Evaluation of a treatment protocol based on conservative therapy for fragility fractures of the pelvis.

PURPOSE: In an aging society, fragility fractures of the pelvis (FFP) have increased significantly. However, there is no clear consensus on the timing and criteria for transitioning from conservative treatment to surgery for these fractures. Thus, we aimed to investigate the effects of our treatment protocol for FFP based on conservative treatment. METHODS: We conducted a retrospective study including 74 patients with FFP at our institution between 2015 and 2021. All patients were treated conservatively for the first two weeks. During this period, only wheelchair transfer was allowed. If the patient could not walk after this period, surgery was performed. Fracture type (Rommens classification), walking ability, presence of complications after admission, presence of fracture union, and surgical treatment was investigated. Patients were divided into two groups: a stable group (type I/II) and an unstable group (type III/IV). RESULTS: Fracture union was achieved in all patients. Thirteen patients developed complications after being admitted to our hospital; seven showed decreased walking ability, and six required surgeries. The stable and unstable groups comprised 47 and 27 patients, respectively. There were no statistically significant differences between the groups regarding the percentage of patients who developed complications or experienced decrease in walking ability. The percentage of patients who required surgery was significantly higher in the unstable group (p < 0.05). CONCLUSION: Our FFP management protocol was effective regardless of fracture type. It is important to provide a period for careful assessment of instability, and to try to prevent fracture progression.

Pseudarthrosis of Pelvic Fracture With Charcot Arthropathy Successfully Treated With Constrained Total Hip Arthroplasty.

Charcot arthropathy is a rapidly progressive and destructive form of arthropathy caused by various neurological diseases. Total hip arthroplasty (THA) is usually contraindicated in patients with Charcot arthropathy; however, recent studies have reported good results following THA in this patient population. Herein, we report a case of Charcot arthropathy secondary to syphilis in a patient who was successfully treated with constrained THA, a new type of THA. A 56-year-old man was injured in a car accident, and a displaced acetabular fracture was revealed three weeks later. He was treated conservatively but soon developed greater displacement of the fracture and femoral head destruction. The patient was referred to our hospital for further treatment. The patient had pelvic pseudarthrosis secondary to Charcot arthropathy at the time of the first visit to our hospital. First, THA was performed with the acetabular reconstruction of the deficient bone. However, the acetabular implant was displaced one week postoperatively. THA revision was performed using a constrained cup. Postoperatively, the patient exhibited good hip stability without dislocation. However, displacement of the acetabular cup occurred one year after the second surgery. We performed a re-revision of THA using a new type of constrained cup that offers a high level of constraint to maintain range of motion (ROM) and prevent dislocations. The patient was able to walk with a T-cane one year postoperatively. Herein, we report a difficult case of revision THA in a patient with Charcot arthropathy concomitant with syphilis. THA is usually contraindicated in patients with Charcot arthropathy; however, we propose that THA using constrained cups that offer a wider ROM may be a useful therapeutic strategy for the treatment of Charcot arthropathy.

Multicenter study on atypical femoral fractures in patients with bone metastases taking bone- modifying agents.

Bone-modifying agents (BMAs), with bone-resorptive inhibitory effects, such as zoledronic acid and denosumab, are widely used at higher doses for bone-related events caused by bone metastasis of malignant tumors. These drugs have been suggested to be associated with atypical femoral fractures (AFFs), and the relationship between BMAs and AFFs has attracted attention. To investigate the clinical features including bone union time of AFFs in patients administered BMA for bone metastasis, we conducted a retrospective multicenter study. Thirty AFFs from 19 patients were enrolled in this study. Thirteen patients had bilateral AFFs, and nineteen AFFs had prodromal symptoms. Eighteen AFFs underwent surgery after complete fracture, three failed to achieve bone union and required nonunion surgery, and 11 AFFs that achieved bone union had an average period until bone union of 16.2 months, which was much longer than that previously reported for ordinary AFFs. Seven patients discontinued the BMAs, but not due to AFFs. Stopping BMAs in patients with bone metastasis would make it difficult to secure their performance of activities of daily living, and AFF with BMA administration might require a longer time for union. Therefore, it would be important to prevent incomplete AFF from becoming complete AFF via prophylactic internal fixation.

Nonunion of Hoffa Fracture Successfully Treated by Total Knee Arthroplasty: A Case Report.

