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This study evaluated major vascular injury risk in distal femoral osteotomy (DFO) via the subvastus approach and examined the relationship between the posterior border of the vastus medialis (VM) and the superficial femoral artery (SFA) and vein (SFV).Eighty limbs from 80 patients were evaluated using lower extremity computed tomographic venography. The positional relationship between the VM, SFA, and SFV was evaluated by measuring the angle between each structure and the horizontal reference point (VMA: VM angle, FAA (femoral arterial angle), FVA (femoral venous angle) and the distance between VM and the SFA and SFV (VMAD: VM-arterial distance, VMVD: VM-venous distance) in each axial slice (0/10/20/30/40 mm) proximal to the level of the superior patellar margin. The proximity of the posterior border of the VM and the SFA/SFV as a vertical distance, measured between the slice of the superior border of the patella and the slice where the posterior border of the VM contacted the SFA was evaluated. Single and multiple regression analyses were performed using the vertical distance as the objective variable.As the slice shifted proximally, the VMA significantly increased (24.9 ± 8.5, 36.3 ± 8.8, 47.4 ± 11.8, 59.9 ± 14, 70.3 ± 13.7 degrees, respectively, p 0.001 between all slices) and moved posteromedially from a medial direction. FAA (94.2 ± 7, 86.9 ± 9.2, 78.4 ± 9.7, 71.4 ± 9.8, 66.6 ± 10.5 degree, respectively, p 0.001 between all slices) and FVA (100.6 ± 4.9, 98.3 ± 5.9, 93.7 ± 7.5, 88 ± 9.2, 81.1 ± 10.5 degrees, respectively, p 0.001 between all slices) decreased and moved from a posterolateral to a posteromedial direction, while VMAD (35.4 ± 7.8, 24.1 ± 7.3, 14.3 ± 6, 8.4 ± 7, 6.2 ± 6.3 mm, respectively, p 0.001 between all slices) and VMVD significantly decreased (42.7 ± 7.3, 32 ± 7.4, 22.4 ± 6.8, 14.5 ± 10.6, 8.7 ± 7.1 mm, respectively, p 0.001 between all slices). The average vertical distance was 36 ± 9.3 mm (range 18.6-61.5 mm). The body height and the patellar length significantly affected the vertical distance.The posterior border of the VM shifted posteromedially from distal to proximal and contacted the SFA at an average of 36 mm from the suprapatellar border. Surgeons should be aware of the risk of major vascular injury during exposure and osteotomy.Case series, Level IV.

A 49-year-old woman underwent anatomic double-bundle anterior cruciate ligament reconstruction using a hamstring tendon. Due to knee osteoarthritis progression, total knee arthroplasty was performed 13 years after the surgery. The anteromedial (AM) bundle was composed partly of tendon-like tissue and partly of scar-like tissue. In the tendon-like part of the AM bundle, the collagen fibers were slightly loose and showed a low-frequency crimp structure with an ovoid cell shape. In contrast, the collagen arrangement in the scar-like part was irregular, edematous, and sparsely cell-dense, with an ovoid cell shape. The posterolateral bundles were generally composed of spindle-shaped cells, and the collagen was arranged in tight cohesion and had well-demarcated bundles with normal crimping. Within the tibial tunnel, the graft was mainly connected to the surrounding lamellar bone on the posterior sides, with sparser connections on the anterior and medial/lateral side. The findings of this long-term case provide valuable information to enable understanding of multiple-folded hamstring tendons.Level of evidence V.

Purpose The aim of this study was to verify the effects of a new remnant augmentation technique with anatomical double-bundle anterior cruciate ligament (ACL) reconstruction for postoperative clinical scores, anterior stability and frequency of complications compared to remnant removal and cases with remnant defects. Methods The 105 patients who underwent anatomical double-bundle ACL reconstruction were divided into three groups. If the remnant was a Crain I-III type, remnant-preserving bone tunnel creation was attempted. After the creation of the bone tunnel, good continuity was maintained in 34 patients (preserved group). Due to lost continuity, the remnant was resected in 26 patients (resected group). No identifiable remnant continuity remained (Crain IV) in 45 patients (absent group). The Lysholm knee score, Tegner activity scale, International Knee Documentation Committee (IKDC) subjective score, anterior stability measured using the KT-1000 arthrometer at 2 years postoperatively, and frequency of complications were compared among the three groups. Univariate and multiple linear regression analysis were performed to clarify the factors affecting postoperative anterior stability. Results The Lysholm knee score, Tegner activity scale, IKDC subjective score, and frequency of complications were not significantly different among the groups. The mean side-to-side difference of anterior stability was significantly better in the preserved group (0.3 ± 1.6 mm) compared to the resected group (1.6 ± 2.3 mm, p = 0.003) and absent group (1.6 mm ± 1.7, p = 0.009). The multiple linear regression analysis showed remnant preservation significantly related to postoperative anterior stability. Conclusion Although there were no differences in clinical scores, the ACL reconstruction with new preservation technique showed good anterior stability and no difference in the frequency of complications.

