The Medical Healthcare Products Regulatory Agency (MHRA June-2015) warned of higher risks with 46-48mm sizes of BHR hip resurfacing arthroplasty (HRA). The most common condemnation of adverse results in MOM bearings has been termed edge loading. We originally developed a margin-of-safety (MOS) algorithm to define edge loading of cups in simulator studies. This method integrated simulator wear-patterns with respect to cup diameters and cup designs. The algorithm’s simplicity lay in the fact that with wear-patterns and rim-profile angles predetermined, the only input required was the cup inclination-angle. The algorithm demonstrated that the margin-of-safety decreased in smaller cups due to the tribo-mechanics of spherical CoCr bearings, a previously unrecognized feature. For the 46mm and 48mm cups highlighted in the MHRA alert, the critical cup inclinations where edge-wear became a risk occurred at 65-66°, revealing an insignificant difference with respect to diameters. The MOS-algorithm also indicated that lower lateral-inclination angles were particularly beneficial, i.e. a 46mm cup positioned at 50° inclination would exhibit a higher margin of safety than either 48mm or 50mm sizes positioned at 55° inclination. This evidence supported clinical studies that recommended BHR cup inclinations up to 50-55° and lower as optimal for reducing metal-ion concentrations. In a patient with normal spine mobility, our EOS imaging demonstrated that the inclination in the 46mm cup steepened by 9° from standing to the seated position while margin-of-safety was reduced by 50%. Our 2nd patient with a stiff spine sat with the same component orientations as in his standing posture. Thus MOM impingement and subluxation in different functional postures may also provoke rim-damage mechanisms. Here the combination of EOS imaging and the MOS-algorithm may aid understanding of such risks. Thus the margin-of-safety algorithm confirmed and helped explained the relative risks in the 46mm and 48mm cups highlighted by the MHRA. The algorithm’s stratification by cup rim-profile, inclination angle and cup diameter may assist the surgeon determine which patients may be more at risk for edge wear with the smaller BHR cups.
{"title":"Margin-of-safety Algorithm Used with EOS Imaging to Interpret MHRA Warning for 46-48mm MOM Arthroplasty","authors":"I. Clarke, J. Lazennec","doi":"10.15438/RR.5.3.115","DOIUrl":"https://doi.org/10.15438/RR.5.3.115","url":null,"abstract":"The Medical Healthcare Products Regulatory Agency (MHRA June-2015) warned of higher risks with 46-48mm sizes of BHR hip resurfacing arthroplasty (HRA). The most common condemnation of adverse results in MOM bearings has been termed edge loading. We originally developed a margin-of-safety (MOS) algorithm to define edge loading of cups in simulator studies. This method integrated simulator wear-patterns with respect to cup diameters and cup designs. The algorithm’s simplicity lay in the fact that with wear-patterns and rim-profile angles predetermined, the only input required was the cup inclination-angle. The algorithm demonstrated that the margin-of-safety decreased in smaller cups due to the tribo-mechanics of spherical CoCr bearings, a previously unrecognized feature. For the 46mm and 48mm cups highlighted in the MHRA alert, the critical cup inclinations where edge-wear became a risk occurred at 65-66°, revealing an insignificant difference with respect to diameters. The MOS-algorithm also indicated that lower lateral-inclination angles were particularly beneficial, i.e. a 46mm cup positioned at 50° inclination would exhibit a higher margin of safety than either 48mm or 50mm sizes positioned at 55° inclination. This evidence supported clinical studies that recommended BHR cup inclinations up to 50-55° and lower as optimal for reducing metal-ion concentrations. In a patient with normal spine mobility, our EOS imaging demonstrated that the inclination in the 46mm cup steepened by 9° from standing to the seated position while margin-of-safety was reduced by 50%. Our 2nd patient with a stiff spine sat with the same component orientations as in his standing posture. Thus MOM impingement and subluxation in different functional postures may also provoke rim-damage mechanisms. Here the combination of EOS imaging and the MOS-algorithm may aid understanding of such risks. Thus the margin-of-safety algorithm confirmed and helped explained the relative risks in the 46mm and 48mm cups highlighted by the MHRA. The algorithm’s stratification by cup rim-profile, inclination angle and cup diameter may assist the surgeon determine which patients may be more at risk for edge wear with the smaller BHR cups.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"146 1","pages":"13-21"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681759","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}
Hip Resurfacing (HR) development of the 1970s was an attempt to address the failures of conventional cemented stems. Those early HR designs failed because problems with maintaining bone under the resurfaced femoral head, and loosening of the socket with substantial acetabular bone loss. However technology, knowledge and surgical techniques have evolved over the past 45 years. The more recent designs like the Birmingham Hip Resurfacing (BHR) focused on metal to metal bearing surfaces. These devices are under attack and maybe they should be. However, lets not ignore the significant amount of information and potential improvements in both design technology and surgical techniques that have come about over the past few years.
