Robotic arm-assisted total hip arthroplasty via a minimally invasive anterolateral approach in the supine position improves the precision of cup placement in patients with developmental dysplasia of the hip.

Robotic arm-assisted THA using a minimally invasive technique via an anterolateral approach in the supine position allows accurate cup placement in patients with DDH.

The mean absolute error of the inclination angle and the anteversion angle between the preoperative planning and the postoperative measurement was significantly smaller in the RA-THA group (inclination, 1.1° ± 0.9; anteversion, 1.3° ± 1.0) than in the NA-THA group (inclination, 2.2° ± 1.5; anteversion, 3.3° ± 2.5). For acetabular cup positioning, the mean discrepancy between the preoperative planning and the postoperative measurement was 1.3 ± 1.3 mm on the transverse axis, 2.0 ± 2.0 mm on the longitudinal axis, and 1.3 ± 1.7 mm on the sagittal axis in the RA-THA group and 1.6 ± 1.4 mm, 2.6 ± 2.3 mm, and 1.8 ± 1.3 mm, respectively, in the NA-THA group. High precision of cup positioning was observed in both groups with no statistically significant difference.


Can TBS reference values be a valid indicator for clinical vertebral fracture? A cross-sectional study.

Trabecular bone score (TBS) is partially independent of fracture risk. Reference values for TBS have not been established in official guidelines, and thus clinicians often have difficulty interpreting TBS results. This study aimed to investigate whether reference values for TBS could be a valid indicator for clinical vertebral fracture (CVF).

The reference value for low TBS (≤ 1.23) was useful as an indicator for CVF, especially in patients with osteoporosis. It is expected that reference values for TBS will be established in official guidelines in the future.


Robotic-assisted total knee arthroplasty improved component alignment in the coronal plane compared with navigation-assisted total knee arthroplasty: a comparative study.

The purpose of this study was to directly compare implant placement accuracy and postoperative limb alignment between robotic-assisted total knee arthroplasty and navigation-assisted total knee arthroplasty. This retrospective case-control study included a consecutive series of 182 knees (robotic-assisted group, n = 103 knees; navigation-assisted group, n = 79). An image-free handheld robotic system (NAVIO) or an image-free navigation system (Precision N) was used. Component and limb alignment were evaluated on three-dimensional computed tomography scans and full-length standing anterior-posterior radiographs. We compared the errors between the final intraoperative plan and the postoperative coronal and sagittal alignment of the components and the hip-knee-ankle angle between the two groups. The orientation of the femoral and tibial components in the coronal plane were more accurate in the robotic-assisted group than in the navigation-assisted group (p < 0.05). There was no significant difference in the orientation of the femoral and tibial component in the sagittal plane between the two groups. There were fewer outliers in the tibial coronal plane in the robotic-assisted group (p < 0.05). There was also no significant difference in the frequency of outlying values for coronal or sagittal alignment of the femoral component or sagittal alignment of the tibial component or the hip-knee-ankle angle between the two groups. Robotic-assisted total knee arthroplasty using a handheld image-free system improved component alignment in the coronal plane compared with total knee arthroplasty using an image-free navigation system. Robotic surgery helps surgeons to achieve personalised alignment that may result in better clinical outcomes.


Clinical Outcome of Full Endoscopic Trans Kambin's Triangle Lumbar Interbody Fusion: A Systematic Review.

Full-endoscopic (FE) lumbar interbody fusion (LIF) is now a widely used type of minimally invasive surgery (MIS). Although FE-LIF includes LIF with foraminoplasty via a Kambin's triangle approach (FE-KLIF) and LIF with foraminotomy via an interlaminar approach, these techniques are rarely discussed separately. This review evaluates the outcomes and complications of FE-KLIF reported in the literature. The PubMed, Medline, Embase, Web of Science, and Cochrane Library databases were searched for studies reporting the outcomes of FE-KLIF. Of 464 publications assessed, 11 met our inclusion criteria. Although the most frequently treated level was L4/5, L5/S1 was also treated. FE-KLIF was performed under local anesthesia and sedation or under epidural anesthesia without general anesthesia. Visual analog scale and Oswestry Disability Index scores were improved postoperatively in all uncontrolled studies; however, there was no significant difference in these scores in studies that compared FE-KLIF with posterior LIF (PLIF) or MIS-transforaminal LIF (TLIF). There was also no significant difference in the fusion rate between FE-KLIF and PLIF or MIS-TLIF. In terms of complications, although there were no reports of hematoma, dural tear and surgical site infection were reported in 1 paper each, with transient nerve disorders reported in 5 studies (frequency, 1.8%-23.5%). This review indicates that FE-KLIF is a feasible and viable surgical option for lumbar degenerative disease. However, the amount and level of evidence is low for the studies included in this review, and the data on long-term outcomes remain limited.


caused by asymptomatic gallbladder abscess: a case report and literature review.

, other sources of infection should be suspected and investigated regardless of whether they are symptomatic.

that occurred as a result of an asymptomatic gallbladder abscess. The patient was a 78-year-old man who underwent bilateral total knee arthroplasty 6 years ago. He had pain and swelling in his right knee. The synovial fluid culture of the right knee revealed


Kinematic comparison between the knee after bicruciate stabilized total knee arthroplasty and the native knee: A cadaveric study.

Kinematics of BCS-TKA is close to that of the native knee. However, there is a statistically significant difference in AP position of the femur during mid flexion and initial rotational position of the tibia between the BCS-TKA knee and the native knee.


Impact of the hip-spine relationship and patient-perceived leg length discrepancy after total hip arthroplasty: A retrospective study.

Patient-perceived leg length discrepancy (PLLD) is one of the major postoperative complications of total hip arthroplasty (THA). This study aimed to identify factors that cause PLLD following THA.

