Functional and clinical anatomy of the obturator externus muscle: Cadaveric studies and clinical findings for total hip arthroplasty in the posterior approach

Repairing released posterior soft tissues is important in preventing dislocation after total hip arthroplasty (THA) via the posterior approach. We clarify the functional and the clinical anatomy of obturator externus. We performed cadaveric studies and investigated clinically in primary THA cases. The location, trajectory, and size of the muscular tendon was recorded. The trajectory of the obturator externus ran orthogonal to the femoral axis with the hip in 90° flexion whereas that of the obturator internus muscle ran parallel. Because the trajectory of obturator externus and the obturator internus differ, their functions also differ.

The position of the vertebral artery V1 segment relative to the C7 vertebra

BACKGROUND

The vertebral artery (VA) usually enters the transverse foramen at the C6 level. Thus, surgeons prefer to insert pedicle screws (PSs) at C7, but this does not eliminate the risk of VA injury. We aimed to clarify anatomical features of the VA V1 segment at the C7 pedicle level, based on computed tomographic angiography (CTA) of 81 consecutive patients.

METHODS

We examined the course of the VA V1 segment on axial CTA images. VA position was classified according to its alignment with the anterior (A), middle (M), or posterior (P) third of the C7 vertebral body at the pedicle level. We also assessed the prevalence of hypoplastic VA (HVA). We measured the distance (VED) from the optimum C7 PS entry point (Ep) to the center of the VA. We also measured the angles formed by the vertebral midline and a line from the inner edge of the VA to the Ep (the VEA), and by the vertebral midline and a line from the inner edge of the pedicle to the Ep (the PEA).

RESULTS

The variant location of the VA to the C7 vertebra was A in 13 courses (8.1%), M in 123 (76.9%), and P in 20 (12.5%). HVA was present in the contralateral side in 7 of 20 courses (35%) in the P group, and in 8 of 127 courses (6.3%) in the M group (p < 0.05). The mean VED was 20.2 mm, the mean VEA 6.9°, and the mean PEA angle was 36.3°.

CONCLUSION

The 20 VA courses in the P group (12.5% of the total VA courses) were relatively close to the C7 Ep. HVA was present contralateral to the VA in 7 of 20 courses in the P group. CTA should be considered before proceeding with, even if, C7 PS instrumentation, to avoid unexpected pitfall.

A Five-Year-Old Slipped Capital Femoral Epiphysis Treated With Dynamic Single Screw Fixation

Slipped capital femoral epiphysis (SCFE) commonly occurs during puberty. Onset of SCFE at either less than 10 years old or over 16 years is defined as atypical. As in our patient, atypical onset at less than 10 years occurred in 9%, and the age of onset has been decreasing in recent years and that the probability of concomitant obesity is particularly high in young patients without obvious underlying disease or background factors. In the treatment of SCFE, preventing further slipping and permitting femoral bone growth by physeal closure is difficult, especially for young patients. We adopted 'dynamic single screw fixation' using SCFE short thread screw for continuous fixation without disturbing the growth of proximal femur or damaging to growth plate. Refixation was necessary once. The screw worked for 7 years 4 months while physeal closure was avoided. At the 10-year follow-up, her growth had stopped. She had no problem clinically, no increase in the posterior sloping angle (PSA), and no obvious growth disturbance of the femur.

Can sterility of stripped iodophor-impregnated plastic adhesive drape be maintained at the time of incision closure in total hip arthroplasty?

OBJECTIVE

The aim of this study was to analyze the contamination rates of the skin under the iodophor-impregnated plastic adhesive drape (IOD) at the time of incision closure in total hip arthroplasty (THA).

METHODS

A total of 225 patients undergoing primary THA (28 men, 197 women; mean age=65 years; age range=30-85) were included in this study. After asepsis using a solution of 1% chlorhexidine with 83% alcohol by volume, the surgical site was painted with a 10% povidone-iodine solution, and IOD was attached tautly at the start of surgery. Swabs of the surgical site were collected as follows: swab A from the skin before IOD application, swab B from the surface of the IOD at the time of incision closure, and swab C from the skin after peeling back the IOD. The obtained samples were promptly sent for microbiological analysis. The contamination rate was determined for swabs A, B, and C, and the contamination rate of swab C was compared with that of swabs A and B, and the bacterial species were identified.

RESULTS

Positive cultures were seen in 8 cases (3.6%) for swab A, 10 cases (4.4%) for swab B, and 22 cases (9.8%) for swab C. The contamination rate of swab C was significantly higher than that of swabs A (p=0.008) and B (p=0.028). Coagulase-negative Staphylococcus (n=10) and Cutibacterium acnes (n=7) were the most frequently cultured microorganisms from swab C.

CONCLUSION

In THA, the contamination rate of the skin after peeling off the IOD before incision closure was higher than that of the skin immediately after sterilization with povidone-iodine and higher than that on the IOD at the time of incision closure. The detected bacterial species were considered clinically significant pathogens. Preventive measures against infection, such as minimizing stripping of the IOD or re-sterilizing bare skin after IOD stripping, should be instituted in consideration of these findings when performing THA using IOD.

Intracellular Accumulation of Advanced Glycation End Products Induces Osteoblast Apoptosis Via Endoplasmic Reticulum Stress

Osteoporosis is an aging-associated disease that is attributed to excessive osteoblast apoptosis. It is known that the accumulation of advanced glycation end products (AGEs) in bone extracellular matrix deteriorates osteoblast functions. However, little is known about the interaction between intracellular AGE accumulation and the induction of osteoblast apoptosis. In this study, we investigated the effect of intracellular AGE accumulation on osteoblast apoptosis in vitro and in vivo. In vitro, murine osteoblastic MC3T3-E1 cells were treated with glycolaldehyde (GA), an AGE precursor. GA-induced intracellular AGE accumulation progressed in time- and dose-dependent manners, followed by apoptosis induction. Intracellular AGE formation also activated endoplasmic reticulum (ER) stress-related proteins (such as glucose-regulated protein 78, inositol-requiring protein-1α (IRE1α), and c-Jun N-terminal kinase) and induced apoptosis. In agreement, treatment with the ER stress inhibitor 4-phenylbutyric acid and knocking down IRE1α expression ameliorated osteoblast apoptosis. Furthermore, the ratio between AGE- and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive osteoblasts in human vertebral bodies was significantly higher in an elderly group than in a younger group. A positive linear correlation between the ratio of AGE-positive and TUNEL-positive osteoblasts (r = 0.72) was also observed. Collectively, these results indicate that AGEs accumulated in osteoblasts with age and that intracellular AGE accumulation induces apoptosis via ER stress. These findings offer new insight into the mechanisms of osteoblast apoptosis and age-related osteoporosis. © 2020 American Society for Bone and Mineral Research.

New Method for the Quantitative Assessment of Sensory Disturbances in Cervical Myelopathy: Application for Neurological Level Diagnosis

Introduction

Cervical myelopathy frequently manifests as sensory disturbances, including numbness, and their distribution pattern aids in neurological level diagnosis. However, the objective assessment of sensory disturbances is challenging. In this study, we attempted to quantitatively evaluate sensory symptoms in patients with cervical myelopathy according to lesion level using PainVision^Ⓡ.

Methods

Dermal sensations were evaluated in patients (n = 158) and healthy volunteers (n = 100) using PainVision^Ⓡ PS-2100, which measured the current perception threshold (CPT). The results were analyzed for their correlation with magnetic resonance imaging (MRI) data, visual analog scale (VAS) scores, and patient functional status assessed by the Japanese Orthopaedic Association (JOA) and JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) scores.

Results

Forearm and palm CPT values were significantly higher in patients with cervical myelopathy (both sites, P < 0.001) and were negatively correlated with the JOA score (forearm, r = −0.33; palm, r = −0.35; P < 0.001) and the JOACMEQ scores for upper extremity function (forearm, r = −0.37; palm, r = −0.39; P < 0.001), lower extremity function (forearm, r = −0.39; palm, r = −0.40; P < 0.001), and quality of life (forearm r = −0.27, P = 0.0025); however, no correlation was observed with the VAS score. Stratification of patients according to their lesion levels determined by MRI revealed that the C3/C4 subgroup had significantly higher forearm CPT values than the C4/C5 (P = 0.024) and C5/C6 (P = 0.0013) subgroups and higher palm CPT values than the C5/C6 subgroup (P = 0.009).

Conclusions

Quantitative measurements of sensory disturbances using the PainVision^Ⓡ device correspond to the degree of patient functional disability and the lesion level. This indicates that both the distribution and intensity of sensory abnormalities are important for neurological level diagnosis in patients with cervical myelopathy.