{"title":"Safety Issue of Hip Resurfacing","authors":"T. Mctighe","doi":"10.15438/RR.5.3.123","DOIUrl":"https://doi.org/10.15438/RR.5.3.123","url":null,"abstract":"Hip Resurfacing (HR) development of the 1970s was an attempt to address the failures of conventional cemented stems. Those early HR designs failed because problems with maintaining bone under the resurfaced femoral head, and loosening of the socket with substantial acetabular bone loss. However technology, knowledge and surgical techniques have evolved over the past 45 years. The more recent designs like the Birmingham Hip Resurfacing (BHR) focused on metal to metal bearing surfaces. These devices are under attack and maybe they should be. However, lets not ignore the significant amount of information and potential improvements in both design technology and surgical techniques that have come about over the past few years.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"66 1","pages":"51-53"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681981","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}
Background: Patients with hip pathology often complain of various symptoms, e.g. pain or discomfort of low back, lower extremity, hip, groin, thigh, buttock or knee. Physicians may be distracted by these complaints, and misdiagnose and mistreat hip pathology. To avoid this, the pendulum test, which is performed with a patient seated on the examination table and hips and knees are flexed at 90 degrees, while the examiner passively swings the patient's lower extremity in and out as a pendulum, has been employed for all patients with the complaint of low back, hip and knee. Objective: The efficacy and the accuracy of the pendulum test were evaluated. Patients and methods: Consecutive 40 patients, who had complained pain or discomfort of low back, lower extremity, hip, groin, thigh, buttock and knee were examined by the pendulum test. Results: Eighteen patients were positive for the pendulum test, and all of them correlated to the hip pathology. Conclusions: The pendulum test was confirmed to be easily performed and reliable in detecting the hip pathology. Therefore, this test is highly recommended for the differentiation of patients with low back, hip and knee complaints.
{"title":"Pendulum Test: A Highly Accurate and Simple Physical Examination Maneuver to Identify Hip Pathology","authors":"Y. Oshima, J. Fetto","doi":"10.15438/RR.5.3.119","DOIUrl":"https://doi.org/10.15438/RR.5.3.119","url":null,"abstract":"Background: Patients with hip pathology often complain of various symptoms, e.g. pain or discomfort of low back, lower extremity, hip, groin, thigh, buttock or knee. Physicians may be distracted by these complaints, and misdiagnose and mistreat hip pathology. To avoid this, the pendulum test, which is performed with a patient seated on the examination table and hips and knees are flexed at 90 degrees, while the examiner passively swings the patient's lower extremity in and out as a pendulum, has been employed for all patients with the complaint of low back, hip and knee. Objective: The efficacy and the accuracy of the pendulum test were evaluated. Patients and methods: Consecutive 40 patients, who had complained pain or discomfort of low back, lower extremity, hip, groin, thigh, buttock and knee were examined by the pendulum test. Results: Eighteen patients were positive for the pendulum test, and all of them correlated to the hip pathology. Conclusions: The pendulum test was confirmed to be easily performed and reliable in detecting the hip pathology. Therefore, this test is highly recommended for the differentiation of patients with low back, hip and knee complaints.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"45-49"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681780","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}
Eddy D Zandee van Rilland, Joseph Varcadipane, O. Geling, M. Kuba, Cass K. Nakasone
INTRODUCTION: Early failure of tibial components remains a concern in total knee arthroplasty (TKA). Loss of fixation with cemented implants continues to be problematic in young, active patients. We sought to determine outcomes in patients receiving trabecular metal (TM) implants in a single-surgeon community hospital setting. METHODS: A retrospective analysis was performed on 167 consecutive primary TKAs performed on 133 patients utilizing a TM tibial implant with a minimum two years follow-up. RESULTS: Failure due to aseptic loosening occurred in 4 of the 167 cases (2.4%). Local and systemic complication rates were low. Length of hospital stay and tourniquet time data were also reported. CONCLUSION: Overall complications were low in our cohort of patients receiving TM implants. Longer follow-up is necessary to determine if the outcomes we observed are sustained over time.