Sixty-nine patients were classified as having type 1 PO (rising toward the unaffected side) and 26 were classified as having type 2 PO (rising toward the affected side). Eight patients with type 1 PO and seven with type 2 PO had PLLD postoperatively. In the type 1 group, patients with PLLD had larger preoperative and postoperative PO values and larger preoperative and postoperative RLLD than those without PLLD (p = 0.01, p < 0.001, p = 0.01, and p = 0.007, respectively). In the type 2 group, patients with PLLD had larger preoperative RLLD, larger amount of leg correction, and a larger preoperative L1-L5 angle than those without PLLD (p = 0.03, p = 0.03, and p = 0.03, respectively). In type 1, postoperative PO was significantly associated with postoperative PLLD (p = 0.005), but spinal alignment was not an indicator of postoperative PLLD. The area under the curve (AUC) for postoperative PO was 0.883 (good accuracy) with a cut-off value was 1.90° CONCLUSION: Rigidity of the lumbar spine might lead to postoperative PO as a compensatory movement, resulting in PLLD after THA in type 1. Further research on the relationship between flexibility of the lumbar spine and PLLD is needed.


Insertion of a spacer block translates the tibia anteriorly during evaluation of soft tissue balance in cruciate-retaining total knee arthroplasty.

Assessment of soft tissue balance using a spacer block in CR TKA during knee flexion changes the location of the tibia. Surgeons should be aware of the potential for overestimating the postoperative flexion gap in CR TKA when using a spacer block to assess the flexion gap.

The mean sagittal location of the tibial center relative to the femoral center in knee flexion was 5.16 (range, -2.4, 16.3) mm at insertion of the spacer block and 6.60 (range, -1.4, 15.1) mm after CR TKA, and this difference was significant (p = 0.016).


Relationship between iliopsoas muscle surface pressure and implant alignment after total hip arthroplasty: a cadaveric study.

Iliopsoas impingement after total hip arthroplasty is caused by the implant irritating the iliopsoas muscle, but changes in the iliopsoas muscle have not been quantitatively evaluated. This study assessed changes in the surface pressure of the iliopsoas muscle when the implant alignment was varied. Total hip arthroplasty was performed in 10 fresh-frozen cadaveric hips. We evaluated the maximum and mean surface pressure of the iliopsoas muscle with the hip in 20° and 10° extension, the neutral position, and 10° flexion when the anterior cup protrusion length (ACPL), stem version, and stem offset were varied. When the ACPL was changed to 0, 3, and 6 mm in 20° extension, the maximum surface pressure was significantly increased for ACPL of 6 mm compared with 0 mm. Decreased stem anteversion resulted in a significant reduction in both the maximum and mean surface pressure compared with native anteversion from 20° extension to the neutral position. Increased stem offset resulted in significant increases in the maximum and mean surface pressure of the iliopsoas muscle compared with decreased stem offset in 20° extension. Not only large ACPL but also changes in stem version and offset affected the maximum surface pressure of the iliopsoas muscle.


Identifying vertebral fractures in the Japanese population using the trabecular bone score: a cross-sectional study.

TBS was a significant indicator of vertebral fractures in the Japanese population and might contribute to identifying patients with vertebral fractures, particularly those with osteopenia who need pharmacologic therapy.

Of the 104 patients in the VF group, 75 had 1 vertebral fracture and 29 had 2 or more fractures. The mean TBS was 1.28 in the VF group and 1.35 in the non-VF group (p < 0.001). The mean BMD values at the lumbar spine and femoral neck were lower in the VF group (p < 0.001). The areas under the receiver-operating characteristic curve for incidence of vertebral fractures were 0.700, 0.737, and 0.689 for TBS, lumbar spine BMD, and femoral neck BMD, respectively. Multiple logistic regression analysis identified lumbar spine BMD, TBS, and female sex as significant risk factors for vertebral fractures. The proportion of patients in the group with osteoporosis or osteopenia who had vertebral fractures was higher in those with a low TBS (≤ 1.23) than in those with a non-low TBS (> 1.23).


Increased hip flexion angle and protrusion of the anterior acetabular component can predict symptomatic iliopsoas impingement after total hip arthroplasty: a retrospective study.

Symptomatic IPI had an incidence of 11.0% and a predilection for hips with osteonecrosis. Pre- and postoperative hip flexion angles were significantly greater in hips with symptomatic IPI (

An increased hip flexion angle and protrusion of the anterior acetabular component predicted symptomatic IPI. The threshold cup protrusion length suggesting mild IPI might be about 3.9 mm and could be useful for identifying candidates for conservative treatment.


Association of spinal anomalies with spondylolysis and spina bifida occulta

To investigate the association of spinal anomalies with lumbar spondylolysis and spina bifida occulta (SBO). A total of 1190 patients with thoracic, abdominal, and pelvic computed tomography scans available were categorized according to the number of presacral (thoracic and lumbar) mobile vertebrae and the presence or absence of lumbosacral transitional vertebrae (LSTV). The prevalence of spondylolysis and SBO and the association of spinal anomalies with these disorders were evaluated. Normal morphology (17 mobile vertebra with no LSTV) was found in 607 men (86.5%) and 419 women (85.9%) and about 14% of patients had anomalies. Spondylolysis was found in 74 patients (6.2%), comprising 54 men (7.7%) and 20 women (4.1%). SBO involving the lumbar spine was found in 9 men (1.3%) and 2 women (0.4%). Spondylolysis was significantly more common in men with 18 vertebrae without LSTV (21.1%) than in those with 17 vertebrae without LSTV (7.2%) (p = 0.002). The prevalence of spinal anomalies was 55.6% in men and 50.0% in women with SBO that included a lumbar level was significantly higher than in both men (13.5%, p < 0.001) and women (4.8%, p = 0.003) without SBO. These findings indicate that there is a relationship between spinal anomalies and both spondylolysis and SBO, which may lead to elucidation of the mechanism of onset of spondylolysis and improve its treatment and prognosis. Awareness that patients with SBO involving the lumbar spine have an increased likelihood of a spinal anomaly may help to prevent level errors during spinal surgery.


