Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE. We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH-specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in silico analyses. The Japanese GWAS identified 4 significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 [odds ratio (OR) = 1.99, P-value = 1.1 × 10-9)], TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH. We identified three novel susceptibility loci for S-ONFH in SLE.

Corticosteroid-associated osteonecrosis of the femoral head in an 87-year-old patient following treatment for COVID-19-associated pneumonia: A case report.

Coronavirus disease 2019 is known to cause severe acute respiratory syndrome, and serious cases need to be treated with corticosteroids. Herein, we report an 87-year-old woman who developed bilateral osteonecrosis of the femoral head after corticosteroid treatment for coronavirus disease 2019-related pneumonia. Sixteen months after treatment, she developed right hip pain without any evidence of trauma. A diagnosis of bilateral osteonecrosis of the femoral head was made based on sclerotic bands on plain radiographs and low-signal bands on T1-weighted magnetic resonance images. The patient underwent right total hip arthroplasty 4 months after symptom onset. Histological examination of the resected femoral head revealed pathological evidence of osteonecrosis. The postoperative course was good, and the patient can now walk unassisted. To the best of our knowledge, this is the first report of histologically proven osteonecrosis after corticosteroid therapy for coronavirus disease 2019-related disease.

Minimum 10-Year Survivorship of Uncemented Acetabular Reconstruction With Bulk Femoral Head Autografting in Crowe Type IV Developmental Hip Dysplasia.

BACKGROUND: In total hip arthroplasty (THA) for severe dislocations such as Crowe type IV developmental dysplasia of the hip (DDH), sufficient bone volume for stable fixation of the acetabular component can be achieved by placing a reinforcing bone graft prepared from the resected femoral head into the deficient acetabulum. The purpose of the current study was to examine the long-term survivorship of uncemented THA in conjunction with a bulk femoral head autograft in patients who have Crowe type IV DDH. METHODS: A total of 35 patients (42 hips) who have Crowe type IV DDH and underwent THA using uncemented cup fixation with bulk femoral head autografting were followed up for a mean period of 15.0 years (range, 10.0 to 20.0) postoperatively. Anteroposterior pelvic radiographs were used for measurements such as the horizontal coverage of the grafted bone and the center-edge angle. Kaplan-Meier survivorship analyses were performed with revision of the acetabular component as the endpoint. RESULTS: The Kaplan-Meier analysis indicated 15-year survival rates of 90.4%. The mean horizontal coverage of grafted bone was 46.1% (range, 23.7 to 66.0), and there were 16 cases with horizontal coverage of ≥ 50%. There was no difference in the appearance of a thin (< 1 mm) radiolucency line around the cup between cases with < 50% versus ≥ 50% of the horizontal coverage of grafted bone (4 versus 2 hips; P = .446). Trabecular bridging and remodeling were seen in all cases after mean periods of 4.1 and 9.0 months postoperatively, respectively. Trabecular reorientation was seen in 41 of 42 hips (97.6%) at a mean follow-up of 19.9 months. CONCLUSIONS: Acetabular reconstruction with femoral bulk bone grafting for Crowe type IV DDH resulted in high survival rates and was a good method to restore bone stock and obtain long-term fixation.

The role of torsional stress in the development of subchondral insufficiency fracture of the femoral head: A finite element model analysis.

BACKGROUND: Subchondral insufficiency fracture of the femoral head generally occurs without evidence of trauma or with a history of minor trauma. Insufficient bone quality is considered one cause; however, the detailed mechanism of fracture development at the subchondral area (SA) is not understood. The aim of this study was to clarify the directions of force that cause subchondral fracture using finite element model analysis. METHODS: Two types of finite element models were generated from the CT data of femurs obtained from three individuals without osteoporosis (normal models) and another three with osteoporosis (osteoporosis models). Three directions of force, including compressive, shearing, and torsional, were applied to the femoral head. The distribution of von Mises stress (Mises stress) was evaluated at the SA, principal compressive trabeculae (PC), and principal tensile trabeculae. RESULTS: Under compressive force, the mean Mises stress value was greatest at the PC in both the normal and osteoporosis models. Under shearing force, the mean Mises stress value tended to be greatest at the SA in the normal model and at the PC in the osteoporosis model. Under torsional force, the mean Mises stress value was greatest at the SA in both types of models. CONCLUSIONS: The torsional force showed the greatest Mises stress at the SA in both the normal and osteoporosis models, suggesting the importance of torsion as a possible force responsible for subchondral insufficiency fracture development.