To investigate the effects of a new remnant-preserving double-bundle anterior cruciate ligament reconstruction (ACLR) technique, focused on avoiding remnant damage and preserving continuity of remnants, on graft maturity using magnetic resonance imaging (MRI).A total of 169 patients were divided into three groups: 41 in the preservation group, 70 in the resection group, and 58 in the absent group. In the preservation group, rather than passing the graft through the remnant tissue, the graft was reconstructed such that the anteromedial and posterolateral bundles sandwiched the remnant to avoid damage to the remnant and maintain its continuity. Based on 1-year postoperative MRI, the grafts were divided into three regions: distal, middle, and proximal. The signal/noise quotient (SNQ) of each region of interest was calculated to evaluate the signal intensity of the graft and was compared among the three groups. Additionally, to identify factors influencing graft maturity, a multiple regression analysis was performed with SNQ as the dependent variable and patient demographics, bone morphology, and surgical factors as independent variables.In a three-group comparison of mean SNQs, the distal region was 3.3 ± 3.4, 8.9 ± 8.3, and 9.0 ± 8.6 (p 0.001), the middle region was 5.3 ± 3.7, 10.9 ± 11.1, and 11.3 ± 10.2 (p 0.001), and the proximal region was 6.8 ± 4.5, 11.1 ± 8.8, and 11.7 ± 10.8 (p = 0.017), in order of the preservation, resection, and absent groups, respectively. That indicated that the remnant-preserving ACLR was more hypointense than ACLR with remnant resection or absent in all three regions. Multiple regression analysis showed that remnant preservation remained the relevant factor affecting SNQ of the graft at the distal and middle levels.The new remnant-preserving anatomic double-bundle ACLR had significantly better graft maturity, measured by SNQ on MRI, than the remnant resection and absent groups. The remnant procedure was the relevant factor affecting graft maturity.Level III.

Recent studies on the detailed anatomy of the medial patellar stabilizer have revealed that the medial patellofemoral ligament (MPFL) not only attaches to the patella but also has fibers that attach to the quadriceps muscle, known as the medial quadriceps tendon femoral ligament (MQTFL). Reconstruction of the medial stabilizer for patellar dislocation that includes both the MPFL and MQTFL may achieve better anatomical and physiological correction. In this Technical Note, we will describe a simultaneous reconstruction technique of the MPFL and MQTFL for patellar dislocation using an artificial ligament.

To investigate the effect of a new remnant preservation technique with a focus on remnant continuity on postoperative femoral and tibial tunnel enlargement after anatomical double-bundle anterior cruciate ligament reconstruction (ACLR).A total of 150 knees were divided into three groups: Preservation Group (Group P: 49 knees), wherein the remnant continuity remained after tunnel creation; Resection Group (Group R: 47 knees), wherein the remaining remnant was resected, and Absent Group (Group A: 54 knees), wherein the remnant had no femoral attachment before tunnel creation. In Group P, the remnant maintained continuity, and the anteromedial (AM) and posterolateral (PL) bundles were positioned anterior and posterior to the remnant, respectively. Computed tomographic scans were performed at 1 week and 1 year after surgery, and the cross-sectional area of each tunnel aperture was measured. Tunnel enlargement was compared among the three groups by one-way analysis of variance (ANOVA) and the Bonferroni test. Univariate and multivariate logistic analyses were performed to identify the risk factors for tunnel enlargement in demographic and radiographic data.For femoral AM tunnels, the tunnel enlargement of Group P was significantly smaller than Groups R and A (p 0.001), femoral PL (p 0.001 vs. R and A), tibial AM (p 0.001 vs. R, 0.002 vs. A), and tibial PL (p 0.001 vs. R, 0.002 vs. A). There was no significant difference between Groups R and A. Multivariate logistic analysis showed that remnant preservation was a significant factor in reducing tunnel enlargement in the femoral AM, femoral PL, tibial AM, and tibial PL.The new remnant-preserving anatomical double-bundle ACLR, which preserves the continuity of the remnant, prevented all bone tunnel enlargement at 1 year postoperatively.Level III.

Case. We report a rare case of prefemoral fat pad impingement syndrome that was caused by a hyperplasia of the normal suprapatellar fat pad. Pain and catching were observed in the proximal-lateral patellofemoral joint, and MRI imaging confirmed a hyperplasic mass in the same area. Although conservative treatment showed no signs of improvement, symptoms improved after an arthroscopic excision of the mass. Conclusion. Prefemoral fat pad impingement syndrome is related to patellar motion and should be considered as one of the underlying causes of anterior knee pain (AKP). Surgeons should recognize that a small hyperplasia composed of normal adipose tissue can cause AKP.

Background: Ankle sprains are one of the most common musculoskeletal injuries. However, they may be more serious than commonly believed since many patients reportedly experience chronic problems afterwards. It is necessary to improve the treatment, such as the method and duration of fixation, of sprained ankles.Methods: Magnetic resonance imaging of 70 patients with acute moderate or advanced ankle sprains presenting consecutively between November 2014 and December 2019 were reviewed for analysis of bone bruising associated with ankle sprains. The patients were treated conservatively with a solid splint or cast until walking pain could be resolved without external fixation. In cases with pain at the time of weight bearing after solid fixation, crutches were prescribed for pain relief. The fixation period ranged from 8 days to 72 days (mean: 29.5 days). Afterwards, 54.0% of patients had walking pain and required the use of crutches. The ankle joint pain disappeared after conservative treatment in all patients.Results: The incidence of bone bruises detected by magnetic resonance imaging in the ankle and midfoot associated with ankle sprain was 81.4%. Bone bruises of the midfoot, including the tarsal bone and Chopart joint, were found in 34.3% of ankle sprains. Bone bruises of the talus were the most common, being present in 60% of ankle sprains. Bone bruises were also evident in the tibia (44.3%), the calcaneus (21.4%), and the tarsal bone (25.7%). There was a significant association between bone bruises of the talocrural joint surface and use of the crutches after fixation (P=0.041). Multiple regression analysis adjusted for age and gender revealed that bone bruises of the talocrural joint surface of the talus was a significant independent predictor of crutch use (P=0.045), with an odds ratio (95% confidence interval) of 3.03 (1.03-8.94).Conclusion: Bone bruises of the ankle and midfoot are often present in ankle sprains. In moderate or advanced cases of ankle sprain, external solid fixation of both the ankle and midfoot should be performed. In cases with pain at weight bearing following solid fixation, crutches are advised for pain relief and proper ligament and bone healing.