A Hoffa fracture is a rare type of femoral fracture that is difficult to treat. Nonoperative treatments usually result in failure; hence, in most cases, surgical treatments are essential. Nonunion following Hoffa fracture appears to be relatively uncommon, and there are limited reports in the literature about this type of nonunion. These reports suggest that open reduction and rigid internal fixation is the standard treatment for this type of nonunion. This study reports the case of a 61-year-old male patient who suffered from left lateral Hoffa fracture after falling from a truck bed. At the former hospital, open reduction and internal fixation were performed with plates and screws at 8 days post-injury. Postoperatively, displacement of the lateral proximal fragment was observed, and the patient reported left knee pain. Therefore, a revision open reduction and internal fixation was performed 4 months post-surgery. However, 6 months after the revision surgery, the patient reported instability and pain in the left knee, and subsequent radiography revealed nonunion of the fracture in the lateral condyle. The patient was referred to our hospital for further treatment. Treatment by re-revision open reduction and internal fixation was deemed challenging, and so rotating hinge knee (RHK) arthroplasty was performed as a salvage treatment. At 3 years post-surgery, no significant problems were observed, and the patient could walk without any assistance. The range of motion of the left knee was 0 to 100° without extension lag, and there was no lateral instability. Standard treatment for Hoffa fracture nonunion is commonly anatomical reduction and rigid internal fixation. However, total knee arthroplasty may be a better option for the treatment of Hoffa fracture nonunion in older patients.

Risk factors of residual pivot-shift after anatomic double-bundle anterior cruciate ligament reconstruction.

INTRODUCTION: Although anterior cruciate ligament reconstruction (ACLR) is considered a successful procedure, residual pivot-shift after surgery remains to be solved. The purpose of this study was to comprehensively evaluate the risk factors of residual pivot-shift after anatomic double-bundle (DB) ACLR. MATERIALS AND METHODS: A total of 164 patients who underwent primary anatomic DB-ACLR between January 2014 and December 2019 and screw removal after the index ACLR in our hospital were included in this retrospective case-control study. The manual pivot-shift test was performed under general anesthesia during screw removal surgery, and patients with grade 1 or higher pivot-shift were classified as the positive pivot-shift group, and those with grade 0 were defined as the negative pivot-shift group. Univariate and logistic regression analyses were performed to identify the factors associated with postoperative residual pivot-shift. Assessment included sex, age, time to surgery, preoperative Tegner activity scale, preoperative pivot-shift grade, preoperative anterior tibial translation by the KT-2000 arthrometer measurement, meniscus injury and its surgical procedure, knee hyperextension, cartilage damage, Segond fracture, medial and lateral posterior tibial slope, lateral-medial slope asymmetry, participation in pivoting sport/activity at the time of injury, and return to sports at postoperative one year line. RESULTS: Postoperative positive pivot-shift was observed in 14 (8.5%) of 164 patients. The KT-2000 measurement at 1-year postoperatively was significantly higher in the residual pivot-shift-positive group than in the negative group (P < 0.05). Logistic regression analysis revealed that age of patients < 20 years [P < 0.05, odds ratio (OR): 6.1)], preoperative pivot-shift grade (P < 0.05, OR: 4.4), and hyperextended knee (P < 0.05, OR: 11.8) were risk factors of postoperative pivot-shift. There were no statistically significant differences between other variables. CONCLUSIONS: Patients < 20 years of age, with high-grade preoperative pivot-shift, or hyperextended knees had a higher risk of residual postoperative pivot-shift.

The Effect of Prosthesis Type on Intraoperative Soft-Tissue Balance and Clinical Outcomes in Modified Kinematically Aligned Cruciate-Retaining Total Knee Arthroplasty.