Contributions of the ischiofemoral ligament, iliofemoral ligament, and conjoined tendon to hip stability after total hip arthroplasty : a cadaveric study

An adequate soft tissue balance is important in total hip arthroplasty (THA). This study assessed the contribution of the iliofemoral ligament, ischiofemoral ligament, and conjoined tendon to the range of hip rotation after THA and hip stability in response to axial traction. THA was performed in eight fresh-frozen cadaveric specimens via an anterolateral approach using a navigation system. The ischiofemoral ligament, the medial arm of the iliofemoral ligament, and the conjoined tendon were resected in that order. The ranges of external and internal rotation and the amount of movement of the femoral head in response to axial traction were measured with the hip in 10° of extension, the neutral position, and in 10°, 30°, and 60° of flexion. Resection of the medial arm of the iliofemoral ligament significantly increased the range of external rotation in 10° of extension, the neutral position, and in 10°, 30°, and 60° of flexion. The conjoined tendon was the most important inhibitor of internal rotation from 10° of extension to 30° of flexion. Although each single element had a minor role in stabilizing the hip when axial traction was applied, resection of two or more elements significantly affected joint stability. The iliofemoral ligament and conjoined tendon are the main inhibitors of external rotation and internal rotation, respectively, when THA is performed using an anterior or anterolateral approach. Resection of two or more elements could greatly affect hip stability when axial traction is applied.


Clinical and radiological outcomes of total hip arthroplasty using a highly porous titanium cup or a conventional hydroxyapatite-coated titanium cup: A retrospective study in Japanese patients.

Despite excellent clinical outcomes in both study groups, the incidence of RLLs was higher in the OsseoTi group than in the Trident group. Although none of our cases with RLL have required revision surgery for aseptic loosening so far, these patients require careful follow-up.

The clinical outcome was excellent in both groups. The incidence of RLLs was 12.9% at 3 months, 20.8% at 6 months, 23.8% at 12 months, and 22.8% at 24 months after surgery in the OsseoTi group; there were no cases of RLL at any time after surgery in the Trident group. The RLLs were mainly distributed in zone 2. Despite the high rate of RLL in the OsseoTi group, the RLL were narrow and only 5% had a width of >1 mm at 24 months postoperatively. There were no cases with RLLs in all three zones.


Influence of the glenoid baseplate position on the direction and length of the superior and inferior locking screws.

Introduction : Superior screw insertion in reverse shoulder arthroplasty (RSA) carries the potential risk of suprascapular injury. The purpose of this study was to evaluate how the baseplate position affects the superior screw position and length in RSA. Methods : Three-dimensional (3D) computer simulation models of RSA were established using computed tomography data of baseplates with superior and inferior screws and 3D scapular models from 10 fresh cadavers. Superior screw position, the distance from the superior screw hole to the suprascapular notch, and the screw lengths were measured and compared among various baseplate positions with two inferior tilts (0 and 10 degrees) and three rotational patterns (11-5, 12-6, and 1-7 o'clock in the right shoulder). Results : For the 1-7 o'clock / inferior tilt 0 degrees baseplate, the superior screw located anterior to the SS notch in all shoulders, the distance to the SS notch was the longest (12.8 mm), and the inferior screw length was the shortest (23.1 mm). Conclusion : Although there is a concern of a short inferior screw length, initial fixation using a baseplate with 1-7 o'clock rotation and an inferior tilt of 0 degrees appears preferable for SS nerve injury prevention during superior screw insertion. J. Med. Invest. 69 : 185-190, August, 2022.

The Journal of Medical Investigation : JMI


Postoperative radiographic evaluation and simulation study for optimal cup placement in high-hip centre total hip arthroplasty.

We retrospectively reviewed 214 patients who underwent primary total hip arthroplasty (THA) and identified 30 hips with Crowe II (

Even in severe DDH, a high-hip centre positioned approximately 25 mm superior to the inter-teardrop line was sufficient to achieve optimal bone coverage, which could lead to more secure cup fixation.


Optimal baseplate position in reverse shoulder arthroplasty in small-stature Japanese women : a cadaveric study.

The purpose of this study was to determine the optimal position of the baseplate on the small glenoid of female Japanese. Two sets of 3D scapular models were made according to the CT data of 7 female cadavers. We set two scenarios of the baseplate placement : A and B. In scenario A, the baseplate was placed on the glenoid face centrally in the anteroposterior direction. In scenario B, the baseplate was implanted at the point where the baseplate post was contained within the glenoid vault. Whether or not the baseplate post perforated the scapular neck was recorded. In scenario A, the central post penetrated the scapular neck posteriorly in 5 scapulae. In scenario B, the average distances from the guide pin position to the anterior glenoid rim was 9.7 ± 1.7 mm and the optimal position of the guide pin was 1.9 ± 1.7 mm anterior from the glenoid center. The central post was contained within the scapula without breakage of the cortex. This study demonstrated that shifting the center of the baseplate slightly anterior to the anatomic center is necessary to avoid perforation of the scapular neck in small female Japanese. J. Med. Invest. 68 : 175-180, February, 2021.


Insufficient lateral joint laxity after bicruciate-retaining total knee arthroplasty potentially influences kinematics during flexion: A biomechanical cadaveric study.

Restoring optimal joint laxity was not always straightforward in BCR TKA if the 4 ligaments were preserved. Lateral joint laxity was potentially decreased in BCR TKA and may result in kinematic conflict during flexion. Surgeons should be aware of the need to achieve sufficient lateral joint laxity in this type of BCR TKA.

