Long term results of the Bicontact D stem in dysplastic osteoarthritis: a 10-15 year follow-up study.

PURPOSE: The purpose of the present study was to investigate the results of total hip arthroplasty (THA) using the Bicontact D stem with a minimum 10 year follow-up that focused on patients with developmental dysplasia of the hip (DDH). METHODS: One hundred five patients with osteoarthritis due to DDH who underwent primary THA were included in this study. The mean final follow-up period was 12.7 ± 1.2 years (range 10-15 years). All cases were evaluated both clinically and radiographically, and Kaplan-Meier survivorship was determined as stem revision for any reason as the end point. RESULTS: Modified Harris hip score averaged 89.0 ± 1.1 (range 60-98) at the final follow-up. The survivorship was 99.0% (95% confidence interval 93.4-99.9%) at 15.0 years, and only one hip with a well-fixed stem required stem revision due to recurrent dislocations. Cortical hypertrophy (CH) was observed in 40 of 105 hips (38.1%), and stress shielding (SS) progressed to grade 3 or 4 in six hips (6 of 105 hips: 5.7%) during the study period. Among the six hips with progressed SS, Dorr type C proximal femoral geometry was seen in five hips. CONCLUSION: This study of 105 THAs using the Bicontact D stem that focused on DDH patients with a minimum 10 year follow-up period achieved satisfactory clinical and radiological outcomes. Dorr type C proximal femoral geometry could be considered a risk factor for progressed SS.

New combined anteversion technique in hybrid THA: cup-first procedure with CT-based navigation.

PURPOSE: Combined anteversion (CA) technique (stem-first procedure) is generally accepted as the optimal technique to attain an appropriate CA value in total hip arthroplasty (THA). However, cup anteversion is strongly influenced by the native femoral anteversion. Accordingly, anterior protrusion of the cup in the acetabulum might occur. The purpose of the present study is to investigate the achievement of the optimal CA while avoiding anterior cup protrusion and examine the significance of our new CA technique with cup-first procedure in hybrid THA. METHODS: Seventy-nine hybrid THAs with the cup-first procedure used a CT-based navigation system for cup positioning. In the preoperative planning, cup anteversion was aimed at approximately 20°. However, in actuality, sufficient cup coverage in the original acetabulum based on individual anatomy is given priority over cup placement based on CT-based planning to ensure adequate cup coverage. The target stem anteversion was determined following Widmer's mathematical formula (37.3 = femoral stem anteversion × 0.7 + cup anteversion). Cemented stem was inserted according to the target stem anteversion angle. RESULTS: Regarding the assessment of overall alignment, the calculated Widmer's CA values during surgery and postoperative CT evaluation were 34.1° ± 6.0° (range 20.7°-51.2°) and 35.1° ± 6.7° (range 21.6°-50.7°). There were 72 hips (91.1%) within 25°-50° of CA. Cup protrusion length averaged 2.0 mm ± 2.6 mm (0-8.8 mm) in the axial view and 0.4 mm ± 1.0 mm (0-3.6 mm) in the sagittal view. Cup protrusion length of more than 5 mm was indicated in 10 hips, and no hips observed more than 10 mm. CONCLUSION: Our new CA technique (cup-first procedure) with hybrid THA was able to achieve optimal CA value while avoiding anterior cup protrusion.

Total hip arthroplasty using stem-first technique with navigation: the potential of achievement of the optimal combined anteversion being a risk factor for anterior cup protrusion.

PURPOSE: In the combined anteversion (CA) technique for total hip arthroplasty (THA) with a cementless stem, cup anteversion is strongly influenced by the native femoral anteversion. It is hypothesized that in cases with large native femoral anteversion, cup anteversion can be decreased, and anterior cup protrusion from the anterior edge of the acetabulum could occur due to the achievement of optimal CA. In this study, the accuracy of CA in THA with the CA technique using imageless navigation and the relationship between the protrusion of the anterior edge of cup and optimum CA was retrospectively evaluated. METHODS: Ninety-seven patients (104 hips) who underwent primary THA by the CA technique using image-free navigation were enrolled in the study. The femoral stem was placed following the individual femoral anteversion so that the target cup anteversion could be determined following a mathematical formula (37 = femoral stem anteversion × 0.7 + cup anteversion). Results The resulting CA values effectively achieved accurate CA with 39.49 ± 5.03° postoperatively. On the other hand, anterior cup protrusion was measured by computed tomography image. A cup protrusion length of more than 3 mm was indicated for 60 cases (57.7%). All included patients were divided into two groups: Group 1 as protrusion positive and Group 2 as protrusion negative. In Group 1, preoperative femoral anteversion and postoperative stem anteversion were significantly higher, while postoperative cup anteversion was significantly lower. However, the postoperative CA value indicated no significant difference between the groups. CONCLUSIONS: The CA (stem-first) technique with image-free navigated THA could effectively achieve accurate CA. On the other hand, a large number of cases revealed anterior cup protrusion due to the low cup anteversion.