Impact of posterior femoral condylar cartilage and posterior intercondylar distance on rotation of femoral component in total knee arthroplasty

Background

Greater accuracy is needed when determining the final femoral component (FC) rotation during total knee arthroplasty (TKA), because this parameter affects soft tissue balance during flexion and patellar tracking. Anatomical markers, such as the epicondylar axis, are typically used to determine the final FC rotation, although intraoperative confirmation may be challenging. Therefore, rotational position is frequently determined with the posterior condylar axis (PCA) as a landmark. However, the thickness of the posterior condylar cartilage has not been considered and may not be represented on preoperative images. We used plain X-rays to measure the thickness of the medial and lateral posterior condylar cartilage fragments postoperatively, and investigated the effects of differences in cartilage thickness on final FC rotation.

Methods

Fifty knees (19 men, 31 women) underwent primary TKA to treat medial knee osteoarthritis at our hospital between August 2015 and May 2017. All knees were treated using an Attune PS (DePuy Synthes, Inc., Warsaw, IN). We first measured the distance between the posterior femoral condyles, resected the posterior condyle, and measured the thickness of the resected cartilage fragments. We then took X-ray images from a direction tangential to the osteotomy surface, secured the cartilage fragments with digital calipers, and measured the thickness of the cartilage. We investigated the effects of differences in cartilage thickness on final FC rotation of the residual medial and lateral cartilage with a trigonometric function.

Results

Medial condylar cartilage thickness averaged 0.6 ± 0.5 mm and the lateral condylar thickness averaged 1.8 ± 0.6 mm; posterior intercondylar distance averaged 46.1 ± 3.3 mm and average impact on rotation of the cartilage remnant was 1.5 ± 0.9° (− 0.1–3.9°). There may be measurement error of up to 4° in the maximum values compared with the preoperative plan in cases with short intercondylar distance.

Conclusions

In cases where the FC external rotation angle is determined using the posterior condyles as landmarks, this angle can be affected by the intercondylar distance, especially in Japanese women who have small physical stature. This angle can potentially be much larger, so caution is advised. Our results suggest that several anatomical landmarks should be referenced to achieve accurate FC rotation.

Pre-operative hemoglobin level and use of sedative-hypnotics are independent risk factors for post-operative delirium following total knee arthroplasty

BACKGROUND

Delirium is a well-known complication following surgery, especially with the increasing age of patients undergoing surgery. The increasing demands resulting from a prolonged healthy life expectancy has resulted in more arthroplasties despite their age and existing comorbidities. The purpose of this study is to explore the various risk factors that may contribute to delirium in unilateral and bilateral total knee arthroplasties in the elderly population.

METHODS

170 patients who underwent unilateral or bilateral total knee arthroplasties were analyzed retrospectively for delirium. Age, sex, comorbidities, use of sedative-hypnotics, peri-operative blood loss, pre- and post-operative laboratory blood test results were investigated and analyzed.

RESULTS

The incidence of post-operative delirium was 6.5% (11 out of 170 patients) with a mean age of 79.5 (± 6.9) years, compared to 73.0 (± 9.0) years in the non-delirium group. Higher age, use of sedative-hypnotics, low pre-operative Hb and Ht, low post-operative Hb, Ht and BUN were observed in the delirium group. Multivariate logistic regression analysis identified that the use of sedative-hypnotics and pre-operative Hb level were independent risk factors for post-operative delirium after TKA. The odds ratios for the use of sedative-hypnotics and pre-operative Hb level were 4.6 and 0.53, respectively. Receiver operating characteristic curve analysis showed that pre-operative Hb of less than 11.1 g/dL was a predictor for the development of delirium, with a sensitivity of 54.6% and a specificity of 91.6%.

CONCLUSION

Patients with a pre-operative Hb level of < 11.1 g/dL or those using sedative-hypnotics are associated with post-operative delirium. Peri-operative management and preventative measures are therefore needed to reduce the risks of post-operative delirium in such patients.

Enhancement of tendon-bone interface healing and graft maturation with cylindrical titanium-web (TW) in a miniature swine anterior cruciate ligament reconstruction model: histological and collagen-based analysis

Background

Tendon-bone interface healing and ligamentization of the graft in anterior cruciate ligament (ACL) reconstruction with autografts are important factors affecting treatment outcome. This study aimed to investigate the effectiveness of a cylindrical titanium-web (TW) in tendon-bone interface healing and graft maturation in ACL reconstruction.

Methods

Fourteen mature female CLAWN miniature swine underwent bilateral ACL reconstructions with patellar tendon (PT) autografts. In one limb, the TW/tendon complex was placed into the proximal side of the tibial tunnel. Only the graft was transplanted into the tunnel in the control limb. The proximal side of the graft was sutured into the stump of the native ACL and the distal end was stapled to the tibia. The animals were euthanized at 4 and 15 weeks postoperatively, for histological and biochemical analyses.

Results

Microscopic images in TW limbs showed that ingrowth of tendon-like tissue and mineralized bone tissue into the TW connected the bone and the tendon directly. In contrast, fibrous tissue intervened between the bone and tendon in the control limbs. The total amount of collagen cross-links (which defines the strength of collagen fibers) and the maturation of collagen cross-links in TW tendons were significantly higher (p < 0.05) than those of control limbs. There was no significant difference in the ratio of dihydroxy-lysinonorleucine to hydroxy-lysinonorleucine (an indicator of tissue specific collagen maturation) between TW tendons and that of the native PT.

Conclusions

TW promoted the maturation and formation of collagen cross-links in the grafted tendon while maintaining the cross-links pattern of native tendon collagen, and enabled direct binding of tendon to bone.

Non-invasive skin autofluorescence, blood and urine assays of the advanced glycation end product (AGE) pentosidine as an indirect indicator of AGE content in human bone

Background

Bone mineral density (BMD) measurements are widely used to assess fracture risk. However, the finding that some fracture patients had high BMD together with the low contribution of drugs to osteoporosis suggests that bone strength factors other than BMD contribute to bone quality. We evaluated the amount of advanced glycation end products (AGEs) by non-invasive assays of serum and urine as well as by skin autofluorescence to measure the levels of a representative AGE, pentosidine, to investigate whether pentosidine can serve as an indirect indicator of AGEs formation in bone collagen.

Methods

A total of 100 spinal surgery patients without fragility fracture (54 males and 46 females) treated at our hospital were enrolled. The amount of pentosidine in blood, urine, skin and bone (lumbar lamina) samples from these patients was measured. AGE accumulation was assessed by measuring skin autofluorescence. We examined the correlation between pentosidine content in tissues and body fluid, as well as skin AGEs with age, height, body weight, BMI, and estimated glomerular filtration rate (eGFR).

Results

A significant age-related increase in pentosidine levels in tissues was observed, while there was a significant negative correlation between tissue pentosidine and eGFR. The amount of skin pentosidine was significantly and positively correlated with pentosidine content of the bone in those under 50 years of age. Urine pentosidine also correlated positively with bone pentosidine and skin pentosidine, but only in females. The total amount of AGEs in skin did not correlate with bone pentosidine.

Conclusion

In this study, the strong correlation between the pentosidine content in each sample and eGFR may indicate that renal dysfunction with advancing age increases oxidative stress and induces AGEs formation in collagen-containing tissues. The correlation of skin pentosidine concentration and eGFR, with AGEs formation in bone collagen suggests that pentosidine would be a useful indirect index of decreased bone quality. Skin AGEs estimated by autofluorescence in clinical situations may not be suitable as an indirect assessment of bone quality. Because urine pentosidine correlated positively with bone pentosidine and skin pentosidine in females, urine pentosidine may be a candidate for an indirect assessment of bone quality.

Local application of alendronate controls bone formation and β-tricalcium phosphate resorption induced by recombinant human bone morphogenetic protein-2

This study examined the ability of local alendronate (ALN) administration to control β-tricalcium phosphate (β-TCP) resorption as well as the induction of bone formation by recombinant human bone morphogenetic protein-2 (rhBMP-2). A 15-mm critical-sized bone defect was created in the diaphysis of rabbit ulnae. Nine female rabbits (4 to 5 months-old) were divided into 3 groups. Group 1 (n = 6 ulnae) animals received implants consisting of β-TCP granules and 25 μg of rhBMP-2 in 6.5% collagen gel. Group 2 (6 ulnae) and Group 3 (6 ulnae) animals received the same implants, but with 10^-6 M and 10^-3 M ALN-treated TCP granules, respectively. Two weeks postsurgery, tartrate-resistant acid phosphatase-positive cell counts, new bone formation, and residual β-TCP were evaluated. This study showed that a high dose of ALN strongly reduced osteoclastic resorption of β-TCP induced by rhBMP-2, resulting in decreased bone formation. In contrast, a low dose of ALN slightly reduced the bone resorptive effect but increased bone formation. These results suggest that osteoclast-mediated resorption plays an important role in bone formation and a coupling-like phenomenon could occur in the β-TCP-implanted area, and that administration of a low dose of ALN may solve clinical bone resorptive problems induced by rhBMP-2.

