rats (67.7%) in the CWR group (15 female and 16 male) (P0.005). The incidence of sarcoma induction was lower in female rats than in male rats in both the SHR (female 13.3%male 33.3%) and CWR (female 53.3%male 81.4%) groups. Primary tumors in the SHR group exhibited a lower grade of metastasis to lymph nodes (P0.001) and lungs (P0.05) than in the CWR group. Our study demonstrated that rats in a certain specific inbred colony are less susceptible to nickel tumorigenesis in soft tissue than rats in a common closed colony.

Administration of phenobarbital for 5 to 7.5 weeks to aged C3HfB/HeN mice with spontaneous liver tumors produced an enhancement of gamma glutamyl transpeptidase activity in the tumors and a decrease in glucose-6-phosphatase and adenosine triphosphatase activity. Discontinuation of phenobarbital feeding for 5.5 weeks resulted in the loss of gamma glutamyl transpeptidase activity in tumors. These findings of alterations in three membrane-associated enzymes indicate that phenobarbital produces substantial changes in the composition of cellular membranes which may be related to its promoting activity.

A 56-year-old man died of widespread metastases of malignant fibrous histiocytoma (MFH) primarily developed in the left lower gingiva after a rapid clinical course is reported. Primary and metastatic tumors showed light and electron microscopic, histochemical and immunohistochemical characteristics of MFH together with cytoplasmic hyaline globules and stromal osteoids. Hyaline globules revealed periodic acid-Schiff positive and diastase resistant reactions but not positive with any histochemical and immunohistochemical reactions. Osteoids were partially calcified and rimmed by osteoblastic tumor cells. The present case of MFH may provide difficulties in the differential diagnosis from some osteoid-forming sarcomas in soft tissues with relation to the histogenesis.

This report concerns an ultramicroscopic study of an autopsy case of primary leiomyosarcoma of the prostate in a patient who died of widespread blood-borne metastases after a rapid clinical course. Ultrastructural observation of tumor cells demonstrated some characteristics of leiomyosarcoma and furthermore revealed frequent intranuclear structures in paracrystalline array together with aggregates of interchromatin granules and cytoplasmic viruslike particles. ACTA PATHOL. JPN. 34: 631–638, 1984.

Histopathological study of the endstage kidney in a 50-year-old male who died after intermittent maintainance hemodialysis for 10 years was reported. At autopsy, both kidneys were contracted and characterized by grossly visible discrete multiple cysts. Histopathological study of consecutive sections of both kidneys revealed that these cysts were distributed throughout a completely disorganized parenchyma and were composed of dysplastic epithelial cells of different types and of structures, some of which revealed neoplastic transformation.

The histochemical characteristics of spontaneous hepatocellular neoplasms in mice of both sexes were examined and compared with those of hepatocellular neoplasms induced in female mice by administration of polycyclic aromatic hydrocarbon carcinogens as initiators with or without subsequent phenobarbitone treatment. Controls treated with phenobarbitone alone was also induced. Spontaneous neoplasms in the livers of mice rendered siderotic by subcutaneous iron injection were deficient in cellular accumulation of stainable iron. Glucose-6-phosphatase activity was deficient in the majority of spontaneous and induced neoplasms. ATPase activity was increase in about half of spontaneous and carcinogen-induced neoplasms but all induced neoplasms in mice treated with phenobarbitone showed deficient activity. Gamma-glutamyltransferase activity was present in very few of the spontaneous neoplasms or in the neoplasms induced in the absence of phenobarbitone administration. However, all induced neoplasms in the mice receiving phenobarbitone showed some degree of gamma-glutamyltransferase activity together with deficient glucose-6-phosphatase and ATPase activities. It is concluded that the histochemical characteristics of spontaneous or induced mouse hepatocellular neoplasms are variable and may be influenced by the inducing factors.

This report concerns a case of solitary extramedullary plasmacytoma of the left submandibular lymph node in a 56-year-old man. The tumor showed monoclonal proliferation of abnormal plasma cells which revealed highly positive stainings of both methylgreen pyronin and kappa light chain using the immunoperoxidase technique in the cytoplasms, and further revealed massive‘.amyloid’deposits in the stroma, which suggested the possibility of sequential amyloid formation upon the secretion of paraprotein by tumor cells.

A comparative study was made of the sequential administration of the liver carcinogen, diethylnitrosamine (DEN), or the liver tumor promoter, phenobarbital, given after the liver carcinogen, N-2-fluorenylacetamide (FAA). The effects of the second carcinogen on preneoplastic cellular lesions induced by the first carcinogen were comparable to the effects of the promoter. In addition, both sequential exposures enhanced the ultimate carcinogenic effect, although the combination of FAA followed by DEN resulted in a greater number of malignant neoplasms. Thus, enhancement of carcinogenesis by a second chemical cannot be used by itself as evidence of a promoting action. Approaches to the more precise definition of promoters include exclusion of genotoxicity, identification of epigenetic mechanisms and lack of a summation effect with administration prior to genotoxic carcinogens.

Two cases of meningioma revealing conspicuous plasmo lymphocytic tissue and hyalinized fibrous tissue components are reported. Histopathological examination of the plasmo lymphocytic infiltration was performed. Both lesions showed polyclonality of plasma cells as revealed by positive reactions for 1gG and paraimmunoglobulin χ- and λ light chains, and amyloid infiltration into the fibrous stroma and blood vessel walls. The histochemical and immunohistochemical characteristics of the lesion in relation to its etiology are briefly discussed. Acta Pathol. Jpn. 32: 190∼194, 1989.