Experimental periprosthetic fractures with collarless polished tapered cemented stems

PURPOSE

After cemented total hip arthroplasty, the risk of periprosthetic fracture (PPF) of taper-slip stems is higher than that of composite-beam stems. We aimed to assess the conditions resulting in PPFs of taper-slip stems using a falling weight.

METHODS

Taper-slip stems were fixed to five types of simulated bone models using bone cement, and the fractures were evaluated by dropping stainless-steel weights from a predetermined height onto the heads. The periprosthetic fracture height in 50% of the bone models (PPFH50) was calculated using the staircase method.

RESULTS

For the fixation with 0° of flexion, the values for PPFH50 were 61 ± 11, 60 ± 13, above 110, 108 ± 49, and 78 ± 12 cm for the cobalt-chromium-molybdenum alloy, stainless steel alloy (SUS), titanium alloy (Ti), smooth surface, and thick cement mantle models, respectively; for the fixation with 10° of flexion (considering flexure), the PPFH50 values were 77 ± 5, 85 ± 9, 90 ± 2, 89 ± 5, and 81 ± 11 cm, respectively. The fracture rates of the polished-surface stems were 78.6 and 35.7% at the proximal and distal sites, respectively (p < 0.05); the fracture rates of the smooth-surface stems were 14.2 and 100%, respectively (p < 0.05).

CONCLUSION

The impact tests demonstrated that the conditions that were less likely to cause PPFs were use of Ti, a smooth surface, a thick cement mantle, and probably, use of SUS.

Validity of a preoperative scoring system for surgical management of periprosthetic hip infection: one-stage vs. two-stage revision

INTRODUCTION

There are no widely accepted algorithms for determining optimal treatment for periprosthetic joint infection (PJI). Our study aimed to confirm the validity of a previously published scoring system in a larger number of patients to support a rational surgical treatment strategy for periprosthetic hip infection.

MATERIALS AND METHODS

Between February 2001 and December 2020, we performed 155 consecutive revision total hip arthroplasties (THAs) for PJI, with mean follow-up of 6 years. One-stage revision THA was performed in 56 hips and two-stage revision THA in 99 hips. Prosthesis survival from recurrent infection was determined by Kaplan-Meier analysis, using implant removal as the endpoint. The pre-operative scoring system (full score of 12 points), including 6 essential elements, was retrospectively evaluated.

RESULTS

The 10-year survival rates were 98% for one-stage (95% confidence interval [CI], 94-100) and 87% (95% CI, 79-96) for two-stage revision THA. Multivariate Cox regression analysis provided a total preoperative score as an independent risk factor for implant removal (hazard ratio, 0.17; 95% CI, 0.06-0.49; p < 0.001). The sensitivity and specificity at the cut-off of 4 points on the scoring system were 80% and 91%, respectively. The average score for one-stage revision THA in successful and failed cases were 8.9 and 6.0, and for two-stage revision THA were 6.5 and 3.9, respectively. We found significant differences between successful cases in one- and two-stage revision THA (p < 0.05).

CONCLUSIONS

The preoperative scoring system was useful for managing PJI. One-stage revision THA is recommended in patients scoring ≥ 9 points, and meticulously performed two-stage revision THA is encouraged for patients scoring ≥ 4 points.

The modified Spitzy shelf acetabuloplasty for the dysplastic hip

Aims

Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty.

Methods

Between November 2000 and December 2016, we retrospectively evaluated 144 consecutive hip procedures in 122 patients a minimum of five years after undergoing modified Spitzy shelf acetabuloplasty for acetabular dysplasia including osteoarthritis (OA). Our follow-up rate was 92%. The mean age at time of surgery was 37 years (13 to 58), with a mean follow-up of 11 years (5 to 21). Advanced OA (Tönnis grade ≥ 2) was present preoperatively in 16 hips (11%). The preoperative lateral centre-edge angle ranged from -28° to 25°. Survival was determined by Kaplan-Meier analysis, using conversions to total hip arthroplasty as the endpoint. Risk factors for joint space narrowing less than 2 mm were analyzed using a Cox proportional hazards model.

Results

The mean Merle d'Aubigné clinical score improved from 11.6 points (6 to 17) preoperatively to 15.9 points (12 to 18) at the last follow-up. The survival rates were 95% (95% confidence interval (CI) 91 to 99) and 86% (95% CI 50 to 97) at ten and 15 years. Multivariate Cox regression identified three factors associated with radiological OA progression: age (hazard ratio (HR) 2.85, 95% CI 1.05 to 7.76; p = 0.0398), preoperative joint space (HR 2.41, 95% CI 1.35 to 4.29; p = 0.0029), and preoperative OA (HR 8.34, 95% CI 0.94 to 73.77; p = 0.0466).

Conclusion

Modified Spitzy shelf acetabuloplasty is an effective joint-preserving surgery with a wide range of potential indications.

Trochanteric Claw Plate Fixation for Greater Trochanteric Fracture or Osteotomy in Total Hip Arthroplasty

This study retrospectively evaluated 41 consecutive open reductions and internal fixations following primary or revision total hip arthroplasty, which required trochanteric claw plate fixation for greater trochanteric fracture or osteotomy between January 2008 and December 2020. The mean duration of clinical follow-up was 4.2 years (range, 1-13 years). The patients included 13 men and 28 women, with a mean age of 68 years (range, 32-87 years). The indications for intervention included trochanteric osteotomy, intraoperative fracture, and non-union including postoperative fracture in 6, 9, and 26 cases, respectively. The mean Merle d'Aubigné Clinical Score improved from 9.4 points (range, 5-15 points) pre-operatively, to 14.3 points (range, 9-18 points) at the last follow-up. Bone union occurred in 35 cases (85%), while implant breakage occurred in four cases. At the last follow-up, the mean Merle d'Aubigné Clinical Scores of bone union and non-union were 15.3 and 14.1, respectively (p=0.48). The Kaplan-Meier survival rate, with the endpoint being revision surgery for pain, non-union, dislocation, or implant breakage, at 10 years was 80.0% (95% confidence interval: 62.6-97.4%). Greater trochanteric fixation using a trochanteric claw plate yielded successful results.

Chronic Expanding Hematoma With Progressive Osteolysis After Total Hip Arthroplasty: A Case Report

A 31-year-old man without any other medical history developed severe hip pain seven years after right primary total hip arthroplasty (THA). Radiography revealed extensive progressive osteolysis around the cup and stem. Periprosthetic infections and adverse reactions to the metal debris were absent. Right revision THA was performed, and chronic expanding hematoma (CEH) was diagnosed based on a comprehensive assessment. CEH should be diagnosed early because progressive osteolysis may generate an extensive hematoma. Thus, it should be considered when progressive osteolysis of an unknown cause is encountered after THA.