INTRODUCTION: Kinematically aligned total knee arthroplasty (KA-TKA) has gained interest for achieving more favorable clinical outcomes than mechanically aligned TKA. One of the advantages of KA-TKA is reported to be an easy acquisition of intraoperative soft-tissue balance without excessive medial release for varus osteoarthritis. However, we hypothesized that the prosthesis type affects intraoperative soft-tissue balance even in the KA-TKA. The present study aimed to compare intraoperative soft-tissue balance and clinical outcomes of KA-TKAs using single-radius (SR) or multiradius (MR) prostheses. MATERIALS: AND METHODS: Consecutive 70 cruciate-retaining modified KA-TKAs (31 SR and 39 MR) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative soft-tissue balance including joint component gap and varus/valgus balance was measured with femoral component placement and patellofemoral joint reduction throughout the range of motion using offset-type tensor and compared between the two groups. Two years postoperatively, the range of motion and 2011 Knee Society Scores were compared between the two groups. RESULTS AND CONCLUSION: Joint component gaps showed no significant differences between the two groups from 0 to 30 degrees of flexion. However, during 60 to 120 degrees of flexion, joint component gaps of SR group showed significantly larger values than those of MR group (p < 0.05). There were no significant differences in varus/valgus balance throughout the range of motion between the two groups. The postoperative clinical outcomes showed no significant differences between the two groups. INTERPRETATION: Despite no difference in clinical outcomes, joint component gap showed different patterns due to the prosthesis type in modified KA-TKAs.

Outcomes of palliative surgery for bone metastasis of metastatic renal cell carcinoma in the era of targeted therapy.

INTRODUCTION: The introduction of tyrosine kinase inhibitors has revolutionized treatment strategies for metastatic renal cell carcinoma (RCC) and has improved survival rates. The number of patients with bone metastases from RCC requiring surgery will increase as survival rates improve. However, there is insufficient evidence to standardize the treatment of bone metastases after the introduction of targeted therapy for metastatic RCC. We aimed to determine the outcomes of palliative surgical treatment of bone metastases in the extremities of patients with metastatic RCC. MATERIALS AND METHODS: We retrospectively reviewed 26 lesions from 17 patients who underwent surgery for extremity and acetabular bone metastases and were treated with targeted therapies for advanced RCC between 2008 and 2020. The median follow-up duration was 19 months (range, 4-76). We assessed the patients' activities of daily living, quality of life, and pain and analyzed their postoperative values relative to preoperative values. Postoperative overall survival (OS), local progression-free survival (LPFS), and the factors affecting them were evaluated using the Kaplan-Meier method and log-rank test. RESULTS: The 5-year OS and LPFS rates were 39.5% and 65.6%, respectively. The factors affecting OS were sex, Katagiri score, visceral metastases, and preoperative targeted therapy, while the factors affecting LPFS were pathologic fractures and surgical technique. CONCLUSION: In this study, the postoperative outcomes of palliative surgery for bone metastases from metastatic RCC were good. We suggest that systemic treatment should be prioritized over local control for advanced bone metastasis in RCC and surgery before pathological fracture should be performed for local control.

Development and Analysis of Mouse Medial Meniscus Posterior Root Tear Model.

Medial meniscus posterior root tears (MMPRT) are often associated with osteoarthritis (OA) progression and subchondral bone insufficiency fractures. This study aimed to develop the first MMPRT mouse model. The MMPRT model was created by sectioning the medial meniscus posterior root of 12-week-old CL57BL/6J male mice under stereomicroscopic observation. The sham operation and the destabilization of the medial meniscus (DMM) model groups were also created. OA progression and subchondral bone changes were evaluated histologically using the Osteoarthritis Research Society International (OARSI) subchondral bone scoring system at 2, 4, 8, and 12 weeks after surgery. Microcomputed tomography (µCT) was performed to evaluate the presence of insufficient fractures. OA progression and medial meniscus extrusion were observed in the MMPRT and DMM models 12 weeks after surgery. OA progressed in both models during the time course, without a significant difference in the OARSI score between the two groups. The subchondral bone score was significantly higher at 12 weeks than at 2 and 4 weeks in the MMPRT group, while no significant difference was found between the two groups. In the µCT analysis, destruction of the medial tibial plateau was observed in 4/40 knees, while none were observed in the DMM group. Of the four knees, destruction of the medial femoral condyle was also observed in three knees. Characteristic pathological changes were observed in the mouse MMPRT model. The mouse MMPRT model may be useful for investigating pathological changes after MMPRT.

Human Non-Hypertrophic Nonunion Tissue Contains Osteoblast Lineage Cells and E-BMP-2 Activates Osteogenic and Chondrogenic Differentiation.