The purpose of this study is to evaluate the risk of medial tibial cortical perforation in unicompartmental knee arthroplasty (UKA) due to peg positions on the tibial tray of the Persona Partial Knee (PPK). Preoperative CT images of 60 patients and 60 osteoarthritic knees (30 male and 30 female patients) were used. A tibial multiplanar reconstruction (MPR) image was reconstructed in preoperative planning software, and the implant was placed in a virtual osteotomy plane. In addition to PPK, Zimmer Unicompartmental Knee (ZUK) and TRIBRID (TBD) were used for evaluation. The horizontal distances from the medial tibial cortex to the anterior and posterior pegs (APCD/PPCD, respectively) were measured under neutral, 3-degree varus, 3-degree valgus and 2 mm distal positions. The differences between implants under the same positions and between positions using the same implants were compared. The percentage of total cases with APCD/PPCD of less than 3 mm and the perforation risk rate were calculated. The APCD of PPK was significantly shorter at all positions except for the varus position of TBD. The PPCD of PPK was significantly shorter at all positions compared to ZUK and TBD. There were no cases with an APCD of less than 3 mm. Except for varus positions, the perforation risk rate of PPCD was significantly higher for PPK than the other two implants. The posterior pegs of the PPK are located more medially than the other two implants, which may result in perforation of the medial tibial cortex during implantation. Surgeons should consider the risk involved in the type of implant used.

A 16-year-old female with a history of left recurrent patellar dislocation underwent medial patellofemoral ligament (MPFL) reconstruction surgery. Two months postoperatively, the patient presented with medial patellar pain. Left medial plica syndrome was suspected, and we performed a partial arthroscopic resection of the medial synovial plica. The symptom gradually improved after surgery. To the best of our knowledge, there are no reports that discuss the relationship between postoperative pain of MPFL reconstruction and synovial plica as found in this case report. Surgeons should be aware of the possibility that asymptomatic synovial plica could become symptomatic.

Purpose To evaluate the postoperative change in patellar position after medial closed distal femoral osteotomy (DFO) performed for valgus osteoarthritic knees. Methods The study included 21 consecutive knees in 20 patients undergoing DFO. A minimum of 2-year follow-up data was obtained for all subjects with a mean follow-up period of 42 months (range 31–59 months). The patellar position was evaluated on plain radiographs preoperatively, 1-year postoperatively, and 2-year postoperatively. For patellar height, the modified Insall–Salvati Index (mISI), modified Caton–Deschamps Index (mCDI) and modified Blackburne–Peel Index (mBPI) were measured on the standing lateral radiographs. Patellofemoral alignment on the axial plane was assessed on skyline views with 30° flexion based on the measurements for lateral patellar tilt (LPT) and lateral patellar shift (LPS). Measured values at pre- and postoperative phases were statistically compared using a two-way analysis of variance. Results All indices including mISI, mCDI, mBPI, LPT and LPS showed no statistically significant postoperative changes. Conclusion Medial closed-wedge DFO performed for valgus osteoarthritic knees did not significantly influence patellofemoral alignment either on the sagittal or axial plane. Therefore, to highlight the clinical relevance of our findings, medial closed-wedge DFO for the valgus knee does not adversely affect the patellofemoral joint. Level of evidence Level IV, case series.

Because various biomechanical studies and clinical results have shown the effectiveness of an anatomical approach for anterior cruciate ligament (ACL) reconstruction, this approach has become gradually commonplace to improve postoperative performance. Standard tunnel positioning methods with accuracy, reproducibility, and adaptability to varied concepts are essential for the success of anatomical ACL reconstruction. However, there were no standard tibial tunnel positioning methods to satisfy these conditions. This technical note reports our tibial tunnel positioning technique using bony and/or anatomical landmarks for anatomical ACL reconstruction.

Purpose To assess (1) if 6 anatomic landmarks (ALs) could be arthroscopically confirmed with remnant preservation and (2) if creating tibial tunnels using these landmarks reduces individual variation and improves reproducibility in double-bundle anterior cruciate ligament (ACL) reconstruction. Methods We retrospectively reviewed data of patients who chronologically underwent double-bundle ACL reconstruction by either referencing the footprint after remnant dissection (non-AL group) or subsequently with the ALs (AL group). Using operative videos, 3 independent observers judged whether they could confirm 6 ALs (medial intercondylar ridge, medial and lateral intercondylar tubercles, anterior horn of lateral meniscus, Parsons' knob, and L-shaped ridge) in 20 patients randomly selected from the AL group. We then compared tunnel positions between the 2 groups, measured from the anterior and medial borders of the proximal tibia and expressed as percentage of the total depth and width of the proximal tibia using 3-dimensional computed tomography. Results One hundred four patients (non-AL group, n = 54; AL group, n = 50) were included. All 6 ALs were arthroscopically confirmed in most cases (89.7% to 100%). The mean percentages of the anteroposterior (AP) depth for anteromedial (AM) tunnel, mediolateral (ML) width for AM tunnel, AP depth for posterolateral (PL) tunnel, and ML width for PL tunnel, respectively, were 27.8% ± 6.6%, 46.7% ± 2.8%, 41.4% ± 7.3%, and 46.1% ± 2.6% for the non-AL group and 30.7% ± 4.5%, 45.7% ± 2.2%, 45.2% ± 4.5%, and 46.9% ± 2.1% for the AL group, revealing significantly less variation in the AL group compared with the non-AL group, excluding the ML width of the PL tunnel ( P = .007, .046, .002, .209, respectively). Conclusions Six landmarks could be reliably confirmed in cases with remnant preservation, and creating tibial tunnels using these landmarks were reproducible and resulted in less individual variation. Level of Evidence Level III, retrospective comparative study.