Knee joint laxity after BCR TKA under varus-valgus movement, anterior translation, and internal-external rotation loadings was similar to that of the native knee. However, lateral joint laxity was decreased during flexion in some cases. BCR TKA-treated knees with decreased lateral joint laxity at 90° of flexion demonstrated more limited tibial internal rotation in deep flexion than the native knee (p < 0.05). The loss of internal rotation in deep flexion was partly recovered by using a lateral insert with a posterior slope of +3°.


Quadriceps strength to body weight ratio is a significant indicator for initiating jogging after anterior cruciate ligament reconstruction.

Quadriceps strength recovery after anterior cruciate ligament (ACL) reconstruction is an important criterion for progress in rehabilitation and return to sports. The purpose of this study was to determine whether quadriceps strength to body weight ratio (QS/BW) is a significant indicator for initiating jogging after ACL reconstruction.

QS/BW is a significant indicator for safely initiating jogging 3 months after ACL reconstruction. The cut-off value of QS/BW for initiating jogging was 1.45 Nm/kg.


Anatomic evaluation of the insertional footprints of the iliofemoral and ischiofemoral ligaments: a cadaveric study.

Understanding the size and location of each capsular ligament footprint in relation to an osseous landmark may help surgeons to manage the hip capsule intraoperatively even under a narrow surgical view. The findings of this study underscore the importance of recognizing that the distal ISFL footprint is located relatively forward and very close to the distal lateral arm footprint.

The mean length of the distal medial arm of the ILFL footprint was 17.9 mm and the mean width was 9.0 mm. The mean length of the distal lateral arm of the ILFL footprint was 23.0 mm and the mean width was 9.7 mm. For the footprint of the medial arm, the insertion was in the distal third of the intertrochanteric line and that of the lateral arm was in the proximal 42% of this line. The mean distance from the lesser trochanter to the footprint of the medial arm was 24.6 mm. The mean length of the distal ISFL footprint was 11.3 mm and the mean width was 6.9 mm. The footprint of the distal ISFL was located forward of the femoral neck axis in all specimens.


Intra- and inter-rater reliability of a three-dimensional classification system for intertrochanteric fracture using computed tomography

Intertrochanteric fractures are common fragility fractures in elderly patients. The importance of a reliable classification system for these fractures has been increasingly recognized. The aim of this study was to test the hypothesis that three-dimensional classification by CT has better intra- and inter-observer reliability than conventional two-dimensional classification. Two hundred and three consecutive patients (39 male, 164 female; mean age 84.5 years) with intertrochanteric fracture were included in the study. In each case, the fracture was classified using the two-dimensional Evans-Jensen and AO/OTA systems that rely on plain radiographs and using a three-dimensional fragment-based CT system. The second evaluation was performed 1 month after the first evaluation by the same examiner to determine intra-observer reliability. Another blinded examiner also classified each case to assess inter-observer reliability. The kappa coefficient was used for determination of intra- and inter-observer reliability. The kappa values for the two-dimensional Evans-Jensen and AO/OTA classification systems showed moderate intra-observer reliability (κ=0.65 and κ=0.61, respectively) and slight inter-observer reliability (κ=0.20 and κ=0.19). The intra-observer kappa value for the three-dimensional classification system was 0.88, indicating almost perfect reliability; the inter-observer kappa value was 0.70, indicating substantial reliability. The findings of this study confirm that the fragment-based classification system has high reliability. Surgeons should be aware that the three-dimensional fragment-based CT system for classification of intertrochanteric fractures has better intra-observer and inter-observer reliability than the conventional two-dimensional systems.


Clinical outcome of bi-unicompartmental knee arthroplasty for both medial and lateral femorotibial arthritis: a systematic review-is there proof of concept?

Unicompartmental knee arthroplasty (UKA) is a well-accepted treatment for isolated unicompartmental osteoarthritis (OA) of the knee. In previous literature, it has been suggested that bi-unicompartmental knee arthroplasty (bi-UKA) which uses two UKA implants in both the medial and lateral compartments of the same knee is a feasible and viable option for the treatment of knee OA. Given the advantages of UKA treatment, it is warranted to review the literature of bi-UKA and discuss the evidence in terms of implant selection, indications, surgical techniques, and outcomes, respectively. Following the PRISMA guidelines, PubMed, Medline, Embase, CINAHL, Web of Science, and Cochrane Library were searched for studies presenting outcome of bi-UKA. Studies were included if they reported clinical outcomes using two unicompartmental prostheses for both medial and lateral femorotibial arthritis. Studies with the addition of patellofemoral arthroplasty or concomitant soft-tissue reconstruction and those not published in English were excluded. In the early literature, the procedure of bi-UKA were performed for very severe OA and rheumatoid arthritis, but indications have evolved to reflect a more contemporary case-mix of knee OA patients. Both mobile and fixed bearing implants have been used, with the latter being the most frequent choice. A medial parapatellar approach for incision and arthrotomy has been the most frequently used technique. The present review found a promising clinical outcome of both simultaneous and staged bi-UKA although the number of long-term follow-up studies was limited. Both simultaneous and staged bi-UKA has demonstrated good functional outcomes. However, the volume and level of evidence in general is low for studies captured in this review, and the data on long-term outcomes remain limited. The present review indicates that bi-UKA is a feasible and viable surgical option for bicompartmental femorotibial OA in carefully selected patients.

Archives of Orthopaedic and Trauma Surgery


Joint distraction force changes the three-dimensional articulation of the femur and tibia in total knee arthroplasty: a cadaveric study.

Joint distraction force changed three-dimensional articulation regardless of PCL preservation. PCL function was revealed as a factor restraining both tibial posterior translation and internal rotation. Surgeons should recognize that joint gap evaluation using a tensor device is subject to three-dimensional changes depending on the magnitude of the joint distraction force.