In this study, we examined the proliferation capability and osteogenic and chondrogenic differentiation potential of non-hypertrophic nonunion cells (NHNCs), and the effect of Escherichia coli-derived BMP-2 (E-BMP-2) on them. We enrolled five patients with non-hypertrophic nonunion. NHNCs isolated from nonunion tissue sampled during surgery were cultured, passaged, counted every 14 days, and analyzed. NHNCs were homogenous fibroblastic adherent cells and long-lived through at least 10 passages, with a slight decline. The cells were consistently positive for mesenchymal stem cell-related markers CD73 and CD105, and negative for the hematopoietic markers CD14 and CD45. NHNCs could differentiate into osteoblast lineage cells; however, they did not have strong calcification or sufficient chondrogenic differentiation capability. E-BMP-2 did not affect the proliferative capability of the cells but improved their osteogenic differentiation capability by increasing alkaline phosphatase activity and upregulating the gene expression of osterix, bone sialoprotein, and osteocalcin. E-BMP-2 enhanced their chondrogenic differentiation capability by upregulating the gene expression of aggrecan and collagen type II. We showed, for the first time, that NHNCs have the capacity to differentiate into osteoblast-lineage cells, although the chondrogenic differentiation potential was poor. Local application of E-BMP-2 with preservation of nonunion tissue is a potential treatment option for non-hypertrophic nonunion.

Continuous Local Antibiotic Perfusion (CLAP) for Post-operative Infection of Open Tibial Fractures: A Case Report.

Introduction: We encountered a case of post-operative infection of an open tibial fracture that was controlled by continuous local antibiotic perfusion (CLAP), a novel method of fracture-related infection (FRI) that we have developed. CLAP is a procedure in which a bone marrow needle and a double lumen tube are placed in the infected area, and an appropriate concentration of antimicrobial agent is continuously administered and perfused. Case Report: The patient was a 78-year-old woman. She was hit by a motor vehicle and fell to the farmyard floor. She suffered multiple traumas, including a lower leg open fracture, multiple rib fractures, clavicle fracture, pelvic fracture, mandibular fracture, and liver injury. Her tibial fracture was a Gustilo-Anderson type IIIA open fracture. After debridement and external fixation of the tibial open fracture on the same day, open reduction and internal fixation with an intramedullary nail was performed 3 days after the injury. Twelve days after the injury, local heat and redness were observed at the nail insertion wound and the posteromedial calf, and a purulent clot was discharged from the open wound. We performed curettage of the lesion and retained the implant. CLAP was then constructed to perfuse local antibiotics along the nail and large hematoma area. Locally, the inflammation improved and the inflammatory response became negative 3 weeks after the initiation of CLAP. Six months after surgery, bony union was achieved. At present, 3.5 years after the internal operation, there is no sign of infection, and the patient has returned to her pre-injury life with no abnormalities in motor function. Conclusion: CLAP may be a novel treatment method that can be expected to achieve bone healing while preserving the implant in FRI cases after open tibial fracture.

Clinical Outcomes and Prognostic Factors in Soft Tissue Sarcoma Patients After Unplanned Excision.

Purpose: Soft tissue sarcomas (STSs) constitute a group of rare, heterogeneous tumors representing approximately 1% of all cancers. Owing to the rarity and pathological diversity of the disease, unplanned excision (UE) has often been performed for STS, resulting in an unfavorable prognosis. This study aimed to clarify clinical outcomes and prognostic factors in STS patients who underwent UE. Patients and Methods: In a retrospective review of the medical records of patients with STS who underwent surgery at our institution between 1999 and 2015, patients were enrolled to either a UE group or a planned excision (PE) group. An analysis was then conducted to identify factors associated with prognosis after UE. Results: Of 134 patients undergoing surgery for STS, 110 were enrolled to the PE group and 24 to the UE group. The median size of the primary tumor was significantly smaller, and more lesions were located in the superficial layer in the UE group than in the PE group. In addition, plastic reconstruction after additional radical resection was required significantly more often in the UE group than in the PE group. No significant difference in overall survival, local recurrence-free survival, or disease-free survival (DFS) between the UE and PE groups was observed; however, metastasis-free survival was significantly better in the UE group. In the UE group, poorer DFS was associated with older age (≥61 years) and a larger primary tumor (≥2.9 cm). Conclusion: A prognosis similar to that in patients undergoing PE could be achieved by appropriate additional surgeries in patients initially undergoing UE. However, UE for STS should be avoided, especially in older patients and those with a larger primary tumor.