The purpose of this study was to evaluate quantitative, morphological and positional differences between the anterior cruciate ligament (ACL) tibial footprint and anterolateral meniscal root (ALMR) insertion and investigate an intraoperative landmark to estimate their boundaries.Thirty-three fixed human cadaveric knees were evaluated. After resecting the components, the anterior fiber (AF) and posterior fiber (PF) of ALMR, the tibial center of ACL bundles (anteromedial (AM) and posterolateral (PL) bundles) and ACL were marked. Insertion morphology was classified into three categories, and the distance and relative positional relationship between AF/PF insertions and the center of each attachment were measured on three-dimensional computed tomography images.There was no significant difference between the AF of AM and ACL (P = 0.16), but both were significantly shorter than the AF of PL (both P 0.001). There was no significant difference between the PF of ACL and PL (P = 0.99), which were significantly shorter than PF of AM (both P 0.001). Morphology of the ACL tibial insertion was classified as follows: triangular, 15 knees (45.5%); oval, 18 knees (54.5%); none, C-shape. Quantitative and positional analyses showed that the AF insertion was significantly closer to AM and ACL centers in the oval type than in the triangular type. Excluding two cases, the AF/PF insertion was located laterally to the ML center of the medial and lateral intercondylar tubercles.Proximity of ACL tibial footprint and ALMR varies by their footprint morphology. The medial and lateral intercondylar tubercles were useful landmarks for ALMR injury prevention.

In anatomical anterior cruciate ligament reconstruction surgery using the outside-in technique, the aperture of the femoral lateral cortex may become elliptical. Retrospective cross-sectional study To evaluate the extent of elliptical eccentricity in lateral apertures relative to aperture positioning and clinical failure rate in anatomical anterior cruciate ligament double-bundle reconstruction using outside-in technique. In 75 patients, the aperture elongation factor was defined as the ratio of the major axis of the elliptical aperture to the drill size. Using the lateral epicondyle as a reference point, the lateral femur was divided into sections by distance and angle, and the minimum area was evaluated to assess the relationship between the elongation factor and aperture position of the lateral cortex for each bundle. The incidence and associated clinical performance regarding cortical button migration were also investigated. Aperture elongation factors were 120.2 ± 13.3% and 120.0 ± 16.3% on the anteromedial (AM) and posterolateral (PL) sides, respectively. Femoral tunnel elongation was smallest when the entry point axis were both between 30 to 60° and distance was between 10 to 20 mm and 0 to 10 mm on the AM and PL sides, respectively. During the postoperative follow-up period, intra-tunnel migration was confirmed in 4 of 75 cases (5.3%). Fixation failure neither affected clinical scores nor knee laxity. Areas of minimum elongation for each bundle on both AM and PL sides were found anteroproximally to the lateral epicondyle and positioned near each other. Elongation did not directly affect the clinical outcome. Level of evidence grade: prognostic level III

Background The tibial tubercle deviation associated with recurrent patellar dislocation (RPD) has not been studied sufficiently. New methods of evaluation were used to verify the extent of tubercle deviation in a group with patellar dislocation compared with that in a control group, the frequency of patients who demonstrated a cutoff value indicating that tubercle transfer was warranted on the basis of the control group distribution, and the validity of these methods of evaluation for diagnosing RPD. Methods Sixty-six patients with a history of patellar dislocation (single in 19 [SPD group] and recurrent in 47 [RPD group]) and 66 age and sex-matched controls were analyzed with the use of computed tomography (CT). The tibial tubercle-posterior cruciate ligament (TT-PCL) distance, TT-PCL ratio, and tibial tubercle lateralization (TTL) in the SPD and RPD groups were compared with those in the control group. Cutoff values to warrant 10 mm of transfer were based on either the minimum or -2SD (2 standard deviations below the mean) value in the control group, and the prevalences of patients in the RPD group with measurements above these cutoff values were calculated. The area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis was used to assess the effectiveness of the measurements as predictors of RPD. Results The mean TT-PCL distance, TT-PCL ratio, and TTL were all significantly greater in the RPD group than in the control group. The numbers of patients in the RPD group who satisfied the cutoff criteria when they were based on the minimum TT-PCL distance, TT-PCL ratio, and TTL in the control group were 11 (23%), 7 (15%), and 6 (13%), respectively. When the cutoff values were based on the -2SD values in the control group, the numbers of patients were 8 (17%), 6 (13%), and 0, respectively. The AUC of the ROC curve for TT-PCL distance, TT-PCL ratio, and TTL was 0.66, 0.72, and 0.72, respectively. Conclusions The extent of TTL in the RPD group was not substantial, and the percentages of patients for whom 10 mm of medial transfer was indicated were small. Level of evidence Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Case: We report a case of recurrent acute arthritis and restricted range of motion in the knee joint, with magnetic resonance imaging subsequently detecting a nodular lesion within the lateral meniscus. Knee arthroscopy and histology revealed that the lesion was intrameniscal gouty tophi. After arthroscopic synovectomy and excision of the tophi, the symptoms resolved and the patient remained symptom-free at two years of follow-up. Conclusion: Surgeons should be aware of the presence of such pathology and consider arthroscopic surgery if the mechanical symptoms persist.