Treatment strategy for amyloid hip arthropathy in long-term hemodialysis patients.

BACKGROUND: The number of hemodialysis patients has been progressively increasing in our country. On the other hand, chronic hip arthropathy associated with long-term hemodialysis is a devastating problems affecting patients' quality of life. In our previous study, we proposed a classification system for radiological abnormalities seen in hemodialysis-related hip lesions. The purpose of the study was to propose the surgical strategy for hip disorders caused by long-term hemodialysis. METHODS: Patients with a history of hemodialysis for more than 10 years, 191 hip lesions in 165 consecutive patients who visited our institute due to hip symptoms. Various abnormalities were identified in 116 out of 191 hips. A retrospective assessment of the patient record and radiographs was performed for the included subjects examining the natural course of the disease process as well as the results of surgical treatment. RESULTS: Seventy-six hip lesions (69.0%) were conservatively managed at the time of the initial visit. Surgeries were performed for 75 hips (64.7%) during the study period. Among those, surgical treatment was indicated for 40 hips at the time of the initial visit. On the other hand, surgeries were performed for 35 hips during the subsequent follow-up period due to progression of the disease process. CONCLUSIONS: Based on the analysis of our surgical experiences by the retrospective chart review, we have established a flowchart of the treatment strategy for chronic hip arthropathy in long-term hemodialysis patients. STUDY DESIGN: This study is retrospective clinical study.

Accuracy of combined anteversion in image-free navigated total hip arthroplasty: stem-first or cup-first technique?

PURPOSE: In total hip arthroplasty (THA), combined anteversion (CA) is used as a parameter for assessment of overall prosthetic alignment. The purpose of this study was to comparatively examine the CA value in patients who underwent primary THA using the image-free navigation system either with a cup-first or stem-first technique. METHODS: Eighty-three hips undergoing primary THA using the OrthoPilot® image-free navigation system (B. Braun-Aesculap, Tuttlingen, Germany) were included in this study. The patient population was divided into two groups depending on the procedure used: cup-first technique and stem-first technique. In the cup-first group, inclination and anteversion (AV) angles were targeted at 35-45° and 15-25°, respectively, while stem antetorsion (AT) was determined for each patient based on the amount of individual native femoral AT angle. In the stem-first group, the femur was prepared first with the target angle corresponding to the native femoral AT and the cup AV was decided considering the CA calculated with Widmer's formula (aiming at the optimal Widmer's CA of 37.3°). RESULTS: Better consistency in Widmer's CA values was attained in the stem-first group as indicated by the smaller SD values. In the assessment of overall alignment, Widmer's CA values were within the satisfactory range (37 ± 5°) in 41.9 and 92.3 % of the subjects in the cup-first group and the stem-first group, respectively. CONCLUSIONS: The stem-first technique with image-free navigated THA could effectively achieve accurate and consistent control of the CA value and thus is expected to improve the surgical outcome.

Arthroscopic labral repair concomitantly performed with curved periacetabular osteotomy.

A 23-year-old female presented with pain in the left hip. Radiological examination showed developmental dysplasia of the hip (DDH) combined with acetabular retroversion and posterior wall deficiency. Findings in the physical examination were coincident with femoroacetabular impingement. At surgery, we performed curved periacetabular osteotomy concomitant with arthroscopic labral repair and osteochondroplasty, simultaneously addressing dysplastic acetabulum and femoroacetabular impingement. The final follow-up examination at 18 months showed satisfactory outcome with the D'Aubigne and Postel hip score of 17/18. In addition to accurate diagnosis, the arthroscopic procedure for associated intra- and peri-articular problems seems to help improve the surgical outcome of periacetabular osteotomy performed for patients with DDH.

