Effect of femoral component offset on polyethylene wear in total hip arthroplasty

Seventeen staged, bilateral total hip arthroplasties performed in 17 patients were reviewed to compare side-to-side polyethylene wear. Implants used on both sides were similar except for implant offset: one hip in each patient was replaced using a femoral component having a standard implant offset, whereas the other side had a lateral offset implant. The mean followup was 5.70 years (range, 2-10.2 years) on the side with a standard femoral implant and 5.67 years (range, 2-9.7 years) on the side with a lateralized femoral component. The only statistically different parameter between the sides was the femoral component offset. All other parameters affecting polyethylene wear, such as period of followup, head size, head type, cup size, cup inclination, medialization of cup, and patient-related factors were similar on both sides. On the side with a standard femoral component, the mean actual prosthetic offset (determined by manufacturer's specifications) was 35.2 mm and the radiologic offset was 31.5 mm. On the side with a lateralized femoral component, the actual prosthetic offset was 42.5 mm and the radiologic offset was 40.1 mm. The difference in offsets between the sides was statistically significant. The mean preoperative offset of the femur was 38.8 mm. Regression analysis revealed that only femoral component offset and cup size correlated significantly with linear wear rate. On the side with a standard femoral component, the linear wear rate was 0.21 mm per year, whereas on the side with a lateralized femoral component, the linear wear rate was 0.10 mm per year. The differences in the linear wear rates were significant. Lateralization of the femoral component in this series more closely restored preoperative hip biomechanics and significantly decreased polyethylene wear.

Decreasing length of stay after pancreatoduodenectomy

HYPOTHESIS

Decreased length of stay (LOS) after pancreatoduodenectomy is due to multiple factors, including a lower complication rate and more efficient perioperative care for all patients, with and without complications.

DESIGN

A retrospective review, validation cohort.

SETTING

A single university hospital referral center.

PATIENTS

A consecutive sample of patients undergoing pancreatoduodenectomy from January 9, 1986, to December 21, 1992 (group 1 [n = 104]) and from February 16, 1993, to November 9, 1998 (group 2 [n = 111]).

INTERVENTION

Mann-Whitney test and linear [correction of logistic] regression analysis applied to clinical variables and LOS.

MAIN OUTCOME MEASURES

Difference in median LOS between early and late groups and identification of factors predictive of decreased LOS.

RESULTS

Total LOS decreased between the 2 groups (26 days [range, 13-117 days] vs 15 days [range, 5-61 days]; P<.001), with a decrease in preoperative (4 days [range, 0-28 days] vs 2 days [range, 0-36 days]; P<.001) and postoperative (19 days [range, 11-95 days] vs 12 days [range, 4-58 days]; P<.001) LOS (data given for group 1 vs group 2). Major complications decreased from 49% in group 1 to 25% in group 2 (P<.001). Postoperative LOS decreased for patients with (25 days [range, 15-95 days] vs 20 days [range, 8-58 days]; P = .05) and without (15 days [range, 11-47 days] vs 11 days [range, 4-55 days]; P<.001) major complications (data given for group 1 vs group 2). Multivariate analysis identified age (P = .01), pancreatic fistula (P<.001), delayed gastric emptying (P<.001), biliary complications (P<.001), operative time (P<.005), extra-abdominal infection (P<.005), use of a percutaneous stent (P = .04), and year of operation (P<.001) as independent predictors of total LOS.

CONCLUSION

A reduction in complications in combination with factors leading to a streamlining of perioperative care has contributed to the decreased LOS after pancreatoduodenectomy.