Trunnionosis in Metal-on-Polyethylene Total Hip Arthroplasty With Periprosthetic Infection: A Case Report

A 67-year-old man who underwent right hemiarthroplasty and left total hip arthroplasty (THA) experienced left hip pain two years previously. No previous diagnosis was made at other hospitals. Radiography revealed left hip trunnionosis because of stem-neck shortening, with periprosthetic joint infection (PJI) spreading to both hips. Bilateral revision THA was performed, but the treatment was difficult due to the delayed diagnosis, necessitating the extraction of the well-fixed stem for PJI. Trunnionosis is caused by implant-related, surgical, and patient factors, and early diagnosis is important because of its association with PJI. Furthermore, even implants with few reports of trunnionosis can lead to this complication. Surgeons should always consider that performing THA using a large-diameter head predisposes the patient to trunnionosis.

Can serum C-reactive protein determine the timing of reimplantation in two-stage revised arthroplasty for periprosthetic hip infection?

BACKGROUND

There are no definitive guides to determine the timing of reimplantation in two-stage revision total hip arthroplasties (THA) for periprosthetic joint infection (PJI). This study was to design to support a rational strategy of surgical treatment using serum C-reactive protein (CRP).

METHODS

We analyzed a total of 75 hips for PJI in the process of performing two-stage and multiple-stage revision THAs. CRP level was retrospectively evaluated every week and transformed to log2 (CRP) using a logistic regression model. Prosthesis survival from recurrent infection was determined by Kaplan-Meier analysis, using implant removal as the endpoint. Receiver operating characteristic curves were calculated using each log2 (CRP) to assess predictions of recurrent infection.

RESULTS

The 10-year survival rates were 85% (95% confidence interval, 76-95) and 100% for two-stage and multiple-stage revision THAs, respectively. Preoperatively, at 1, 2, 3, and 5 weeks, log2 (CRP) was not associated with recurrent infection. In failed two-stage revision THAs, log2 (CRP) at 3 weeks divided by that at 2 weeks showed a significant difference. Failure was associated with a ratio of >4.0 for the CRP level between 3 and 2 weeks.

CONCLUSION

In two-stage revision THA for PJI, patients with CRP elevation from 2 weeks to 3 weeks, especially 4-fold elevation, suggests the need for further debridement and postponement of second-staged reimplantation.

Treatment strategies for recurrent dislocation following total hip arthroplasty: relationship between cause of dislocation and type of revision surgery

Background

There are many therapeutic options for dislocation following total hip arthroplasty (THA). The aim of this study was to evaluate the results of revision surgery for dislocated hips.

Methods

Between November 2001 and December 2020, 71 consecutive revision hip surgeries were performed at our institution for recurrent dislocation following THA. We conducted a retrospective study of all 65 patients (71 hips), who were followed for a mean of 4.7 ± 3.2 years (range, 1–14). The cohort included 48 women and 17 men, with a mean age of 71 ± 12.3 years (range, 34–92). The mean number of previous surgeries was 1.6 ± 1.1 (range, 1–5). From intraoperative findings, we created six categories of revision hip surgery for recurrent dislocation following THA: open reduction and internal fixation (2 hips); head change or liner change only (6 hips); cup change with increased head size only (14 hips); stem change only (7 hips); cup and stem change (24 hips); and conversion to constrained cup (18 hips). Prosthesis survival was analyzed by the Kaplan-Meier method, with repeat revision surgery for re-dislocation or implant failure as the endpoint. A cox proportional hazards model was used for risk factors of re-revision surgery.

Results

Re-dislocation occurred in 5 hips (7.0%) and implant failure in 1 hip (1.4%). The 10-year survival rate was 81.1% (95% confidence interval, 65.5–96.8). A Dorr classification of “positional” was a risk factor for re-revision surgery due to re-dislocation.

Conclusion

Clear understanding of the cause of dislocation is essential for optimizing revision procedures and improving the rate of successful outcomes.

Endofemoral Shooting Technique for Removing Well-fixed Cementless Stems

Background

The removal of a well-fixed cementless stem poses technical challenges. The aim of this study was to evaluate the outcomes of our endofemoral extraction technique established in 2001.

Methods

Between January 2001 and December 2016, 118 consecutive revisions following bipolar or total hip arthroplasty, which required cementless femoral stem removal, were performed at our institution. This retrospective study evaluated 106 patients (108 hips) who were followed up for a mean of 9.2 years (range, 5-20 years). The patients included 15 men and 91 women with a mean age of 65 years (range, 33-87 years). Endofemoral extracted stem removal was performed as follows. Multiple Kirschner wires were sequentially inserted into the interface between the implant and cortical bone, after which the implant was detached using a thin chisel. After the cementless stem was removed, it was replaced with a cemented stem using an autograft, as needed. Radiological loosening of the femoral stem was defined as definite or probable loosening, based on the criteria of Harris et al. Prosthesis survival was analyzed using the Kaplan-Meier method, with the endpoint set as repeat revision surgery for stem loosening or femoral fracture.

Results

Re-revision surgery was performed in 7 hips. Stem loosening was observed in 4 hips, and the mean subsidence was 0.3 mm (0-3 mm). The 10-year survival rate was 97.7% (95% confidence interval, 93.2-100).

Conclusions

Our technique for removing well-fixed cementless stems yielded successful results.

8-Prenylnaringenin tissue distribution and pharmacokinetics in mice and its binding to human serum albumin and cellular uptake in human embryonic kidney cells

8-Prenylnaringenin (8-PN), a hop flavonoid, is a promising food substance with health benefits. Compared with nonprenylated naringenin, 8-PN exhibits stronger estrogenic activity and prevents muscle atrophy. Moreover, 8-PN prevents hot flushes and bone loss. Considering that prenylation reportedly improves the bioavailability of flavonoids, we compared the parameters related to the bioavailability [pharmacokinetics and tissue distribution in C57/BL6 mice, binding affinity to human serum albumin (HSA), and cellular uptake in HEK293 cells] of 8-PN and its mother (non-prenylated) compound naringenin. C57/BL6 mice were fed an 8-PN or naringenin mixed diet for 22 days. The amount of 8-PN (nmol/g tissue) in the kidneys (16.8 ± 9.20), liver (14.8 ± 2.58), muscles (3.33 ± 0.60), lungs (2.07 ± 0.68), pancreas (1.80 ± 0.38), heart (1.71 ± 0.27), spleen (1.36 ± 0.29), and brain (0.31 ± 0.09) was higher than that of naringenin. A pharmacokinetic study in mice demonstrated that the C _max of 8-PN (50 mg/kg body weight) was lower than that of naringenin; however, the plasma concentration of 8-PN 8 h after ingestion was higher than that of naringenin. The binding affinity of 8-PN to HSA and cellular uptake in HEK293 cells were higher than those of naringenin. 8-PN bioavailability features assessed in mouse or human model experiments were obviously different from those of naringenin.