Significance of preoperative 3D-CT angiography for localization of the femoral artery in complicated THA.

BACKGROUND: Major vascular injury is one of the most devastating complications in total hip arthroplasty (THA). Risk for intraoperative vascular injury is increased when the normal vascular anatomy is distorted by previous surgery or dislocation with displacement. Therefore, an appreciation of the vascular anatomy in relation to the anticipated surgical field is critical to avoid this complication during preoperative assessment for a complicated THA. METHODS: Preoperative three-dimensional (3D) CT angiography was performed for 24 complicated THAs when altered vascular anatomy around the acetabulum was suspected. When assessing the CT images, the presence of apparent proliferation of vessels close to the original acetabulum as well as a distance of <10 mm from the artery to the acetabulum was deemed a potential risk factor for intraoperative vascular injury. Additionally, the relationships of clinical characteristics and the presence of these risk factors were analyzed to identify the patient population at risk. RESULTS: The incidence of proliferation of collateral vessels was higher in patient groups with proximal femoral migration of 5 cm or more and multiple previous surgeries prior to the index THA. Moreover, in three ankylosed hips, lateral deviation of the main vascular trunk with an artery-acetabulum distance of <10 mm was identified in all cases. CONCLUSION: Preoperative 3D-CT angiography in cases of complicated THA revealed altered vascular anatomy which may increase the risk for intraoperative vascular injuries. Patient characteristics related to the risk for this complication were marked proximal femoral migration, multiple previous surgeries, and hip ankylosis. Preoperative image examination of the vascular anatomy is thought to help reduce the risk of inadvertent vascular injury in these complicated THA cases.

Treatment of Severe Hip Dysplasia with Leg Length Discrepancy Using Spherical Periacetabular Osteotomy.

Case. A 20-year-old woman with severe subluxation of the hip displayed a leg length discrepancy of approximately 20 mm. The proposed treatment was a spherical periacetabular osteotomy (SPO) for joint preservation and postoperative leg length maintenance. SPO is a novel periacetabular osteotomy procedure. At her 3-year follow-up, the patient had functional, pain-free motion and high satisfaction. In this case, the SPO technique was able to achieve satisfactory clinical results without further exacerbating the leg length discrepancy after surgery.

Adjustment of leg length using imageless navigation THA software without a femoral tracker.

BACKGROUND: Adjustment of leg length discrepancy is an important factor influencing the outcome of total hip arthroplasty (THA). However, leg length discrepancy after THA has been reported to be associated with inferior clinical outcome in previous studies. A new version of the imageless navigation software "OrthoPilot THAplus" has been developed to assess the leg length adjustment and offset value. The clear advantage of this system is the elimination of the need for femoral pin insertion, which is associated with potential complications and additional surgical invasion. METHODS: In this study, the accuracy of this newly developed system was evaluated in 50 consecutive hips implanted with primary THA. The operative results of these 50 patients were compared with those of another 50 consecutive primary THA patients operated on with the previous navigation system that was not equipped with the leg length adjustment system. RESULTS: After surgery, the average leg length discrepancy in the THA plus group was 0.9 mm (range -5 to 5 mm), while the corresponding value in the other group with the older software was 2.9 mm (range -13 to 20 mm), showing a significant difference. CONCLUSION: The accuracy and reproducibility of new software added to the imageless THA navigation system in achieving equalization of leg length were assessed. Comparison of the surgical results as compared with the control group performed with the conventional navigation system showed the advantage of this system over the previous system.

Revision Total Hip Arthroplasty due to Catastrophic Osteolysis Caused by Massive Chronic Expanding Hematoma.

An 84-year-old woman who underwent bilateral cementless total hip arthroplasty (THA) for dysplastic osteoarthritis 22 years ago was subjected to analysis. A huge soft-tissue mass was revealed in her left medial thigh. Plain radiographs of the left hip joint revealed severe osteolysis around the stem, cup, and ischium. Magnetic resonance imaging showed a 25 × 14-cm multilobulated mass with a thick-walled pseudocapsule. Two-stage surgery was performed with resection of the mass followed by a subsequent revision THA. The mass was diagnosed as a chronic expanding hematoma through gross and histologic findings. Two years after the revision THA, there was no recurrence of a hematoma. Two-stage revision THA was useful for definitive diagnosis, and good functional recovery was obtained after surgery.