Expression of Von Willebrand factor, an endothelial cell marker, is up-regulated by angiogenesis factors: a potential method for objective assessment of tumor angiogenesis

von Willebrand factor (vWF), a glycoprotein produced uniquely by endothelial cells and megakaryocytes, is routinely used to identify vessels in tissue sections. Vessel density in tumor specimens, as determined by immuno-histochemical staining for vWF or other endothelial cell markers, is a negative prognostic factor for many solid tumors. vWF is heterogeneously distributed throughout the vasculature, transcriptional control in response to the tissue microenvironment being responsible for local variations in endothelial cell levels of vWF. Here, we report that fibroblast growth factor-2 and vascular endothelial growth factor, potent angiogenesis inducers expressed in a variety of tumors, up-regulate expression of vWF mRNA and protein in cultured endothelial cells with a synergistic effect. Our data support the measurement of vWF mRNA in tumors to detect activated endothelium or angiogenesis. For this purpose, we developed a semi-quantitative RT-PCR for vWF mRNA. Preliminary results obtained with specimens from colon carcinoma and the corresponding normal colonic mucosa showed higher vWF mRNA levels in most tumors than in their normal counterparts. The differences in vWF mRNA levels were much larger than the differences in vessel counts between a tumor and the corresponding normal mucosa, indicating that high vWF mRNA levels in tumors may indeed be an early sign of activation of the endothelium. The rapidity, objectivity, sensitivity and specificity of this technique make it suitable for routine clinical application to identify aggressive, highly angiogenic tumors.

Complications of aesthetic laser surgery

Aesthetic laser surgery is not risk free. It behooves the laser surgeon to become intimately familiar with the potential adverse effects of laser use to guard against and to minimize their occurrence. Moreover, patients must be thoroughly, clearly, and honestly educated about the procedure and its risks so that their expectations are realistic and so that any complications that do occur can be recognized early and treated appropriately. This review summarizes basic laser safety and discusses the nature of complications that may occur during continuous-wave, pulsed dye, pigment-specific, hair removal, and resurfacing laser procedures.

Minimum 10-year results of a tapered cementless hip replacement

Seventy-one total hip arthroplasties with a cementless, wedge fit, cobalt chrome femoral component were reviewed in 60 patients at a minimum 10-year followup (mean, 11.5 years). For the femoral component, the mechanical failure rate was 5% and the revision rate for aseptic loosening was 0%. The mean Charnley scores for pain, function, and motion changed from preoperative mean values of 3.0, 2.7, and 3.2 to followup mean values of 5.7, 5.5, and 5.2, respectively. The followup mean Harris hip Score was 91. The incidence of thigh pain was 1.4% at 10-year followup. Ninety-five percent of femoral components showed radiologic evidence of stable, bone ingrowth fixation, whereas loosening was seen in 5% of stems. Despite the high incidence of acetabular osteolysis, no osteolysis was seen on the femoral side distal to the lesser trochanter. Nonmodularity of the femoral component led to unavoidable revision of stably fixed femoral components in seven (9.8%) hips during the revision of a loose socket. Design features (collarless, tapered, wedge fit, and circumferentially porous coated) were thought to be crucial to the superlative results with the cobalt chrome femoral component.

Evidence for F-actin-dependent and -independent mechanisms involved in assembly and stability of the medial actomyosin ring in fission yeast

Cell division in a number of eukaryotes, including the fission yeast Schizosaccharomyces pombe, is achieved through a medially placed actomyosin-based contractile ring. Although several components of the actomyosin ring have been identified, the mechanisms regulating ring assembly are still not understood. Here, we show by biochemical and mutational studies that the S.pombe actomyosin ring component Cdc4p is a light chain associated with Myo2p, a myosin II heavy chain. Localization of Myo2p to the medial ring depended on Cdc4p function, whereas localization of Cdc4p at the division site was independent of Myo2p. Interestingly, the actin-binding and motor domains of Myo2p are not required for its accumulation at the division site although the motor activity of Myo2p is essential for assembly of a normal actomyosin ring. The initial assembly of Myo2p and Cdc4p at the division site requires a functional F-actin cytoskeleton. Once established, however, F-actin is not required for the maintenance of Cdc4p and Myo2p medial rings, suggesting that the attachment of Cdc4p and Myo2p to the division site involves proteins other than actin itself.