Side-to-side variability in the femoral neck anteversion angle: A study of the Japanese population with osteonecrosis of the femoral head.

BACKGROUND: Side-to-side variability in the femoral neck anteversion angle (FA) reportedly varies from 0.0° to 17.3°. To investigate the side-to-side variability in the FA and the relationship between the FA and the morphology of the acetabulum in the Japanese population, we performed a three-dimensional computed tomography (CT)-based study involving patients with osteonecrosis of the femoral head (ONFH). METHODS: CT data were obtained from 170 nondysplastic hips of 85 patients with ONFH. The FA and acetabular coverage parameters, including the acetabular anteversion angle, acetabular inclination angle, and acetabular sector angle in the anterior, superior, and posterior directions, were measured using three-dimensional CT. The distribution of the side-to-side variability in the FA was evaluated separately for each of the five degrees. RESULTS: The mean side-to-side variability in the FA was 6.7° ± 5.3° (range, 0.2°-26.2°). The distribution of the side-to-side variability in the FA was 0.0°-5.0° in 41 patients (48.2%), 5.1°-10.0° in 25 patients (29.4%), 10.1°-15.0° in 13 patients (15.3%), 15.1°-20.0° in 4 patients (4.7%), and >20.1° in 2 patients (2.4%). There was a weak negative correlation between the FA and anterior acetabular sector angle (r = -0.282, P < 0.001) and a very weak positive correlation between the FA and acetabular anteversion angle (r = 0.181, P < 0.018). CONCLUSIONS: The mean side-to-side variability in the FA was 6.7° ± 5.3° (range, 0.2°-26.2°) in Japanese nondysplastic hips, and about 20% of the patients had a side-to-side variability of >10°.

Bone morphology and physical characteristics of the pro-cyclist hip joint.

PURPOSE: This study aimed to investigate the radiographic findings for the hip joint and hip range of motion in professional cyclists, and to determine their bone morphology and physical characteristics. The effects of physical characteristics on athletic performance were examined in terms of metabolic efficiency using simulation analysis. METHODS: We performed a case-control research study on 22 hips in 11 male professional cyclists (average age 28.5, height 1.73 m, weight 77.6 kg). Thirty hips in 15 healthy male volunteers were selected as controls. As radiographic evaluations, acetabular dysplasia was assessed on standardized radiographs. During physical evaluations, the hip range of motion was examined. We used simulation analysis to investigate the metabolic efficiency in the different cycling forms. RESULTS: The radiographic evaluations showed a significant difference in the incidence of acetabular dysplasia (p = 0.01): 59% (13/22 hips) in the pro-cyclist group versus 10% (3/30 hips) in the control group. The physical evaluations revealed significant differences in the hip internal rotation angle (p = 0.01), with greater ranges of internal rotation in the pro-cyclist group versus the control group. The simulation analyses showed that metabolism was reduced in the cycling form with hip internal rotation, especially in the lower extremities. CONCLUSIONS: Pro-cyclists showed a high frequency of acetabular dysplasia and superior hip internal rotation. According to the cycling model analyses, hip internal rotation allowed pedaling with reduced metabolic power.

Efficacy of bone marrow stimulation for arthroscopic knotless suture bridge rotator cuff repair: a prospective randomized controlled trial.

