The Journal of Bone & Joint Surgery最新文献

{"title":"Anconeus Arthroplasty: A New Technique for Reconstruction of the Radiocapitellar and/or Proximal Radioulnar Joint","authors":"B. Morrey, A. Schneeberger","doi":"10.2106/00004623-200211000-00009","DOIUrl":"https://doi.org/10.2106/00004623-200211000-00009","url":null,"abstract":"Background: Management of posttraumatic radiocapitellar and/or proximal radioulnar joint dysfunction and pain is a challenging problem, often with more than one pathological feature, and to date there are no consistently reliable solutions. The unreliability of prosthetic replacement prompted us to develop an anconeus arthroplasty wherein the anconeus muscle is rotated into the radiocapitellar and/or proximal radioulnar joint.Methods: Three interposition options were assessed in our laboratory and were employed clinically: interposition at the radiocapitellar joint (Type I), interposition at the radiocapitellar and proximal radioulnar joints (Type II), and proximal radioulnar interposition (wrap) (Type III). The clinical outcomes in fourteen patients who had been treated with one of the three types of anconeus interposition arthroplasty were reviewed at least two years (mean, 6.1 years) postoperatively.Results: Anatomic dissection of twenty-five specimens revealed that all three applications were possible. Of the fourteen patients, twelve (all six with a Type-I interposition, three of the five with a Type-II interposition, and all three with a Type-III interposition) had a satisfactory overall subjective result. The Mayo Elbow Performance Score averaged 63 points before the surgery and 89 points after it.Conclusions: Anconeus interpositional arthroplasty offers a reasonable likelihood of improved subjective and objective function in patients with the challenging problem of radiocapitellar and/or proximal radioulnar joint dysfunction and pain after trauma, even when there is Essex-Lopresti axial instability.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"21 1","pages":"1960–1969"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90539107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computer-Assisted Navigation in Total Knee Replacement: Results of an Initial Experience in Thirty-five Patients","authors":"S. Stulberg, P. Loan, V. Sarin","doi":"10.2106/00004623-200200002-00011","DOIUrl":"https://doi.org/10.2106/00004623-200200002-00011","url":null,"abstract":"The success of total knee replacement surgery depends on several factors, including proper patient selection, appropriate implant design, correct surgical technique, and effective perioperative care. The outcome of total knee replacement surgery is particularly sensitive to variations in surgical technique 1-9. Incorrect positioning or orientation of the implant and improper alignment of the limb can lead to accelerated implant wear and loosening as well as suboptimal functional performance. A number of studies have suggested that alignment errors of >3° are associated with more rapid failure and less satisfactory functional results after total knee arthroplasty 1,10-20. Recent studies have also emphasized that the most common cause for revision total knee replacement is error in surgical technique.\u0000\u0000Mechanical alignment guides have improved the accuracy with which implants can be inserted. Although mechanical alignment systems are continually being refined, errors in implant and limb alignment continue to occur. It has been estimated that errors in tibial and femoral alignment of >3° occur in at least 10% of total knee arthroplasties, even when performed by experienced surgeons using mechanical alignment systems of modern design. Mechanical alignment systems have fundamental problems that limit their ultimate accuracy. The accuracy of preoperative planning is limited by the errors inherent in standard radiographs. It is difficult to determine accurately, with standard instrumentation, the correct location of crucial alignment landmarks (e.g., the center of the femoral head, the center of the ankle). Moreover, mechanical alignment and sizing devices presume a standardized bone geometry that may not apply to a specific patient. Even the most elaborate mechanical instrumentation systems rely on visual inspection to confirm the accuracy of limb and implant alignment and stability at the conclusion of the total knee replacement procedure.