Characteristic Poses in Ballet in the Case of a Retired Classical Ballerina after Bilateral THA: A Case Report and Review of Literature.

BACKGROUND: Ballet dance involves extreme range of motion (ROM) in the hip joint. This ROM can cause injuries including labral strain, tears, and subluxation episodes. Case Presentation. A 69-year-old female classical ballet dance instructor presented bilateral hip pain. The plain radiograph showed end-stage osteoarthritic change in the bilateral hip. She could neither dance nor perform daily activities. Bilateral hybrid total hip arthroplasty (THA) was performed. After surgery, she was able to demonstrate the split position on the floor as an active classical ballerina. The plain radiograph was taken in the split position, and the radiograph did not show any characteristics of impingement or subluxation of the femoral head. CONCLUSION: She was able to continue working as a classical ballet instructor after bilateral THA. Additionally, any characteristics of impingement or subluxation of the femoral head were not revealed in the postoperative radiograph in the split position.

RNA editing in P transposable element read-through transcripts in Drosophila melanogaster.

RNA editing is proposed as a modulator of transcriptomes, but its biological impact has not been fully elucidated. In particular, its importance for transposable elements is controversial. We found RNA editing on antisense read-through transcripts of KP elements, one of the deletion derivatives of P transposable elements in Drosophila melanogaster. Three kinds of RNA editing were detected at 20 sites around the terminal inverted repeats (TIR); 15 A-to-G, four U-to-C, and one C-to-U conversions. A-to-G conversions are suggested to be attributed to A-to-I RNA editing on KP element RNAs, because inosine (I) in RNA is recognized as G by reverse transcriptase. TIRs were deduced to form dsRNAs as a putative target of ADAR. This is the first report of RNA editing on mobile elements of Drosophila.

Radiological Evaluation of the Relationship Between Cortical Hypertrophy and Stress Shielding After Total Hip Arthroplasty Using a Cementless Stem.

BACKGROUND: Unloading of the proximal medial femoral cortex is usually associated with an increased bone strain at the distal part of the prosthesis, which may cause distal femoral cortical hypertrophy (CH). The objective of this study was to determine the factors that may be considered a predisposition to distal femoral CH and its effect on the stress shielding (SS) or durability of the fixation of the stem. METHODS: A total of 240 total hip arthroplasties were performed between January 2006 and December 2016, with all hips implanted with a Bicontact stem. The minimum follow-up period was more than 2 years, and the mean follow-up period was 7.2 years. The radiographic outcome was assessed on an anteroposterior hip radiograph. CH and SS were assessed on postoperative radiographs in the Gruen zone. We defined CH that appeared in zone 3 or 5 as 'the focal type' and defined CH that appeared in zones 2, 3, 4, 5, and 6 as 'the diffuse type.' SS followed the procedures from the Engh classification. RESULTS: CH was found in 72 hips (30% of the 240 hips), the focal type was found in 23 hips (9.6% of the 240 hips), and the diffuse type was found in 49 hips (20.4% of the 240 hips). SS was found in 41 hips (17.1% of 240 hips), including 32 hips with SS, which was found after the development of CH. One hip was from the focal-type CH and 31 hips were from the diffuse-type CH. SS, which is typically found in Engh classification types 1 and 2 developed in 13 hips, and SS, which is widely seen in Engh classification types 3 and 4 developed in 19 hips. All 19 hips with progressed SS were found after the diffuse-type CH had developed. In addition, among the 19 hips with progressed SS, Dorr type A was found in 0 hips, Dorr type B in 8 hips, and Dorr type C in 11 hips. CONCLUSIONS: According to the results of our radiological evaluation, development of the diffuse-type CH after total hip arthroplasty using Bicontact stems is one of the critical causes of the later development of SS and could be predicted to progress to SS. To prevent the development of the diffuse-type CH, the indication to choose a Bicontact stem for a Dorr type C with osteoporotic bone should be considered.

Results of total hip arthroplasty for dialysis arthropathy in long-term hemodialysis patients.