{"title":"A Minimum 2-Year Follow-up Using Modular Trabecular Metal Tibial Components in Total Knee Arthroplasty","authors":"Eddy D Zandee van Rilland, Joseph Varcadipane, O. Geling, M. Kuba, Cass K. Nakasone","doi":"10.15438/RR.5.3.113","DOIUrl":"https://doi.org/10.15438/RR.5.3.113","url":null,"abstract":"INTRODUCTION: Early failure of tibial components remains a concern in total knee arthroplasty (TKA). Loss of fixation with cemented implants continues to be problematic in young, active patients. We sought to determine outcomes in patients receiving trabecular metal (TM) implants in a single-surgeon community hospital setting. METHODS: A retrospective analysis was performed on 167 consecutive primary TKAs performed on 133 patients utilizing a TM tibial implant with a minimum two years follow-up. RESULTS: Failure due to aseptic loosening occurred in 4 of the 167 cases (2.4%). Local and systemic complication rates were low. Length of hospital stay and tourniquet time data were also reported. CONCLUSION: Overall complications were low in our cohort of patients receiving TM implants. Longer follow-up is necessary to determine if the outcomes we observed are sustained over time.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"23-28"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681671","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}
P. Meere, J. Lamont, J. Baez, Michael N. Kang, V. Rasquinha, C. Anderson, C. Jacobs
Purpose : The purpose of this study was to determine if using a sensor-equipped tibial insert would reduce medial (MED) and lateral (LAT) gapping and create more equivalent compressive forces in the MED and LAT compartments. Methods : 7 orthopedic surgeons each performed bilateral TKA on complete lower extremity cadaveric specimens. Left TKA was performed first without the use of the instrumented tibial insert. With trial components placed, the patella was reduced and joint capsule closed with towel clips. Surgeons performed varus and valgus stress tests on each knee and the mm of MED and LAT gapping were recorded. Compressive forces in the MED and LAT compartment were measured at 10°, 45°, and 90° of flexion. Sensor-assisted TKA was then performed on the right knee and compressive forces and gapping were again recorded. MED, LAT, and total mediolateral (ML) gapping and MED and LAT compressive forces were compared between conventional TKA and sensor-assisted TKA with paired t-tests. Results : Sensor-assisted TKA resulted in significantly reduced MED (1.2 vs. 1.9 mm, p<.001), LAT (0.8 vs. 1.4 mm, p = 0.003), and total ML gapping (2.0 vs. 3.4 mm, p<.001). There were no differences in the MED and LAT compressive forces between conventional and sensor-assisted TKA. However, sensor-assisted TKAs demonstrated greater MED compartment forces as the knee was flexed whereas conventional TKAs had greater LAT forces. Conclusions : Sensor-assisted TKA significantly reduced MED and LAT gapping with the knee in 20° of flexion. Future clinical studies are needed to determine the most appropriate compressive forces in the MED and LAT compartments.