The linear penetration rates for ceramic femoral heads on conventional and highly cross-linked polyethylene were measured and compared with radiographs taken in the standing and supine position taken three weeks postoperatively and at final follow-up. Seventy-five patients (83 hips) with conventional polyethylene (group-1) and two hundred and seventy five patients (300 hips) with highly cross-linked polyethylene (group-2) were studied. Follow-up periods were 14.5years in group-1 and 8.6years in group-2. The average penetration rates in group-1 were 0.17mm/year in supine position and 0.18mm/year in standing position (P

[Purpose] The aim of this study was to investigate the feasibility of using the current perception threshold (CPT), in a comparison with the visual analog scale (VAS), to assess its selectivity in assessing the excitability of Aβ, Aδ and C fibers in subjects with sub-acute post-operative pain who were being treated with conventional transcutaneous electrical nerve stimulation (TENS). [Subjects and Methods] A total of 17 subjects (mean age of 29.2 ±10.8 years) participated in this study. For all subjects, the study commenced on the fifth post-operative day and continued for the next five consecutive days following a descriptive time-series design. Both CPT and VAS were measured for all subjects on all five days following 15 minutes rest with the TENS output intensity set at zero on the baseline days (Days 1, 3, 5), and after 15 minutes TENS stimulation on the intervention days (Days 2 and 4). [Results] The results demonstrate that CPT was able to selectively assess the excitability of the Aβ and Aδ fibers. However, the selectivity of CPT in assessing the C fibers could not be verified in this study. [Conclusion] The various limitations of the time series design used in this study suggest the need to verify some of these results in a different experimental design in future studies.

Accurate and detailed knowledge of ACL footprint anatomy is essential for successful anatomical ACL reconstruction. On the femoral side, the discovery of bony landmarks led to the standardization of femoral bone tunnel construction; however, the detailed morphology and location of ACL tibial footprint continue to be a topic of debate, and there are still no standardized methods for tibial tunnel construction. We previously reported the ACL tibial attachment site anatomy and bony landmarks and compared 3D images with visual and histological evaluations. The results from the study found a unique bony landmark surrounding the ACL attachment site, showing the relationship of these bony landmarks and surrounding anatomical landmarks as a useful indicator for determining tunnel positions during arthroscopic surgery. This section will clarify the detailed anatomy and bony landmark of the ACL tibial footprint necessary for reconstructive surgery by reviewing our previous research in conjunction with the available literature.

Fourteen hips in 14 patients (all female; average age, 64 years) with severe bone defects due to developmental dysplasia of the hip or migration of the socket were treated with hydroxyapatite block with impacted morselized bone graft in conjunction with a cemented socket. All patients were followed clinically in a prospective fashion, and radiographs were analyzed retrospectively. One initial patient had 17-year follow-up, whereas the remaining 13 patients had follow-up between 4 and 6.5 years. No acetabular components were revised, including the socket of a 17-year postoperative case that remains rigidly fixed and supported by the graft and hydroxyapatite block with only mild polyethylene wear and minor osteolysis. Osteointegration and good clinical outcome were achieved in all cases by reconstruction with this technique in total hip arthroplasty.

Background: The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercle transfer; however, to our knowledge, no studies have verified whether this distance is strongly affected by tubercle lateralization at the proximal part of the tibia. We hypothesized that the tibial tuberosity-trochlear groove distance is mainly affected by tibial tubercle lateralization at the proximal part of the tibia. Methods: Forty-four patients with a history of patellar dislocation and forty-four age and sex-matched controls were analyzed with use of computed tomography. The tibial tuberosity-trochlear groove distance, tibial tubercle lateralization, trochlear groove medialization, and knee rotation were measured and were compared between the patellar dislocation group and the control group. The association between the tibial tuberosity-trochlear groove distance and three other parameters was calculated with use of the Pearson correlation coefficient and partial correlation analysis. Results: There were significant differences in the tibial tuberosity-trochlear groove distance (p < 0.001) and knee rotation (p < 0.001), but there was no difference in the tibial tubercle lateralization (p = 0.13) and trochlear groove medialization (p = 0.08) between the patellar dislocation group and the control group. The tibial tuberosity-trochlear groove distance had no linear correlation with tubercle lateralization (r = 0.21) or groove medialization (r = −0.15); however, knee rotation had a good positive correlation in the patellar dislocation group (r = 0.62). After adjusting for the remaining parameters, knee rotation strongly correlated with the tibial tuberosity-trochlear groove distance (r = 0.69, p < 0.001), whereas tubercle lateralization showed moderate significant correlations in the patellar dislocation group (r = 0.42; p = 0.005). Conclusions: Because the tibial tuberosity-trochlear groove distance is affected more by knee rotation than by tubercle malposition, its use as an indicator for tibial tubercle transfer may not be appropriate. Clinical Relevance: Surgical decisions of tibial tubercle transfer should be made after the careful analysis of several underlying factors of patellar dislocation.

The proliferation of human bone marrow mesenchymal stem cells (MSCs) employing xeno-free materials not containing fetal calf serum (FCS) and porcine trypsin was investigated for the regenerative medicine of cartilage using MSCs. Four sequential subcultivations of MSCs using a medium containing 10% FCS and recombinant trypsin (TrypLESelect™) resulted in cell growth comparable to that with porcine trypsin. There was no apparent difference in the cell growth and morphology between two kinds of MSC stored in liquid nitrogen using 10% FCS plus DMSO or serum-free TC protector™. MSCs were isolated from human bone marrow cells, stored in liquid nitrogen, and sequentially subcultivated four times employing conventional materials that included FCS, porcine trypsin, and DMSO, or xeno-free materials that included serum-free medium (MesenCult-XF™), TC protector™ and TrypLESelect™. Cells in the culture using the xeno-free materials maintained typical fibroblast-like morphology and grew more rapidly than the cells in the culture using the conventional materials, while the cell surface markers of MSCs (CD90 and CD166) were well maintained in both cultures. Chondrogenic pellet cultures were carried out using these subcultivated cells and a medium containing TGFβ3 and IGF1. The pellet culture using cells grown with the xeno-free materials showed an apparently higher gene expression of aggrecan, a chondrocyte marker, than the pellet culture using cells grown with the conventional materials. Consequently, MSCs that are isolated, stored, and grown using the xeno-free materials including the serum-free medium (MesenCult-XF™), TC protector™, and recombinant trypsin (TrypLESelect™) might be applicable for regenerative medicine of cartilage.

