Relationship between Stress Shielding and Optimal Femoral Canal Contact Regions for Short, Tapered-Wedge Stem Analyzed by 2D and 3D Systems in Total Hip Arthroplasty.

Although tapered-wedge short stem has been widely employed with its availability for minimally invasive surgeries in total hip arthroplasty (THA), post-operative stress shielding matter remains unresolved in cementless procedures. This study aimed to clarify the most optimal femoral canal contact regions of the stem design taking stress shielding incidence into consideration. This investigation included 60 joints from 60 patients (mean age at operation: 65.9 years), of which follow-up duration after primary THA had been more than 2 years. Frequencies of spot welds, subsidence, and stress shielding were examined 2 years after surgery. The most suitable femoral canal contact regions were evaluated by plain radiograph (2D) and 3D-computed tomography analyses according to Nakata's division for fitting manners. Spot welds were observed in 38 cases (63.3%), and no subsidence case was seen. Respective number of stress shielding cases, based on Engh's classification, categorized as degree 0, 1, and 2, were 2 (3.3%), 31 (51.7%), and 27 (45.0%), while no cases for degree 3 or 4 were found. When assessed by 3D fitting analysis, 27 cases of stress shielding degree 2 were constituted by 13/42 cases of mediolateral (ML) fit, 2/4 cases of flare fit, and 12/14 cases of multi point fit. In 42 cases of ML fitting, stem contact rate of the most proximedial region in stress shielding degree 0 and 1 was significantly higher compared to stress shielding degree 2 cases. Meanwhile, the rates of distal regions were significantly lower or absent in stress shielding degree 0 and 1 cases. The initial fixation of this stem design was very good in our cohort regardless of fitting manners. This study successfully revealed that ML fitting with femoral component, especially the most proximedial calcar site restricted fitting, would be optimal for reducing stress shielding occurrence in cementless short, tapered-wedge stem THA. Thus, the ideal stem contact region should be considered during THA procedures in light of the reduction of stress shielding development.

Short- to Mid-Term Clinical Outcomes of Posterior-Stabilized Cementless Total Knee Arthroplasty with Trabecular Metal Components.

OBJECTIVE: This study aimed to evaluate the short- to mid-term clinical results of posterior-stabilized trabecular metal total knee arthroplasty (TKA) with cementless fixation of all components and investigate the radiographic changes of tibial and patellar components and cut bone surfaces over time. METHODS: We retrospectively collected the data of 128 knees from 88 consecutive patients who had undergone initial TKA with NexGen LPS-Flex TM implants. A total of 66 knees from 45 patients (mean ± standard deviation age: 70.3 ± 7.5 years) met the selection criteria, which had been employed cementless fixation of all parts and at least 3 years of postoperative follow-up duration. Clinical evaluations included range of motion, conventional knee score, function score, postoperative complications, and revision. For radiological evaluations, the bone contact surface of each implant was divided into 7 zones for tibial component and 2 zones for patellar component. Each region was examined immediately after surgery, at 6 and 12 months, and then every year afterwards. RESULTS: The mean observation period of 45 subjects was 4.2 years. Adequate fixation of tibial components was maintained during follow-up, although the patellar components of 2 knees required revision after repeated falls. No loosening was observed in any implants. The initial gap in tibial components disappeared in all knees, and a reactive line remained in 4 knees. There were no revisions, except for 2 cases, which were ascribed to patellar component fracture caused by repeated falls. CONCLUSION: Cementless posterior-stabilized trabecular metal TKA appears to be a good surgical option. Longer-term examination for revision cases is required to validate our results.

The incidence and risk factor of deep venous thrombosis after arthroscopically assisted anterior cruciate ligament reconstruction.

PURPOSE: To retrospectively analyze the incidence and risk factors of deep venous thrombosis (DVT) detected by ultrasonography after arthroscopically assisted Anterior Cruciate Ligament Reconstruction (ACLR). METHODS: We retrospectively reviewed medical records of arthroscopically assisted ACLR surgery performed at our institution between 2012 and 2015. Revision ACLR, bone patella tendon bone (BTB) graft reconstruction, and concomitant multiple ligament reconstructions were excluded. We performed a standardized double-bundle reconstruction procedure using hamstrings graft for ACLR. All patients routinely received DVT screening by using venous ultrasonography on postoperative day 7 from 2012 to 2013, and postoperative days 7 and 14 from 2014 to 2015. The prevalence of DVT was calculated and clinical factors such as age, gender, Body Mass Index (BMI), operative time, and duration of tourniquet application were evaluated in relation to the risk factor of DVT. RESULTS: Two hundred and fifty-six patients (129 men and 127 women) with a mean age of 28.9 were enrolled. Sixteen patients (6.6%) were detected with DVT on postoperative day 7. Among 146 patients who received venous ultrasonography on both postoperative days 7 and 14, DVT were detected in five additional patients on postoperative day 14. In a total of 21 patients who were diagnosed with DVT, two were proximal, the remaining 19 were distal, and no patient had progressed to pulmonary embolism (PE). In terms of predisposing factors for developing DVT on postoperative day 7, only age ≥30 showed a statistically significant higher risk of DVT (P = 0.03). CONCLUSION: Incidence of DVT after ACLR detected by ultrasonography on postoperative day 7 was 6.6%. Patients aged ≥30 years have a potentially higher risk for developing DVT. Great care for DVT should be taken if prolonged immobilization is applied after ACLR surgery. LEVEL OF EVIDENCE: Level Ⅳ.