目的:本研究的目的是确定使用配备传感器的胫骨插入物是否会减少内侧(MED)和外侧(LAT)间隙，并在内侧(MED)和外侧(LAT)隔室中产生更等效的压缩力。方法:7名骨科医生分别对完整的下肢尸体标本行双侧TKA。首先进行左侧TKA，不使用固定的胫骨插入物。放置试验组件后，髌骨复位，并用毛巾夹闭合关节囊。外科医生对每个膝关节进行内翻和外翻应力测试，并记录MED和LAT间隙的mm。在屈曲10°，45°和90°时测量MED和LAT室的压缩力。然后对右膝进行传感器辅助TKA，再次记录压缩力和间隙。采用配对t检验比较传统TKA和传感器辅助TKA的MED、LAT和总中外侧(ML)间隙以及MED和LAT压缩力。结果:传感器辅助TKA导致MED (1.2 vs. 1.9 mm, p<.001)、LAT (0.8 vs. 1.4 mm, p = 0.003)和总ML间隙(2.0 vs. 3.4 mm, p<.001)显著降低。传统TKA和传感器辅助TKA在MED和LAT压缩力方面没有差异。然而，当膝关节屈曲时，传感器辅助tka显示出更大的MED隔室力，而传统tka具有更大的LAT力。结论:传感器辅助TKA可显著减少膝关节屈曲20°时的MED和LAT间隙。未来的临床研究需要确定MED和LAT室中最合适的压缩力。
{"title":"Surgeon Assessment of Gapping Versus Kinetic Loading Using Intraoperative Sensors During TKA","authors":"P. Meere, J. Lamont, J. Baez, Michael N. Kang, V. Rasquinha, C. Anderson, C. Jacobs","doi":"10.15438/RR.5.3.112","DOIUrl":"https://doi.org/10.15438/RR.5.3.112","url":null,"abstract":"Purpose : The purpose of this study was to determine if using a sensor-equipped tibial insert would reduce medial (MED) and lateral (LAT) gapping and create more equivalent compressive forces in the MED and LAT compartments. Methods : 7 orthopedic surgeons each performed bilateral TKA on complete lower extremity cadaveric specimens. Left TKA was performed first without the use of the instrumented tibial insert. With trial components placed, the patella was reduced and joint capsule closed with towel clips. Surgeons performed varus and valgus stress tests on each knee and the mm of MED and LAT gapping were recorded. Compressive forces in the MED and LAT compartment were measured at 10°, 45°, and 90° of flexion. Sensor-assisted TKA was then performed on the right knee and compressive forces and gapping were again recorded. MED, LAT, and total mediolateral (ML) gapping and MED and LAT compressive forces were compared between conventional TKA and sensor-assisted TKA with paired t-tests. Results : Sensor-assisted TKA resulted in significantly reduced MED (1.2 vs. 1.9 mm, p<.001), LAT (0.8 vs. 1.4 mm, p = 0.003), and total ML gapping (2.0 vs. 3.4 mm, p<.001). There were no differences in the MED and LAT compressive forces between conventional and sensor-assisted TKA. However, sensor-assisted TKAs demonstrated greater MED compartment forces as the knee was flexed whereas conventional TKAs had greater LAT forces. Conclusions : Sensor-assisted TKA significantly reduced MED and LAT gapping with the knee in 20° of flexion. Future clinical studies are needed to determine the most appropriate compressive forces in the MED and LAT compartments.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"29-34"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681659","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}
In recent years, specialized, non-sterile, traction table systems have facilitated Direct Anterior Approach (DAA) hip arthroplasty. To combat the potential downsides of these traction systems, a sterile, intra-operative retractor option has emerged as a means to access the surgical site more easily, minimize soft-tissue trauma, and reduce the degree of required human assistance. This chapter describes the setup, surgical approach, and early results of a retractor system (the Phantom MIS Anterior Hip Retractor system [TeDan Surgical Innovations, Inc. {TSI}, Houston, Texas, US Patent # 8,808,176 B2]), which uses a standard operating table, allows preparation of both lower extremities free in the surgical field, is compatible with fluoroscopy, and aids in both acetabular and femoral exposure, preparation, and implantation. Early outcome data indicates that this system significantly minimizes the need for surgical assistance, while allowing for safe and effective DAA performance, facilitating the procedure for high-volume surgeons and shortening the learning curve for surgeons new to the procedure.