\u0000\u0000Computer-based alignment systems have been developed to address the …","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"19 1","pages":"S90–S98"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89346266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What's New in Hip Arthroplasty","authors":"M. Huo","doi":"10.2106/00004623-200509000-00029","DOIUrl":"https://doi.org/10.2106/00004623-200509000-00029","url":null,"abstract":"There were numerous papers, abstracts, and presentations on the topic of adult hip reconstructive surgery during the past year. I elected to review the published articles from the Journal of Bone and Joint Surgery (American Volume), Journal of Arthroplasty, and Clinical Orthopaedics and Related Research. In addition, I reviewed all of the abstracts from major meetings focusing on hip reconstructive surgery, including the annual meeting of the American Academy of Orthopaedic Surgeons, the annual meeting of The American Association of Hip and Knee Surgeons, and the open meeting of the Hip Society. I also reviewed several abstracts from the meeting of the Orthopedic Research Society. The time-interval for the review was June 2001 to April 2002. The review involved more than 165 papers and 250 abstracts. I have organized the data into eight categories: (1) results of primary total hip arthroplasty, (2) results of revision total hip arthroplasty, (3) outcome measures, (4) metal ion release, (5) implant liability, (6) osteolysis, bone-remodeling, and bearing surface, (7) osteonecrosis of the femoral head, and (8) complications. Last year’s review included extensive data regarding the clinical results of a variety of surgical techniques, disease entities, and associated complications. In the current review, I have focused principally on newer data that were presented over the past year.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"60 1","pages":"1894–1905"},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88163561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dislocation After Revision Total Hip Arthroplasty: An Analysis of Risk Factors and Treatment Options","authors":"G. Alberton, W. High, B. Morrey","doi":"10.2106/00004623-200210000-00008","DOIUrl":"https://doi.org/10.2106/00004623-200210000-00008","url":null,"abstract":"Background: Dislocation is a leading and underemphasized cause of failure in revision total hip arthroplasty. Although this fact is generally well recognized, we are aware of no detailed assessments of this problem to date. Our purpose therefore was to evaluate the risk factors leading to instability after revision as well as the expected outcome of various treatment strategies. Methods: Data were obtained from 1548 revision arthroplasties in 1405 patients who were followed for a minimum of two years (range, 2.0 to 16.4 years; mean, 8.1 years) or until dislocation occurred. Revisions specifically performed because of instability were excluded from the analysis. Risk factors were recorded along with treatment strategies and their success. The statistical relevance of both sets of variables was calculated. Results: A dislocation occurred after 115 (7.4%) of 1548 revision hip arthroplasties. The use of an elevated rim liner was associated with significant decreases (p < 0.05) in dislocation following revision of femoral and acetabular components. The presence of trochanteric nonunion was a significant risk factor for subsequent dislocation (p < 0.001). Revisions with 32-mm and 28-mm-diameter femoral heads were both more stable than was revision with a 22-mm-diameter head (p < 0.05 for each). Surgery was the initial treatment for twelve of the 115 dislocations. Six of the twelve hips had no further instability. Of the 103 postoperative dislocations initially managed nonoperatively, only thirty-six did not redislocate. Thirty-eight of the sixty-seven hips that had an additional dislocation after closed treatment had repeat surgery for treatment of the instability. Only eleven of the thirty-eight hips were stable at one year after surgery. Overall, at the time of the final assessment, sixty-five (57%) of the 115 hips were stable, forty-one (36%) remained unstable, and the status of nine (8%) was unknown. Conclusions: The risk factors for instability after a total hip revision are not the same as those after a primary procedure. The extent of the soft-tissue dissection is probably the most important variable since head size and trochanteric nonunion are related to \"soft-tissue tension.\" Modular acetabular components with an elevated rim help to stabilize a hip undergoing a revision procedure.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"31 1","pages":"1788–1792"},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88536710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Congenital Pseudarthrosis of the Tibia: Results of Technical Variations in the Charnley-Williams Procedure","authors":"C. Johnston","doi":"10.2106/00004623-200210000-00010","DOIUrl":"https://doi.org/10.2106/00004623-200210000-00010","url":null,"abstract":"Background: Results of the Charnley-Williams method of intramedullary fixation for treatment of congenital pseudarthrosis of the tibia have varied, in part because of variations in surgical technique. The outcomes of three variations of this procedure were compared to determine which