Regardless of PCL resection, the joint center gap became larger (p = 0.002, p = 0.020) and varus ligament balance became more varus (p = 0.002, p = 0.002) with increasing joint distraction force, whereas the tibia was more internally rotated (p = 0.015, p = 0.009) and more anteriorly located (p = 0.004, p = 0.009). The tibia was more internally rotated (p = 0.015) and more posteriorly located (p = 0.026) after PCL resection than before resection.

Knee Surgery, Sports Traumatology, Arthroscopy


Proximal Femoral Rotational Osteotomy for Symptomatic Femoral Retroversion : A Case Report

The Rotational osteotomy for femoral retroversion has been extremely rare despite the known association between femoral neck retroversion, hip pain, and osteoarthritis. Here, we describe a case of femoral neck retroversion for which proximal femoral rotation osteotomy. A 16-year-old boy with a past history of developmental dysplasia of the both hip treated conservatively presented with a complaint of pain in left hips. On physical examination, flexion of the left hip was limited to 90° with terminal pain. Internal rotation was also limited to 10°. Computed tomography (CT) showed -7.1° anteversion of the left femur. We performed rotational osteotomy to increase femoral anteversion because conservative treatment was not effective. The postoperative course was uneventful. At 12 postoperative months, his left hip pain was completely disappeared and femoral anteversion was 34° on CT scans. Retroversion of the femur is a distinct dynamic factor that should be considered in the evaluation of mechanical causes of hip pain. Restoring the normal rotational alignment of the hip resulted in cure of the impingement due to femoral retroversion. J. Med. Invest. 67 : 214-216, February, 2020.

The Journal of Medical Investigation : JMI


Rotational and varus-valgus laxity affects kinematics of the normal knee: A cadaveric study.

The present study revealed that the rotation angle of the tibia was correlated to the intermediate angle of IE laxity at 0°, 30°, 60°, and 90° of knee flexion and the coronal alignment of the lower limb also correlated to the intermediate angle of VV laxity. These findings provide important reference data on soft tissue laxity and kinematics of the normal knee.

Journal of Orthopaedic Surgery (Hong Kong)


The medial constrained insert restores native knee rotational kinematics after bicruciate-retaining total knee arthroplasty.

This study shows that the rotational kinematics of the native knee is reproduced after BCR TKA with the medial constrained insert. Surgeons and implant designers should be aware that constraint of the medial side in BCR TKA is a crucial factor for restoration of native kinematics which may lead to better clinical outcome.

The rotation angles of the tibia in BCR-XP were significantly different from those of the native knees both in the early flexion phase (p = 0.002 at minimum knee flexion, p = 0.002 at 0°, p = 0.041 at 10°, p = 0.009 at 20°, p = 0.026 at 30°) and in the late flexion phase (p = 0.015 at 130°, p = 0.015 at maximum knee flexion), whereas the rotational angles of the tibia in BCR-AS were similar to those of the native knee.


Intraoperative analysis of the kinematics of the native knee including two-dimensional translation of the femur using a navigation system : a cadaveric study.

The aim of this cadaveric study was to evaluate the intraoperative kinematics of the native knee including two-dimensional translation of the femur using a navigation system. Eight native knees of 4 fresh-frozen whole-body cadavers were used for the study. The kinematics of each knee were analyzed intraoperatively using the navigation system. Although anterior-posterior translation could not be assessed directly, it could be calculated using a formula derived from the parameters in the navigation system. The native knee showed external rotation of the femur in early knee flexion, transient internal rotation in mid flexion, and gradual external rotation in late flexion. There was no marked change in the coronal rotation angle of the mechanical axis during knee flexion. The femoral center moved anteriorly in early knee flexion and posteriorly in late flexion. The distance moved in the medial-lateral direction was relatively smaller than that in the anterior-posterior direction. Two-dimensional translation of the surgical epicondylar axis showed a medial pivot-like motion. In this cadaveric study, the kinematics of the native knee, including two-dimensional translation of the femur, could be satisfactorily assessed intraoperatively using a navigation system. The intraoperative kinematics of the knee can be analyzed in more detail using this methodology. J. Med. Invest. 66 : 367-371, August, 2019.


A novel three-dimensional classification system for intertrochanteric fractures based on computed tomography findings.

A novel three-dimensional fragment-based classification system based on computed tomography findings was established to characterize femoral intertrochanteric fractures. The intertrochanteric bone fragments were defined as follows : neck, posterior portion of the greater trochanter, anterior portion of the greater trochanter, lesser trochanter, and shaft. Each type of fracture was classified as 2-, 3-, 4-, or 5-fragment according to the number of floating bone fragments. Following the description of the fracture type, each floating bone fragment was appended, with the exception of a fragment involving the shaft. Ninety-five intertrochanteric fractures were classified by the same surgeon. The fractures occurred in 14 men and 81 women with a mean age of 84.7 years. The frequency of each type of fracture was investigated. Thirty-one fractures (32.6%) were 2-fragment and 64 (67.4%) were ≥ 3-fragment. A fragment of the anterior portion of the greater trochanter, which cannot be classified using conventional systems, was included in 29 cases (30.5%). A 5-fragment fracture was detected in two cases (2.1%). Using this fragment-based classification system, intertrochanteric fractures can be evaluated in more detail than is possible using conventional classification systems. J. Med. Invest. 66 : 362-366, August, 2019.


Native rotational knee kinematics are lost in bicruciate-retaining total knee arthroplasty when the tibial component is replaced.

The rotational kinematics of the native knee are not always preserved after BCR TKA. Native rotational kinematics are preserved after meniscectomy and femoral replacement, but are lost after tibial replacement in BCR TKA. Surgeons should pay close attention to maintain the anteroposterior stabilizing function of the ACL in BCR TKA, rather than to restore the native rotational kinematics.