Efficacy of Laminoplasty in Improving Sensory Disturbances in Patients with Cervical Spondylotic Myelopathy: A Prospective Study

OBJECTIVE

Upper extremity sensory disturbances are primary symptoms that affect the quality of life (QOL) of patients with cervical spondylotic myelopathy. Although laminoplasty is 1 of the surgical options, its effects on sensory disturbances have remained unclear. We aimed to determine whether surgical intervention would improve the sensory disturbances of patients with cervical spondylotic myelopathy.

METHODS

We conducted a prospective clinical trial of 101 patients who had undergone open door laminoplasty. For an objective sensory assessment, we measured the current perception thresholds (CPTs) in the patients' forearms and palms using PainVision PS-2100. For a subjective sensory assessment, numbness in the upper extremities was rated using a visual analog scale (VAS). Using the VAS scores, the patients were divided into those with improvement and without improvement. Their self-reported 36-item short-form health survey and Japanese Orthopaedic Association cervical myelopathy evaluation questionnaire scores were compared.

RESULTS

The postoperative CPTs in relationship to the preoperative CPTs at 3, 6, and 12 months was 99.3%, 98.1%, and 93.8% in the forearm and 93.6%, 90.6%, and 87.8% in the palm, respectively. The corresponding postoperative numbness VAS scores were 63.8%, 50.5%, and 48.0%. At 12 months postoperatively, the 36-item short-form health survey physical and role component summary scores, cervical spine function effectiveness rates, upper and lower extremity function, and QOL items in the Japanese Orthopaedic Association cervical myelopathy evaluation questionnaire were significantly higher in the improvement group.

CONCLUSIONS

Our findings have indicated that improvement in postoperative subjective sensory disturbances will occur relatively earlier and will be significantly greater than the improvement in objective sensory disturbances. Furthermore, improvement in the subjective sensory disturbances contributes to functional spinal cord recovery and patients' health-related QOL.

Postoperative creatine kinase elevation following hip arthroscopy and associated risk factors

Objective

The aim of this study was to investigate postoperative CK and risk factors for CK elevation after hip arthroscopy.

Methods

This retrospective study reviewed 122 patients (50 males, 72 females; mean age, 44.1 years) who underwent hip arthroscopy from September 2012 to March 2018. For all patients, CK was investigated preoperatively, on postoperative days 1 and 3, and at postoperative weeks 1 and 2. Univariate and multivariate analysis was performed for parameters including sex, age, body mass index, preoperative glomerular filtration rate, diagnosis, duration of surgery, and duration of traction to determine the risk factors for CK > 10 upper limit of normal (CK > 10 ULN; 1900 IU/L for males and 1500 IU/L for females) after surgery.

Results

Mean CK was 104.7 ± 68.7 IU/L preoperatively and 839.2 ± 2214.0, 523.9 ± 1449.4, 186.0 ± 690.7, and 122.0 ± 307.1 IU/L on postoperative days 1 and 3 and at postoperative weeks 1 and 2, respectively. CK was significantly higher on postoperative days 1 and 3 than before surgery. In total, 11 patients (9.0%), including 8 males (16.0%) and 3 females (4.2%), had CK > 10 ULN. Younger age and longer duration of traction are independent risk factors for CK > 10 ULN.

Conclusion

After hip arthroscopy, CK levels should be monitored, especially in young patients and cases of prolonged duration of traction during surgery.

Level of evidence

Level IV, therapeutic study.

Primary Role of the Amygdala in Spontaneous Inflammatory Pain- Associated Activation of Pain Networks - A Chemogenetic Manganese-Enhanced MRI Approach

Chronic pain is a major health problem, affecting 10–30% of the population in developed countries. While chronic pain is defined as “a persistent complaint of pain lasting for more than the usual period for recovery,” recently accumulated lines of evidence based on human brain imaging have revealed that chronic pain is not simply a sustained state of nociception, but rather an allostatic state established through gradually progressing plastic changes in the central nervous system. To visualize the brain activity associated with spontaneously occurring pain during the shift from acute to chronic pain under anesthetic-free conditions, we used manganese-enhanced magnetic resonance imaging (MEMRI) with a 9.4-T scanner to visualize neural activity-dependent accumulation of manganese in the brains of mice with hind paw inflammation. Time-differential analysis between 2- and 6-h after formalin injection to the left hind paw revealed a significantly increased MEMRI signal in various brain areas, including the right insular cortex, right nucleus accumbens, right globus pallidus, bilateral caudate putamen, right primary/secondary somatosensory cortex, bilateral thalamus, right amygdala, bilateral substantial nigra, and left ventral tegmental area. To analyze the role of the right amygdala in these post-formalin MEMRI signals, we repeatedly inhibited right amygdala neurons during this 2–6-h period using the “designer receptors exclusively activated by designer drugs” (DREADD) technique. Pharmacological activation of inhibitory DREADDs expressed in the right amygdala significantly attenuated MEMRI signals in the bilateral infralimbic cortex, bilateral nucleus accumbens, bilateral caudate putamen, right globus pallidus, bilateral ventral tegmental area, and bilateral substantia nigra, suggesting that the inflammatory pain-associated activation of these structures depends on the activity of the right amygdala and DREADD-expressing adjacent structures. In summary, the combined use of DREADD and MEMRI is a promising approach for revealing regions associated with spontaneous pain-associated brain activities and their causal relationships.

Treatment of periprosthetic hip infection with retention of a well-fixed stem: six to 13-year outcomes

Background

Treatment of periprosthetic joint infection (PJI) is challenging, generally requiring complete implant removal. However, recently reported treatments involve partial retention of implants because of the severe local and systemic burden on the patients and difficulties in functional preservation. Long-term results should be evaluated because of the risk of residual biofilm on the retained implant and late infection recurrence. We evaluated 6 to 13-year clinical outcomes of two-stage treatment of chronic PJI retaining well-fixed cementless stems.

Methods

Among 36 surgeries for deep infection following hip arthroplasty performed from 2004 to 2011, six hips had a well-fixed and well-functioning cementless stem. These six hips were all chronic PJI and were treated without stem removal. The first-stage surgery involved acetabular cup removal and reconstruction by filling the acetabular defect with antibiotic-loaded acrylic cement, creating a socket-like hemispherical dent, and reducing the retained femoral head to this dent. After confirming infection eradication the second-stage acetabular reconstruction was performed. One patient died of an unrelated noninfective cause 1 year after the operation. Clinical outcomes of the remaining five patients were followed for 6 to 13 years.

Results

Between the two surgeries (range; 2–5 months), patients underwent active range-of-motion and ambulation exercises. No dislocation was found during the interval. No recurrence of infection was found and good functional outcomes and radiographic findings were observed during the average follow-up of 109 months in all five patients.

Conclusions

Two-stage treatment with retention of a well-fixed stem may minimize local and systemic burden of the patient and enhance functional preservation while obtaining long-term infection control. Although further study could establish the effectiveness and indications for this treatment option, currently used indications should be carefully evaluated considering factors including local and systemic conditions of the patient, implant fixation status, and type of bacteria.

Effects of micro-porosity and local BMP-2 administration on bioresorption of β-TCP and new bone formation

Background

It has been reported that the microporous structure of calcium phosphate (CaP) ceramics is important to osteoconduction. Bone morphogenetic protein-2 (BMP-2) has been shown to be a promising alternative to bone grafting and a therapeutic agent promoting bone regeneration when delivered locally. The aim of this study was to evaluate the effects of micro-porosity within beta-tricalcium phosphate (β-TCP) cylinders and local BMP-2 administration on β-TCP resorption and new bone formation.

Methods

Bilateral cylindrical bone defects were created in rabbit distal femora, and the defects were filled with β-TCP. Rabbits were divided into 3 groups; defects were filled with a β-TCP cylinder with a total of approximately 60% porosity (Group A: 13.4% micro- and 46.9% macropore, Group B: 38.5% micro- and 20.3% macropore, Group C: the same micro- and macro-porosity as in group B supplemented with BMP-2). Rabbits were sacrificed 4, 8, 12, and 24 weeks postoperatively.