Accurate placement of separate anteromedial and posterolateral bundle bone tunnels is crucial for anatomic, double-bundle anterior cruciate ligament (ACL) reconstruction. However, identifying the anatomic footprint at which to make the tibial and femoral bone tunnels is not a straightforward procedure. To overcome this problem, we used a CT-based navigation technique with a registration procedure based on fiducial markers (FMs). Preoperatively, 10 FM points were placed on skin around knee joint and scanned with CT. Imaging data of the knee were recorded on the computer system for preoperative registration and surgical planning. Intraoperatively, with a reference frame fixed to the distal medial aspect of femur and tibia, paired-point matching registration was performed with the use of points marked on skin through FM center holes. During tibial tunnel guide wire placement, tibial aiming guide with tracking device fed back the position of tip and direction of the guide wire on the three-dimensional (3D) tibia bone surface image and multiple image planes in real time. For the femoral side, the navigation pointer was placed at the footprint center with visual guidance of 3D image of lateral wall sagittal view on navigation monitor and marked with navigation awl. The average registration accuracy of 22 consecutive patients was 0.7 +/- A 0.2 mm and 0.6 +/- A 0.2 mm for femoral and tibial bone, respectively. Most of the bone tunnel positions evaluated with 3D-CT image were confirmed to be accurately placed in reference to the preoperative plan. There was no damage to femoral condyle cartilage and no other complication. This new CT-based computer navigation system opens the possibility for surgeons to plan bone tunnel positioning preoperatively and control it during technically demanding anatomic double-bundle ACL reconstruction., Article, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY. 19(3):378-383 (2011)

Background The acetabular fossa is thought to be located in the center of the acetabulum, and acetabular reaming in total hip arthroplasty is conventionally performed in the center of the fossa. However, the actual location of the fossa and the influence that hypoplasia or deformity may have on the position of the fossa are unknown. We hypothesized that the fossa is located in the center of the acetabulum, regardless of hypoplasia or deformity. Methods Fifty patients with normal hips (normal hip group), 50 patients with dysplasia who underwent rotational acetabular osteotomy (dysplastic hip group), and 46 patients with osteoarthritis who underwent total hip arthroplasty (osteoarthritic hip group) were evaluated by computed tomography (CT) imaging. On the horizontal plane that passes through the center of the femoral head, the center line of the acetabulum was defined as the perpendicular bisector of the anterior and posterior rims of the acetabulum. The angle and distance of the center of the acetabular fossa in relation to the center line of the acetabulum were evaluated; furthermore, the center position of the fossa from the anterior margin of the acetabulum was calculated as a ratio relative to acetabular size. A 1-way analysis of variance was performed to compare measurements among the 3 groups. Results The center of the acetabular fossa was positioned anteriorly to the center line of the acetabulum in all 3 groups. The mean center angle of the acetabular fossa was 14.0° ± 3.8°, 15.2° ± 5.6°, and 14.9° ± 5.5° in the normal, dysplastic, and osteoarthritic hip groups, respectively (p = 0.33). The mean center distance of the acetabular fossa was 5.6 ± 1.8, 5.8 ± 2.3, and 6.1 ± 2.2 mm, respectively (p = 0.55). The mean center position of the acetabular fossa was 38.8% ± 3.3%, 38.5% ± 4.2%, and 38.3% ± 3.9%, respectively (p = 0.71). Conclusions The center of the acetabular fossa is positioned anteriorly to the center of the acetabulum, and the positioning is affected by neither dysplasia nor osteoarthritis. The preconception that the center of the acetabulum corresponds to the center of the acetabular fossa may risk eccentric reaming, possibly damaging the anterior wall. Level of evidence Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as a bearing surface of joint implants. Since wear of UHMWPE component has been the primal cause of implant failure, crosslinking of UHMWPE is now widely used to improve its wear property. On the other hand, crosslinking degrades its fatigue property and increase of fatigue related failure, such as delamination, is possible. However, the relationship between degraded fatigue property and implant failure is not clear, primarily because the fatigue properties of failed and retrieved UHMWPE components are not known. In this study, we propose a new test method to evaluate the fatigue property of retrieved UHMWPE components or final products using small specimens. First, the effects of test conditions were investigated using virgin UHMWPE. Then, tests were repeated using specimens from UHMWPE components of retrieved knee implants. The fatigue properties of virgin and retrieved UHMWPE were suc- cessfully evaluated by the new test method and a relationship was found among the extent of oxidation, the fatigue property, and occurrence of delamination. This result suggested that evaluation of fatigue property of UHMWPE component can predict the occurrence of fatigue related implant failure during operation in vivo.

Background and purpose Osteochondral defects have a limited capacity for repair. We therefore investigated the effects of tumor necrosis factor (TNF) signal blockade by etanercept (human recombinant soluble TNF receptor) on the repair of osteochondral defects in rabbit knees. Material and methods Osteochondral defects (5 mm in diameter) were created in the femoral patellar groove in rabbits. Soon after the procedure, a first subcutaneous injection of etanercept was performed. This single injection or, alternatively, 4 injections in total (twice a week for 2 weeks) were given. Each of these 2 groups was divided further into 3 subgroups: a low-dose group (0.05 μg/kg), an intermediate-dose group (0.4 μ g/kg), and a high-dose group (1.6 μ g /kg) with 19 rabbits in each. As a control, 19 rabbits were injected with water alone. The rabbits in each subgroup were killed 4 weeks (6 rabbits), 8 weeks (6 rabbits), or 24 weeks (7 rabbits) after surgery and repair was assessed histologically. Results Histological examination revealed that the natural process of repair of the osteochondral defects was promoted by 4 subcutaneous injections of intermediate-dose etanercept and by 1 or 4 injections of high-dose etanercept at the various time points examined postoperatively (4, 8, and 24 weeks). Western blot showed that rabbit TNFα had a high affinity for etanercept. Interpretation Blocking of TNF by etanercept enabled repair of osteochondral defects in rabbit knee. Anti-TNF therapy could be a strategy for the use of tissue engineering for bone and cartilage repair.