BACKGROUND: The purpose of this study was to investigate the efficacy of bone marrow stimulation (BMS) on the repair integrity of the rotator cuff insertion treated with arthroscopic knotless suture bridge (K-SB) rotator cuff repair. We hypothesized that BMS during K-SB repair can improve the healing of the rotator cuff insertion. METHODS: Sixty patients who underwent arthroscopic K-SB repair of full-thickness rotator cuff tears were randomly allocated to 2 treatment groups. Patients in the BMS group underwent K-SB repair augmented with BMS at the footprint. Patients in the control group underwent K-SB repair without BMS. Cuff integrity and retear patterns were evaluated by postoperative magnetic resonance imaging. The clinical outcomes included the Japanese Orthopaedic Association score, University of California at Los Angeles score, Constant-Murley score, and Simple Shoulder Test. RESULTS: Clinical and radiological evaluations were completed in 60 patients at 6 months postoperatively, in 58 patients at 1 year postoperatively, and in 50 patients at 2 years postoperatively. Both treatment groups showed significant improvements in the clinical outcome from baseline to the 2-year follow-up, but no significant differences were found between the 2 groups. At 6 months postoperatively, the retear rate at the tendon insertion was 0.0% (0 of 30) in the BMS group and 3.3% (1 of 30) in the control group (P = .313). The retear rate at the musculotendinous junction was 26.7% (8 of 30) in the BMS group and 13.3% (4 of 30) in the control group (P = .197). All retears in the BMS group occurred at the musculotendinous junction, and the tendon insertion was preserved. There was no significant difference in the overall retear rate or retear patterns between the 2 treatment groups during the study period. CONCLUSIONS: No significant differences were detected in the structural integrity or retear patterns regardless of the use of BMS. The efficacy of BMS for arthroscopic K-SB rotator cuff repair was not proven in this randomized controlled trial.

Assessment of the Hip Flexor Muscles Shortly after Curved Periacetabular Osteotomy using Magnetic Resonance Imaging.

BACKGROUND: Curved periacetabular osteotomy requires detachment and retraction of the hip flexors. In this study, we evaluated hip flexor muscle status by magnetic resonance imaging (MRI) shortly after curved periacetabular osteotomy. METHODS: We retrospectively evaluated 60 hips of 56 patients by MRI 1 week and 3 months after curved periacetabular osteotomy performed from August 2017 to December 2019. We classified the condition of the flexors as follows: Grade 0, normal; Grade I, strain/edema; Grade II, partial tear; and grade III, complete tear. RESULTS: At 1 week after surgery, the iliacus muscle was classified as grades I and II in 12.0 and 88.0% of hips; psoas as grades 0, I and II in 22.0, 72.0, and 6.0%; sartorius muscle as grades 0, I and II in 6.0, 62.0, and 32.0%; and rectus femoris muscle as grades 0 and I in 86.0 and 14.0%, respectively. At 3 months, 82.0, 88.0, and 96.0% of psoas, sartorius, and rectus femoris muscles, respectively, had improved to grade 0, whereas the iliacus was grades I and II in 94.0 and 6.0%, respectively. These changes in the iliacus muscle at 3 months were not significantly associated with patient characteristics, radiographic data, or clinical scores. CONCLUSIONS: All the iliacus, 78% of psoas, 94% of sartorius, and 14% of rectus femoris muscles appeared abnormal on MRI 1 week after curved periacetabular osteotomy. However, at 3 months, only 18% of psoas, 12% of sartorius, and 4% of rectus femoris muscles appeared abnormal, whereas all iliacus muscles still appeared abnormal. These abnormalities did not significantly affect clinical scores.

Suspension arthroplasty using the palmaris longus tendon with a suture button for thumb trapeziometacarpal arthritis: a retrospective observational study.