Clinical Outcome of Patients with Pelvic and Retroperitoneal Bone and Soft Tissue Sarcoma: A Retrospective Multicenter Study in Japan.

This study aimed to retrospectively analyze the clinical outcomes of patients with pelvic and retroperitoneal bone and soft tissue sarcoma (BSTS). Overall, 187 patients with BSTS in the pelvis and retroperitoneal region treated at 19 specialized sarcoma centers in Japan were included. The prognostic factors related to overall survival (OS), local control (LC), and progression-free survival (PFS) were evaluated. The 3-year OS and LC rates in the 187 patients were 71.7% and 79.1%, respectively. The 3-year PFS in 166 patients without any distant metastases at the time of primary tumor diagnosis was 48.6%. Osteosarcoma showed significantly worse OS and PFS than other sarcomas of the pelvis and retroperitoneum. In the univariate analyses, larger primary tumor size, soft tissue tumor, distant metastasis at the time of primary tumor diagnosis, P2 location, chemotherapy, and osteosarcoma were poor prognostic factors correlated with OS. Larger primary tumor size, higher age, soft tissue tumor, chemotherapy, and osteosarcoma were poor prognostic factors correlated with PFS in patients without any metastasis at the initial presentation. Larger primary tumor size was the only poor prognostic factor correlation with LC. This study has clarified the epidemiology and prognosis of patients with pelvic and retroperitoneal BSTS in Japan.

Continuous local antibiotic perfusion: A treatment strategy that allows implant retention in fracture-related infections.

PURPOSE: Fracture-related infections are difficult to treat because of the formation of biofilms around implants. Systemic antibiotics are notoriously ineffective against biofilms due to their insufficient penetration of tissues with poor vascularity. The goal of treating fracture-related infections is to achieve bone union while retaining the implant. Our proposal of continuous local antibiotic perfusion is a sustained local delivery system of sufficient antibiotics to bone and soft tissue infection sites, including to bone marrow via needles as intra-medullary antibiotics perfusion and to soft-tissue via double-lumen subcutaneous tubes as intra-soft tissue perfusion. METHODS: In this study, we examined the outcomes of 40 patients treated for fracture-related infections using continuous local antibiotic perfusion between 2015 and 2021 at Steel Memorial Hirohata Hospital, Himeji, Japan. RESULT: The antibiotic used for continuous local antibiotic perfusion was gentamicin in all cases. Implant removal was required in five patients. Two patients required toe amputation and knee arthrodesis, while the remaining 38 patients achieved fracture union. Only one case of transient acute renal injury as a systemic side effect was observed, but it soon resolved. The blood concentration of gentamicin could be adjusted to less than the trough level. CONCLUSIONS: Continuous local antibiotic perfusion is a novel local drug delivery system that has the potential of delivering sufficient concentrations of antibiotics with few systemic side effects; it is a useful option for the treatment of fracture-related infections.

A Case of Nonunion with Ballooning Deformity after Periprosthetic Humeral Fracture.

Introduction: We report a very rare case of nonunion with ballooning deformity of the humeral bone after a periprosthetic humeral fracture nonunion. Case Report: A 79-year-old woman underwent hemiarthroplasty 19 years ago for her proximal humerus fracture. She injured her right humeral diaphysis (stem distal end fracture) 6 years ago. She underwent revision hemiarthroplasty with long stem, but bony union was not obtained, and her right upper limb function was subsequently abolished due to extreme instability and pain in her right upper arm. She was then referred to our hospital for further treatment. X-ray showed nonunion in the humeral diaphysis and a severe ballooning deformity in the distal humeral bone fragment. Due to the advanced age and low activity of the patient, we chose total humerus replacement surgery instead of osteosynthesis. After the surgery, her upper arm pain and instability immediately improved. Three years after the last surgery, there have been no implant failures, and the upper arm is stable and painless. Conclusion: Although there are some reports of total humerus replacement as surgical treatment for humeral tumor and severe periprosthetic fracture, we found no reports of such ballooning deformity around the nonunion site. Total humerus replacement can be one of the treatment options in cases where nonunion surgery is extremely difficult, depending on the patient's age and activities of daily living.

Analysis of popliteal artery location for high tibial and distal tuberosity osteotomy using contrast-enhanced computed tomography.