Disease patterns among Canadian aboriginal children. Study in a remote rural setting

OBJECTIVE

To describe disease patterns among children in an isolated aboriginal community, and to compare them with patterns found among other aboriginal and non-aboriginal Canadian children.

DESIGN

Retrospective review of logbooks and patient charts extracted from nursing station records for all visits to the community's nursing station between April 1, 1990, and March 31, 1991.

SETTING

An isolated aboriginal community located in northwestern Ontario.

PARTICIPANTS

All aboriginal children younger than 5 years.

MAIN OUTCOME MEASURES

Disease-specific incidence per 100 person-years by age, sex, and season.

RESULTS

Upper and lower respiratory tract infections, skin conditions, otitis media, and chickenpox were the leading causes of illness. Except for chickenpox, these illnesses occurred at a significantly higher rate among infants than among children 1 to 4 years old. No important differences were found by sex for any condition, except asthma where boys predominated. Autumn and winter seasonal patterns were most evident for respiratory tract infections. The rate of illness for most conditions was higher than that reported among other aboriginal and non-aboriginal Canadian children.

CONCLUSIONS

The illnesses most frequently seen in these children are respiratory tract infections and skin conditions. Etiologic factors are likely to be related to multiple interacting forces (both environmental and genetic) and require further investigation.

Rng2p, a protein required for cytokinesis in fission yeast, is a component of the actomyosin ring and the spindle pole body

BACKGROUND

An actomyosin-based contractile ring plays a pivotal role in cytokinesis. Despite the identification of many components of the ring, the steps involved in its assembly are unknown. The fission yeast Schizosaccharomyces pombe is an attractive organism in which to study cytokinesis because its cell cycle has been well characterized; it divides by medial fission using an actomyosin ring; and a number of S. pombe mutants defective in actomyosin ring assembly have been isolated. Here, we have characterized one such mutant, rng2.

RESULTS

Temperature-sensitive rng2 mutants accumulated F-actin cables in the medial region of the cell but failed to organize the cables into a ring. In rng2-null mutants, only a spot-like structure containing F-actin was detected. The rng2+ gene encodes a protein related to human IQGAP1, a protein that binds actin and calmodulin and is a potential effector for the Rho family of GTPases. Rng2p localized to the actomyosin ring and to the spindle pole body (SPB) of interphase and mitotic cells. Localization of Rng2p to the actomyosin ring but not the SPB required F-actin. Rng2p interacted with calmodulin, a component of the SPB and the actomyosin ring. The rng2 gene showed genetic interactions with three other actomyosin ring assembly mutants, cdc4, cdc12, and rng5.

CONCLUSIONS

The S. pombe IQGAP-related protein Rng2p is a component of the actomyosin ring and the SPB and is required for actomyosin ring construction following assembly of F-actin at the division site.

Soluble factor(s) released from neutrophils activates endothelial cell matrix metalloproteinase-2

OBJECTIVE

Polymorphonuclear leukocyte (PMN) infiltration and microvascular injury are hallmarks of the tissue remodeling associated with multiple organ failure. These processes require the concerted action of various proteolytic enzymes, including serine and matrix metalloproteinases (MMPs). Matrix metalloproteinase-2 (MMP-2) plays an important role in the turnover of various ECM components, including type IV collagen, fibronectin, and gelatins. Like all MMPs, MMP-2 is secreted as an inactive zymogen (proMMP-2) and activated extracellularly by limited proteolytic cleavage. The physiologic mechanism(s) of proMMP-2 activation remains unclear. This study was designed to characterize the effect of PMNs on the activation of proMMP-2 produced by endothelial cells.

METHODS

PMNs and human umbilical vein endothelial cells (HUVECs) were grown either separately or together for 2-16 h. To evaluate the role of cell-cell contact, cocultures were also established in which the two cell types were separated by a semipermeable polycarbonate membrane. Alternatively, PMN-conditioned medium was added to HUVEC cultures with or without various proteinase inhibitors (aprotinin, 1,10-phenanthroline, Batimastat, E-64, eglin c peptide, or pepstatin A). After incubation, the culture supernatants were analyzed by gelatin zymography to characterize the gelatinases.