technique was the most likely to result in union. Methods: The results in twenty-three consecutive patients with congenital pseudarthrosis of the tibia were reviewed at four to fourteen years following initial surgical treatment with an intramedullary rod. Three types of procedures were performed: type A, which consisted of resection of the tibial pseudarthrosis with shortening, insertion of an intramedullary rod into the tibia, and tibial bone-grafting combined with fibular resection or osteotomy and insertion of an intramedullary rod into the fibula; type B, which was identical to type A except that it did not include fibular fixation; and type C, which consisted of insertion of a tibial rod and bone-grafting but no fibular surgery. The outcome was classified as grade 1 when there was unequivocal union with full weight-bearing function and maintenance of alignment requiring no additional surgical treatment; grade 2 when there was equivocal union with useful function, with the limb protected by a brace, and/or valgus or sagittal bowing for which additional surgery was required or anticipated; and grade 3 when there was persistent nonunion or refracture, requiring full-time external support for pain and/or instability. Results: Eleven patients (48%) ultimately had a grade-1 outcome; nine, a grade-2 outcome; and three, a grade-3 outcome. The final outcome was not associated with either the initial radiographic appearance of the lesion or the age of the patient at the time of the initial surgery. The results following type-A and B operations were better than those after type-C procedures. Surgery on an intact fibula resulted in a lower prevalence of grade-3 outcomes than was found when an intact fibula was not operated on (p = 0.05). Transfixation of the ankle joint by the intramedullary rod did not decrease the prevalence of grade-3 outcomes. Conclusions: There is little justification for a type-C operation, as it either resulted in a persistent nonunion or failed to improve an equivocal outcome in every case. Leaving an intact fibula undisturbed to maintain stability or length also was not successful in this series. In addition, the presence of fibular insufficiency (fracture or a pre-pseudarthrotic lesion) was highly prognostic for subsequent valgus deformity (occurring in ten of twelve cases), whether or not the fibula eventually healed.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"180 1","pages":"1799–1810"},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80136639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intramuscular and Blood Pressures in Legs Positioned in the Hemilithotomy Position: Clarification of Risk Factors for Well-Leg Acute Compartment Syndrome","authors":"R. S. Meyer, K. White, J. Smith, E. Groppo, S. Mubarak, A. Hargens","doi":"10.2106/00004623-200210000-00014","DOIUrl":"https://doi.org/10.2106/00004623-200210000-00014","url":null,"abstract":"Background: Acute compartment syndrome has been widely reported in legs positioned in the lithotomy position for prolonged general surgical, urologic, and gynecologic procedures. The orthopaedic literature also contains reports of this complication in legs positioned on a fracture table in the hemilithotomy position. The purpose of this study was to identify the risk factors for development of acute compartment syndrome resulting from this type of leg positioning. Methods: Eight healthy volunteers were positioned on a fracture table. Intramuscular pressures were continuously measured with a slit catheter in all four compartments of the left leg with the subject supine, in the hemilithotomy position with the calf supported, and in the hemilithotomy position with the heel supported but the calf free. Blood pressure was measured intermittently with use of automated pressure cuffs. Results: Changing from the supine to the calf-supported position significantly increased the intramuscular pressure in the anterior compartment (from 11.6 to 19.4 mm Hg) and in the lateral compartment (from 13.0 to 25.8 mm Hg). Changing from the calf-supported to the heel-supported position significantly decreased intramuscular pressure in the anterior, lateral, and posterior compartments (to 2.8, 3.4, and 1.9 mm Hg, respectively). The mean diastolic blood pressure in the ankle averaged 63.9 mm Hg in the supine position, which significantly decreased to 34.6 mm Hg in the calf-supported position. Changing to the heel-supported position had no significant effect on the diastolic blood pressure in the ankle (mean, 32.8 mm Hg). The mean difference between intramuscular pressure and diastolic blood pressure in the supine position was approximately 50 mm Hg in each of the four compartments. This mean difference significantly decreased to <20 mm Hg in the calf-supported position and then, when the leg was moved into the heel-supported position, significantly increased