Daptomycin for the Treatment of Gram-Positive Periprosthetic Hip Infections: Can Daptomycin Prevent the Implant Removal?

Introduction

Management of periprosthetic hip infections (PHIs) generally consists of implant removal and thorough debridement, accompanied by appropriate antibiotic therapy. Daptomycin (DAP) is a novel antibiotic, which allowed for implant retention in several patients after treating their infected joints. However, there is no consensus about implant retention or removal during the treatment of PHIs. The aim of this study was to examine the effect of DAP and to determine a surgical treatment strategy.

Methods

This study retrospectively evaluated 20 patients between August 2014 and December 2018, divided into implant retention (n=9) and implant removal groups (n=11). Infection control and risk of recurrent infection were evaluated. Infection control was defined as not requiring implant removal after the final treatment.

Results

Infection control rates in implant retention and implant removal groups were 67% and 90%, respectively. All late chronic infections resulted in failure cases within the implant retention group. In the implant retention group, mean preoperative risk scores for successful cases were significantly higher than those for failure cases (p<0.05).

Conclusions

Patients with low risk did not require implant removal, suggesting that DAP may be a breakthrough alternative to traditional PHI management.

A Possible Protective Effect of the 'Cam Deformity' on Femoral Neck Fracture: The Relationship between Hip Morphology and the Types of Hip Fracture

We retrospectively evaluated the cases of 169 hip fracture patients, their previous fractures, and the contralateral hip joint's morphology. A history of contralateral hip fracture was present in 23 patients (Contra group). The other patients had a unilateral hip fracture: a trochanteric fracture (Troch group, n=73) or a femoral neck fracture (Neck group, n=73). In the Troch and Neck groups, we used anteroposterior and cross-table axialview radiographs of the contralateral hip to evaluate the proximal femur's anatomy. In the Contra group, the concordance rate between the first and second types of hip fracture was 65.2%, and the second hip fracture's morphology indicated that the trochanteric fracture had a cam deformity in terms of the femoral head-neck ratio. The average alpha angle and femoral head-neck offset in the Troch group were significantly larger than those in the Neck group. In the Neck group, pistol-grip deformities of Arbeitsgemeinschaft für Osteosynthesefragen types B1 (subcapital), B2 (transcervical), and B3 (displaced) were observed in 42.1%, 75%, and 6% of cases, respectively. There was a smaller alpha angle and a larger femoral head-neck offset in the contralateral hip of femoral neck fractures; thus, the "cam deformity" may protect against femoral neck fractures.

Correlation between the Computed Tomography Values of the Screw Path and Pedicle Screw Pullout Strength: An Experimental Study in Porcine Vertebrae

Study Design

Biomechanical study.

Purpose

To assess the correlation between the computed tomography (CT) values of the pedicle screw path and screw pull-out strength.

Overview of Literature

The correlation between pedicle screw pull-out strength and bone mineral density has been well established. In addition, several reports have demonstrated a correlation between bone mineral density and CT values. However, no previous biomechanical studies investigated the correlation between CT values and pedicle screw pull-out strength.

Methods

Sixty fresh-frozen lumbar vertebrae from 6-month-old pigs were used. Before screw insertion, the CT values of the screw path were obtained for each sample. Specimens were then randomly divided into three equal groups. Each group had one of three pedicle screws inserted: 4.0-mm LEGACY (4.0-LEG), 4.5-mm LEGACY (4.5-LEG), or 4.5-mm SOLERA (4.5-SOL) (all from Medtronic Sofamor Danek Inc., Memphis, TN, USA). Each screw had a consistent 30-mm thread length. Axial pull-out testing was performed at a rate of 1.0 mm/min. Correlations between the CT values and pedicle screw pull-out strength were evaluated using Pearson’s correlation coefficient analysis.

Results

The correlation coefficients between the CT values of the screw path and pedicle screw pull-out strength for the 4.0-LEG, 4.5-LEG, and 4.5-SOL groups were 0.836 (p<0.001), 0.780 (p<0.001), and 0.873 (p<0.001), respectively. Greater CT values were associated with greater screw pull-out strength.

Conclusions

The CT values of the screw path were strongly positively correlated with pedicle screw pull-out strength, regardless of the screw type and diameter, suggesting that the CT values could be clinically useful for predicting pedicle screw pull-out strength.

Linezolid versus daptomycin treatment for periprosthetic joint infections: a retrospective cohort study

Background

Linezolid (LZD) and daptomycin (DAP) are predominantly used to target gram-positive pathogens; however, treatment effectiveness and adverse reactions for periprosthetic joint infections (PJIs) remain unknown. The aim of this study was to compare the effectiveness and adverse reactions of LZD and DAP for PJIs.

Methods

This study retrospectively evaluated 82 patients between June 2009 and December 2017, to compare the effectiveness of LZD (group L, n = 39) and DAP (group D, n = 43) for treatment of PJIs harboring gram-positive microorganisms. Surgical options used with LZD or DAP therapy included implant retention, implant removal, and a shift to another appropriate antibiotic. Infection control was defined as not requiring implant removal after the final treatment.

Results

Gram-positive pathogens were isolated from 72% of group L and 70% of group D patients, respectively. Whole infection control rates against gram-positive pathogens in groups L and D were 79% and 77%, respectively. Furthermore, infection control rates were 94% and 58% in group L and 75% and 80% in group D, without and with implant removal, respectively. Significantly higher clinical success rates and lower adverse event rates were observed in group D, including higher red blood cell and platelet counts and lower C-reactive protein (CRP) levels.

Conclusions

Although the effectiveness of LZD and DAP was equivalent in terms of infection control rates for refractory PJIs with gram-positive pathogens, DAP therapy significantly decreased CRP levels and caused fewer adverse events than LZD treatment.

Sonication of Extracted Implants Improves Microbial Detection in Patients With Orthopedic Implant-Associated Infections

BACKGROUND

We assessed whether combining the conventional culture and implant sonicate fluid culture (SFC) methods increased the diagnostic accuracy of orthopedic implant-associated infection (OIAI).

METHODS

Consecutive patients (n = 66) undergoing implant removal (OIAI, 17; non-OIAI, 49) were evaluated prospectively. We analyzed 493 samples (39 preoperative joint aspirates, 243 peri-implant tissue specimens, 124 implant sonication, 67 controls, and 20 water bath samples). OIAI was preoperatively evaluated based on clinical evidence of infection or aspirate culture (AC). Conventional methods required positive results in either preoperative ACs or intraoperative tissue cultures (TCs), whereas the combination method required at least 1 positive culture among 3 sources (AC, TC, or SFC). The application of SFC and the detection rate, sensitivity, and specificity of the diagnostic methods were assessed.