RESULTS

HUVECs produce MMP-2 in its inactive (72 kDa) form. PMNs produce high levels of MMP-9 (gelatinase B, 92 kDa) but no MMP-2. Coculture of PMNs with or addition of PMN-conditioned medium to HUVECs results in the production of active (62 kDa) MMP-2. ProMMP-2 activation by PMN-conditioned medium is not blocked by inhibitors of plasmin, cysteine-, acid-, or metalloproteinases.

CONCLUSION

PMNs release a soluble factor that activates endothelial cell MMP-2 through a novel mechanism independent of cell-cell contact and not attributable to the activities of plasmin, cysteine-, acid-, or metalloproteinases. These findings may provide insight into the tissue remodeling that accompanies PMN-mediated microvascular injury.

Immediate weightbearing after uncemented total hip arthroplasty

Radiographic subsidence of the femoral prosthesis and clinical results after unilateral and simultaneous bilateral uncemented total hip arthroplasty were compared. Patients who had bilateral total hip arthroplasty began weight-bearing as tolerated on both lower extremities the day after surgery. Patients who had undergone unilateral total hip arthroplasty were maintained at 10% weightbearing on the operative limb for 6 weeks after surgery. Patients in both groups were matched for age, gender, and weight. Minimal followup was 2 years. There was no difference between the two groups in terms of clinical results. Radiographic assessments were performed immediately after surgery, 6 weeks after surgery, and again at 2 years after surgery. Radiographs were reviewed by a single observer and analyzed with a digitized data recorder. Increased subsidence of the femoral prosthesis within the bilateral group was found at 6 weeks. The mean subsidence of the femoral prosthesis at 6 weeks for the bilateral total hip arthroplasty group was 0.86 mm (range, 0.18-2.60 mm) and for the unilateral group was 0.39 mm (range, 0.07-1.46 mm). However, subsidence occurring between 6 weeks and 2 years averaged 0.50 mm (range, 0.09-1.10 mm) for the bilateral group and 0.54 mm (range, 0.03-0.99 mm) for the unilateral group. This difference was not significant. At the 2-year followup, all femoral prostheses in both groups appeared radiographically stable with evidence of bone ingrowth and no indications of loosening. Thus, immediate weightbearing after bilateral total hip arthroplasty in this study resulted in more initial subsidence (during the first 6 weeks after surgery) of the femoral prosthesis but did not preclude the prosthesis from becoming stable and achieving bone ingrowth. Patients in both groups obtained satisfactory clinical results. Because initial stability and bone ingrowth are factors influenced by prosthesis design, the results of this study may not be applicable to all implants.

Endoscopic biliary drainage before pancreaticoduodenectomy for periampullary malignancies

Despite decreased operative mortality, pancreaticoduodenectomy (PD) remains a formidable operation with substantial morbidity. We have evaluated the influence of preoperative endoscopic biliary drainage (EBD) on morbidity after PD for malignant biliary obstruction by retrospectively reviewing the medical records of 182 patients undergoing PD between April 1985 and August 1996. Of 52 study patients with malignant obstructive jaundice, 22 underwent preoperative EBD, and 30 were not drained. Eighty-three patients were excluded for bilirubin levels less than 5 mg/dl, 43 had other biliary drainage, and 4 had jaundice with benign pathology. Preoperative, intraoperative, and postoperative factors were compared. The two groups were well matched for clinical presentation and operative characteristics except for lower preoperative values of liver chemistries in patients undergoing EBD. Length of postoperative hospitalization for patients undergoing EBD was 13.5 days, compared with 19 days for patients who were not drained (p = 0.02). Patients who were not drained tended to have more overall complications (p = 0.054). Multivariate analysis revealed time to regular diet (p < 0.0001) and no preoperative drainage (p = 0.04) to be independent factors significantly increasing the length of hospitalization. Endoscopic biliary drainage before PD significantly reduced the length of postoperative hospitalization and was associated with less postoperative morbidity. Further studies, including cost analysis, are warranted.