to approximately 30 mm Hg in all compartments. Conclusions: The combination of increased intramuscular pressure due to external compression from the calf support and decreased perfusion pressure due to the elevated position causes a significant decrease in the difference between the diastolic blood pressure and the intramuscular pressure when the leg is placed in the hemilithotomy position in a well-leg holder on a fracture table. Combined with a prolonged surgical time, this position may cause an acute compartment syndrome of the well leg. Leaving the calf free, instead of using a standard well-leg holder, increases the difference between the diastolic blood pressure and the intramuscular pressure and may decrease the risk of acute compartment syndrome.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"114 1","pages":"1829–1835"},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85394902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What's New in Adult Reconstructive Knee Surgery","authors":"M. Archibeck, R. White","doi":"10.2106/00004623-200607000-00034","DOIUrl":"https://doi.org/10.2106/00004623-200607000-00034","url":null,"abstract":"The purpose of this update on adult reconstructive knee surgery is to discuss, in summary fashion, topics presented at selected orthopaedic meetings and published in related orthopaedic journals between January and December 2001. The sources for this review are articles published in The Journal of Bone and Joint Surgery (American edition) and The Journal of Arthroplasty. The podium presentations mentioned in this article include those given at the annual meeting of the American Academy of Orthopaedic Surgeons (held in San Francisco, California, on February 28 through March 4, 2001), on Specialty Day at the meeting of The Knee Society (held in San Francisco, California, on March 3, 2001), and at the meeting of The American Association of Hip and Knee Surgeons (held in Dallas, Texas, on November 9 through 11, 2001). The Interim Meeting of the Knee Society was cancelled as a result of the events of September 11, 2001.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"6 1","pages":"1719–1726"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78094665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Treatment of Unreduced Elbow Dislocations with Hinged External Fixation","authors":"J. Jupiter, D. Ring","doi":"10.2106/00004623-200209000-00017","DOIUrl":"https://doi.org/10.2106/00004623-200209000-00017","url":null,"abstract":"Background: The results of operative treatment of an unreduced elbow dislocation have been regarded with pessimism. Suggested procedures have included tendon-lengthening, tendon transfer, or reconstruction of ligament or bone.Methods: Three women and two men (average age, forty-nine years) with an unreduced dislocation of the elbow without associated fractures were treated with open relocation of the joint and hinged external fixation at an average of eleven weeks (range, six to thirty weeks) after the initial injury. The lateral soft tissues, including the origin of the lateral collateral ligament complex, were reattached to the lateral epicondyle in three patients, but no attempt was made to reconstruct the ligaments, tendons, or bone. A passive worm gear incorporated into a hinged external fixator was used to mobilize the elbow initially, and active mobilization was gradually introduced. The hinge was removed at an average of five weeks after the procedure.Results: At an average of thirty-eight months (range, twelve to ninety-eight months), a stable, concentric reduction had been maintained in all five patients, with radiographic signs of mild arthrosis in four. The average arc of flexion was 123×, and all patients had full forearm rotation. The average score on the Mayo Elbow Performance Index was 89 points, with two excellent and three good results. The average scores on the Disabilities of the Arm, Shoulder and Hand (DASH) and American Shoulder and Elbow Surgeons outcome instruments (13 and 92 points, respectively) reflected mild residual pain and disability.Conclusions: Treatment of unreduced elbow dislocations with open reduction and hinged external fixation as much as thirty weeks after the injury can restore a stable, mobile joint without the need for tendon-lengthening or transfer, ligament reconstruction, or deepening of the trochlear notch of the ulna.