BACKGROUND: This study was performed to assess the clinical and radiographic results at a minimum of 2 years after ligament reconstruction suspension arthroplasty (LRSA) that comprised full trapeziectomy and suspensionplasty using the palmaris longus tendon and the Mini TightRope (Arthrex, Naples, FL) for advanced thumb carpometacarpal arthritis. METHODS: We clinically and radiographically evaluated 26 thumbs in 26 patients who had undergone LRSA at least 2 years previously. The mean follow-up period was 35.9 months. We evaluated the subjective clinical outcomes (visual analogue scale and Quick Disabilities of the Arm, Shoulder, and Hand scores) and objective clinical outcomes (range of motion, pinch strength, grip strength, and trapezial space height ratio). RESULTS: At the final follow-up evaluation, the mean visual analogue scale score was 11.1 (standard deviation (SD) 13.4) and the mean Quick Disabilities of the Arm, Shoulder, and Hand questionnaire score was 9.39 (SD 10.1). The mean palmar and radial abduction were 62.3° (SD 11.8°) and 63.8° (SD 9.09°), respectively. The mean key pinch and grip strength were 3.92 (SD 1.07) kg and 19.7 (SD 7.77) kg, respectively. The mean trapezial space ratio was 0.21 (SD 0.10). The subjective clinical outcomes, range of motion, and pinch strength were significantly improved compared with preoperatively. CONCLUSIONS: LRSA for advanced-stage thumb carpometacarpal osteoarthritis relieves pain, improves range of motion and strength, and obtains favourable subjective patient-reported clinical outcomes.

Prognostic factors and clinical features in metacarpophalangeal joint hyperextension after ligament reconstruction with trapeziectomy: A retrospective cohort study.

BACKGROUND: Management of metacarpophalangeal (MCP) hyperextension deformity in thumb carpometacarpal (CMC) joint arthritis is challenging. It remains unclear how the preoperative MCP joint angle affects the outcomes. The present study aimed to clarify the associations between postoperative MCP hyperextension deformity and outcomes, and to determine the preoperative MCP joint angle that can predict poor outcomes. METHODS: We investigated the functional outcomes of patients who underwent surgery for CMC arthritis at two institutions from 2016 to 2020. All patients received a modified Thompson technique, ligament reconstruction suspension arthroplasty, and had no additional treatment for MCP hyperextension. The patients were divided into three groups according to their postoperative MCP joint angles: Group A, <10°; Group B, 10°-20°; Group C, >20°. Evaluations included preoperative and postoperative VAS, Quick DASH, range of motion (ROM), grip power, pinch strength, first web space angle, and postoperative trapezial space ratio (TSR). RESULTS: Overall, 66 eligible patients (72 thumbs) were identified and received follow-up for a mean of 25.2 months. The 72 thumbs were assigned to Group A (n = 38), Group B (n = 16), and Group C (n = 18). Group C had significantly lower preoperative MCP joint angle and postoperative grip power, pinch strength, and TSR compared with the Group A (P < 0.05). However, there were no significant differences in VAS, Quick DASH, ROM, and first web space angle (P > 0.05). The preoperative risk factor for highly residual MCP hyperextension was preoperative MCP joint angle (OR = 1.078; P = 0.001), with a cut-off value of 21.5° (AUC = 0.79; sensitivity = 0.813; specificity = 0.821). CONCLUSIONS: Postoperative MCP hyperextension of >20° after ligament reconstruction with trapeziectomy has adverse effects on functional outcomes. In cases with preoperative MCP joint angle of >21.5°, additional treatment for MCP hyperextension should be considered.

Pathophysiology of abnormal compensation ability of the subtalar joint in the varus knee.