Simultaneous bilateral versus unilateral total knee arthroplasty. Outcomes analysis

One hundred consecutive, primary simultaneous bilateral total knee arthroplasties were prospectively compared with 100 consecutive, primary unilateral total knee arthroplasties in reference to relative risk, complications, cost, and need for rehabilitation. All procedures were performed using identical preoperative, intraoperative, and postoperative protocols. Postoperative confusion was approximately four times greater in the simultaneous bilateral total knee arthroplasties group (29% versus 7%), which was thought to represent an increased incidence of fat embolism. Cardiopulmonary complications were approximately three times greater after simultaneous bilateral total knee arthroplasties (14% versus 5%), and most commonly involved arrhythmias. The increased stress on the cardiopulmonary system with simultaneous bilateral total knee arthroplasties may make this procedure contraindicated in certain patients with preexisting disease. There was an approximately 17 times greater need for banked blood in the simultaneous bilateral total knee arthroplasties group (17% versus 1%), which is alarming given the persistent concerns of transfusion related disease transmission. Although the length of hospitalization was similar (6.4 days simultaneous bilateral total knee arthroplasties versus 6 days unilateral total knee arthroplasty), 89% of the patients in the simultaneous bilateral total knee arthroplasties group required a rehabilitation stay versus 45% of the patients in the unilateral total knee arthroplasty group. Total hospital charges averaged $53,168 for simultaneous bilateral total knee arthroplasties versus $32,598 for unilateral total knee arthroplasty. Total rehabilitation charges were similar. The relative cost savings implicit by doing simultaneous bilateral total knee arthroplasties seem to be at least partially offset by the approximately two times greater need for rehabilitation in this group. The true safety, efficacy, relative risk, and total cost analysis of simultaneous bilateral total knee arthroplasties demands further critical evaluation.

Relationship of total hip arthroplasty outcomes to other orthopaedic procedures

The Medical Outcomes Study Short Form-36 was used preoperatively and 2 years postoperatively to compare patients' self reported assessment of health and function between 151 patients who had primary total hip replacement and 49 patients who had total hip revision, 149 patients who had primary total knee replacements, 41 patients who had lumbar laminectomy, and 43 patients who had scoliosis surgery. Primary total hip arthroplasty and lumbar laminectomy posted equivalent followup scores. Primary total hip arthroplasty showed significant improvements in physical function and health perception when compared with revision total hip arthroplasty; all other health parameters were similar. Primary total hip arthroplasty showed significantly better followup scores and greater improvement in scores in four of nine categories of the SF-36 when compared with primary total knee arthroplasty (despite identical scores preoperatively). Despite a higher level of assessed health preoperatively, patients who had scoliosis surgery compared least favorably with patients who had primary total hip arthroplasty at 2 years followup. In terms of patient self assessment of health and function, primary total hip arthroplasty and lumbar laminectomy for radiculopathy gave the best results.