近年来，专门的、非无菌的牵引台系统促进了直接前路(DAA)髋关节置换术。为了克服这些牵引系统的潜在缺点，无菌术中牵开器作为一种更容易进入手术部位、最大限度地减少软组织损伤和减少人工辅助程度的手段出现了。本章描述了牵开系统的设置、手术入路和早期结果(Phantom MIS髋关节前路牵开系统[TeDan surgical Innovations, Inc. {TSI}， Houston, Texas, US Patent # 8,808,176 B2])，该系统使用标准手术台，允许在手术视野中自由地准备双下肢，与透视兼容，并有助于髋臼和股骨的暴露、准备和植入。早期结果数据表明，该系统显著减少了对手术辅助的需求，同时允许安全有效的DAA性能，促进了大批量外科医生的手术，缩短了新手外科医生的学习曲线。
{"title":"“Table-less” and “Assistant-less” Direct Anterior Approach to Hip Arthroplasty","authors":"D. Allison, L. Menendez, W. Brien, T. Mctighe","doi":"10.15438/RR.5.3.122","DOIUrl":"https://doi.org/10.15438/RR.5.3.122","url":null,"abstract":"In recent years, specialized, non-sterile, traction table systems have facilitated Direct Anterior Approach (DAA) hip arthroplasty. To combat the potential downsides of these traction systems, a sterile, intra-operative retractor option has emerged as a means to access the surgical site more easily, minimize soft-tissue trauma, and reduce the degree of required human assistance. This chapter describes the setup, surgical approach, and early results of a retractor system (the Phantom MIS Anterior Hip Retractor system [TeDan Surgical Innovations, Inc. {TSI}, Houston, Texas, US Patent # 8,808,176 B2]), which uses a standard operating table, allows preparation of both lower extremities free in the surgical field, is compatible with fluoroscopy, and aids in both acetabular and femoral exposure, preparation, and implantation. Early outcome data indicates that this system significantly minimizes the need for surgical assistance, while allowing for safe and effective DAA performance, facilitating the procedure for high-volume surgeons and shortening the learning curve for surgeons new to the procedure.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"35-44"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681854","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}
A 63-year old female with bilateral hip replacements was referred to our clinic for pain and elevated metal ions. Her left hip had been revised earlier. The right hip had an SROM Ti6Al4V stem implanted with a 28mm head, a 28mm CoCr liner and Pinnacle Ti6Al4V shell. The patient reported pain, numbness, tingling, and repeated clicking and popping sensations with gait. She specifically noted that her hip would freeze while walking and could pop rising from a chair. Repeated metal ion levels showed Co (blood)17ppb, Cr (serum) 21ppb, and Ti (blood) at 69ppb. CT-images of right hip revealed femoral stem anteversion was 43° and cup anteversion was 40°, for a combined anteversion of 83°. The right hip was revised 3.5 years postoperatively for persistent pain and elevated metal ions. At surgery, large twin notches were evident on her posterior femoral neck and 10mm-wide scalloped damage was evident in the rim of the Ti6A4V shell. SEM-imaging revealed contaminating layers on CoCr head containing elements Al, V and Ti. These indicated that titanium-alloy particles liberated by cup-to-neck impingements had transferred to the CoCr bearings. Our intent in this case was not to document that a MOM bearing produced impingement damage, because this case clearly implicated adverse surgical positioning. Rather, the intent was to document sequelae likely in a THA case that has a metal cup impinging on a metal femoral neck. In particular, twin notches on the femoral neck indicated that this patient was routinely impinging her Ti6Al4V shell against the Ti6Al4V neck and also subluxing her femoral head out of the cup. These signs are a clear indication that one or both components must be revised, as opposed to simply replacing the CoCr liner with a revision polyethylene liner.