BACKGROUND: Our objective was to evaluate the location of popliteal artery (PA) in osteotomy planes during high tibial osteotomy (HTO) and to determine a safer angle for screw drilling to the tibial tuberosity during distal tuberosity osteotomy (DTO). METHODS: Twenty knees in 20 patients who underwent contrast-enhanced computed tomography for cardiovascular diseases were examined. Osteotomy planes for open-wedge HTO (OWHTO) and hybrid closed-wedge HTO (hybrid CWHTO) were created using three-dimensional bone models. The distance from the posterior cortex of the tibia to the PA (dPC-PA) in the osteotomy planes was measured in the virtual osteotomy planes. The dangerous point (Point D1) was defined as the point 17.5 mm away from PA, setting the working length of the bone saw as 35 mm. The distance between the most medial point of the tibial cortex (Point M) and Point D1 in OWHTO and the most lateral point (Point L) and Point D1 in hybrid CWHTO were examined (dM-D1 and dL-D1, respectively). The location of Point D1 to the osteotomy line (%D1) was expressed as percentage, setting the start and end of the osteotomy line as 0% and 100%, respectively. To determine the safe angle for screw drilling in DTO, the angle between the line tangential to the medial cortex of the tibia and that passing through the center of the tibial tuberosity and PA were measured. RESULTS: In OWHTO and hybrid CWHTO, the mean dPC-PA was 10.6 mm (6.9-16.5 mm) and 10.2 mm (7.3-15.4 mm), respectively. The mean dM-D1 in OWHTO was 25.9 mm (24.6-27.2 mm) and dL-D1 in hybrid CWHTO was 5.1 mm (2.9-7.4 mm). The mean %D1 was 47.6 ± 3.7% in OWHTO and 9.3 ± 4.1% in hybrid CWHTO, respectively. The minimal angle between the two lines in DTO was 35.2°. CONCLUSION: PAs could run within 10 mm from the posterior cortex in the osteotomy planes of HTO. Therefore, proper posterior protection is necessary when cutting posterior cortex. An angle of less than 35° against the medial cortex line would be safe for screw fixation to avoid vascular injury in DTO.

Co-occurring Acromioclavicular Joint Cyst and Hemarthrosis of the Shoulder Associated With Rotator Cuff Tear Arthropathy.

Both acromioclavicular joint (ACJ) cysts and hemarthrosis of the shoulder are rare conditions of massive rotator cuff tear that eventually lead to cuff tear arthropathy. We herein report the first case of a patient with co-occurring ACJ cyst and hemarthrosis of the shoulder. An 80-year-old right-hand-dominant man presented to our outpatient department with a six-month history of repeatable right shoulder pain and swelling. Clinical examination revealed a 5 x 5 x 5 cm elastic hard or hard shoulder lump overlying the ACJ on skin with subcutaneous bleeding and swelling of the shoulder. Shoulder pain at rest and a fully reduced active range of motion (ROM), particularly in flexion and abduction, were also noted. Radiographs demonstrated moderate degeneration of the glenohumeral joint including a bone cyst of the humeral head. Magnetic resonance imaging (MRI) revealed a massive rotator cuff tear with atrophy of the supraspinatus, infraspinatus, and subscapularis muscles. The T2-weighted MRI images showed that the cyst was in direct contact with the markedly degenerated glenohumeral joint. Based on these findings, the patient was diagnosed with massive rotator cuff tear with ACJ cyst and hemarthrosis of the shoulder. The patient underwent distal clavicle resection and reverse total shoulder arthroplasty (RSA). At 12-month follow-up, the patient showed no pain symptoms, no recurrence of the cyst, and excellent ROM. We experienced a very rare case of ACJ cyst and hemarthrosis of the shoulder occurring simultaneously with rotator cuff tear arthropathy. This report is very valuable in that it suggests that RSA is useful for both ACJ cysts and hemarthrosis of the shoulders associated with rotator cuff tear arthropathy.

Combined treatment using cross-leg free flap and the Masquelet technique: a report of two cases.

We introduce a treatment that combines the cross-leg free flap with the Masquelet technique and describe two cases using this method for bone and soft tissue reconstruction. Both patients were successfully treated and ambulatory. This novel method can be safely performed using the delay technique, indocyanine-green angiography and near-infrared spectroscopy.

A phase I/IIa clinical trial of third-generation autologous chondrocyte implantation (IK-01) for focal cartilage injury of the knee.