Results

The number of TRAP-positive cells and new bone formation in group B were significantly greater than those in group A at every period. The amount of residual β-TCP in group C was less than that in group B at all time periods, resulting in significantly more new bone formation in group C at 8 and 12 weeks. The number of TRAP-positive cells in group C was maximum at 4 weeks.

Conclusions

These results suggest that the amount of submicron microporous structure and local BMP-2 administration accelerated both osteoclastic resorption of β-TCP and new bone formation, probably through a coupling-like phenomenon between resorption and new bone formation.

Preoperative Pain Control in Arthroscopic Rotator Cuff Repair: Does It Matter?

Background

The purpose of this study was to clarify the importance of preoperative pain control using corticosteroid injections in patients with persistent rest pain (RP) before arthroscopic rotator cuff repair (ARCR).

Methods

A total of 360 patients (374 shoulders) who underwent primary ARCR and were followed up for at least 2 years were enrolled. After one-to-one propensity score matching, 266 patients (145 men and 128 women, 273 shoulders) were included in the study. Their mean age was 65.2 ± 7.7 years (range, 42 to 88 years) at the time of surgery. The patients were divided into three groups: those who required several intra-articular or subacromial bursa corticosteroid injections preoperatively for refractory RP (group A+), those in whom RP was resolved preoperatively (group A−), and those who had no RP and did not require any injections (group B). The incidence of postoperative RP and preoperative and final follow-up American Shoulder and Elbow Surgeons (ASES) scores were compared among the three groups.

Results

The incidence of postoperative RP was significantly higher in group A+ (35/91 cases, 38.5%) than in group A− (10/91, 11.0%) and group B (7/91, 7.7%, p < 0.001 for both). The preoperative ASES score was significantly lower in group A+ (33.2 ± 14.2) than in group A− (53.9 ± 11.9) and group B (62.3 ± 11.2, p < 0.001 for both), and it was significantly lower in group A− than in group B (p = 0.000). The final follow-up ASES score was significantly lower in group A+ (92.1 ± 8.4) than in group A− (97.6 ± 5.4) and group B (99.0 ± 2.5, p < 0.001 for both). There was no significant difference in the final follow-up ASES score between group A− and group B (p = 0.242).

Conclusions

Patients in whom preoperative RP could be resolved before surgery achieved postoperative outcomes comparable to those in patients who had no RP before surgery, whereas the outcomes in patients with refractory preoperative RP were inferior. The results suggest that preoperative pain control is important in patients undergoing ARCR.

Positioning the femoral bone socket and the tibial bone tunnel using a rectangular retro-dilator in anterior cruciate ligament reconstruction

Purpose

The purpose of this study was to evaluate the positions of femoral bone sockets and tibial bone tunnels made with the rectangular retro-dilator (RRD), which we manufactured for anterior cruciate ligament reconstruction (ACLR) with a bone-patella tendon-bone (BPTB) graft which is fixed into the rectangular bone socket and tunnel made at anatomical ACL insertion sites.

Methods

42 patients who had undergone ACLR with BPTB using the RRD were evaluated to assess bone socket and tunnel positions by the quadrant method and Magnussen classification using three-dimensional (3-D) CT. Intra-operative complications were also investigated in all patients.

Results

3-D CT of the operated knee joints using the RRD showed that the bone socket and tunnel were placed in anatomical positions. In the quadrant method, the mean position of the femoral bone socket aperture was located at 22.0 ± 4.2% along the Blumensaat’s line, and 37.4 ± 7.2% across the posterior condylar rim. The mean positions of the tibial bone tunnel aperture were 37.7 ± 5.2% and 46.1 ± 2.2% antero-posteriorly and medio-laterally, respectively. In addition, according to the Magnussen classification, 39 cases were evaluated as type 1, and almost all were located behind the lateral intercondylar ridge (also known as the resident’s ridge). 3 cases were classified as type 2, which overlapped with the resident’s ridge. A partial fracture of BPTB bone fragment was observed in 2 patients, but no serious complications including neurovascular injury were observed.

Conclusion

The study indicates that the use of RRD achieves a safe anatomical reconstruction of the ACL.

The Effects of Homocysteine on the Skeleton

PURPOSE OF REVIEW

Homocystinuria is a congenital metabolic disorder in which cystathionine β-synthase deficiency results in a prominent increase in homocysteine (serum levels > 100 μM), causing mental retardation, atherosclerotic cerebral infarction, and osteoporosis accompanied by fragility fractures. Encountering a case with excessive homocysteinemia such as that seen in hereditary homocystinuria is unlikely during usual medical examinations. However, in individuals who have vitamin B or folate deficiency, serum homocysteine concentrations are known to increase. These individuals may also have a polymorphism in methylenetetrahydrofolate reductase, MTHFR (C677T: TT type), which regulates homocysteine metabolism. These changes in homocysteine levels may elicit symptoms resembling those of homocystinuria (e.g., Alzheimer's disease, atherosclerosis, osteoporosis).

RECENT FINDINGS

High serum homocysteine has been shown to have detrimental effects on neural cells, vascular endothelial cells, osteoblasts, and osteoclasts. Homocysteine is also known to increase oxidative stress, disrupt cross-linking of collagen molecules, and increase levels of advanced glycation end products, which results in reduced bone strength through a mechanism that goes beyond low bone density and increased bone resorption. Therefore, high serum homocysteine may be regarded as a factor that can reduce both bone mass and impair bone quality. In this review, we outline the epidemiology and pathophysiology of osteoporosis associated with hyperhomocysteinemia.

Clinical accuracy and precision of hip resurfacing arthroplasty using computed tomography-based navigation

PURPOSE

To avoid malalignment of components during hip resurfacing arthroplasty (HRA), we used a computed tomography (CT)-based navigation system for guidance. This study aimed to evaluate the clinical accuracy and precision of HRA performed using the CT-based navigation systems.

METHODS

HRA was performed on 17 hips guided by the CT-based navigation systems. We measured cup alignment deviation, deviation of the stem position, and alignment from the plan by image matching between pre-operative and post-operative CT images.

RESULTS

Cup anteversion was within 5° of that in the plan in all cases. Cup inclination was within 5° of that in the plan in 82.4% and within 10° in all cases. The angular difference of the stem was within 5° in all cases, and the entry point of the stem was within 4 mm in all cases.

CONCLUSION

The CT-based navigation system for HRA guided accurate component placement according to the plan.

Target range of motion at 3 months after arthroscopic rotator cuff repair and its effect on the final outcome

PURPOSE

The postoperative protocol after arthroscopic rotator cuff repair (ARCR) is still controversial. Some surgeons recommend slower rehabilitation in order to improve the integrity of the repair, while others prefer early range-of-motion (ROM) exercise to avoid postoperative stiffness. The purpose of this study was to determine target ROM (T-ROM) measurements at 3 months after ARCR that are predictive of eventual full recovery without structural failure.

METHODS

The cases consisted of 374 shoulders in 360 patients who underwent primary ARCR and were followed up for at least 2 years. Forward flexion (FF) and side-lying external rotation (ER) were measured preoperatively at 3, 6, 9, 12, and 24 months after surgery, and the patients were divided into six subgroups according to the values for each type of ROM at 3 months (ROM-3M). In each subgroup, the final ROM at 24 months after surgery was compared to determine the T-ROM. The average ROMs with time and re-tear rate were then compared between the under-T-ROM and over-T-ROM groups.

RESULTS

The only significant difference in FF was between the 120-129° and 110-119° ROM-3M groups. Therefore, the T-ROM for FF was determined to be 120°. Similarly, the T-ROM for ER was determined to be 20°. Each ROM in the over-T-ROM group was significantly better than that in the under-T-ROM group at all assessments. There was no significant difference in the re-tear rate between the groups.

CONCLUSION

To acquire sufficient ROM in 2 years without high re-tear rate, a target FF of 120° and ER of 20° should be achieved within 3 months after surgery.

Comparison of Intercuneiform 1-2 Joint Mobility Between Hallux Valgus and Normal Feet Using Weightbearing Computed Tomography and 3-Dimensional Analysis

BACKGROUND

An association has been reported between hallux valgus and hypermobility of the first ray, but subluxation of the intercuneiform 1-2 joint was also suspected in some cases. However, dynamics of the intercuneiform 1-2 joint has seldom been investigated. This study used weightbearing computed tomography (CT) and a 3-dimensional (3D) analysis system to evaluate displacement of the intercuneiform 1-2 joint, intercuneiform 2-3 joint, and second cuneonavicular joint due to weightbearing in hallux valgus and normal feet.