RESULTS

No controls or water bath samples harbored bacteria. Three patients (18%) were detected by SFC only and Peptostreptococcus and Corynebacterium species were isolated by SFC only. The OIAI detection rate attributable to SFC was significantly higher than that of TC (61% vs 36%; P = .02). The sensitivities of AC, TC, and SFC at a cutoff point of 1 colony-forming unit/plate and 1 positive culture were 60%, 59%, and 71%, respectively. At a cutoff point of 2 positive cultures, the combination (vs conventional) method showed significantly greater sensitivity (71% vs 47%; P = .008).

CONCLUSION

By incorporating SFCs into conventional culture methods, the diagnostic accuracy in the context of OIAI was significantly improved.

Reattachment of an osteotomized greater trochanter in total hip arthroplasty using an ultra-high molecular weight polyethylene fiber cable

BACKGROUND

The optimum approach in total hip arthroplasty (THA) should reduce the risk of postoperative dislocation or limping, be applicable in every case, and be reusable in the future. The purpose of this study was to introduce our transgluteal approach for THA and to evaluate the type and frequency of complications around the greater trochanter.

METHODS

This study retrospectively evaluated 892 THA cases between January 2010 and March 2015 performed using our transgluteal approach that osteotomized only the lateral anteroinferior greater trochanter. The trochanteric fragment was reattached using one of three different protocols: Group A, three non-absorbable polyester sutures; Group B, two non-absorbable polyester sutures and one ultra-high molecular weight polyethylene (UHMWPE) fiber cable; or Group C, two UHMWPE fiber cables. Postoperative complications were assessed and recorded, and univariate logistic regression analyses were performed to determine whether risk factors and radiological complications around the greater trochanter were correlated.

RESULTS

None of the hips required revision for infection, dislocation, or limping. The rate of radiological complications around the greater trochanter at 1 year was 19.2% in Group A, 16.3% in Group B, and 7.9% in Group C (p < 0.001). Risk factors for radiological complications included the patient's disease or the surgeon's experience in Group A and the patient's age or the surgeon's experience in Group C. In the relationship between postoperative pain around the greater trochanter and radiological complications, there were no significant differences in all groups; no group interaction was observed (p= 0.3875).

CONCLUSION

The UHMWPE fiber cable was effective to reduce complications of the reattached osteotomized greater trochanter in THA.

Altered expression of microRNA during fracture healing in diabetic rats

OBJECTIVES

Diabetes mellitus (DM) is known to impair fracture healing. Increasing evidence suggests that some microRNA (miRNA) is involved in the pathophysiology of diabetes and its complications. We hypothesized that the functions of miRNA and changes to their patterns of expression may be implicated in the pathogenesis of impaired fracture healing in DM.

METHODS

Closed transverse fractures were created in the femurs of 116 rats, with half assigned to the DM group and half assigned to the control group. Rats with DM were induced by a single intraperitoneal injection of streptozotocin. At post-fracture days five, seven, 11, 14, 21, and 28, miRNA was extracted from the newly generated tissue at the fracture site. Microarray analysis was performed with miRNA samples from each group on post-fracture days five and 11. For further analysis, real-time polymerase chain reaction (PCR) analysis was performed at each timepoint.

RESULTS

Microarray analysis showed that there were 14 miRNAs at day five and 17 miRNAs at day 11, with a greater than twofold change in the DM group compared with the control group. Among these types of miRNA, five were selected based on a comparative and extended literature review. Real-time PCR analysis revealed that five types of miRNA (miR-140-3p, miR-140-5p, miR-181a-1-3p, miR-210-3p, and miR-222-3p) were differentially expressed with changing patterns of expression during fracture healing in diabetic rats compared with controls.

CONCLUSIONS

Our findings provide information to further understand the pathology of impaired fracture healing in a diabetic rat model. These results may allow the potential development of molecular therapy using miRNA for the treatment of impaired fracture healing in patients with DM.Cite this article: S. Takahara, S. Y. Lee, T. Iwakura, K. Oe, T. Fukui, E. Okumachi, T. Waki, M. Arakura, Y. Sakai, K. Nishida, R. Kuroda, T. Niikura. Altered expression of microRNA during fracture healing in diabetic rats. Bone Joint Res 2018;7:139-147. DOI: 10.1302/2046-3758.72.BJR-2017-0082.R1.

Bone Remodeling in Acetabular Reconstruction Using a Kerboull-Type Reinforcement Device and Structural Bone-Grafting in Total Hip Arthroplasty

BACKGROUND

The purpose of this study was to identify the long-term durability of the Kerboull-type reinforcement device (KT plate) in acetabular reconstruction for massive bone defects, assessing the remodeling of structural bone grafts.

METHODS

This study retrospectively evaluated 106 hips that underwent acetabular reconstruction using a KT plate between November 2000 and December 2010. Thirty-eight primary total hip arthoplasties (THAs) and 68 revised THAs were performed, and the mean duration of clinical follow-up was 8 years (5-14 years). Regarding reconstructing the acetabular bone defects, autografts were used in 37 hips, allografts in 68 hips, and A-W glass ceramics in 2 hips.

RESULTS

One hip exhibited radiological migration and no revision for aseptic loosening. The mean Merle d'Aubigné Clinical Score improved from 7.5 points (4-12 points) preoperatively to 10.9 points (9-18 points) at the last follow-up. The Kaplan-Meier survival rate for radiological migration of primary and revised THAs at 10 years was 100% and 97% (95% confidence interval: 96%-100%), respectively. Bone remodeling was evaluated using the radiological demarcation at the bone-to-bone interface, and an improvement of 100% in primary THAs and 94% in revised THAs was observed.

CONCLUSION

For massive bone defects, acetabular reconstruction using the KT plate with a structural bone grafting can yield successful results.

Long-term results of acetabular reconstruction using three bulk bone graft techniques in cemented total hip arthroplasty for developmental dysplasia

PURPOSE

The aims of this retrospective study were to firstly introduce three practical bulk bone graft techniques based on acetabular morphology for dysplasia and secondly evaluate the long-term durability of acetabular reconstruction using those techniques combined with cemented total hip arthroplasty (THA).

METHODS

The study comprised 101 consecutive THAs with a minimum follow-up of ten years; these procedures were categorised as being L shape (n = 58), Wall (n = 33) and D shape (n = 10) types.

RESULTS

At the last follow-up, all bone grafts acquired trabecular reorientation, and no evidence of revision for aseptic or radiological loosening was noted.

CONCLUSIONS

These bone graft techniques will be effective for improving the management of dysplasia in cemented THA by providing both acetabular reconstruction and cement containment.