Synovial deposition of wild-type transthyretin-derived amyloid in knee joint osteoarthritis patients.

OBJECTIVE: To investigate histological features of deposited amyloid in the synovial tissue and its clinical significance in knee joint osteoarthritis (OA) patients. METHODS: We prospectively enrolled 232 consecutive patients who underwent arthroplasty or total replacement of the knee joint for treatment of OA. Congo red staining and immunohistochemistry were performed in the synovial tissue obtained at surgery. When transthyretin (TTR)-derived amyloid was positive, we analyzed all 4 exons of the TTR gene using the direct DNA sequencing method in order to detect mutations. RESULTS: We analyzed 322 specimens in this study. Twenty-six specimens (8.1%) obtained from 21 patients (5 men and 16 women; mean, 79.0 ± 4.6 years) showed deposition of amyloid, which was positively stained with the anti-TTR antibody. Eighteen patients showed inhomogeneous accumulations of amyloid in the loose connective tissue under the synovial epithelia sometimes with nodule formation, while in the remaining three, small vessels in the adipose tissue were involved. Medical records of these patients revealed nothing remarkable in the clinical course, laboratory data or macroscopic intraarticular findings at surgery. No mutations were detectable in the TTR gene analysis. CONCLUSION: Wild-type TTR-derived amyloid may affect the synovial tissue as a result of long-term mechanical stress or as a part of senile systemic amyloidosis in approximately 8% of knee joint OA patients. No obvious clinical significance was found in synovial deposition of amyloid.

Safety of autologous bone marrow-derived mesenchymal stem cell transplantation for cartilage repair in 41 patients with 45 joints followed for up to 11 years and 5 months.

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

Blocking of tumor necrosis factor activity promotes natural repair of osteochondral defects in rabbit knee.

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

Human amniotic mesenchymal cells differentiate into chondrocytes.

Recently, cartilage diseases have been treated by auto- or allogenic chondrocyte transplantation. However, such treatments are limited by the necessity of having a large amount of cells for transplantation, the risk of rejection, and donor shortage. Since the human amnion is immune-privileged tissue suitable for allotransplantation, the potential of human amniotic mesenchymal cells (HAMc) to differentiate into chondrocytes was assessed. The expression of gene encoding transcription factors SOXs and bone morphogenetic proteins (BMPs) as well as BMP receptors were assessed. Chondrocyte phenotype was characterized by positive expression of the cartilage marker genes collagen type II and aggrecan by RT-PCR, collagen type II protein were analyzed by immunofluorescence analysis. HAMc expressed chondrocyte-related genes, including SOXs, BMPs, as well as BMP receptors. Collagen type II and aggrecan were detected after the induction of chondrogenesis with BMP-2. HAMc, transplanted into noncartilage tissue of mice with BMP-2, or implanted with collagen-scaffold into the defects generated in a rat's bone, underwent morphological changes with deposition of collagen type II. These results showed that HAMc have the potential to differentiate into chondrocytes in vitro and in vivo, suggesting that they have therapeutic potential for the treatment of damaged or diseased cartilage.

Repair of articular cartilage defects in the patello-femoral joint with autologous bone marrow mesenchymal cell transplantation: three case reports involving nine defects in five knees.

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

Expression profiles and functional analyses of Wnt-related genes in human joint disorders.

Rheumatoid arthritis (RA) and osteoarthritis (OA) are joint disorders that cause major public health problems. Previous studies of the etiology of RA and OA have implicated Wnt genes, although the exact nature of their involvement remains unclear. To further clarify the relationship between RA, OA, and the Wnt gene family, gene expression analyses were performed on articular cartilage, bone, and synovial tissues in knee joints taken from RA, OA, and nor-mal/control patients. Cytokine assays were also performed in cells transfected with Wnt-7b, a member of the gene family most closely linked to RA and OA. Of the human Wnt genes, real-time PCR analysis revealed significant up-regulation of Wnt-7b in OA cartilage and RA synovium. In situ hybridization and immunohistochemistry also revealed that Wnt-7b was present in articular cartilage, bone, and synovium of RA samples and in osteophytes, articular cartilage, bone marrow, and synovium of OA samples. The levels of the cytokines tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 were significantly increased in RA synovium and Wnt-7b-transfected normal synovial cells when compared with normal samples. These results point to the potential involvement of Wnt signaling in the pathobiology of both RA and OA.