Native rotational knee kinematics is restored after lateral UKA but not after medial UKA.

The rotational kinematics of the native knee was not restored after medial UKA but was preserved after lateral UKA. There were no significant differences in the varus/valgus kinematics after either medial or lateral UKA when compared with those of the native knees. Thus, the geometry of the medial tibial articular surface is a determinant of the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should be aware that the anatomical medial articular geometry is an important factor in restoration of the native knee kinematics after knee arthroplasty.

The rotation angles of the tibia in the early flexion phase of medial UKA were significantly larger than those of native knees (p = 0.008 at minimum knee flexion, p = 0.008 at 0° knee flexion). The rotational kinematics of lateral UKA was similar to those of the native knees throughout knee flexion. There were no significant differences in varus/valgus kinematics between native and UKA knees.

Knee Surgery, Sports Traumatology, Arthroscopy


Location and direction of the nutrient artery to the first metatarsal at risk in osteotomy for hallux valgus.

Location and direction of the first metatarsal nutrient artery was established.


Acetabular Reconstruction Using a Trabecular Metal Cup with a Novel Pelvic Osteotomy Technique for Severe Acetabular Bone Defect.

The advantages of this technique are twofold, namely, stable fixation of the cup sandwiched between the anterior and posterior walls and reconstruction of the anterior wall using living bone, which allows bone ingrowth into the cup.


A New Method of Image Evaluation for Diagnosis of Pain : Clinical Application of Diffusion-weighted Imaging

痛み診断の新規画像評価 : 特に拡散強調画像の臨床応用について (日本腰痛学会 特集号) -- (特集 腰痛治療の革新 : 慢性腰痛・神経障害性疼痛に対する治療のbreakthrough)


Compression of the Femoral Vessels by a Pseudotumor after Metal-on-Metal Total Hip Arthroplasty.

Here we present a case of pseudotumor following total hip arthroplasty (THA) that resulted in a circulatory disturbance caused by compression of the femoral vasculature. A 63-year-old man presented with pain, swelling, and redness of the left leg 5 years after primary metal-on-metal THA using the AML-Plus stem, Pinnacle® acetabular cup, and 36 mm diameter Ultamet metal head system (DePuy Orthopaedics, Warsaw, IN). Enhanced computed tomography and magnetic resonance imaging revealed a large cystic lesion extending from the left hip anteriorly to the intrapelvic region and compressing the left femoral vessels. Percutaneous puncture of the lesion yielded a dark red aspirate and the patient was diagnosed to have a pseudotumor causing compression of the femoral vessels. We performed revision surgery to replace the metal head and metal liner with a smaller ceramic head and polyethylene liner without removal of the stem. Corrosion of the head-neck junction was identified intraoperatively with no obvious wear on the bearing surfaces. The left leg swelling and redness improved immediately postoperatively. A large pseudotumor should be kept in mind as a cause of vascular compression with unilateral leg edema in a patient who has undergone metal-on-metal THA.

Here we present a case of pseudotumor following total hip arthroplasty (THA) that resulted in a circulatory disturbance caused by compression of the femoral vasculature. A 63-year-old man presented with pain, swelling, and redness of the left leg 5 years after primary metal-on-metal THA using the AML-Plus stem, Pinnacle® acetabular cup, and 36 mm diameter Ultamet™ metal head system (DePuy Orthopaedics, Warsaw, IN). Enhanced computed tomography and magnetic resonance imaging revealed a large cystic lesion extending from the left hip anteriorly to the intrapelvic region and compressing the left femoral vessels. Percutaneous puncture of the lesion yielded a dark red aspirate and the patient was diagnosed to have a pseudotumor causing compression of the femoral vessels. We performed revision surgery to replace the metal head and metal liner with a smaller ceramic head and polyethylene liner without removal of the stem. Corrosion of the head-neck junction was identified intraoperatively with no obvious wear on the bearing surfaces. The left leg swelling and redness improved immediately postoperatively. A large pseudotumor should be kept in mind as a cause of vascular compression with unilateral leg edema in a patient who has undergone metal-on-metal THA.


Piriformis muscle syndrome with assessment of sciatic nerve using diffusion tensor imaging and tractography: a case report.

Piriformis muscle syndrome (PMS) is difficult to diagnose by objective evaluation of sciatic nerve injury. Here we report a case of PMS diagnosed by diffusion tensor imaging (DTI) and tractography of the sciatic nerve, which can assess and visualize the extent of nerve injury. The patient was a 53-year-old man with a 2-year history of continuous pain and numbness in the left leg. His symptoms worsened when sitting. Physical examination, including sensorimotor neurologic tests, the deep tendon reflex test, and the straight leg raise test, revealed no specific findings. The hip flexion adduction and internal rotation test and resisted contraction maneuvers for the piriformis muscle were positive. There were no abnormal findings on magnetic resonance imaging (MRI) of the lumbar spine. The transverse diameter of piriformis muscle was slightly thicker in affected side on MRI of the pelvis. A single DTI sequence was performed during MRI of the pelvis. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve were quantified at three levels using the fiber-tracking method. FA values were significantly lower and ADC values were significantly higher distal to the piriformis muscle. We performed endoscopic-assisted resection of the piriformis tendon. Intraoperatively, the motor-evoked potentials in the left gastrocnemius were improved by resection of the piriformis tendon. The patient's symptoms improved immediately after surgery. There was no significant difference in FA or ADC at any level between the affected side and the unaffected side 3 months postoperatively. MRI-DTI may aid the diagnosis of PMS.


Efficacy of a computed tomography-based navigation system for placement of the acetabular component in total hip arthroplasty for developmental dysplasia of the hip.