BACKGROUND: In recent years, the involvement of the compensation ability of the subtalar joint in lower extremity alignment has been reported. We previously showed that hindfoot alignment angle (HAA) is an indicator of compensation ability of the subtalar joint. The abnormal compensation ability of the subtalar joint was defined by the mobility of the subtalar joint, and evaluation of the mobility of the subtalar joint may help to further clarify the pathophysiology of abnormal compensation ability of the subtalar joint. This study was performed to evaluate the mobility of the subtalar joint and clarify the pathophysiology of abnormal compensation ability of the subtalar joint in the varus knee. METHODS: Seventy-two knees of 72 patients aged ≥40 years with varus knee were included in this study. Preoperative radiographs were used for measurement of this study parameters. Based on our previous study, we defined HAA of ≥15.9°as abnormal compensation ability of the subtalar joint. The patients were divided into an abnormal group (A-group) and normal group (N-group). All measurement parameters were compared between the groups, and correlations between the HAA and each measurement parameter were analyzed. RESULTS: The weight-bearing hindfoot angle (WBHA) (p < 0.001) and non-weight-bearing hindfoot angle (non-WBHA) (p = 0.003), were significantly greater in the A-group than in the N-group. Conversely, the ratio of change in hindfoot alignment (p = 0.006), were significantly smaller in the A-group than in the N-group. The HAA was positively correlated with WBHA (r = 0.66) and non-WBHA (r = 0.43) and negatively correlated with the ratio of change in hindfoot alignment (r = -0.32). CONCLUSIONS: The pathophysiology of abnormal compensation ability of the subtalar joint in the varus knee is thought to involve a state of increased valgus of hindfoot alignment and an inability to move into normal hindfoot alignment. LEVEL OF EVIDENCE: Level Ⅲ, retrospective study.

Femoral nerve status during the anterolateral approach for total hip arthroplasty: Motor-evoked potential analysis and an influencing factor.

BACKGROUND: Femoral nerve palsy is an uncommon but serious complication during the anterolateral approach for total hip arthroplasty. One of the reported reasons for femoral nerve palsy is retractor-induced intraoperative damage after retractor placement on the anterior wall of the acetabulum. The present study aimed to clarify the femoral nerve status during anterolateral approach total hip arthroplasty using motor-evoked potential analysis and to identify risk factors influencing the nerve status. METHODS: From June 2019 to September 2020, 32 hips in 31 patients underwent primary total hip arthroplasty via the anterolateral approach. The integrity of the femoral nerve was tested by the motor-evoked potential at three time points: preoperatively as a control (first period), immediately after retractor placement on the anterior wall of the acetabulum (second period), and after the procedure (third period). In the second period, the hips were divided into the following two groups: a <50% femoral nerve amplitude group and a ≥50% group. The iliopsoas muscle volume was evaluated by measuring the muscle cross-sectional area on preoperative computed tomography images, and compared between the two groups. RESULTS: The mean amplitude of the femoral nerve was significantly reduced from 100% in the first period to 35% in the second period (p < 0.01), but then significantly recovered to 54% in the third period (p < 0.01). In 26 (81%) hips, the femoral nerve amplitude was <50% in the second period. The muscle cross-sectional area of the iliopsoas muscle in the <50% group was significantly smaller than that in the ≥50% group (p < 0.05). CONCLUSIONS: The mean amplitude of the femoral nerve was significantly reduced to 35% in the second period, and the iliopsoas muscle volume was considered to influence this femoral nerve status.

Influence of hindfoot alignment on postoperative lower limb alignment in medial opening wedge high tibial osteotomy.

INTRODUCTION: We have experienced unexpected under-correction after medial opening wedge high tibial osteotomy (MOWHTO). Although the tibia was corrected accurately, the postoperative mechanical axis (MA) was less than 57%. The purpose of this study was to evaluate the relationship between hindfoot alignment and postoperative lower limb alignment, and to reveal whether hindfoot alignment affects lower limb alignment after MOWHTO. Our hypothesis was that hindfoot alignment influences the postoperative MA in MOWHTO. MATERIALS AND METHODS: This study was a retrospective comparative study. The study cohort comprised 43 knees in 43 patients who underwent MOWHTO and had standing long-leg anteroposterior view and hindfoot alignment view radiographs taken preoperatively and at 3 months postoperatively. To evaluate the hindfoot alignment, the absolute value of the ankle joint line orientation relative to the ground was added to the absolute value of the hindfoot angle. We defined a postoperative MA of 57-67% as acceptable correction (A group) and a MA of < 56% as under-correction (U group). The two groups were analyzed to identify factors that affected postoperative limb alignment. RESULTS: The preoperative hindfoot alignment angle was significantly larger in the U group than the A group. The preoperative hindfoot alignment angle was a significant predictive factor of the postoperative MA, and the cut-off value that distinguished under-correction from acceptable correction was 15.9 degrees. CONCLUSION: Abnormal hindfoot alignment is one of the causes of under-correction after MOWHTO. Attention should be paid to the preoperative ankle joint line orientation relative to the ground and hindfoot angle. If the preoperative hindfoot alignment angle is ≥ 15.9 degrees, surgeons should reconsider the operative procedure and correction angle. LEVEL OF EVIDENCE: Therapeutic level III, retrospective study.