Continuous local cooling for pain relief following total hip arthroplasty.

This study is the first to evaluate whether continuous cryotherapy can relieve pain soon after total hip arthroplasty (THA). Patients who had undergone THA for osteoarthritis were divided into 2 prospective, randomized groups: the cryotherapy group was fitted with a computer-controlled cooling device for 4 days, and the control group was not. The pain scores measured on a visual analog scale between days 1 and 4 following surgery were significantly lower for the cryotherapy group than for the control group. Furthermore, postoperative analgesic use by the cryotherapy group was significantly lower than by the control group. The results of this study support the potential benefit of a cold compressive device for pain reduction during the postoperative recovery of patients undergoing THA.

Osteonecrosis of the femoral head in Japanese adults after liver transplantation: a preliminary report.

Patients who are treated with high-dose corticosteroids as an immunosuppressive therapy are at high risk of developing osteonecrosis, especially in the femoral head. We examined whether symptomatic osteonecrosis of the femoral head (ONFH) would be a clinical problem after liver transplantation. From June 1990 to December 2001, a total of 169 patients underwent liver transplantation at the Shinshu University Hospital. Within this group, 65 patients were more than 18 years old at the time of surgery, and all were enrolled in the present study. All patients were referred to the Orthopaedic Department of Shinshu University Hospital when they experienced musculoskeletal symptoms, including hip or groin pain. In addition, they were informed of the potential risk of osteonecrosis associated with immunosuppressive therapy after the liver transplant. As result, the patients were advised to have a magnetic resonance imaging (MRI) check for osteonecrosis after transplant surgery. In terms of outcomes, none of the patients presented with symptomatic hip difficulties due to osteonecrosis. Additional clinical investigation revealed that of the 18 patients who underwent MRI screening, only one was found to have asymptomatic unilateral ONFH. In conclusion, ONFH after liver transplantation has not been a clinical problem for our patients.

Total hip arthroplasty with bulk femoral head autograft for acetabular reconstruction in DDH. Surgical technique.

BACKGROUND: The long-term results of total hip arthroplasty performed with cement and use of a bulk autograft for acetabular reconstruction in patients with developmental dysplasia of the hip have varied considerably. We evaluated the results of total hip arthroplasties performed with acetabular bulk autograft to identify the factors that influence the results of this procedure. METHODS: Acetabular roof defects secondary to developmental dysplasia of the hip were reconstructed with a bulk femoral head autograft at the time of total hip arthroplasties performed with use of the Charnley technique and prosthesis. Thirty-seven hips in thirty patients (mean age at the time of the operation, fifty-seven years) were followed for ten to twenty-six years (mean, nineteen years). The Crowe classification of hip subluxation or dislocation was Group II for sixteen hips, Group III for seventeen, and Group IV for four. RESULTS: Coverage of the socket by the graft ranged from 5% to 49% (mean, 33%). Twenty-nine sockets were located within the true acetabulum, and eight were placed more proximally. At the time of the latest follow-up, all of the patients had an excellent clinical result, all of the grafts had united, and no hip had radiographic evidence of failure of the fixation. CONCLUSIONS: We found that total hip arthroplasty performed with cement and use of a bulk autograft to reconstruct an acetabulum with severe bone deficiency secondary to developmental dysplasia of the hip can provide long-term success in patients forty-eight years of age and older when coverage of the socket by the graft does not exceed 50%. When it is not possible to achieve >50% coverage of the socket by the ilium at the level of the true acetabulum, more proximal placement of the socket to obtain adequate coverage is recommended.

Locking of the knee caused by localized pigmented villonodular synovitis: a case report.

Pigmented villonodular synovitis (PVS) occurs in two forms: diffuse PVS and localized pigmented villonodular synovitis. In this report, a 40-year-old woman presented with a history of recurrent episodes of knee locking and pain. Arthroscopy revealed a nodular pedunculated mass occupying the area anterior to the intercondylar notch of the femur. Histological examination of the tissue confirmed the diagnosis of PVS. After surgery, the patient's symptoms of pain and recurrent locking promptly resolved.

Sequential changes in periprosthetic bone mineral density following total hip arthroplasty: a 3-year follow-up.