THA using a CT-based navigation system achieved quite high accuracy of cup alignment angles and spatial cup positioning in primary THA for patients with DDH.

Journal of Orthopaedic Surgery (Hong Kong)


Bilateral osteochondritis dissecans of the capitellum in fraternal twins: A case report

We report the cases of 15-year-old male fraternal twins with bilateral osteochondritis dissecans (OCD) of the capitellum in the absence of syndromic features. At the time of presentation, they had been actively engaged in competitive rhythmic gymnastics for 3 years. Both patients had chronic symptoms in the right elbow, and both underwent arthroscopic evaluation and management. The cases of these 2 patients provide evidence to support the theory that the etiology of OCD may have a genetic background.


Custom-Made Alumina Ceramic Total Talar Prosthesis for Idiopathic Aseptic Necrosis of the Talus: Report of Two Cases.

Two women aged 65 years and 78 years presented to our center with idiopathic necrosis of the talus. In both cases, imaging examinations showed collapse and sclerotic changes of the talar body caused by the necrosis. Both women underwent resection and placement of a third-generation custom-made alumina ceramic total talar prosthesis. Immobilization of the ankle in a short-leg cast for 3 weeks was followed by early rehabilitation. One year and 6 months after surgery, both women were able to walk without pain. Their Japanese Society for Surgery of the Foot ankle-hindfoot scale scores improved from 22 and 29/100 points to 90 and 95/100 points, respectively. To the best of our knowledge, the successful treatments of these two rare cases of idiopathic necrosis of the talus are among only a few reported cases of using a third-generation alumina ceramic prosthesis.


Pseudoaneurysm of the Anterior Tibial Artery following Ankle Arthroscopy in a Soccer Player.

Ankle arthroscopy carries a lower risk of vascular complications when standard anterolateral and anteromedial portals are used. However, the thickness of the fat pad at the anterior ankle affords little protection for the thin-walled anterior tibial artery, rendering it susceptible to indirect damage during procedures performed on the anterior ankle joint. To our knowledge, only 11 cases of pseudoaneurysm involving the anterior tibial artery after ankle arthroscopy have been described in the literature. Here we reported a rare case of a 19-year-old soccer player who presented with pseudoaneurysm of the anterior tibial artery following ankle arthroscopy using an ankle distraction method and underwent anastomosis for the anterior tibial artery injury. Excessive distraction of the ankle puts the neurovascular structures at greater risk for iatrogenic injury of the anterior tibial artery during ankle arthroscopy. Surgeons should look carefully for postoperative ankle swelling and pain after ankle arthroscopy.


Cementless calcar-replacement stem with integrated greater trochanter plate for unstable intertrochanteric fracture in very elderly patients.

Hemiarthroplasty using the MOD-Centaur stem for unstable intertrochanteric fracture in very elderly patients offers favorable outcomes. These findings encourage early walking without any loading limitations, despite severe osteoporosis, and emphasize the importance of greater trochanteric fixation, which reconstructs the mechanism of the gluteus medius muscle.


Can intraoperative kinematic analysis predict postoperative kinematics following total knee arthroplasty? A preliminary.

The preliminary study analyzed the relationship between intraoperative navigation-based kinematics and postoperative 2-dimensional/3-dimensional (2D/3D) image registration-based kinematics in total knee arthroplasty (TKA). Six knees in 5 patients were analyzed. All TKA procedures were performed using an image-free knee navigation system. Tibial internal rotation was assessed by intraoperative knee kinematics. At 1 year after surgery, tibial internal rotation was evaluated using a 2D/3D image registration technique under loaded and unloaded conditions. The correlation between intraoperative and postoperative data for the tibial internal rotation angle at 10 increments of knee flexion was then assessed. Difference in the knee flexion angle between the intraoperative and postoperative evaluations was adjusted to account for the sagittal cutting angle of the distal femur and proximal tibia. A correlation was found between the intraoperative and postoperative data for loaded knee flexion with this adjustment (Pearson's r = 0.725, p = 0.012). However, intraoperative kinematics was not significantly correlated with postoperative kinematics in the absence of loading. Larger adequately powered prospective studies are now needed to confirm our preliminary finding that postoperative loaded kinematics can be predicted by intraoperative evaluation. J. Med. Invest. 65:21-26, February, 2018.

The Journal of Medical Investigation : JMI


Radiographic changes of cervical destructive spondyloarthropathy in long-term hemodialysis patients: A 9-year longitudinal observational study.

Analyses of radiographic changes and clinical symptom of destructive spondyloarthropathy (DSA) on consecutive 42 patients managed with long-term hemodialysis were performed to elucidate radiographic changes of DSA and the factors that influence to the destructive changes. Patients underwent plain radiographs of the cervical spine with 9 years interval. Grading of radiological feature from lateral view was classified into grade 0 to grade 3. Clinical symptom was evaluated using modified Japanese Orthopaedic Association scoring system for cervical myelopathy (mJOA score). Destructive changes were observed in 3 patients at the first examination, and those were observed in 15 patients 9 years after the first examination. There is no statistically significant difference between the duration of hemodialysis and the grade. The mean age at the onset of hemodialysis, however, was significantly higher in patients of grade 2 and 3 than those of grade 1. Older patients with long-term hemodialysis had destructive changes. Destructive changes commonly observed in lower cervical spine. The average numbers of the involved disc level were 1.6 in grade 2 and 1.0 in grade 3. Clinical symptoms were varied in each grade and there was no statistically significant difference in total mJOA score among these grades. J. Med. Invest. 64: 68-73, February, 2017.


The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis.