Effect of plantar fascia-specific stretching and Achilles tendon stretching on shear wave elasticity of the plantar fascia in healthy subjects.

BACKGROUND: The effect of stretching on the mechanical properties of the plantar fascia (PF) remain unclear. This study was performed to determine the effect of PF-specific stretching (PFSS) and Achilles tendon stretching (ATS) on the viscoelastic properties of the PF with shear wave elastography (SWE). METHODS: We recruited 14 participants (8 men, 6 women) with no history of PF disorders or painful episodes. The mean age of the participants was 30.9 ± 4.8 (range, 25-41) years. All participants performed sustained PFSS (sPFSS) on one foot and intermittent PFSS (iPFSS) on the other foot. Two weeks later, all participants performed sustained ATS (sATS) on one foot and intermittent ATS (iATS) on the other foot. SWE measurements were performed immediately after each stretching. RESULTS: The PF elasticity immediately before stretching ranged from 133.8 kPa to 144.7 kPa. The PF elasticity after stretching ranged from 158.9 kPa to 215.8 kPa. There was a significant increase in PF elasticity after sPFSS, iPFSS, sATS, and iATS (P < .01). The elasticity after sATS was greater than that after iATS (P = .03). In contrast, there were no differences in PF elasticity after stretching between sPFSS and iPFSS (P = .13), sPFSS and sATS (P = .17), or iPFSS and iATS (P = .50). CONCLUSIONS: PF elasticity increased after stretching regardless of the frequency and type of PFSS and ATS. LEVEL OF EVIDENCE: Level II, prospective cohort study.

Predicting motor function recovery in cervical spinal cord injury-induced complete paralysis with reflex response.

STUDY DESIGN: A retrospective clinical study. OBJECTIVE: To elucidate the usefulness of the patellar tendon reflex (PTR), bulbocavernosus reflex (BCR), and plantar response (PR) as factors in the prognostic prediction of motor function in complete paralysis due to cervical spinal cord injuries (CSCIs) at the acute phase. SETTING: Department of Orthopedic Surgery, Spinal Injuries Center, Japan. METHODS: 99 patients assessed as the American Spinal Injury Association Impairment Scale (AIS) grade A (AIS A) were included in this study. The PTR, BCR, and PR were evaluated respectively as positive or negative at the time of injury. We classified the patients into two groups based on their neurological recovery at 3 months after injury: "recovered" group was defined as AIS C, D, or E; "non-recovered" group was defined as AIS A or B. RESULTS: Eight patients demonstrated positive PTR, while 91 demonstrated negative. Three out of eight patients with positive PTR (37.5%) were R group, while 83 out of 91 patients with negative PTR (91.2%) were N group. A significant difference was observed (p = 0.043). For BCR, no significant difference was observed (p > 0.05). Twenty-six patients demonstrated positive PTR, while 73 demonstrated negative. Nine out of twenty-six patients with positive PR (34.6%) were R group, while 71 out of 73 patients with negative PR (97.3%) were N group. A significant difference was observed (p = 0.000068). CONCLUSION: The PTR and PR are useful for poor prognostic prediction of motor function in CSCI at the acute phase.

Traumatic cervical spinal cord injury after cervical laminoplasty for ossification of posterior longitudinal ligament: a case series.