Anterior Cruciate Ligament Reconstruction Using a Bone-Patellar Tendon-Bone Autograft to Avoid Harvest-Site Morbidity in Knee Arthroscopy

Although anterior cruciate ligament reconstruction using a bone-patellar tendon-bone (BPTB) autograft has many advantages (e.g., high strength and solid fixation), there are also several complications (e.g., anterior knee pain or kneeling pain) due to harvest-site morbidity associated with the use of this graft type compared with the use of hamstring tendon. Therefore the ultimate goal of anterior cruciate ligament reconstruction using a BPTB graft is to minimize harvest-site morbidity. We have used a technique for harvesting central-third BPTB grafts that involves only a 3-cm-long, longitudinal, curved incision in the medial tibial tuberosity for both graft harvesting and fixation. The purpose of this report is to describe the technique, which can avoid the harvest-site morbidities associated with BPTB autografts during knee arthroscopy. We believe that this less invasive reconstruction may reduce the harvest-site morbidities associated with BPTB grafts because it allows for BPTB graft harvesting without incising the synovial bursa or paratenon and mitigates scarring and adhesion formation.

Induction of autoimmune arthritis after direct injection of bone marrow cells from arthritis-prone SKG/Jcl mice into bone cavity of normal mice

SKG/Jcl (SKG) mice spontaneously develop T cell-mediated autoimmune arthritis and may be an effective model for studying human rheumatoid arthritis. We sought to confirm that arthritis in SKG mice was caused by stem cell disorders. We induced systemic arthritis in normal C57/BL6 (B6) mice (H-2(b) type) by injecting lineage-negative (lin(-)) immature cells isolated from bone marrow cells (BMCs) of SKG mice (H-2(d) type) directly into bone cavities. Twenty weeks later, we analyzed arthritis scores, hematoxylin-eosin (H-E) staining and tartrate-resistant acid phosphatase (TRAP) staining in ankle joints, H-2 type of hematolymphoid and osteoblast-like cells, serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and percentages of CD4(+) T cells and osteoblast-like cells expressing receptor activator of nuclear factor kappa-B ligand (RANKL) in recipient mice. Donor-derived hematolymphoid cells and osteoblast-like cells had completely replaced donor-derived cells in the recipients (H-2(b) to H-2(d)). All recipients showed severe joint swelling with hyperemia and developed hypertrophic synovitis with lymphocytes accumulated around joints. All recipients also had higher TNF-α and IL-6 levels than untreated B6 controls. Furthermore, the percentages of CD4(+) T cells and osteoblast-like cells expressing RANKL and the number of TRAP(+) cells were greater in treated animals. Donor-derived hematolymphoid cells and osteoblast-like cells persisted in these recipients and promoted autoimmune arthritis and an increase in osteoclasts. Because autoimmune arthritis may be associated with abnormal lin(-) immature cells, patients with intractable autoimmune arthritis may be treated by replacing these cells with direct injection of lin(-) immature cells isolated from normal BMCs.

Evaluation of the clinical performance of ultrahigh molecular weight polyethylene fiber cable using a dog osteosynthesis model

The purpose of this study was to assess the removability and biological reactivity of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable as a new biomaterial for osteosynthesis. We used a pull-out test and an implantation test to analyze the performance of the UHMWPE fiber cable using a dog model, and compared its characteristics with those of a wire cable and a soft wire. In the pull-out test, the UHMWPE fiber cable was as easy to remove as the soft wire, and both the UHMWPE fiber cable and the soft wire were significantly easier to remove than the wire cable. The fixation capability and the biological reactivity of the UHMWPE fiber cable were examined in an osteosynthesis model of the dog greater trochanter, and were compared with those of the soft wire. The bone union rate, assessed radiographically, was very similar when using the UHMWPE fiber cable and the soft wire. However, in the soft wire group, both the surface of the greater trochanter under the fixation material and the penetration area around the fixation material showed an increased tendency toward a biological reaction, including inflammation and granulation tissue formation, as compared to the UHMWPE fiber cable group. The UHMWPE fiber cable was as easily removed from the bone tissue as the soft wire, and was easier to remove than the wire cable. Additionally, the UHMWPE fiber cable caused reduced biological reactivity with the surrounding tissue, as compared with the soft wire. In conclusion, the UHMWPE fiber cable appeared to be a suitable fixation material for osteosynthesis.

Subtrochanteric shortening osteotomy combined with cemented total hip arthroplasty for Crowe group IV hips

BACKGROUND

Total hip arthroplasty (THA) is a challenging surgical procedure that can be used to treat severely dislocated hips. There are few reports regarding cemented THAs involving subtrochanteric shortening osteotomy (SSO), even though cemented THAs provide great advantages because the femur is generally hypoplastic with a narrow, deformed canal.

PURPOSES

We evaluated the utility of cemented THA with SSO for Crowe group IV hips, and assessed the relationship between leg lengthening and nerve injury. Our goal was to describe surgical techniques for optimizing surgical outcomes while minimizing the risk of nerve injury.

METHODS

We retrospectively reviewed 34 cases of cemented THAs with transverse SSO for Crowe group IV. Prior to surgery, mean hip flexion was 93.1° (40°-130°). The mean follow-up period was 5.2 years (3-10 years).

RESULTS

Bone union took an average of 7.7 months (3-24 months). Mean leg lengthening was 40.5 mm (15-70 mm) and was greater in patients without hip flexion contracture. None of the patients experienced any nerve injuries associated with leg lengthening, and radiographic evidence of loosening was not observed at the final follow-up.

CONCLUSIONS

SSO combined with cemented THA is an effective treatment for severely dislocated hips. Leg lengthening is not necessarily associated with nerve injuries, and the likelihood of this surgical complication may be related to the presence of hip flexion contracture.

Treating Achilles tendon rupture in rats with bone-marrow-cell transplantation therapy

BACKGROUND

Bone marrow cells possess multipotentiality and have been used for several treatments. We hypothesized that bone marrow cells might differentiate into regenerated tendon and that several cytokines within bone marrow cells might accelerate tendon healing. Therefore, we treated Achilles tendon ruptures in a rat model with transplantation of whole bone marrow cells.

METHODS

Nine F344/Nslc (Fisher) rats were the source of bone marrow cells and mesenchymal stem cells as well as normal Achilles tendons. Eighty-seven Fisher rats were used for the experiments. The rats were divided into three groups: the BMC group (bone marrow cells injected around the tendon), the MSC group (mesenchymal stem cells injected around the tendon), and the non-treated control group (incision only). Outcome measures included mechanical testing, collagen immunohistochemistry, histological analysis, and reverse transcription-polymerase chain reaction to detect expression of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF).

RESULTS

The ultimate failure load in the BMC group was significantly greater than that in the non-treated or the MSC group at seven days after incision (3.8 N vs. 0.9 N or 2.1 N, p < 0.016) and at fourteen days after incision (10.2 N vs. 6.1 N or 8.2 N, p < 0.016). The ultimate failure load in the BMC group at twenty-eight days after incision (33.8 N) was the same as that of normal tendon (34.8 N). The BMC group demonstrated stronger staining for type-III collagen at seven days after incision and stronger staining for type-I collagen at twenty-eight days than did the MSC group. Expression of TGF-β and VEGF in the BMC group was significantly increased compared with that in the other groups at four days after incision (TGF-β: 1.6 vs. 1.3 or 0.6, p < 0.01; VEGF: 1.7 vs. 1.1 or 0.9, p < 0.01).