We sequentially measured the periprosthetic bone mineral density (BMD) of the femur after cementless total hip arthroplasty, using dual-energy X-ray absorptiometry, over a 3-year period. The periprosthetic bone was divided into three regions (proximo-medial, middle, and distal to the prosthetic stem). After the insertion of a fully porous coated stem in 21 patients, the BMD was measured within 3 weeks, and 6, 12, 24, and 36 months after surgery. At 6 months, all zones showed a decrease in BMD relative to the BMD within 3 weeks, but subsequently the BMD was unchanged. The lower the BMD within 3 weeks of surgery, or the lower the body weight, the higher the percent loss of BMD at 6 months.

Repair of a proximal femoral bone defect in dogs using a porous surfaced prosthesis in combination with recombinant BMP-2 and a synthetic polymer carrier.

Total hip arthroplasty (THA) has become an almost standard procedure for the treatment of various hip lesions. However, one of the limitations has been the mechanical loosening of the prosthesis, a condition termed peri-prosthetic osteolysis. Consequently, at revision surgery, various grades of bone defect are often noted. Alternative approaches aimed at overcoming this problem have included a special design of the revision prosthesis and allo- or autogeneic bone grafting in combination with or without biomaterials. In a further attempt to address the loosening of the prosthesis, we have combined human bone morphogenetic protein-2, produced by DNA recombination (rhBMP-2) with a new synthetic biodegradable polymer (poly-D,L-lactic-acid-para-dioxanone-polyethyleneglycol block co-polymer; PLA-DX-PEG). We present data on the efficacy of the rhBMP-2 laden prosthesis to reconstruct a bone defect in a canine model. In this model, medial half of the proximal femur was surgically resected to create a bone defect that was repaired with the rhBMP-2/PLA-DX-PEG composite. Twelve weeks after implantation, the original bone defects in the rhBMP-2 treatment groups had been repaired. Thus, this type of 'hybrid' prosthesis may provide a new modality to repair bone defects or restore lost bone mass encountered in revision arthroplasty.

Total hip arthroplasty with bulk femoral head autograft for acetabular reconstruction in developmental dysplasia of the hip.

BACKGROUND: The long-term results of total hip arthroplasty performed with cement and use of a bulk autograft for acetabular reconstruction in patients with developmental dysplasia of the hip have varied considerably. We evaluated the results of total hip arthroplasties performed with acetabular bulk autograft to identify the factors that influence the results of this procedure. METHODS: Acetabular roof defects secondary to developmental dysplasia of the hip were reconstructed with a bulk femoral head autograft at the time of total hip arthroplasties performed with use of the Charnley technique and prosthesis. Thirty-seven hips in thirty patients (mean age at the time of the operation, fifty-seven years) were followed for ten to twenty-six years (mean, nineteen years). The Crowe classification of hip subluxation or dislocation was Group II for sixteen hips, Group III for seventeen, and Group IV for four. RESULTS: Coverage of the socket by the graft ranged from 5% to 49% (mean, 33%). Twenty-nine sockets were located within the true acetabulum, and eight were placed more proximally. At the time of the latest follow-up, all of the patients had an excellent clinical result, all of the grafts had united, and no hip had radiographic evidence of failure of the fixation. CONCLUSIONS: We found that total hip arthroplasty performed with cement and use of a bulk autograft to reconstruct an acetabulum with severe bone deficiency secondary to developmental dysplasia of the hip can provide long-term success in patients forty-eight years of age and older when coverage of the socket by the graft does not exceed 50%. When it is not possible to achieve >50% coverage of the socket by the ilium at the level of the true acetabulum, more proximal placement of the socket to obtain adequate coverage is recommended.

Three-dimensional computed tomography evaluation of bony birth canal morphologic deformity (small pelvic cavity) after dome pelvic osteotomy for developmental dysplasia of the hip.

OBJECTIVE: Using three-dimensional computed tomography, we investigated the morphologic deformity of the birth canal in patients with developmental dysplasia of the hip who underwent dome pelvic osteotomy. STUDY DESIGN: Thirty-five normal subjects, 34 patients with developmental dysplasia of the hip who did not undergo dome pelvic osteotomy, and 21 patients with developmental dysplasia of the hip who underwent dome pelvic osteotomy were recruited for the study. We assessed the underlying pelvic deformities together with the postoperative pelvic morphologic changes (iatrogenic deformity). RESULTS: Sagittal diameters of the pelvic contraction were longer, and transverse diameters of the pelvic inlet, expansion, and contraction were shorter in patients after dome pelvic osteotomy than in normal control subjects. CONCLUSION: Anthropoid-type pelvis (a long pelvic inlet diameter in the sagittal dimension while the corresponding measurement in the transverse dimension is short) was observed in as many as 90.5% of patients with developmental dysplasia of the hip after dome pelvic osteotomy.