METHODS

Patients were 11 women with hallux valgus (mean age, 56 years; mean hallux valgus angle, 43 degrees; mean first-second intermetatarsal angle, 22 degrees) and 11 women with normal feet (mean age, 57 years; mean hallux valgus angle, 14 degrees; mean first-second intermetatarsal angle, 9 degrees). Each patient was placed supine with the lower limbs extended, and CT was performed under nonweightbearing and weightbearing conditions (load equivalent to body weight). 3D models reconstructed from CT images were used to compare displacement of the intermediate cuneiform relative to the medial cuneiform under nonweightbearing and weightbearing conditions.

RESULTS

Relative to the medial cuneiform, the middle cuneiform was displaced by 0.1 and 0.8 degrees due to dorsiflexion, 0.2 and 1.0 degrees due to inversion, and 0.7 and 0.7 degrees due to abduction in normal feet and feet with hallux valgus, respectively, with the latter having significantly greater dorsiflexion ( P = .0067) and inversion ( P = .0019). There was no significant intergroup difference at the intercuneiform 2-3 joint and second cuneonavicular joint.

CONCLUSION

This study clarified the detailed load-induced displacement of the cuneiform 3-dimensionally. Compared with normal feet, hallux valgus feet had significantly greater mobility of the intercuneiform 1-2 joint, suggesting hypermobility of this joint.

LEVEL OF EVIDENCE

Level III, case-control study.

Downregulation of CD24 suppresses bone metastasis of lung cancer

Suppression of bone metastasis can improve patient quality of life. Current drugs for bone metastasis have been shown to prolong progression‐free survival but not overall survival; therefore, other potential therapeutic targets for bone metastasis should be investigated. Cell‐surface antigens, such as CD24, have been recently shown to be involved in the metastasis of various cancers. However, whether CD24 plays a role in bone metastasis of lung cancer remains unknown. To observe metastasis of lung cancer cells by imaging technology, we introduced a near‐infrared fluorescent protein, iRFP720, into a bone‐seeking subclone established from lung cancer cells, HARA‐B4 cells. The anchorage‐independent growth of these cells was then evaluated by colony formation assays. We also compared cancer cell tropism to bone tissue with HARA‐B4 cells in the presence or absence of CD24 by cell adhesion assays. To clarify the role of CD24 in bone metastasis, we intracardially injected CD24‐knockdown HARA‐B4 cells into mice and monitored metastasis through detection of iRFP720 using an in vivo imaging system. CD24‐knockdown HARA‐B4 cells in vitro showed reduced anchorage‐independent growth and cancer cell tropism to bone. Bone metastasis was diminished in mice inoculated with CD24‐knockdown HARA‐B4 cells, which was rescued by add‐back of CD24 in cells. Our findings indicate that iRFP720 is effective for in vivo imaging analysis of bone metastasis and that downregulation of CD24 suppresses bone metastasis of lung cancer cells. These findings collectively indicate that CD24 may be considered a promising new therapeutic candidate for the prevention of bone metastasis of lung cancer.

Eldecalcitol, an Active Vitamin D3 Derivative, Prevents Trabecular Bone Loss and Bone Fragility in Type I Diabetic Model Rats

Diabetes mellitus is known to adversely affect the bones and be associated with increased fracture risk. We examined whether eldecalcitol (ELD), an active vitamin D₃ derivative, could inhibit the diabetic bone loss in streptozotocin-induced type I diabetic rats. ELD (10, 20, or 40 ng/kg), alfacalcidol (ALF; 25, 50, or 100 ng/kg), or vehicle was administered 5 times per week for 12 weeks from 1 week after diabetes induction. Normal control rats received the vehicle. Bone turnover markers, bone mineral density (BMD), and biomechanical strength of the lumbar spine and femur were measured, and bone histomorphometry was performed. Content of advanced glycation end products (AGEs) in the femoral shaft was also determined. In diabetic rats, serum osteocalcin (OC) concentration was lower and urinary excretion of deoxypyridinoline (DPD) tended to be higher than in normal rats. Areal BMD and maximum load of the lumbar vertebrae and femoral shaft were lower in diabetic rats than in normal rats. All doses of ELD and the highest dose of ALF reduced urinary DPD excretion, but had no effect on serum OC. The 20 and 40 ng/kg doses of ELD prevented decreases in BMD and the highest dose of ELD prevented the reduction in maximum load of the lumbar vertebrae, while ALF did not change these parameters. ELD and ALF did not affect areal BMD or biomechanical strength of the femoral shaft. In diabetic rats, bone volume and trabecular thickness in the trabecular bone of the lumbar vertebrae decreased and trabecular separation increased compared to normal rats. ELD and ALF prevented diabetes-induced deterioration of trabecular microstructure. AGE content in the femoral cortical bone increased in the diabetic rats, and ELD and ALF did not change AGE content compared to the diabetic rats. These results indicated that ELD suppressed bone resorption and prevented trabecular bone loss and deterioration of trabecular microstructure, resulting in prevention of reduction in biomechanical strength in type I diabetic rats.

Mobility Changes in the First TMT Joint after Proximal First Metatarsal Osteotomy for Hallux Valgus Evaluated by Weightbearing CT and a 3D Analysis System

Category:

Bunion

Introduction/Purpose:

In a previous study, we found that feet with hallux valgus show significantly greater three-dimensional mobility than normal feet in all joints of the first ray. Displacement was particularly pronounced in the first TMT joints, indicating that this is the primary cause of first ray hypermobility. We developed a plate used specifically for proximal first metatarsal osteotomy to perform three-dimensional correction of hallux valgus and associated deformities. In this study, we evaluated changes in mobility of the first TMT joints after surgery in 3D using weightbearing CT.

Methods:

The subjects were 5 feet of 5 female patients with hallux valgus (mean age 56 years, mean hallux valgus angle 38°). We performed non-weightbearing and weightbearing (using a load equivalent to body weight) CT scans before surgery using an original loading device (Fig a). We reconstructed 3D models from captured images by segmentation and defined axial coordinate system (Fig b). Next, we measured the three-dimensional displacement of the first metatarsal bone relative to the medial cuneiform bone under weightbearing conditions. At 1 to 1.5 years after proximal metatarsal osteotomy for all patients, we performed a follow-up CT scans using the same method and compared preoperative and postoperative displacement. Student’s t- test was performed to statistically compare data and statistical significance was set at p < 0.05.

Results:

Postoperatively (when performing a follow up CT), the mean hallux valgus angle improved from 38° to 10° and the mean first-second metatarsal angle improved from 23° to 7°. The mean score on the Japanese Society for Surgery of the Foot hallux scale improved from 62 points to 97 points. Displacement of the first metatarsal bone relative to the medial cuneiform bone between non-weightbearing and weightbearing conditions decreased significantly in all directions, from 4.2° ± 1.8° to 1.6° ± 1.1° of dorsiflexion (p = 0.02), 4.9° ± 1.8° to 0.7° ± 0.9° of inversion (p = 0.001), and 4.4° ± 1.9° to 1.7° ± 0.8° of adduction (p = 0.01).

Conclusion:

Displacement of the first TMT joints under weightbearing conditions decreased after our surgery. This indicates that the surgery corrected hallux valgus and associated pes planus and produced favorable functional outcomes by improving the shape of the foot and hypermobility of the first ray through correction of the orientation and tension of surrounding tendons and ligaments and the plantar aponeurosis. In the future, we plan to further examine the pathology and treatment of hallux valgus with a focus on postoperative changes in soft tissue orientation.

Basic research and clinical application of beta-tricalcium phosphate (β-TCP)

The mechanism of bone substitute resorption involves two processes: solution-mediated and cell-mediated disintegration. In our previous animal studies, the main resorption process of beta-tricalcium phosphate (β-TCP) was considered to be cell-mediated disintegration by TRAP-positive cells. Thus, osteoclast-mediated resorption of β-TCP is important for enabling bone formation. We also report the results of treatment with β-TCP graft in patients since 1989. Two to three weeks after implantation, resorption of β-TCP occurred from the periphery, and then continued toward the center over time. Complete or nearly complete bone healing was achieved in most cases within a few years and was dependent upon the amount of implanted material, the patient's age, and the type of bone (cortical or cancellous). We have previously reported that an injectable complex of β-TCP granules and collagen supplemented with rhFGF-2 enabled cortical bone regeneration of rabbit tibiae. Based on the experimental results, we applied this technique to the patients with femoral and humeral fractures in elderly patients, and obtained bone union.

Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Graft Through a Rectangular Bone Tunnel Made With a Rectangular Retro-dilator: An Operative Technique

Good clinical results have been reported with anatomic anterior cruciate ligament (ACL) reconstructions in which rectangular bone-patellar tendon-bone (BTB) grafts were fixed into rectangular bone tunnels made at anatomic ACL insertion sites of the femur and tibia (anatomic rectangular tunnel BTB ACL reconstruction). Notwithstanding these good results, some problems have remained unsolved, including procedural complexity and risk of damage to the femoral posterior tunnel wall, damage to nerves and blood vessels, and damage to cartilage. The purpose of this report is to present our technique of ACL reconstruction with BTB graft through a rectangular bone tunnel made with a rectangular retro-dilator. Our procedure may become a safe option for anatomic rectangular tunnel BTB ACL reconstruction because of the following advantages: (1) bone tunnels can be created more safely and accurately than in methods using transtibial and far medial portals, (2) the bone tunnel preparation procedure is less invasive than the standard outside-in method, (3) technical failure-related risks are lower because the guidewire is inserted only once, and (4) the operation time is shorter because the method is a single-bundle procedure.

Effects of raloxifene and alendronate on non-enzymatic collagen cross-links and bone strength in ovariectomized rabbits in sequential treatments after daily human parathyroid hormone (1-34) administration

This study investigated the effects of raloxifene and alendronate to follow parathyroid hormone (PTH) on bone collagen and biomechanical properties in ovariectomized rabbits. Sequential treatments of raloxifene and alendronate after hPTH(1-34) treatment improved biomechanical properties with and without bone collagen improvement, respectively.

INTRODUCTION

The standard sequential treatment to follow human parathyroid hormone (hPTH) (1-34) therapy for osteoporosis has yet to be determined. The objective of this study was to compare the effects of raloxifene and alendronate treatments to follow daily hPTH(1-34) treatment on non-enzymatic collagen cross-links, bone mass, and bone strength in ovariectomized (OVX) rabbits.

METHODS

From 3 months after ovariectomy, seven month-old female New Zealand white rabbits were given either vehicle or hPTH(1-34) (8 μg/kg/day), once daily for 5 months. After hPTH(1-34) treatment, the hPTH(1-34)-treated animals were divided into two groups, and given raloxifene (10 mg/kg, daily) orally or alendronate (100 μg/kg, twice weekly) subcutaneously for 5 months. We evaluated bone mineral density (BMD), bone structural parameters, advanced glycation end product (AGE) content in collagen, and bone mechanical parameters including intrinsic parameters in the femur.

RESULTS

Raloxifene (hPTH/RLX) and alendronate (hPTH/ALN) to follow hPTH(1-34) increased cortical thickness, maximum load, and maximum stress and decreased endocortical surface in the diaphysis, in addition to increasing total BMD in the distal metaphysis. Decreased trabecular AGE, pentosidine, and homocysteine contents and increased toughness and breaking energy were noted with hPTH/RLX treatment only. With hPTH/ALN treatment, no effects on non-enzymatic collagen cross-link AGEs were noted although increases in stiffness and elastic modulus were observed.

CONCLUSION

These results suggest that sequential treatments with hPTH(1-34) and antiresorptive drugs (raloxifene and alendronate) have a beneficial effect on bone mass and biomechanical properties in OVX rabbits.

Evaluation of First-Ray Mobility in Patients with Hallux Valgus Using Weight-Bearing CT and a 3-D Analysis System: A Comparison with Normal Feet

BACKGROUND

Some physicians report that patients with hallux valgus have hypermobility at the tarsometatarsal (TMT) joint of the first ray and 3-dimensional (3-D) deformity. With use of non-weight-bearing and weight-bearing computed tomography (CT), we evaluated the 3-D mobility of each joint of the first ray in feet with hallux valgus compared with normal feet.

METHODS

Ten feet of 10 patients with hallux valgus and 10 feet of 10 healthy volunteers with no foot disorders were examined. All participants were women. Weight-bearing (a load equivalent to body weight) and non-weight-bearing CT scans were made with use of a device that we developed. Orthogonal coordinate axes were set and a 3-D model was reconstructed. Each joint of the first ray was aligned with the respective proximal bone, and 3-D displacement of the distal bone relative to the proximal bone under loading was quantified.

RESULTS

At the talonavicular joint, significantly greater dorsiflexion of the navicular relative to the talus was observed in the hallux valgus group compared with the control group. At the medial cuneonavicular joint, the hallux valgus group showed significantly greater eversion and abduction of the medial cuneiform relative to the navicular. At the first TMT joint, the hallux valgus group showed significantly greater dorsiflexion, inversion, and adduction of the first metatarsal relative to the medial cuneiform. At the first metatarsophalangeal joint, the hallux valgus group showed significantly greater eversion and abduction of the first proximal phalanx relative to the first metatarsal (all p < 0.05).

CONCLUSIONS

The results of this study suggest that loading of the foot causes significant 3-D displacement not only at the TMT joint but also at the other joints of the first ray. There is increased mobility in the first ray in patients who have hallux valgus.

DS02R1: Improvements to Atomic Bomb Survivors' Input Data and Implementation of Dosimetry System 2002 (DS02) and Resulting Changes in Estimated Doses

Individual dose estimates calculated by Dosimetry System 2002 (DS02) for the Life Span Study (LSS) of atomic bomb survivors are based on input data that specify location and shielding at the time of the bombing (ATB). A multi-year effort to improve information on survivors' locations ATB has recently been completed, along with comprehensive improvements in their terrain shielding input data and several improvements to computational algorithms used in combination with DS02 at RERF. Improvements began with a thorough review and prioritization of original questionnaire data on location and shielding that were taken from survivors or their proxies in the period 1949-1963. Related source documents varied in level of detail, from relatively simple lists to carefully-constructed technical drawings of structural and other shielding and surrounding neighborhoods. Systematic errors were reduced in this work by restoring the original precision of map coordinates that had been truncated due to limitations in early data processing equipment and by correcting distortions in the old (WWII-era) maps originally used to specify survivors' positions, among other improvements. Distortion errors were corrected by aligning the old maps and neighborhood drawings to orthophotographic mosaics of the cities that were newly constructed from pre-bombing aerial photographs. Random errors that were reduced included simple transcription errors and mistakes in identifying survivors' locations on the old maps. Terrain shielding input data that had been originally estimated for limited groups of survivors using older methods and data sources were completely re-estimated for all survivors using new digital terrain elevation data. Improvements to algorithms included a fix to an error in the DS02 code for coupling house and terrain shielding, a correction for elevation at the survivor's location in calculating angles to the horizon used for terrain shielding input, an improved method for truncating high dose estimates to 4 Gy to reduce the effect of dose error, and improved methods for calculating averaged shielding transmission factors that are used to calculate doses for survivors without detailed shielding input data. Input data changes are summarized and described here in some detail, along with the resulting changes in dose estimates and a simple description of changes in risk estimates for solid cancer mortality. This and future RERF publications will refer to the new dose estimates described herein as "DS02R1 doses."

Accuracy of Computed Tomography-Based Navigation-Assisted Total Knee Arthroplasty: Outlier Analysis

BACKGROUND

Achieving neutral limb alignment during total knee arthroplasty (TKA) has been identified as a potential factor in long-term prosthesis survival. This study aimed to analyze the accuracy of component orientation and postoperative alignment of the leg after computed tomography (CT)-based navigation-assisted TKA, compare these parameters with those of a conventional technique, and analyze differences in the data of outliers.

METHODS

We retrospectively compared the alignment of 130 TKAs performed with a CT-based navigation system with that of 67 arthroplasties done with a conventional system. The knee joints were evaluated using radiographs.

RESULTS

Mean hip-knee-ankle (HKA) angle, frontal femoral component angle, and frontal tibial component angle were 180.7°, 88.8°, and 90.6°, respectively, for the navigation-assisted arthroplasties and 181.1°, 88.7°, and 90.2°, respectively, for the conventional arthroplasties. All preoperative leg axes of 10 outliers in the navigation group were >193°, whereas the data of 17 outliers in the conventional group were scattered.

CONCLUSION

This study demonstrates significant improvements in component positioning with the CT-based navigation system. Furthermore, when analyzing cases with preoperative HKA angles ≤192°, no outliers were found in the navigation group, indicating high alignment accuracy. However, in cases with preoperative HKA angles ≥193°, outliers were found in both groups, and no significant difference between the groups was observed (P = .08). Detailed analysis of the outlier cases in the navigation group revealed that the femoral component was placed in the varus position. These findings indicate that the varus knee is an important factor influencing accurate positioning of the femoral component and the postoperative leg axis.

[Calcium and bone metabolism across women's life stages. Bone quality and treatment of osteoporosis by SERM.]