BACKGROUND: The number of hemodialysis patients has progressively increased in Japan. Among the orthopedic complications in this population, chronic hip arthropathy associated with long-term hemodialysis is one of the most devastating problems. Total hip arthroplasty (THA) is often indicated. However, varying results have been reported for THA in these patients. This study was undertaken to assess the risk-benefit ratio of THA performed in patients with dialysis hip arthropathy. METHODS: We evaluated 17 patients (19 hips) with dialysis hip arthropathy who underwent THA. The duration of hemodialysis before surgery ranged from 10 to 27 years. Histological examination of the tissue samples revealed accumulation of amyloid deposits in all cases. Three patients died within 2 years after operation; the remaining 14 patients (16 hips) were followed for a minimum of 3 years. RESULTS: The cumulative survival rate of the prostheses in these 16 hips up to the latest follow-up was 94%. Regarding surgery-related complications, deep infection occurred in one hip, and revision THA was required in one patient with recurrent dislocation and aseptic loosening. CONCLUSIONS: THA for dialysis hip arthropathy in long-term hemodialysis patients is associated with substantial local and general risks. Despite the substantial risk, THA for this patient population seems to afford reasonably satisfactory results.

Acetabular reconstruction for primary and revision total hip arthroplasty using Kerboull-type acetabular reinforcement devices-case-control study with factors related to poor outcomes of surgery.

Kerboull-type acetabular support rings (KT) and allogenic bone graft were used for severe periacetabular bone loss with primary and revision total hip arthroplasty (THA). The purpose of this case-control study is to evaluate the risk factors related to poor outcomes of surgery.Sixty patients underwent primary THA and revision THA using allogenic bone graft with KT for large acetabular deficiency. These patients were retrospectively evaluated postoperatively and followed-up by radiograph. The minimum follow-up period was 4 years and averaged 7 years. A radiological failure was defined by the following criteria:Expected risk factors were defined as female, age >75 years, body mass index (BMI) >25%, medical history of hypertension, renal failure, liver steatosis, diabetes, hyperlipidemia, cardiac infarction, smoking, American Academy of Orthopedic Surgery (AAOS) classification III or IV, bleeding>500 mL, time of surgery >3hours, high hip center-type KT, inclination of KT >45 degrees, screw angle >25 degrees, morselized bone graft, Kawanabe's classification stage 3 or 4 and revision surgery. Nineteen hips (31.6%) revealed radiological failure according to our criteria, and revision THA was performed in 2 hips (3.3%). In the statistical analysis, morselized bone graft and high hip center-type KT were identified as factors of poor outcomes of surgery.

Genomic P elements content of a wild M' strain of Drosophila melanogaster: KP elements do not always function as type II repressor elements.

The P element is one of the best-studied DNA transposons as a model system to study evolution of mobile DNAs. The P element is a causative factor for P-M hybrid dysgenesis in Drosophila melanogaster and the P-M phenotype (P, Q, or M) has been thought to reflect genomic P elements content. Recent survey of natural populations showed that full-size P (FP) and KP elements are predominant in almost all current populations, irrespective of their phenotype variation. It was also suggested that some P elements are functionally inactive and their inactivation plays an important role in determining P-M phenotype. In order to know how the genomic P elements are inactivated, we characterized molecular features and insertion sites of them in an M' strain. We isolated 20 P elements, one FP, 15 KP, and four other internally deleted defective elements, all of which appeared thoroughly inactive. These FP and KP elements had canonical sequences in each case, but no mutations abolishing their function. In addition, they were mostly located in or within the vicinity of presumably active genes. Our results suggest that inactivation of P elements is associated with neither mutations nor constitutional suppression by heterochromatinization in M' strains and that only a few elements inserted in some special chromosomal regions are likely to be involved in determination of the phenotype of individual flies. Existence of many copies of canonical, but inactive, KP elements in the M' strain is inconsistent with the assumption that type II repression of the KP element is the main reason for its increase in the wild populations of D. melanogaster.

Frequency-dependent ERK phosphorylation in spinal neurons by electric stimulation of the sciatic nerve and the role in electrophysiological activity.