Lexipafant inhibits platelet activating factor enhanced neutrophil functions

Platelet activating factor (PAF) enhances polymorphonuclear leukocyte (PMN) superoxide (.O2-) production, CD11b expression, and elastase release, all essential components in the pathophysiology of multiple-organ failure. This study was designed to determine the effects of Lexipafant, a PAF receptor antagonist, on PAF-mediated PMN functions. PMNs from 10 healthy volunteers were isolated and pretreated with various concentrations of Lexipafant (0-100 microM). PMNs were then incubated for 5 min with 200 nM PAF for .O2- detection or 2000 nM PAF for elastase measurement and activated with 1 microM N-formylmethionylleucylphenylalanine. The mean rate of .O2- production was determined by a cytochrome c reduction assay (nmole .O2-/min/1.33 x 10(5) PMN +/- SEM). Elastase release was measured by the cleavage of the synthetic elastase substrate Meo-Suc-Ala-Ala-Pro-Val-pNA (mean elastolytic activity +/- SEM). In parallel experiments, PMNs were incubated with 200 nM PAF for 30 min following pre-treatment with Lexipafant and CD11b expression was determined by flow cytometry (mean fluorescence intensity +/- SEM). Statistical analysis was performed using repeated-measures ANOVA (P < 0.05). Lexipafant inhibited PAF-enhanced PMN .O2- generation, CD11b expression and elastase release in a dose dependent fashion. The IC50 of Lexipafant for .O2- production, CD11b expression, and elastase release was 0.046, 0.285, and 0.05 microM, respectively. Lexipafant attenuated the PAF-mediated upregulation of PMN .O2- production, CD11b expression, and elastase release in a dose dependent fashion. These data support the hypothesis that Lexipafant may reduce the severity of the inflammatory response to injury produced by PAF-enhanced activation of PMNs.

Primary cementless hip arthroplasty with a titanium plasma sprayed prosthesis

One hundred two patients underwent 105 primary uncemented total hip arthroplasties and were reviewed at a minimum of 5 years after operation (mean, 6.1 years). The components were titanium alloy with a titanium plasma spray coating. The acetabular revision rate was 11.4%. Acetabular cavitary lytic lesions were identified in 25.5% at 5 years. All acetabular revisions were performed for a combination of wear and osteolysis. One femoral revision was performed to facilitate an acetabular revision, but the femoral revision rate for aseptic loosening was 0%. In addition, no femoral components had subsided or were thought to be loose radiographically. Thigh pain was present in 4% at 5 years. Despite the 25.5% incidence of acetabular osteolysis, distal femoral lysis was not seen and only 5% showed focal osteolysis in the trochanteric region proximal to the circumferential porous coating of the femoral component. Component design features were thought to be critical to the excellent performance of the femoral component and to the poor performance of the acetabular component.

Treatment of femoral osteolysis with cementless total hip revision

Fifty-nine total hip revision arthroplasties using cementless femoral components were performed in patients with focal femoral osteolytic defects before surgery. Clinical and radiographic review was performed at 2 to 5 years of follow-up evaluation. Osteolytic defects were located by Gruen zones, evaluated on postoperative radiographs, and classified as stabilized, progressive, regressing, healed, or new. There were no clinical failures in this series of patients, and no femoral revisions have been necessary. Progression of the lytic defects after revision did not occur. No new defects developed. Of the 154 preoperative osteolytic defects identified, 27 stabilized, 65 regressed, and 62 healed. One goal of revision hip surgery is to prevent osteolytic lesions from progressing, and this was achieved in 100% of patients in this series. Another goal of revision surgery is restoration of bone stock. It appears that there is a slow, steady remodeling of the lytic lesion that occurs with a well-fixed porous ingrowth prosthesis. Although this series did not show any additional benefit from cancellous allografting, the grafting technique did not use specifically designed instrumentation. Therefore, the full potential of grafting may not have been realized. If severe osteolysis is present, then regression or healing of defects can be achieved by revision to a cementless femoral component with or without the addition of cancellous allograft.

Treatment of early symptomatic pulmonary embolism after total joint arthroplasty

The purpose of this study was to evaluate the risk of intravenous heparin therapy or the use of Greenfield filters (Meditech, Watertown, MA) in the early postoperative period in patients who have documented symptomatic pulmonary embolism. Symptomatic pulmonary embolism in the first weeks was identified in 52 patients. Twenty-four patients were treated with Greenfield filter insertion and 28 patients with intravenous heparin therapy. One complication associated with insertion of the Greenfield filter-premature opening in the internal jugular vein-resulted in no adverse consequences. Three complications were associated with intravenous heparin therapy: one transient thrombocytopenia, one recurrent symptomatic pulmonary embolism, and one knee hematoma, which did not require surgical evacuation. It appears that Greenfield filter insertion is a viable option for treatment of symptomatic pulmonary embolism in the early postoperative period after total joint arthroplasty. In contrast to other published data, this study suggests that intravenous heparin therapy may also be a reasonable alternative, but is a treatment regimen that requires careful monitoring of platelets, wound complications, and bleeding parameters.