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"81 1","pages":"1630–1635"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81666582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accuracy of Needle Placement into the Intra-Articular Space of the Knee","authors":"D. Jackson, Nicholas A Evans, B. M. Thomas","doi":"10.2106/00004623-200209000-00003","DOIUrl":"https://doi.org/10.2106/00004623-200209000-00003","url":null,"abstract":"Background: To achieve their potential therapeutic benefit, hyaluronic acid derivatives should be injected directly into the knee joint space and not into the anterior fat pad or the subsynovial tissues. In the absence of a knee effusion, reproducible needle placement into the intra-articular space presents a challenge to the clinician.Methods: The accuracy of needle placement was assessed in a prospective series of 240 consecutive injections in patients without clinical knee effusion. The injections were performed by one orthopaedic surgeon using a 2.0-in (5.1-cm) 21-gauge needle through three commonly employed knee joint portals: anteromedial, anterolateral, and lateral midpatellar. Accuracy rates for needle placement were confirmed with fluoroscopic imaging to document the dispersion pattern of injected contrast material.Results: Of eighty injections performed through an anterolateral portal, fifty-seven were confirmed to have been placed in the intra-articular space on the first attempt (an accuracy rate of 71%). Sixty of eighty injections performed through an anteromedial approach were intra-articular on the first attempt (75% accuracy rate), as were seventy-four of eighty injections performed through a lateral midpatellar portal (93% accuracy rate).Conclusions: Using real-time fluoroscopic imaging with contrast material, we demonstrated the difficulty of accurately placing a needle into the intra-articular space of the knee when an effusion is not present. This study revealed that a lateral midpatellar injection (an injection into the patellofemoral joint) was intra-articular 93% of the time and was more accurate than injections performed by the same orthopaedic surgeon using either of the other two portals. This study highlights the need for clinicians to refine injection techniques for delivering intra-articular therapeutic substances that are intended to coat the articular surfaces of the knee joint.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"62 6 1","pages":"1522–1527"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77181219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface Damage in Machined Ram-Extruded and Net-Shape Molded Retrieved Polyethylene Tibial Inserts of Total Knee Replacements","authors":"A. Bērziņš, J. Jacobs, R. Berger, Chris Ed, R. Natarajan, T. Andriacchi, J. Galante","doi":"10.2106/00004623-200209000-00005","DOIUrl":"https://doi.org/10.2106/00004623-200209000-00005","url":null,"abstract":"Background: Polyethylene wear has emerged as a major determining factor in the long-term clinical performance of total knee replacements. This study addresses the in vivo wear performance of two types of polyethylene tibial inserts used in similar total knee arthroplasty designs.Methods: A surface damage assessment of retrieved specimens was performed for twenty-six net-shape molded tibial inserts manufactured from H1900 resin without calcium stearate additive (Miller-Galante) and forty-three machined ram-extruded tibial inserts manufactured from GUR 4150 resin with calcium stearate additive (Miller-Galante II). Stereomicroscopic inspection and digital image analysis were used to quantify the extent and severity of pitting, dimensional change, and delamination.Results: Pitting and dimensional change were the most common modes of damage in both groups, with the prevalence ranging from 77% to 92% for pitting and from 51% to 81% for dimensional change. Delamination was the least common mode of damage, with the prevalence ranging from 21% to 35%. The severity of pitting was higher in association with the cemented implant-bone interface. The extent and severity of delamination increased with implantation time. No severe delamination was observed before sixty months after implantation in the net-shape molded group, whereas severe delamination was present as early as ten months after implantation in the machined ram-extruded group. The time between surgery and the discovery of damage was longer in the net-shape molded group for all modes of damage except for medial dimensional change.Conclusions: On the basis of the components available in our implant retrieval pool, we found that at equivalent levels of surface damage, the net-shape molded H1900 resin tibial inserts demonstrated longer service life than did the machined ram-extruded GUR 4150 components. The superior performance of the net-shape molded components may be related to the resin type, the absence of calcium stearate, the consolidation method, or the method of final geometry shaping. This superior damage resistance is expected to contribute to superior long-term clinical performance of net-shape molded ultra-high molecular weight polyethylene in total knee arthroplasty.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"67 9 1","pages":"1534–1540"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88477714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}