{"title":"Excessive Anteversion Leads to Failure at 3 Years Due to Impingement as Evidenced by Twin Notches in Ti6A4V Stem","authors":"T. Donaldson, M. Burgett-Moreno, I. Clarke","doi":"10.15438/RR.5.2.110","DOIUrl":"https://doi.org/10.15438/RR.5.2.110","url":null,"abstract":"A 63-year old female with bilateral hip replacements was referred to our clinic for pain and elevated metal ions. Her left hip had been revised earlier. The right hip had an SROM Ti6Al4V stem implanted with a 28mm head, a 28mm CoCr liner and Pinnacle Ti6Al4V shell. The patient reported pain, numbness, tingling, and repeated clicking and popping sensations with gait. She specifically noted that her hip would freeze while walking and could pop rising from a chair. Repeated metal ion levels showed Co (blood)17ppb, Cr (serum) 21ppb, and Ti (blood) at 69ppb. CT-images of right hip revealed femoral stem anteversion was 43° and cup anteversion was 40°, for a combined anteversion of 83°. The right hip was revised 3.5 years postoperatively for persistent pain and elevated metal ions. At surgery, large twin notches were evident on her posterior femoral neck and 10mm-wide scalloped damage was evident in the rim of the Ti6A4V shell. SEM-imaging revealed contaminating layers on CoCr head containing elements Al, V and Ti. These indicated that titanium-alloy particles liberated by cup-to-neck impingements had transferred to the CoCr bearings. Our intent in this case was not to document that a MOM bearing produced impingement damage, because this case clearly implicated adverse surgical positioning. Rather, the intent was to document sequelae likely in a THA case that has a metal cup impinging on a metal femoral neck. In particular, twin notches on the femoral neck indicated that this patient was routinely impinging her Ti6Al4V shell against the Ti6Al4V neck and also subluxing her femoral head out of the cup. These signs are a clear indication that one or both components must be revised, as opposed to simply replacing the CoCr liner with a revision polyethylene liner.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"2015-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681433","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}
We describe an uncommon scenario where the femoral diaphysis was subjugated by previous long stemmed revision knee replacements limiting options for primary hip arthroplasty. A short stemmed pressfit femoral componet was implanted bilaterally. At 11 years the implants remain stable with improved clinical function. This case emphasizes the importance of preoperative templating and the utility of considering the use of unconventional stems in the management of unusual situations.
{"title":"Short-Stem Hip Arthroplasty as a Solution for limited Proximal Femoral Bone Stock","authors":"Ai E. Gamboa, D. Campbell, P. Lewis","doi":"10.15438/RR.5.2.114","DOIUrl":"https://doi.org/10.15438/RR.5.2.114","url":null,"abstract":"We describe an uncommon scenario where the femoral diaphysis was subjugated by previous long stemmed revision knee replacements limiting options for primary hip arthroplasty. A short stemmed pressfit femoral componet was implanted bilaterally. At 11 years the implants remain stable with improved clinical function. This case emphasizes the importance of preoperative templating and the utility of considering the use of unconventional stems in the management of unusual situations.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"43-45"},"PeriodicalIF":0.0,"publicationDate":"2015-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681600","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}
E. McPherson, B. K. Vaughn, L. Keppler, D. Brazil, T. Mctighe
Purpose. To evaluate early and mid-term risk factors and dislocation rates in the posterior surgical approach in three separate community private practices using a short curved neck-sparing total hip stem design. Material and Methods. The three senior authors performed 338 short curved neck-sparing stem designs since April 2010 to June 2014. Various cementless acetabular components were used for all three surgical centers based on preoperative and intraoperative risk factors. All cases were reviewed retrospectively for incidence of dislocation after surgery. Version and inclination of the acetabular component and version of the femoral component were assed intra-operatively prior to final implantation. Various risk factors were reviewed including surgical approach, cup position, combined cup and stem positioning, and femoral head size. There have been significant papers in the past ten years that have recommended large head diameters to reduce the chances of head/neck mechanical impingement. Since the neck-sparing designs have a potentially increased risk of mechanical impingement head diameters were restricted to 32 mm or larger. In the smaller patient profile if a 32 mm head size could not be reached a dual-mobility style implant was chosen or stem choice was changed to a conventional style design. Results. Historically the posterior approach has had higher reports of dislocations as compared to direct anterior, anterolateral or straight lateral approach in conventional cemented and cementless implant designs. Older neck-sparing designs of conventional stem length by Freeman, Townley and Whiteside have not reported any increased dislocation problems but these stems have been associated with modified acetabular component designs, including the short curved neck sparing design of Pipino back in the 1980s. Incidence