Health outcome assessment before and after lumbar laminectomy for radiculopathy

STUDY DESIGN

Forty-one patients undergoing lumbar laminectomy for radiculopathy resulting from herniated discs assessed their health status using a generic health outcome instrument (Medical Outcomes Study Short Form 36) before surgery and at an average of 2 years after surgery.

OBJECTIVES

To assess whether lumbar laminectomy for herniated nucleus pulposus is a useful intervention when patients evaluate their own perception of health.

SUMMARY OF BACKGROUND DATA

The medical Outcomes Study Short Form 36 has been used in multiple studies assessing various medical conditions. It is brief, generic, and reliable. Although surgical treatment for radiculopathy by lumbar laminectomy has been shown to be successful using specific criteria for patient selection and an algorithmic approach, the authors are not aware of any study using a patient-based health outcome assessment to evaluate the results of this type of surgery.

METHODS

Forty-one patients (82% completed follow-up evaluation; average follow-up period, 2.08 years) completed Medical Outcomes Study Short Form 36 before and after surgery. Scores from before and after surgery were compared.

RESULTS

Statistically significant improvements (P < 0.01) were seen in eight of the nine health scores comparing scores from before and after surgery at follow-up evaluation. These included physical function, social function, role function resulting from physical limitations, role function resulting from emotional limitations, mental health, vitality, pain, and perceived health change. No significant change was seen in the patients' health perception after surgery.

CONCLUSIONS

This study shows that the patients' self-reported health outcomes after lumbar laminectomy correlate with the excellent results previously seen using physician-driven outcome measures in an appropriately selected population with radiculopathy. The excellent results shown here did not deteriorate with age (> 40 years compared with < 40 years) or with complications after surgery.

Heterotopic ossification. Incidence in cemented versus cementless total hip arthroplasty

To resolve the debate whether cementless total hip arthroplasty (THA) carries an increased risk of heterotopic ossification (HO) as compared with cemented THA, 100 patients undergoing primary cemented THA (both acetabulum and femur) were individually matched to 100 patients undergoing primary cementless THA. Preoperative, 6-week postoperative, and 2-year postoperative radiographs were reviewed for the presence of HO using the Brooker classification. No subject in either group received any postoperative prophylaxis for HO. The matching parameters were age ( +/- 10 years), sex, weight ( +/- 10 lb.), diagnosis (all were osteoarthritis), Charnley class (A/B), and surgical approach (trochanteric osteotomy or modified Hardinge). The overall incidence of HO was 68% in the cemented group and 65% in the cementless group. The extent of HO (grade III) was significant in 9% of the cemented group and 5% of the cementless group. There was no grade IV HO (bone ankylosis) in either group. Neither the overall incidence nor the incidence of grade III HO was statistically different between the two groups. Patient sex and surgical approach had no interactive effect with type of component fixation on the incidence of HO. Fear of HO should not be a factor in the choice of fixation for THA.

Predicting quality-of-life outcomes following total joint arthroplasty. Limitations of the SF-36 Health Status Questionnaire

A group of 114 patients undergoing total hip and knee arthroplasty were evaluated to assess the effect of total joint arthroplasty on quality of life, as measured by the SF-36 Health Status Questionnaire, and to determine the predictive relationship between preoperative and postoperative scores. A highly significant improvement was seen comparing preoperative with postoperative scores at 2 years for physical function, social function, physical role function, emotional role function, mental health, energy, and pain. Despite a significant change in health status (P < or = .001), no change was seen in the patient's health perception (P = .61). Regression analysis failed to indicate a predictive relationship between preoperative and postoperative scores for any scale. Total joint arthroplasty dramatically improves the quality of life and function of patients afflicted with arthritis; however, because of the poor ability of the SF-36 to predict postoperative improvement on an individual basis, it cannot be used alone to determine treatment selection.