The phosphorylation of extracellular signal-regulated kinase (pERK) in DRG and dorsal horn neurons is induced by the C-fiber electrical stimulation to the peripheral nerve. The present study was designed to investigate the expression and modulation of pERK in the rat dorsal horn neurons produced by repetitive electrical stimulation, and its involvement in the electrophysiological activity of dorsal horn neurons. Electrical stimulation of C-fiber intensity at different frequencies was applied to the sciatic nerve; the stimuli-induced pERK expression and the activity in dorsal horn neurons were studied by immunohistochemistry and extracellular recording, respectively. Electrical stimulation of C-fibers (3 mA) induced pERK expression in dorsal horn neurons in a frequency-dependent manner, indicating that the frequency of electrical stimulation is an important factor which activates the intracellular signal pathway in the spinal cord. To demonstrate the underlying mechanism of this frequency-dependent pERK expression, an NMDA receptor antagonist, MK-801, and a voltage sensitive calcium channel antagonist, nifedipine, were administrated intrathecally before the stimulation. We found that high frequency (0.5 Hz and 10 Hz) but not low frequent (0.05 Hz) stimulus-evoked pERK was partially inhibited by MK-801. Both high and low frequency stimulus-evoked pERK were inhibited by the nifedipine treatment. The extracellular single unit activities were recorded from the laminae I-II and V of the L4-5 dorsal horn, and we found that blockage of the intracellular ERK signal suppressed the wind-up responses in a dose-dependent manner. In contrast, any change in the mechanically evoked responses was not observed following the administration of ERK inhibitor. These observations indicate that ERK activation plays an important role in the induction of the wind-up responses in dorsal horn nociceptive neurons.

Comparison of Continuous Femoral Nerve Block with and Without Combined Sciatic Nerve Block after Total Hip Arthroplasty: A Prospective Randomized Study.

In association with the growing interests in pain management, several modalities to control postoperative pain have been proposed and examined for the efficacy in the recent studies. Various modes of peripheral nerve block have been proposed and the effectiveness and safety have been examined for each of those techniques. We have described our clinical experiences, showing that continuous femoral nerve block could provide a satisfactory analgesic effect after total hip arthroplasty (THA) procedure. In this study, we compared the effectiveness and safety of continuous femoral nerve block with and without sciatic nerve blockade on pain control after THA. Forty patients scheduled for THA were included in the study and randomly divided into 2 groups. Postoperative analgesic measure was continuous femoral nerve block alone, while the identical regimen of continuous femoral nerve block was combined with sciatic nerve block. The amount of postoperative pain was evaluated in the immediate postoperative period, 6 hours, and 12 hours after surgery. Moreover, postoperative complications as well as requirement of supplemental analgesics during the initial 12 hours after surgery were reviewed in the patient record. The obtained study results showed that the supplemental sciatic nerve blockade provided no significant effect on arrival at the postoperative recovery room, while the NRS pain score was significantly reduced by the combined application of sciatic nerve blockade at 6 and 12 hours after surgery. In the investigation of postoperative analgesiarelated complications, no major complication was encountered without significant difference in complication rate between the groups.

Use of the G-guide for Measuring Stem Antetorsion During Total Hip Arthroplasty.

Implant positioning is one of the critical factors influencing postoperative outcomes in total hip arthroplasty (THA). Several studies have reported that the postoperative antetorsion (AT) measurement for the femoral stem inserted without navigation showed wide variability. The current authors developed a simple instrument, the Gravity-guide (G-guide), for intraoperative assessment of stem AT and adjustment. They evaluated the effectiveness of the G-guide with postoperative computed tomography (CT) examination. Ninety patients (96 hips) who underwent primary THA using the G-guide for stem adjustment were evaluated. The G-guide consists of 2 parts: one attached to the lower leg and the other attached to the handle of the rasp. The G-guide was used to evaluate the AT at the time of inserting the final rasp. In addition, the AT value in the G-guide evaluation system required correction by the angle obtained in the preoperative epicondylar view. Intraoperative stem AT was defined as the sum of the intraoperative G-guide value and the correction angle. Postoperative AT was evaluated by CT examination. The discrepancy between the intra- and postoperative measurements was 4.6°±4.1°. Acceptable accuracy with discrepancy of less than 5° and 10° was achieved in 66 (69%) hips and 85 (89%) hips, respectively. The use of the G-guide could effectively reduce the variability of stem anteversion compared with manual adjustment. This study proved the effectiveness of the newly developed G-guide system in intraoperative stem AT adjustment.