To investigate the effectiveness of autologous culture-expanded bone marrow mesenchymal cell transplantation for repairing articular cartilage defects, we transplanted autologous culture-expanded bone marrow mesenchymal cells into nine full-thickness articular cartilage defects of the patello-femoral joints (including two kissing lesions) in the knees of three patients, a 31 year-old female, a 44 year-old male and a 45 year-old male. Three weeks before transplantation, bone marrow blood was aspirated from the iliac crest. Adherent cells were cultured with media containing autologous serum. Single-passaged cells were collected, embedded in a collagen solution (5 x 10(6) cells/ml), placed on a collagen sheet, gelated, transplanted into the defect and covered with autologous periosteum or synovium. Six months after transplantation, the patients' clinical symptoms had improved and the improvements have been maintained over the follow-up periods (17-27 months). Histology of the first patient 12 months after the transplantation revealed that the defect had been repaired with the fibrocartilaginous tissue. Magnetic resonance imaging of the second patient 1 year after transplantation revealed complete coverage of the defect, but we were unable to determine whether or not the material that covered the defects was hyaline cartilage. Autologous bone marrow mesenchymal cells transplantation may be an effective approach to promote the repair of articular cartilage defects.

This study was designed to investigate effects of heat on the bone-inducing activity of recombinant human bone morphogenetic protein (rhBMP)-2. rhBMP-2 samples were heated at 50, 70, 90, or 100 degrees C for 15 min, or 1, 2, 4, or 8 h, or autoclaved at 120 degrees C for 15 min. The bone-inducing activity of the rhBMP-2 before and after heating was assayed in in vivo and in vitro systems. For the in vivo assay, 5 microg rhBMP-2 samples were impregnated into porous collagen disks (6 mm in diameter, 1 mm thickness), freeze dried, and implanted into the back muscles of ddY mice. Three weeks later, the implant was harvested from the host and examined for ectopic new bone tissue by radiography. The new bone mass was quantified by single-energy X-ray absorptiometry. The in vitro activity of the rhBMP-2 was assayed by adding the BMP sample at a concentration of 100 ng/ml to cultures of MC3T3-E1 cells. After 48 h, the alkaline phosphatase activity was measured. After heating at 50 degrees or 70 degrees C, no significant reduction in bone-inducing activity was noted in either in vivo or in vitro assay systems unless the protein was exposed to sustained heat at 70 degrees C for 8 h, based on in vitro assay data. However, heating above 90 degrees C and for longer periods led to a decrease in the biological activity of the rhBMP-2 in a time- and temperature-dependent manner. rhBMP-2 was rendered inactive when exposed to temperatures at or in excess of 120 degrees C.

To examine how fibroblast growth factor-2 (FGF-2) affects the BMP signaling pathway during bone morphogenetic protein-2 (BMP-2)-induced ectopic bone formation, we implanted type I collagen disks containing constant amounts of BMP-2 (5 micrograms) and varying amounts of FGF-2 onto the back muscles of adult male mice. We then performed histological analyses and histomorphometry, and measured bone mineral density and radiopaque area on the discs 1, 2, and 3 weeks after implantation. We also determined the expression profiles of several genes involved in bone formation and the BMP signaling pathway in the muscle that had been adjacent to the implanted disc and in muscle-derived primary culture cells that had similarly been treated with a constant concentration of BMP-2 and a varying concentration of FGF-2. In the presence of a constant amount of BMP-2, we confirmed that low doses of FGF-2 increased ectopic bone formation in vivo and high doses inhibited bone formation. Northern and/or Western blots of recovered muscle from the in vivo experiment and treated muscle-derived primary culture cells from the in vitro experiment revealed that low doses of FGF-2, but not high doses, increased the expression BMP receptor (BMPR)-1B, phosphorylated Smad1, Noggin, and Osteocalcin. Our results indicate that low-dose FGF-2 may facilitate BMP-2-induced ectopic bone formation by altering the expression of BMPRs on the surface of bone forming progenitor cells. They also indicate that the inhibitory effect of high-dose FGF-2 is not mediated via increased expression of the BMP inhibitor Noggin.

Objective To evaluate whether microbubble-enhanced ultrasound (US) treatment promotes the delivery of methotrexate (MTX) into synovial cells and the enhanced antiinflammatory effects of intraarticular MTX therapy in a rabbit arthritis model. Methods Arthritis was induced in both knees of 53 rabbits by immunization with ovalbumin. MTX including a microbubble agent was then injected into the left and right knee joints, and the right knees were exposed to US (MTX+/US+ group), while the left knees were not (MTX+/US− group). The knee joints were evaluated histologically in 7 rabbits at 5 time points up to day 56. Quantitative gene expression of interleukin-1β (IL-1β) in synovial tissue was measured on days 7 and 28. Eight rabbits were used for the measurement of MTX concentration in synovial tissue 12 hours after treatment. To evaluate the effect of microbubble-enhanced US treatment in the absence of MTX, only the microbubble agent was injected into the left and right knee joints of 10 rabbits with or without US exposure, and these animals were evaluated histologically on days 7 and 28. Results The MTX concentration in synovial tissue was significantly higher in the MTX+/US+ group than in the MTX+/US− group. Synovial inflammation was less prominent in the MTX+/US+ group compared with the MTX+/US− group, judging from the results of the histologic evaluation and the gene expression levels of IL-1β in synovial tissue. It also appeared that microbubble-enhanced US exposure itself did not affect inflammation. Conclusion Microbubble-enhanced US exposure promoted the uptake of MTX into synovial cells, which resulted in enhancement of the antiinflammatory effects of the intraarticular MTX injection. These results suggest that application of this technique may have clinical benefit.