Background/objective: The purpose of this study was to report the outcomes of a clinical trial conducted in Japan to assess the safety and effectiveness of third-generation autologous chondrocyte implantation (ACI) using IK-01 (CaReS™), which does not require flap coverage, in the treatment of patients with focal cartilage injury of the knee. Methods: This was an open label, exploratory clinical trial. Patients were enrolled between June 2012 and September 2016. The primary endpoint of the study was the International Knee Documentation Committee (IKDC) score at 52 weeks after implantation. The IKDC, Lysholm, and visual analog scale (VAS) scores were evaluated at the time of screening and at 4, 12, 24, 36, and 52 weeks after implantation. Improvements from the baseline scores were evaluated using the equation "(postoperative score) - (preoperative score)." Magnetic resonance imaging (MRI) was performed at 2, 12, 24, and 52 weeks after implantation, and MRI measurements were evaluated using T1 rho and T2 mapping. Results: Nine patients were enrolled in this study and were examined for safety. Product quality did not satisfy the specification in one patient, and bacterial joint infection occurred in one patient. As a result, seven patients were included in the outcome analyses. The mean IKDC score significantly improved from 36.4 preoperatively to 74.1% at 52 weeks after implantation (p < 0.0001). The mean Lysholm and VAS scores also significantly improved from 39.6 to 57.4 to 89.6 and 22.9, respectively, after surgery. In the MRI evaluation, the T1 rho and T2 values of the implanted area were similar to those of the surrounding cartilage at 52 weeks after implantation. Conclusions: Third generation ACI (IK-01) can be an effective treatment option for focal cartilage defects of the knee; however, surgeons must pay careful attention to the risk of postoperative joint infection.

Peri-prosthetic bone remodeling of hydroxyapatite-coated compaction short stem was not affected by stem alignment.

BACKGROUND: To improve implant survival through accelerated early bone remodeling during total hip arthroplasty (THA), hydroxyapatite (HA) is widely used as a bioactive coating, which is believed to enhance initial fixation by osseointegration. We aimed to investigate the relationship between stem insertion alignment and postoperative bone mineral density (BMD) changes in patients with full hydroxyapatite-coated (HA) compaction short stem and short tapered-wedge stem. METHODS: This retrospective cohort study enrolled 115 consecutive patients (115 joints) undergoing THA using the full HA compaction short (n = 59) and short tapered-wedge (n = 56) stems. Stem alignment, including anteversion, valgus, and anterior tilt were measured by a three-dimensional template using computed tomography data. Post-operative peri-prosthetic BMD was measured by dual-energy X-ray absorptiometry. The relationship between stem alignment and BMD changes in the stems was analyzed. RESULTS: Patterns of peri-prosthetic BMD changes were similar in both groups. Stem insertion alignments of anteversion, valgus, and anterior tilt were different between the two stem types. Stem alignment of valgus and anterior tilt did not affect peri-prosthetic BMD in either of the stem type. An absolute anteversion difference between stem anteversion and original canal anteversion caused significant peri-prosthetic BMD loss in Gruen zones one and seven in the tapered-wedge stem. However, stem alignment of absolute anteversion difference did not affect BMD changes in the HA compaction stem. CONCLUSIONS: Peri-prosthetic bone remodeling remained unaffected by stem alignment after THA with the new short full HA compaction stem.

A Piezo1/KLF15/IL-6 axis mediates immobilization-induced muscle atrophy.

Although immobility is a common cause of muscle atrophy, the mechanism underlying this causality is unclear. We here show that Krüppel-like factor 15 (KLF15) and IL-6 are upregulated in skeletal muscle of limb-immobilized mice and that mice with KLF15 deficiency in skeletal muscle or with systemic IL-6 deficiency are protected from immobility-induced muscle atrophy. A newly developed Ca2+ bioimaging revealed that the cytosolic Ca2+ concentration ([Ca2+]i) of skeletal muscle is reduced to below the basal level by immobilization, which is associated with the downregulation of Piezo1. Acute disruption of Piezo1 in skeletal muscle induced Klf15 and Il6 expression as well as muscle atrophy, which was prevented by antibodies against IL-6. A role for the Piezo1/KLF15/IL-6 axis in immobility-induced muscle atrophy was validated in human samples. Our results thus uncover a paradigm for Ca2+ signaling in that a decrease in [Ca2+]i from the basal level triggers a defined biological event.