STUDY DESIGN: A retrospective review of a case series of five participants. OBJECTIVE: To elucidate the effects of post-cervical laminoplasty on the clinical pathophysiology of traumatic CSCI. Cervical laminoplasty has been widely performed with good results in individuals for cervical myelopathy. However, no reports have thus far referred to the incidence of traumatic cervical spinal cord injury (CSCI) after previous history of cervical laminoplasty. SETTING: Spinal Injuries Center, Japan. METHODS: From 2008 to 2017, 999 cervical myelopathy individuals were treated by cervical laminoplasty in our institution. Of these, only five participants were subsequently emergency transported to our institution caused by traumatic CSCI. The pathology of five participants were cervical ossification of posterior longitudinal ligament (C-OPLL). The changes of cervical sagittal range of motion (ROM) and the morphology of OPLL were radiologically evaluated. Moreover, the mechanism of injury, the level of injury, and neurological evaluations were discussed. RESULTS: All of the participants demonstrated ankylosed cervical spine due to developing OPLL and spontaneous bony facet and laminar fusion on post-laminoplasty. A significant difference in cervical ROM was observed between pre-laminoplasty and 6 months post-laminoplasty (p = 0.0065). Three participants were extension injury and the other two were flexion injury. CONCLUSIONS: All of the five traumatic CSCI participants had a history of previous cervical laminoplasty for C-OPLL. Cervical laminoplasty for C-OPLL might lead to cervical spine with rigidity and ankylosing due to developing OPLL and bony facet and laminar fusion, and might have a risk for traumatic CSCI.

Soft tissue stabilization of the hinge position in medial closed wedge distal femoral osteotomy: an anatomical study.

BACKGROUND: Soft tissue has an important role in stabilizing the hinge point of medial closed wedge distal femoral osteotomy (MCWDFO). However, there are conflicting data on the soft tissue anatomy around the hinge point of MCWDFO and, therefore, further anatomical data are needed. The purposes of the study were to: 1) anatomically analyze the soft tissue around the hinge point of MCWDFO; 2) radiologically define the appropriate hinge point to prevent an unstable hinge fracture based on the result of the anatomical analysis; and 3) histologically analyze the soft tissue based on the result of the anatomical analysis. METHODS: In 20 cadaveric knees, the capsule attachment of the distal lateral side of the femur was marked with a radiopaque ball bearing. A digital planning tool was used to calculate the area of the marked capsule attachment around the ideal hinge point of MCWDFO on radiographs. The soft tissue around the hinge point was histologically examined and the periosteal thickness was measured and visualized graphically. The graph and radiograph were overlayed using image editing software, and the appropriate hinge position was determined based on the periosteal thickness. RESULTS: As a result, the periosteal thickness of the distal lateral femur tended to rapidly decrease from the metaphyseal region toward the diaphyseal region. The overlayed graph and radiograph revealed that the periosteal thickness changed in the region corresponding to the apex of the turning point of the femoral metaphysis in all cases. CONCLUSIONS: In conclusion, the periosteum might support the hinge of MCWDFO within the area surrounded by the apex of the turning point of the femoral metaphysis and the upper border of the posterior part of the lateral femoral condyle.

Reliability of various diastasis measurement methods on weightbearing radiographs in patients with subtle Lisfranc injuries.

OBJECTIVE: This study aimed to evaluate the reliability of the diastasis measurements between the medial cuneiform and the second metatarsal on weightbearing radiography. MATERIALS AND METHODS: We retrospectively examined 18 patients who underwent open surgery for subtle Lisfranc injuries. Preoperative weightbearing radiography of the affected and unaffected feet was evaluated in all patients. The diastasis between the medial cuneiform and the second metatarsal was measured in both feet using the following four methods: diastasis between parallel lines, distal point diastasis, middle point diastasis, and proximal point diastasis. Intraclass correlation coefficients with consistency of agreement were calculated to evaluate inter- and intraobserver reliability. RESULTS: The intra- and interobserver reliabilities of all four methods were good. Intraclass correlation coefficients for intraobserver reliability ranged from 0.87 to 0.93. Those for interobserver reliability ranged from 0.81 to 0.91. CONCLUSIONS: The reliabilities of the diastasis measurement methods between the medial cuneiform and the second metatarsal on weightbearing radiography were good. Measuring the diastasis between the medial cuneiform and the second metatarsal on weightbearing radiography is useful in evaluating subtle injuries when uniform measurement methods are used.