Rotational alignment of the femoral component in total knee arthroplasty (TKA) is important for patellar tracking and ligament balance. Preoperative planning based on radiography might have a potential risk for over-rotation because these X-ray based measurements can not detect asymmetric cartilage wear on posterior condyle. The purpose of this study is to evaluate the effect of the posterior condylar cartilage of varus osteoarthritic knee on rotational alignment of the femoral component in TKA. We established two different condylar twist angles (CTA) from intraoperative multiplanar reconstruction (MPR) images and intraoperative information of navigation system. The CTA measured by a navigation system that includes the cartilage (4.8±2.0°) was smaller than those measured by MPR images, which does not include the cartilage (6.6±2.1°) (p<0.05). The difference between these two angles that corresponds to the remaining posterior condylar cartilage was 1.7±1.2°. This result demonstrated that the posterior condylar cartilage might lead to over-rotational of the femoral component in varus osteoarthritic knee. Therefore, when determining rotational alignment of the femoral component, surgeons should consider the effect of the remaining posterior condylar cartilage to avoid the over-rotation of the femoral component, especially in severe varus knees. J. Med. Invest. 64: 24-29, February, 2016.


A new concept of transforaminal ventral facetectomy including simultaneous decompression of foraminal and lateral recess stenosis: Technical considerations in a fresh cadaver model and a literature review.

Percutaneous endoscopic surgery for the lumbar spine, which was established in the last decade, requires only an 8-mm skin incision and causes minimal damage to the paravertebral muscles; thus, it is considered to be a minimally invasive technique for spinal surgery. It has been used to perform percutaneous endoscopic discectomy via two main approaches: the TF approach is a posterolateral one through the intervertebral foramen and can be done under local anesthesia; the IL approach is a more traditional one through the interlaminar space and is difficult to perform under local anesthesia. Recently, these techniques have been applied for lumbar spinal stenosis (LSS), the TF method for foraminal stenosis under local anesthesia, and the IL method for central and lateral recess stenosis under general anesthesia. In this study, using a fresh human cadaver model, we performed simultaneous decompression of the lateral recess and foraminal stenosis at L4-5 using the TF approach. Computed tomography confirmed enlargement of the lateral recess and intervertebral foramen. This technique, which can be performed under local anesthesia, should benefit elderly patients with LSS and poor general condition due to multiple comorbidities. Finally, we introduce the concept of percutaneous transforaminal ventral facetectomy using a spinal percutaneous endoscope. J. Med. Invest. 64: 1-6, February, 2017.


Diffusion tensor imaging and tractography of the sciatic nerve: assessment of fractional anisotropy and apparent diffusion coefficient values relative to the piriformis muscle, a preliminary study.

Piriformis muscle syndrome (PMS) is underdiagnosed. To evaluate the potential of diffusion tensor imaging and diffusion tensor tractography as innovative tools for the diagnosis of PMS by functional assessment of the sciatic nerve, the aims of this study are to assess the reproducibility and to evaluate the changes in the parameters at levels proximal and distal to the piriformis. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve at three levels were quantified twice each by two examiners using the fiber-tracking method. In the first part of the study, laterality and reproducibility were evaluated using intraclass correlation coefficients (ICC) in ten healthy volunteers. In the second part of the study, the healthy side and symptomatic side were assessed in ten consecutive patients with sciatica. There were three patients with no findings on lumbar magnetic resonance imaging (MRI). There was no laterality in either FA or ADC values in asymptomatic patients at any level. The mean intra-rater ICC was 0.90 and the mean inter-rater ICC was 0.87. FA was significantly lower and ADC significantly higher on the symptomatic side at each level in patients with sciatica. In the three sciatica patients with no findings on lumbar MRI, FA was significantly lower and ADC was significantly higher only at levels distal to the piriformis. These patients experienced full pain relief after ultrasound-guided injection of local anesthesia. Diffusion tensor imaging and diffusion tensor tractography might be innovative tools for the diagnosis of PMS.


Variations in the obturator artery around the obturator foramen assessed by three-dimensional computed tomographic angiography and prevention of vascular-related complications in rotational acetabular osteotomy.

Extensive care should be taken during rotational acetabular osteotomy in patients showing variations of the obturator artery with corona mortis.

The prevalence of arterial anastomosis of the obturator artery (corona mortis) was 14.3 %, with the obturator artery being located closer to the superior pubic ramus and the osteotomy site in these subjects.


Influence of Medial collateral ligament release for internal rotation of tibia in posterior stabilized total knee arthroplasty: a cadaveric study

Previous studies suggested that changes in kinematics in total knee arthroplasty (TKA) affected satisfaction level. The aim of this cadaveric study was to evaluate the effect of medial collateral ligament (MCL) release by multiple needle puncture on knee rotational kinematics in posterior-stabilized TKA. Six fresh, frozen cadaveric knees were included in this study. All TKA procedures were performed with an image-free navigation system using a 10-mm polyethylene insert. Tibial internal rotation was assessed to evaluate intraoperative knee kinematics. Multiple needle puncturing was performed 5, 10, and 15 times for the hard portion of the MCL at 90° knee flexion. Kinematic analysis was performed after every 5 punctures. After performing 15 punctures, a 14-mm polyethylene insert was inserted, and kinematic analysis was performed. The tibial internal rotation angle at maximum knee flexion without multiple needle puncturing was significantly larger (9.42°) than that after 15 punctures (3°). Negative correlation (Pearson r = -0.715, P < .001) between tibial internal rotation angle at maximum knee flexion and frequency of puncture was observed. The tibial internal rotation angle with a 14-mm insert was significantly larger (7.25°) compared with the angle after 15 punctures. Tibial internal rotation during knee flexion was reduced by extensive MCL release using multiple needle puncturing and was recovered by increasing of medial tightness. From the point of view of knee kinematics, medial tightness should be allowed to maintain the internal rotation angle of the tibia during knee flexion which might lead to patient satisfaction.