Snapping syndrome rarely occurs at the knee joint. This is the first report of snapping pes syndrome after total knee arthroplasty. Surgeons should be aware of the presence of such a case and pay attention to the fact that snapping symptoms could be caused by a residual bony prominence and a change in alignment after total knee arthroplasty. Level of evidence Therapeutic study, Case report with no comparison group, Level IV.

Aiming to construct an osteochondral-like structure, the combination of a β-tricalcium phosphate (βTCP) block with a scaffold-free sheet formed using mesenchymal stem cells (MSCs) was investigated.Human bone marrow MSCs in a cell culture insert that was set in a 24-well plate were cultivated using a chondrogenic medium containing dexamethasone, IGF-1, and TGFβ3 for 3 weeks during which a cylindrical βTCP block was put on the sheet at day 1, and the cell sheet construct was harvested. In other experiments, at day 14, the construct was put on a cell sheet that was prepared the day before and cultivated for 3 weeks.The addition of a βTCP block resulted in a combined osteochondral-like construct and comparable staining intensity by Alcian blue, while the expression levels of the aggrecan and type II collagen genes decreased a little. During the culture with the βTCP block, the expression levels of the aggrecan gene increased monotonically. The increase in the inoculum cell number from 1.86 to 3.72 × 10(6) cells resulted in marked increases in the thickness of cell sheet parts in the βTCP block and expression levels of the aggrecan and type II collagen genes, while the thickness of cell sheet parts on the βTCP block scarcely changed. On the other hand, the addition of a cell sheet that was prepared a day before to the construct at day 14 resulted in the marked increase in thickness of the cell sheet part on the βTCP block, while the thickness of that in the βTCP block did not increase.A combined osteochondral-like structure was produced by putting a βTCP block on the sheet of MSC. The thickness of the cell sheet parts in and on the βTCP block could be increased by the increase in inoculum cell number and by providing an additional cell sheet, respectively.

Background Broad dissection with a long skin incision and detachment of the gluteus medius muscle performed for rotational acetabular osteotomy (RAO) can result in weakness in abduction strength of the hip. We use a surgical procedure for RAO that minimizes operative invasion of soft tissue and reduces incision length compared with conventional procedures. Questions/Purposes We evaluated the clinical results of this less-invasive RAO comparing it with the more-invasive prior procedure with respect to improvement in clinical hip scores and radiographic coverage and overall hip survival after the procedure. Methods In this less-invasive exposure, the medial gluteus muscle is retracted to expose the ilium without detachment from the iliac crest. Similarly, the rectus femoris muscle tendon is retracted, not excised. The lateral part of the osteotomized ilium is cut to form the bone graft instead of harvesting it from the outer cortical bone of the ilium. Between 2000 and 2009, 62 patients (71 hips) underwent this procedure. Twenty-eight hips had early-stage osteoarthritis and 43 had advanced-stage osteoarthritis. Mean patient age was 40 years at the time of surgery. We evaluated improvement in hip scores (Merle d’Aubigné-Postel, Japanese Orthopaedic Association) and radiographic appearance (lateral center-edge angle, Sharp’s angle, acetabular head index [AHI]). Kaplan-Meier survivorship analysis was performed. Mean followup was 5 years (range, 2.0–10.4 years). Results Clinical hip scores improved postoperatively. On average, lateral center-edge angle, Sharp’s angle, and AHI improved by 38°, 11°, and 42%, respectively. Predicted 10-year survival rates were 100% and 72% for hips with early- and advanced-stage osteoarthritis, respectively. Conclusions In hips with early-stage osteoarthritis treated by this less-invasive approach, no progression of osteoarthritis was documented and Trendelenburg gait was avoided. However, further investigation is necessary for hips with advanced-stage osteoarthritis. Level of Evidence Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fourteen hips in 14 patients (all female; average age, 64 years) with severe bone defects due to developmental dysplasia of the hip or migration of the socket were treated with hydroxyapatite block with impacted morselized bone graft in conjunction with a cemented socket. All patients were followed clinically in a prospective fashion, and radiographs were analyzed retrospectively. One initial patient had 17-year follow-up, whereas the remaining 13 patients had follow-up between 4 and 6.5 years. No acetabular components were revised, including the socket of a 17-year postoperative case that remains rigidly fixed and supported by the graft and hydroxyapatite block with only mild polyethylene wear and minor osteolysis. Osteointegration and good clinical outcome were achieved in all cases by reconstruction with this technique in total hip arthroplasty.

Among autologous somatic stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) are the most widely used worldwide to repair not only mesenchymal tissues (bone, cartilage) but also many other kinds of tissues, including heart, skin, and liver. Autologous BMSCs are thought to be safe because of the absence of immunological reaction and disease transmission. However, it is possible that they will form tumours during long-term follow-up. In 1988, we transplanted autologous BMSCs to repair articular cartilage, which was the first such trial ever reported. Subsequently we performed this procedure in about 40 patients. Demonstration that neither partial infections nor tumours appeared in these patients provided strong evidence for the safety of autologous BMSC transplantation. Thus, in this study we checked these patients for tumour development and infections. Between January 1998 and November 2008, 41 patients received 45 transplantations. We checked their records until their last visit. We telephoned or mailed the patients who had not visited the clinics recently to establish whether there were any abnormalities in the operated joints. Neither tumours nor infections were observed between 5 and 137 (mean 75) months of follow-up. Autologous BMSC transplantation is a safe procedure and will be widely used around the world.