Influence of scapular neck length on the extent of impingement-free adduction after reverse total shoulder arthroplasty.

BACKGROUND: Following reverse total shoulder arthroplasty, a short scapular neck length (SNL) decreases postoperative impingement-free adduction, and impingement between the neck of the scapula and the humeral polyethylene cup may cause scapular notching. However, no reports have evaluated the influence of SNL on impingement-free adduction. The purposes of this study were to evaluate the influence of SNL on impingement-free adduction and to examine the effect of glenoid component lateralization and inferiorization on impingement-free adduction. METHODS: By use of 3-dimensional templating software, a virtual reverse total shoulder arthroplasty model was created in 15 patients who had no osteoarthritic change or any other bony deformity. We measured SNLs separately before implant placement (preoperative SNL) and after implant placement (postoperative SNL). The implant used was the Comprehensive Reverse Shoulder System (Zimmer Biomet, Warsaw, IN, USA), and baseplate bony lateralization of 0, 5, and 10 mm, with inferior eccentricity of 0.5 or 4.5 mm, was tested for impingement-free adduction. Correlations between the preoperative and postoperative SNLs and impingement-free adduction were analyzed. RESULTS: The mean preoperative SNL was 8.2 ± 1.9 mm (range, 5.0-11.7 mm), and the mean postoperative SNL was 6.0 ± 2.0 mm (range, 2.1-9.8 mm). There was a moderate correlation between the preoperative SNL and impingement-free adduction (r = 0.628, P = .12) and a strong correlation between the postoperative SNL and impingement-free adduction (r = 0.771, P = .001). Use of the model with 10 mm of bony lateralization and 4.5 mm of inferior eccentricity provided the best results in terms of impingement-free adduction. CONCLUSION: There were correlations between both the preoperative and postoperative SNLs and impingement-free adduction. Although the lateralized and inferiorized center of rotation may increase the risk of loosening of the glenoid component, this offset significantly increased impingement-free adduction.

Mechanical Influence of Pubic Nonunion on the Stress Distribution After Curved Periacetabular Osteotomy: Patient-Specific Three-Dimensional Finite Element Analysis.

BACKGROUND: Pubic nonunion after curved periacetabular osteotomy (CPO) reportedly occurs in 1%-17% of patients and causes pubic pain in 21%. Furthermore, pubic nonunion is associated with a risk of ischial ramus stress fracture, but the mechanical influence of pubic nonunion has not been fully clarified. METHODS: Patient-specific finite element (FE) analysis was performed using Mechanical Finder software. Three FE models (pre-CPO, union, and nonunion models) were constructed from preoperative and postoperative computed tomographic data. The contact area (mm2) and contact pressure (MPa) in the hip joint as well as the equivalent stress (MPa) at the ischial ramus were evaluated among the 3 FE models. RESULTS: Patient-specific FE models were generated using 18 consecutive hips treated with CPO. The mean contact pressure in the hip joint was not significantly different between the union and nonunion models (0.50 ± 0.10 vs 0.50 ± 0.09 MPa, P = .88). However, the mean equivalent stress at the ischial ramus in the nonunion models was 1.7 times higher than that in the union models (1.13 ± 0.77 vs 0.64 ± 0.45 MPa, P < .01). CONCLUSION: FE analysis revealed that pubic nonunion did not affect the mechanical distribution in the hip joint itself but increased the mean equivalent stress at the ischial ramus. This finding suggests the importance of achieving pubic union after CPO to avoid the risk of ischial ramus stress fracture.