CONCLUSIONS

Transplantation of whole bone marrow cells may be a better and more readily available treatment for Achilles tendon rupture than cultured mesenchymal stem cells.

New strategies for anterior cruciate ligament partial rupture using bone marrow transplantation in rats

The purpose of this study was to compare anterior cruciate ligament (ACL) regeneration between animal groups subjected to intra-articular injection of fresh whole bone marrow cells (BMCs), cultured mesenchymal stem cells (MSCs), or saline. Partially transected ACLs in Fischer 344/Nslc rats were prepared, followed by injection of BMCs, MSCs, or saline into the articular cavity at 1 week after transection. Donor cells expressing green fluorescent protein were detected in the recipient's transected ACLs at 4 weeks in the BMC and MSC groups, and their ACLs appeared almost normal histologically. Further, there were significantly more mature spindle cells in the BMC group than in the saline group at 4 weeks. Biomechanically, the tensile strength in the BMC group reached near normal levels at 4 weeks after injection. The levels of transforming growth factor-β1 in the ACL tissue and knee joint fluid in the BMC group were increased significantly compared with that of the saline group at 4 weeks as detected by immunohistochemical analysis. In conclusion, intra-articular bone marrow transplantation using fresh whole BMCs is an effective treatment for ACL partial rupture. This therapy is easy to apply in a clinical setting because no culture system is required for collecting MSCs.

Efficient Cell-seeding into Scaffolds Improves Bone Formation

Bone marrow stromal cells (BMSCs)/β-tricalcium phosphate (β-TCP) composites have attracted a great deal of attention in bone tissue engineering. If more effective bone regeneration is to be achieved, efficient cell-seeding systems need to be clarified. In this study, we investigated the number of cells contained in composites, and the in vitro/vivo osteogenic differentiation capacity of composites using 4 conventional systems of seeding rat BMSCs into β-TCP: soak, low-pressure, pipette, and syringe systems. The highest number of cells was contained in the composites from the syringe group. Moreover, after two-week osteogenic induction in vitro, the composites in the syringe group exhibited the highest osteogenic potential, which continued at 8 weeks after subcutaneous implantation in vivo. Our results indicated that efficient and appropriate cell-seeding could improve in vitro/vivo bone formation in composites and thus make a potential clinical contribution to successful bone tissue engineering. Abbreviations: BMSCs, bone marrow stromal cells; β-TCP, β-tricalcium phosphate; S-D, Sprague-Dawley; kPa, kilopascal; ALP, alkaline phosphatase; N, Newton; DNA, deoxyribonucleic acid; OCN, osteocalcin; ANOVA, analysis of variance; PLSD, protected least-significant difference; and HE, hematoxylin and eosin.

Allogeneic intra-bone marrow transplantation prevents rheumatoid arthritis in SKG/Jcl mice

The treatment of autoimmune diseases by allogeneic bone marrow transplantation remains a promising therapeutic avenue. However, more intensive studies on murine models are essential before application to a large number of human patients. In particular, the use of bone marrow transplantation to treat rheumatoid arthritis has been problematic. We have taken advantage of the SKG/Jcl mouse that develops a chronic T cell-mediated autoimmune disease that mimics rheumatoid arthritis which attempted to prevent the development of immunopathology in these mice by allogeneic bone marrow transplantation (BMT). In particular, we utilized our unique technology in which bone marrow cells (BMCs) of control C57BL/6J mice are directly injected into the bone marrow cavity in the tibia of SKG mice (intra-bone marrow [IBM]-BMT). As controls, SKG/Jcl mice were transplanted with whole BMCs from syngeneic SKG mice. Importantly, 12 months after IBM-BMT [B6-->SKG] demonstrated no evidence of arthritis, whereas the control [SKG-->SKG] mice demonstrated, the expected immunopathology of a rheumatoid arthritis-like condition. Further, hematolymphoid cells in [B6-->SKG] mice were reconstituted by donor-derived cells and the percentages of Treg (Foxp3+/CD4+) cells, the percentages of receptor activator of nuclear factor-kappaB ligand (RANKL)+ cells on the CD4+ T cells and the serum levels of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 were normalized in the [B6-->SKG] mice. These data suggest that IBM-BMT is a viable method of immunological manipulation that suppresses the severe joint destruction and bone absorption in SKG/Jcl mice and lends further credence to the use of this methodology in humans with intractable rheumatoid arthritis.

Activation of rat nucleus pulposus cells by coculture with whole bone marrow cells collected by the perfusion method

Cell proliferation and matrix synthesis were compared for rat nucleus pulposus cells cocultured with mesenchymal stem cells (MSCs) or fresh whole bone marrow cells (BMCs), harvested by the perfusion or aspiration methods. Nucleus pulposus cells were isolated from tail intervertebral discs of F344/slc rats, and BMCs were obtained from femora. Proteoglycan synthesis, DNA synthesis, and aggrecan mRNA expression were measured. The level of transforming growth factor-beta in supernatants from the culture system was also measured. Cell number, aggrecan mRNA expression, and uptake of [(35)S]-sulfate and [(3)H]-thymidine by nucleus pulposus cells cocultured with fresh whole BMCs all increased significantly compared with nucleus pulposus cells cocultured with MSCs. TGF-beta secreted by nucleus pulposus cells cocultured with fresh whole BMCs also significantly increased when compared with cocultures with MSCs. The perfusion method was superior to the aspiration method for preventing contamination of BMCs with peripheral red blood cells and lymphocytes, which may cause an autoimmune response in the disc. In conclusion, we suggest that fresh whole BMCs harvested by the perfusion method are more effective for increasing the proliferative and matrix synthesis capacity of nucleus pulposus cells.

Prevention of corticosteroid-induced osteonecrosis in rabbits by intra-bone marrow injection of autologous bone marrow cells

OBJECTIVES

Femoral head osteonecrosis (ON) is a serious complication of steroid administration. We evaluated bone marrow transplantation (BMT) for preventing corticosteroid-induced ON.

METHODS

Rabbits, injected with methylprednisolone (MPSL; 20 mg/kg), were divided into four groups: (i) MPSL alone; MPSL injection only, (ii) MPSL+needling; 2 days after MPSL injection, a hole (1.2 mm diameter) was drilled from the outer cortex 2.5 cm distal to the proximal end of the greater trochanter, (iii) MPSL+saline; 2 days after MPSL injection, 2 ml saline was injected directly into the bone marrow cavity, and (iv) MPSL+BMT; 2 days after MPSL injection, 1 x 10(7)/2 ml bone marrow cells (BMCs) were injected directly into the bone marrow cavity. Platelets, fibrinogen, prothrombin time and total cholesterol in peripheral blood were measured before and after treatment. Tissues were stained with haematoxylin and eosion and terminal deoxynucleotidyl-mediated deoxyuridine triphosphate nick-end labelling stain and immunostained for VEGF, while cell proliferation and viability of whole BMCs in the femur were analysed by cell cycle analysis and [(3)H]-thymidine uptake.