Estrogen deficiency induces bone resorption and bone collagen crosslink abnormalities such as reductions in enzymatic cross-links and accumulation of Advanced glycation end products(AGEs). In this review, we described that the mechanism of poor bone quality in estrogen deficiency and how selective estrogen receptor modulators such as raloxifene and bazedoxifene improve bone structural and material properties.

[New methods for the evaluation of bone quality. How does decay bone quality?]

The degree of mineralization and microstructure are regulated by bone turnover. Bone collagen enzymatic cross-links and advanced glycation end products(AGEs)are affected by various factors such as the levels of oxidative stress and glycation as well as tissue lifespan. Deterioration of bone material properties markedly advances due to increases in oxidative stress, glycation stress, reactive oxygen species, carbonyl stress associated with aging and reduced sex hormone levels, and glucocorticoid use. In this review, we described determinants of bone quality and strength.

First Tarsometatarsal Joint Mobility in Hallux Valgus

Category:

Bunion

Introduction/Purpose:

Hypermobility of the tarsometatarsal (TMT) joint has been much debated, but is considered to be an important factor in hallux valgus. However to date, studies investigating such hypermobility have been limited to two-dimensional (2D) evaluations using plain X-ray images or to mobility in the sagittal plane. Three-dimensional evaluation should offer more accurate pathological information given that deformity of the hallux valgus occurs in three dimensions. This study evaluated mobility of the first TMT joint in 3D using weight-bearing computed tomography (CT) and an original weight-bearing device (Figure) and then examined its correlation with the hallux valgus angle and intermetatarsal angle in hallux valgus patients.

Methods:

Ten feet of 10 hallux valgus patients and 10 feet of 10 healthy volunteers without foot disease (control group)were examined. Mean age of the two groups was 58.2 years and 55.9 years, respectively. The hallux valgus angle was 43.2° and 14.1° and the intermetatarsal angle was 22.1° and 9.3°, respectively. CT was performed under two conditions: non-load with the ankle in a neutral position and full-body weight-bearing load. Three-dimensional models of each bone were reconstructed by segmentation, the positions of each bone were adjusted, and the extent of first metatarsal displacement relative to the medial cuneiform was measured in 3D. We defined orthogonal coordinate axes(X-axis, Y-axis, Z-axis), the motion around the X-axis, Y- axis, and Z-axis was defined as plantar flexion/dorsiflexion, inversion/eversion, and adduction/abduction respectively. Data were compared between the hallux valgus and healthy control groups using Student’s t-test. In hallux valgus patients, mobility of the first TMT joint was compared with the hallux valgus angle and intermetatarsal angle using Pearson’s correlation coefficient.

Results:

Dorsiflexion (X-axis), inversion (Y-axis), and adduction (Z-axis)were significantly different between the hallux valgus patients and control subjects (p < 0.05). In the hallux valgus patients, there was no large correlation between mobility of the first TMT joint and either hallux valgus angle (X-axis: г=0.21 p=0.55, Y-axis: г=0.11 p=0.75, Z-axis: г=0.10 p=0.78) or intermetatarsal angle (X-axis: г=0.40 p=0.25, Y-axis: г=0.10 p=0.78, Z-axis: г=0.53 p=0.11).

Conclusion:

We were able to analyze 3D changes in the load on the foot in detail. Hallux valgus patients showed hypermobility of the first TMT joint not only in dorsiflexion (sagittal motion), but also in inversion and adduction. However, larger hallux valgus and intermetatarsal angles did not affect mobility of the first TMT joint. Therefore, the magnitude of hallux valgus deformity may correlate with other joint mobility or complex mobility of first ray. Our technique and findings help to clarify the nature of the pathology of hallux valgus and should assist in the selection and development of treatment methods.

Efficacy of autologous leukocyte-reduced platelet-rich plasma therapy for patellar tendinopathy in a rat treadmill model

BACKGROUND

An autologous platelet-rich plasma (PRP) therapy has currently been applied for the tendinopathy; however, its efficacy and an optimal platelets concentration in PRP were uncertain. We analyzed them in an animal model prepared using a repetitive running exercise.

METHODS

We made the tendinopathy rat model of patellar tendon using a rodent treadmill machine. Rats with tendinopathy were injected with leukocyte-reduced PRP at the platelets concentration of 1.0×10⁶/μL (P10 group), PRP at the platelets concentration of 5.0×10⁵/μL (P5 group) or normal saline (control group) into the space between the patellar tendon and the fat pad bilaterally or were multiply dry-needled at the tibial insertion site (MN group) at once. To assess the pain-reliving effect, the spontaneous locomotor activities at night (12 h) were measured every day. Histological sections of the patellar tendon stained with hematoxylineosin or prepared by TdT-mediated dUTP nick end labeling were microscopically analyzed.

RESULTS

The numbers of spontaneous locomotor activities in the P10 group were significantly larger than those in the P5, MN or control groups and they recovered up to a healthy level. On histologic examinations, the numbers of microtears, laminations, or apoptotic cells in the patellar tendons in the P10 or P5 groups were significantly lower than those in the MN or control groups, although no significant differences were observed between the P10 and P5 groups.

CONCLUSIONS

The injections of an autologous leukocyte-reduced PRP were effective for pain relief and for partial restoration of the patellar tendon in the tendinopathy rat model. The injections of a PRP at the platelets concentration of 1.0×10⁶/μL completely relieved the pain and were more effective than those at the platelets concentration of 5.0×10⁵/μL whereas there was no difference for the effect of histological restoration or apoptosis inhibition between them.

Quantitative and Qualitative Change of Collagen of Achilles Tendons in Rats With Systemic Administration of Glucocorticoids

BACKGROUND

It is unclear whether glucocorticoid (GC) therapy is directly related to Achilles tendon rupture (ATR), because many of the reported patients were receiving long-term GC therapy for underlying diseases. This study aimed to elucidate the mechanism by which systemic GC administration causes weakening of the Achilles tendon by biochemically, mechanically, and morphologically evaluating quantitative and qualitative changes in collagen.

METHODS

Male 8-week-old mice were subcutaneously treated with either prednisolone (10 mg/mL/kg; GC group) or saline (1 mL/kg; control group) for 8 weeks and then subjected to the following experiments: (1) a tensile strength test; (2) quantification of the gene expressions of type 1 collagen and lysyl oxidase; (3) quantification of collagen content, enzymatic crosslinks (immature + mature), and senescent crosslinks; and (4) measurement of collagen fiber diameter by electron microscopy.

RESULTS

The maximum tensile load and gene expressions of type 1 collagen and lysyl oxidase were decreased in the GC group. Collagen content was significantly decreased in the GC group compared with the control group. The content of enzymatic crosslinks was significantly lower in the GC group than in the control group. The corresponding amount of senescent crosslinks was not significantly different. The mean collagen fiber diameter was significantly smaller in the GC group than in the control group. Histogram analysis showed a decreased number of thick fibers and an increased number of thin fibers in the GC group.

CONCLUSION

These observations suggest that systemic GC administration causes decreased strength of the Achilles tendon by decreasing its collagen content, hindering the formation of enzymatic crosslinks and thereby keeping collagen fibers in an immature state with smaller diameters.

CLINICAL RELEVANCE

This animal study showed that systemic GC administration directly prevents maturation of tendon collagen fibers and decreases tendon strength, regardless of the presence or absence of underlying disease.

[Determinants of bone quality and strength independent of bone remodeling]

Bone mineral density(BMD)and bone microstructure are regulated mainly by bone remodeling. In contrast, bone collagen enzymatic immature and mature cross-links and advanced glycation end products such as pentosidine and carboxyl methyl lysine are affected by various factors. Aging bone tissue is repaired in the process of bone remodeling. However, deterioration of bone material properties markedly advances due to increases in oxidative stress, glycation stress, reactive oxygen species, carbonyl stress associated with aging and reduced sex hormone levels, and glucocorticoid use. To improve bone material properties in osteoporosis, we should use different drug (Saito M, Calcif Tissue Int, REVIEW, 97;242-261, 2015). In this review, we summarized determinants of bone quality and strength independent of bone remodeling.

[Bone quality in COPD.]

Chronic obstructive pulmonary disease(COPD)is a chronic inflammatory disease associated with an increase of fracture risk. Bone strength is determined by bone mass and quality.Bone quality is thought to encompass the structural and material properties of bone. Bone collagen crosslinking plays important roles in bone strength. The quantitative and qualitative deterioration of lysyl oxidase control and non enzymatic cross-links(advanced glycation end products, AGEs, pentosidine)of collagen in patients with osteoporotic femoral neck fracture and diabetes, and COPD might be affected by increased oxidative stress and glycation.