Comparison of cemented and cementless total hip arthroplasty in patients with bilateral hip arthroplasties

A consecutive series of 36 patients underwent primary cemented total hip arthroplasty followed by primary cementless total hip arthroplasty of the contralateral hip. Clinical pain scores between the cementless and cemented hips were not different. Subjectively, patients either had no preference or preferred the cementless side. Comparison of results in the same patient eliminates variability introduced by differences in sex, weight, comorbidities, bone quality, and activity level. Control of these factors permits more meaningful comparison of the type of fixation.

Epithelial cell specific properties and genetic complementation in a delta F508 cystic fibrosis nasal polyp cell line

Analysis of vectorial ion transport and protein trafficking in transformed cystic fibrosis (CF) epithelial cells has been limited because the cells tend to lose their tight junctions with multiple subcultures. To elucidate ion transport and protein trafficking in CF epithelial cells, a polar cell line with apical and basolateral compartments will facilitate analysis of the efficacy of different gene therapy strategies in a "tight epithelium" in vitro. This study investigates the genotypic and phenotypic properties of a CF nasal polyp epithelial, delta F508 homozygote, cell line that has tight junctions pre-crisis. The cells (sigma CFNPE14o-) were transformed with an origin-of-replication defective SV40 plasmid. They develop transepithelial resistance in Ussing chambers and are defective in cAMP-dependent Cl- transport as measured by efflux of radioactive Cl-, short circuit current (Isc), or whole-cell patch clamp. Stimulation of the cells by bradykinin, histamine, or ATP seems to activate both K(+)- and Ca(+2)-dependent Cl- transport. Measurement of 36Cl- efflux following stimulation with A23187 and ionomycin indicate a Ca(+2)-dependent Cl- transport. Volume regulatory capacity of the cells is indicated by cell swelling conductance. Expression of the CF transmembrane conductance regulator mRNA was indicated by RT-PCR amplification. When cells are grown at 26 degrees C for 48 h there is no indication of cAMP-dependent Cl- as has been previously indicated in heterologous expression systems. Antibodies specific for secretory cell antigens indicate the presence of antigens found in goblet, serous, and mucous cells; in goblet and serous cells; or in goblet and mucous cells; but not antigens found exclusively in mucous or serous cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Taperloc femoral component. A 2-6-year study of the first 100 consecutive cases

The first 100 consecutive patients who underwent insertion of the Taperloc (Biomet, Warsaw, IN) femoral stem were prospectively studied with a mean follow-up period of 3.8 years (range, 2-6 years). Two of the original 100 patients were lost, giving a 98% follow-up rate. The diagnoses included osteoarthritis (76 patients), avascular necrosis (19), rheumatoid arthritis (3), chrondrolysis (1), and post-traumatic arthritis (1). The mean age at surgery was 56 years (range, 25-79 years), mean weight was 78 kg (range, 45-127 kg), and the female to male ratio was 29:71. Charnley pain and function scores were 3.0 and 2.8 before surgery and 5.5 and 5.4 after surgery. Thigh pain was present in 2% of the patients at the final follow-up evaluation. There were no revisions. Radiographic signs of bone-ingrowth fixation (calcar atrophy, spot welds) were seen in 92 of 94 components (98%). No component had complete demarcation of the porous-coated zones. Fifty-two of 94 patients were able to be matched for age, sex, weight, diagnosis, and length of follow-up period with a series of patients who received a contemporary cemented total hip. In this matched subset, the Charnley pain and function scores were 5.6 and 5.5 for the cementless Taperloc stem and 5.7 and 5.5 for the cemented control group; this is not a significant difference. These data indicate a clinical performance equivalent to a matched group of contemporary cemented total hip arthroplasties.