RESULTS

The ON incidence in rabbits treated with MPSL alone, MPSL+needling and MPSL+saline was 72.7, 70.0 and 66.7%, respectively, while in the MPSL+BMT group, the incidence was 0%. Serological findings in the MPSL+BMT group were almost normalized. VEGF and TUNEL staining were reduced in the MPSL+BMT group compared with all other groups. There were significantly fewer BMCs in G1 phase from the MPSL+BMT group than the other groups, while uptake of [(3)H]-thymidine was significantly increased.

CONCLUSION

Direct injection of autologous BMCs into femurs prevents corticosteroid-induced ON following treatment with high-dose, short-term steroids.

Pigmented villonodular synovitis originating from the lumbar facet joint: a case report

The authors successfully treated a rare case of pigmented villonodular synovitis (PVNS) that originated from the lumbar facet joint (L4-5). A 43-year-old man presented with a complaint of left severe sciatica causing difficulty in walking. Magnetic resonance imaging (MRI) demonstrated an extradural mass on the left side at L4 and the mass compressed the dural tube and was continuous with the left L4-5 facet joint. A computed tomography myelogram revealed an extradural defect of contrast medium at the L4 level and an erosion of the L4 lamina. A total synovectomy with unilateral osteoplastic laminectomy was performed. The histological findings were a diagnosis of PVNS. The patient's symptoms resolved completely and the MRI at postoperative 3 years demonstrated no recurrence of PVNS. It is important to totally remove the synovium, which is the origin of PVNS in order to prevent the recurrence. We think that our procedure is reasonable and adequate for lumbar PVNS.

An in vitro study demonstrating that haematomas found at the site of human fractures contain progenitor cells with multilineage capacity

We isolated multilineage mesenchymal progenitor cells from haematomas collected from fracture sites. After the haematoma was manually removed from the fracture site it was cut into strips and cultured. Homogenous fibroblastic adherent cells were obtained. Flow cytometry revealed that the adherent cells were consistently positive for mesenchymal stem-cell-related markers CD29, CD44, CD105 and CD166, and were negative for the haemopoietic markers CD14, CD34, CD45 and CD133 similar to bone-marrow-derived mesenchymal stem cells. In the presence of lineage-specific induction factors the adherent cells could differentiate in vitro into osteogenic, chondrogenic and adipogenic cells.

Our results indicate that haematomas found at a fracture site contain multilineage mesenchymal progenitor cells and play an important role in bone healing. Our findings imply that to enhance healing the haematoma should not be removed from the fracture site during osteosynthesis.

Implication of spinal protein kinase C in the suppression of morphine-induced rewarding effect under a neuropathic pain-like state in mice

We previously demonstrated that spinal protein kinase C (PKC) is involved in the development of a neuropathic pain-like state induced by sciatic nerve ligation, and the morphine-induced rewarding effect is attenuated by sciatic nerve ligation in rodents. Here we first investigated whether sciatic nerve injury could change the activity of a conventional PKC (cPKC) and an atypical PKC isoform PKCzeta in the mouse spinal cord. The second experiment was to investigate whether direct inhibition of spinal PKC by intrathecal (i.t.) administration of a specific PKC inhibitor, 2-[8-[(dimethylamino)methyl]-6,7,8,9-tetrahydropyrido[1,2-a]indol-3-yl]-3-(1-methyl-1H-indole-3-yl)maleimide (RO-32-0432), could affect the rewarding effect induced by morphine following sciatic nerve ligation in mice. We found here that the activities of both cPKC and PKCzeta in the spinal cord were clearly increased following sciatic nerve ligation. Furthermore, i.t. administration of RO-32-0432 reversed a long-lasting pain-like syndrome as indicated by thermal hyperalgesia following sciatic nerve ligation in mice. These data provide direct evidence that activated cPKC and PKCzeta in the spinal cord may contribute to the development and maintenance of neuropathic pain. In the present study, we confirmed that the morphine-induced place preference was significantly suppressed by sciatic nerve ligation. It should be mentioned that i.t. pretreatment with RO-32-0432 significantly reversed the attenuation of morphine-induced rewarding effect following sciatic nerve ligation. These results suggest that activation of PKCs, including cPKC and PKCzeta, within the spinal cord is directly responsible for the attenuation of the morphine-induced rewarding effect under a neuropathic pain-like state following sciatic nerve ligation in mice.

Significance of adrenomedullin under cardiopulmonary bypass in children during surgery for congenital heart disease

To elucidate the effect of adrenomedullin (AM) on fluid homeostasis under cardiopulmonary bypass (CPB), we investigated the serial changes in plasma AM and other parameters related to fluid homeostasis in 13 children (average age, 28.2 months) with congenital heart disease during cardiac surgery under CPB. Arterial blood and urine samples were collected just after initiation of anesthesia, just before commencement of CPB, 10 min before the end of CPB, 60 min after CPB, and 24 h after operation. Plasma AM levels increased significantly 10 min before the end of CPB and decreased 24 h after operation. Urine volume increased transiently during CPB, which paralleled changes in AM. Simple regression analysis showed that plasma AM level correlated significantly with urinary vasopressin, urine volume, urinary sodium excretion, and plasma osmolarity. Stepwise regression analysis indicated that urine volume was the most significant determinant of plasma AM levels. Percent rise in AM during CPB relative to control period correlated with that of plasma brain natriuretic peptide (r = 0.57, P < 0.01). Our results suggest that AM plays an important role in fluid homeostasis under CPB in cooperation with other hormones involved in fluid homeostasis.

Increased QT dispersion does not reflect the increased regional variation of cardiac sympathetic nervous activity in hypertrophic cardiomyopathy

BACKGROUND

QT dispersion (QTD) reflects regional variation of ventricular repolarization. However, the relationship between QTD and the regional variation of cardiac sympathetic nerve activity in hypertrophic cardiomyopathy (HCM) is not yet elucidated.

METHODS

Cardiac sympathetic nerve activity was evaluated in 25 patients with HCM by iodine 123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy. With planar MIBG imaging, heart and mediastinum ratios (H/M) at early (20 minutes) and delayed (3 hours) acquisition and the washout rate (WR) were calculated. Polar maps of left ventricular myocardium were divided into 20 segments. The SD of early uptake (EU-SD), delayed uptake (DU-SD), and WR (WR-SD) in 20 segments as indices of regional variation were calculated. QT intervals were corrected by use of the Bazett formula.