Applying low-intensity pulsed ultrasounds (LIPUS) to a zoledronate-associated atypical femoral shaft fracture without cessation of zoledronate therapy for 3 years follow up: a case report

Reports are increasing regarding atypical femoral fractures (AFFs) caused by minor trauma in patients using bisphosphonates (BPs) for long periods. Patients with malignant skeletal metastases potentially are at greater risk for these AFFs, especially considering the high dose and the duration of treatment with BPs. We evaluated a case of atypical femoral shaft fracture treated with an intramedullary nail in a patient treated for five years with zoledronate who had breast cancer with metastases to bone. Although bone union was achieved without cessation of zoledronate therapy by applying low-intensity pulsed ultrasounds (LIPUS), the remodeling phase of the fracture healing process was delayed. For BPs-associated AFFs, LIPUS is an alternative to parathyroid hormone (PTH) analogs such as teriparatide that are contraindicated in patients with malignant skeletal metastases. LIPUS is an effective treatment for fracture healing and may avoid the necessity to discontinue BP therapy.

Effects of 18-month treatment with bazedoxifene on enzymatic immature and mature cross-links and non-enzymatic advanced glycation end products, mineralization, and trabecular microarchitecture of vertebra in ovariectomized monkeys

Bazedoxifene (BZA) is used for the treatment of post-menopausal osteoporosis. To elucidate changes in collagen, mineralization, and structural properties and their relationship to bone strength after treatment with BZA in ovariectomized (OVX) monkeys, the levels of collagen and enzymatic immature, mature, and non-enzymatic cross-links were simultaneously examined, as well as trabecular architecture and mineralization of vertebrae. Adult female cynomolgus monkeys were divided into 4 groups (n=18 each) as follows: Sham group, OVX group, and OVX monkeys given either 0.2 or 0.5mg/kg BZA for 18 months. Collagen concentration, enzymatic and non-enzymatic pentosidine cross-links, whole fluorescent advanced glycation end products (AGEs), trabecular architecture, mineralization, and cancellous bone strength of vertebrae were analyzed. The levels of enzymatic immature and mature cross-links, bone volume (BV/TV), and trabecular thickness (Tb.Th) in BZA-treated groups were significantly higher than those in the OVX control group. In contrast, the trabecular bone pattern factor (TBPf), the structure model index (SMI), the enzymatic cross-link ratio, and the levels of pentosidine and whole AGEs in BZA-treated groups were significantly lower than those in the OVX control group. Stepwise logistic regression analysis revealed that BV/TV, Tb.Th, TbPf, and pentosidine or whole AGEs independently affected ultimate load (model R(2)=0.748, p<0.001) and breaking energy (model R(2)=0.702). Stiffness was affected by Tb.Th, enzymatic immature cross-link levels and their ratio (model R(2)=0.400). Treatment with BZA prevented OVX-induced deterioration in the total levels of immature enzymatic cross-links and AGEs accumulation and structural properties such as BV/TV, Tb.Th, and TbPf, which contribute significantly to vertebral cancellous bone strength.

Arthroscopic Release of Flexor Hallucis Longus Tendon Sheath in Female Ballet Dancers: Dynamic Pathology, Surgical Technique, and Return to Dancing Performance

Stenosing tenosynovitis of the flexor hallucis longus (FHL) tendon is known as a major overuse lesion in female dancers. We describe arthroscopic surgical techniques in relation to the dynamic pathology of the disease. Crepitus and pain on moving the great toe with the ankle in plantar flexion on preoperative examination confirm the diagnosis of FHL stenosing tenosynovitis even if the os trigonum is not evident. The ankle is approached through standard posterolateral and posteromedial portals. A 4.0-mm-diameter 30° arthroscope is used. Soft tissues around the talus are cleared with a motorized shaver and a radiofrequency device. The posterior aspects of the talus, os trigonum, and FHL tendon surrounded by the tendon sheath are visualized. The dynamic pathology of the FHL tendon is well observed on passive motion of the great toe. The prominent bone fragment of the talus is removed and the tendon sheath is cut with a retrograde knife and a motorized shaver from the superior border down to the entrance of the fibro-osseous tunnel. Arthroscopic release of the FHL tendon sheath is a useful and easy method to directly approach the dynamic pathology of FHL tenosynovitis in female ballet dancers.

[Bone Cell Biology Assessed by Microscopic Approach. The effects of active vitamin D3 such as alfacalcidol and eldecalcitol on bone quality]

Active vitamin D3 is used for the treatment for osteoporosis in Japan. Recently, data have accumulated that collagen cross-link formation in bone affect bone strength. In fact, impaired enzymatic cross-linking, over-hydroxylation of crosslinks, and an increase in non-enzymatic crosslinking advanced glycation end products (AGEs) such as pentosidine, in bone collagen have been proposed as a major cause of bone fragility in osteoporosis. We reported that alfacalcidol and eldecalcitol improves bone material properties such as collagen cross-link formation, microarchitecture, and microcrack resulting in the increase of bone strength (Saito M, Bone 2010;46:1170-1179, Calcif Tissue Int 2011;88:314-324, Bone, 2015;73:8-15). In this review, we described how active vitamin D3 improve bone collagen cross-link formation and mineral qualities.

[Bone quality]

Bone quality is thought to encompass the structural and material properties of bone. Bone collagen crosslinking plays important roles in bone strength. The quantitative and qualitative deterioration of lysyl oxidase control and non enzymatic cross-links (advanced glycation end products, AGEs, pentosidine) of collagen in patients with osteoporotic femoral neck fracture and diabetes, and chronic kidney disease might be affected by increased oxidative stress and glycation. A higher urinary or plasma pentosidine and homocysteine levels were an independent risk factor for osteoporotic fracture. If confirmed in large, prospective trials, measurements of serum homocysteine and serum or urine levels of pentosidine might be characterized as markers reflecting bone collagen deterioration.

Effects of Collagen Crosslinking on Bone Material Properties in Health and Disease

Data have accumulated to show that various types of collagen crosslinking are implicated in the health of individuals, as well as in a number of disease states, such as osteoporosis, diabetes mellitus, chronic kidney disease, inflammatory bowel disease, or in conditions of mild hyperhomocysteinemia, or when glucocorticoid use is indicated. Collagen crosslinking is a posttranslational modification of collagen molecules and plays important roles in tissue differentiation and in the mechanical properties of collagenous tissue. The crosslinking of collagen in the body can form via two mechanisms: one is enzymatic crosslinking and the other is nonenzymatic crosslinking. Lysyl hydroxylases and lysyl oxidases regulate tissue-specific crosslinking patterns and quantities. Enzymatic crosslinks initially form via immature divalent crosslinking, and a portion of them convert into mature trivalent forms such as pyridinoline and pyrrole crosslinks. Nonenzymatic crosslinks form as a result of reactions which create advanced glycation end products (AGEs), such as pentosidine and glucosepane. These types of crosslinks differ in terms of their mechanisms of formation and function. Impaired enzymatic crosslinking and/or an increase of AGEs have been proposed as a major cause of bone fragility associated with aging and numerous disease states. This review focuses on the effects of collagen crosslinking on bone material properties in health and disease.

Ability of a Novel Foot and Ankle Loading Device to Reproduce Loading Conditions in the Standing Position During Computed Tomography

To describe a loading device, we created for use with current computed tomography (CT) scanners and to evaluate its ability to reproduce loading conditions. Ten feet of five healthy volunteers (three men and two women) with no history of foot or ankle disorders and no foot pain were studied. Subjects lay on the device in the supine position with the legs extended and ankles in a neutral position. An axial load equivalent to their body weight was applied to the soles. A foot scan measured plantar contact area, plantar pressure, and the center of pressure under standing and weight-bearing conditions. Differences between measurements were assessed using the paired t test with a two-sided significance of 5%. No subjects complained of pain or discomfort during loading. Weight-bearing measurements varied from standing measurements as follows: plantar contact area, −4.15 cm2; contact % (forefoot/midfoot/hindfoot), −0.61%/−0.17%/0.79%; plantar pressure, −1.47 N/cm2/−0.49 N/cm2/3.7 N/cm2 (6.40 N/cm2 overall); and center of pressure location (anterior–posterior/medial–lateral), 0.88%/0.36%. With the numbers available, no significant difference could be detected for any tested items. We were able to produce load distributions and intensities resembling standing conditions. Thus, the standing condition can be well produced on CT images if our device is used. Furthermore, images can be compared with those of healthy individuals to yield useful information for elucidating the pathophysiology and pathology of foot disorders.