RESULTS

Maximum QTc correlated positively with H/M early, WR, and left ventricular wall thickness (LVWT). Minimum QTc correlated positively with WR and LVWT. Corrected QTD (QTDc) correlated negatively with EU-SD, DU-SD, and WR-SD and positively with the interventricular septal thickness/posterior wall thickness ratio. Stepwise regression analysis revealed that the most powerful determinants for maximum QTc, minimum QTc, and QTDc were WR, LVWT, and EU-SD, respectively.

CONCLUSIONS

QTD correlated negatively rather than positively with the regional variability index of cardiac sympathetic nerve activity. These results suggest that increased QTD in patients with HCM may not reflect increased heterogeneity of cardiac sympathetic nerve activity.

Systolic dysfunction and blood pressure responses to supine exercise in patients with hypertrophic cardiomyopathy

Left ventricular function and blood pressure responses were evaluated in 56 patients with non-obstructive hypertrophic cardiomyopathy (HCM) and 12 control subjects by using a radionuclide ventricular function monitor during supine ergometer exercise. Patients with HCM were divided into 2 groups: (i) group A had no decrease in ejection fraction (EF) during exercise; and (ii) group B had a decrease in EF during exercise. During exercise, the change in end-diastolic volume did not differ between the 3 groups. In contrast, the change in end-systolic volume differed between the 3 groups (p<0.0001). The change in systolic blood pressure (SBP) also differed significantly between the 3 groups. The change in SBP in group B was smaller than that in the control group and group A, and changes in the EF and changes in the SBP between rest and peak exercise showed a significant correlation (p<0.005). These results suggest that exercise-induced systolic dysfunction in patients with non-obstructive HCM may contribute to abnormal blood pressure response in those patients.

[Four cases of the anomalous origin of the left coronary artery from the pulmonary artery]

We report perioperative management of 4 patients with anomalous origin of the left coronary artery from the pulmonary artery. This report involves with 3 infant cases and an adult. Two infants underwent coronary reimplantation procedure and Takeuchi's method was performed on the other infant. In all infant cases, mitral valve plasty was performed to correct mitral regurgitation secondary to papillary muscle dysfunction. The adult patient underwent CABG with ligation of LCA. General anesthesia was performed with high doses of fentanyl in all cases. We employed a relatively high PaCO2 and low FIO2 in order to maintain a high pulmonary vascular resistance. It aims to decrease the incidence of left to right shunt. We used epinephrine to wean one infant and the adult from cardiopulmonary bypass. Perioperative course was uneventful with the use of catecholamines and high doses of vasodilators for left ventricular dysfunction and coronary perfusion under mechanical ventilation.

Successful reoperation for diffuse supravalvular aortic stenosis

We reoperated for diffuse supravalvular aortic stenosis using a modified technique of patch plasty described by Brom. A 36-year-old woman admitted to our hospital with a peak systolic pressure gradient of 92 mmHg across the ascending aorta had previously undergone Doty's operation at another hospital. Aortography showed an ascending aorta diffusely stenotic from the sinotubular junction to the aortic arch. We transected the ascending aorta just above the stenotic portion and incised the proximal wall to the sinus of Valsalva. Three patches were sewn to each sinus to expand them and the ascending aorta. The pressure gradient decreased postoperatively to 11 mmHg, and we conclude that this technique sufficiently relieves diffuse supravalvular aortic stenosis.

Slow spin relaxation of Rb atoms confined in glass cells filled with dense 4He gas at 1.85 K

At temperatures below 2.1 K, long-lived gaseous Rb atoms in glass cells have been generated with a simple method: irradiating the cells, containing 4He gas and Rb metal, with a cw laser. The obtained atomic Rb density ( approximately 10(8) cm(-3)) decreases with a 1/e time constant of about 10 s at 1.85 K. We have performed optical pumping of the Rb atoms and measured the longitudinal electronic spin relaxation time at 1.85 K as well. For processes (such as Rb-He collisions) which do not remove the atomic Rb from the vapor, this relaxation time is found to be about 60+/-15 s.

Mitral valve replacement in a patient with idiopathic thrombocytopenic purpura

Reports of a cardiac operation in a patient with idiopathic thrombocytopenic purpura are scarce. Here we present a case of successful mitral valve replacement in a patient with idiopathic thrombocytopenic purpura. Preoperative treatment with high-dosage gamma-globulin successfully increased the platelet count from 50,000/microliter to 80,000/microliter. Twenty units of platelet-rich plasma were administered during and after the operation. No other blood products were used. The postoperative convalescence was uneventful. Perioperative management for patients with idiopathic thrombocytopenic purpura undergoing open-heart surgery is discussed.

Modulation of norepinephrine release by ATP-dependent K(+)-channel activators and inhibitors in guinea-pig and human isolated right atrium

OBJECTIVE

The aim of this study was to show, whether ATP sensitive K+ channels (KATP channels), are involved in the modulation of norepinephrine (NE) release from the sympathetic nerves innervating the guinea-pig and human right atrium.

METHODS

The resting and stimulation-evoked release of [3H]norepinephrine ([3H]NE) was measured from the isolated guinea-pig and human right atrium and the effect of activators and inhibitors of ATP sensitive K+ channels was studied.

RESULTS

Cromakalim (30-300 microM), a KATP channel-agonist decreased concentration-dependently the stimulation-evoked release of NE from the guinea-pig atrium, an effect, antagonized by glibenclamide, a KATP channel-antagonist (30 microM). Diazoxide (30-300 microM), another activator of the KATP channels reduced the resting release of NE, and also attenuated the evoked release at a single concentration (100 microM), and this latter action was also counteracted by glibenclamide (30 microM). Pinacidil, increased dose-dependently the resting and stimulation-evoked release of NE in a glibenclamide-sensitive manner and reversed the inhibitory effect of cromakalim (100 microM), suggesting that it acts as an antagonist. Glibenclamide (30-300 microM), by itself enhanced the stimulation-evoked release of [3H]NE, and also increased the resting release of NE. On the other hand, 5-hydroxydecanoate, an ischemia-selective inhibitor of cardiac KATP channels did not change NE release. Adenosine, (30-300 microM), an A1-receptor agonist, clonidine (3 microM), an alpha 2-adrenoceptor agonist and oxotremorine, a muscarinic receptor agonist (30 microM) all reduced the evoked release of [3H]NE, but these effects were not modified by glibenclamide (300 microM), indicating that neuronal adenosine (A1), adrenergic (alpha 2) and muscarinic (M3) receptors do not act on KATP channels. In the human right atrium, cromakalim, and diazoxide did not affect significantly the release of [3H]NE. However, glibenclamide (30-300 microM) and pinacidil (30-300 microM) enhanced dose-dependently the evoked-release of NE, and pinacidil also augmented the resting release.

CONCLUSIONS

Our results indicate that sympathetic nerve endings of the human and guinea-pig atrium are endowed with ATP-sensitive K+ channels. These channels responded to agonists and antagonists under the experimental conditions applied and they could modulate the release of NE thereby affecting the autonomic control of cardiac function under various physiological and pathophysiological conditions.