of dislocation in our series utilizing a short curved neck-sparing stem with more traditional hemispherical cementless acetabular components was 3 or 0.88%. Conclusion. Neck sparing stem designs do save significantly more bone and require less soft tissue dissection as compared to conventional cementless stem designs. Mechanical risk factors are increased with the use of short curved neck-sparing stem designs. Careful pre-operative and intra-operative evaluation does reduce the risk factors resulting in low and in some cases lower than previous published rates with conventional style stems. Short curved neck sparing stems do provide safe and reliable reproduction of the joint mechanics in routine primary total hip arthroplasty in both short and mid term results. Key Words: hip, arthroplasty, posterior approach, dislocation, neck sparing, and risk factors
{"title":"The Incidence of Dislocation (Utilizing a Neck Sparing Stem) in Community Based Practices with the Posterior Approach","authors":"E. McPherson, B. K. Vaughn, L. Keppler, D. Brazil, T. Mctighe","doi":"10.15438/RR.5.2.106","DOIUrl":"https://doi.org/10.15438/RR.5.2.106","url":null,"abstract":"Purpose. To evaluate early and mid-term risk factors and dislocation rates in the posterior surgical approach in three separate community private practices using a short curved neck-sparing total hip stem design. Material and Methods. The three senior authors performed 338 short curved neck-sparing stem designs since April 2010 to June 2014. Various cementless acetabular components were used for all three surgical centers based on preoperative and intraoperative risk factors. All cases were reviewed retrospectively for incidence of dislocation after surgery. Version and inclination of the acetabular component and version of the femoral component were assed intra-operatively prior to final implantation. Various risk factors were reviewed including surgical approach, cup position, combined cup and stem positioning, and femoral head size. There have been significant papers in the past ten years that have recommended large head diameters to reduce the chances of head/neck mechanical impingement. Since the neck-sparing designs have a potentially increased risk of mechanical impingement head diameters were restricted to 32 mm or larger. In the smaller patient profile if a 32 mm head size could not be reached a dual-mobility style implant was chosen or stem choice was changed to a conventional style design. Results. Historically the posterior approach has had higher reports of dislocations as compared to direct anterior, anterolateral or straight lateral approach in conventional cemented and cementless implant designs. Older neck-sparing designs of conventional stem length by Freeman, Townley and Whiteside have not reported any increased dislocation problems but these stems have been associated with modified acetabular component designs, including the short curved neck sparing design of Pipino back in the 1980s. Incidence of dislocation in our series utilizing a short curved neck-sparing stem with more traditional hemispherical cementless acetabular components was 3 or 0.88%. Conclusion. Neck sparing stem designs do save significantly more bone and require less soft tissue dissection as compared to conventional cementless stem designs. Mechanical risk factors are increased with the use of short curved neck-sparing stem designs. Careful pre-operative and intra-operative evaluation does reduce the risk factors resulting in low and in some cases lower than previous published rates with conventional style stems. Short curved neck sparing stems do provide safe and reliable reproduction of the joint mechanics in routine primary total hip arthroplasty in both short and mid term results. Key Words: hip, arthroplasty, posterior approach, dislocation, neck sparing, and risk factors","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"13-18"},"PeriodicalIF":0.0,"publicationDate":"2015-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67680097","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}
P. Burton, E. Medina, M. Burgett-Moreno, T. Donaldson, I. Clarke
In the majority of retrievals, femoral heads and cups are sent for analysis with no designation as to positioning in-vivo. In addition, when patients retain the femoral prosthesis, evidence of neck impingement damage is lost. In this case report we studied head and cup wear-patterns and stripe damage in a novel case that included a large diameter metal-on-metal THA that was retrieved with the head still fused to the stem. This provided anatomical positioning of head wear-pattern and stripe damage as represented by the orientation of the femoral stem in radiographic images. We investigated (1) size, shape and location of head and cup wear-patterns, (2) cup-to-stem impingement damage, and (3) head stripe-wear. The head wear-pattern was elliptical in shape, 40mm diameter with area covering 2200 sq.mm. Its hemispherical ratio was 56% with aspect ratio 1.2 and typical of large-diameter MOM retrievals. Wear-pattern extended from 12° above superior head-margin to approximately 40° inferior to polar axis. Centroidal vector in coronal plane was 13° posterior to polar axis and in transverse plane was 19° superior to polar axis. These vector data corresponded well with biomechanical predictions of resultant load axes in gait studies. Stripe damage was identified on the head, and the cup rim could thereby be aligned to verify neck impingement and also head subluxation mechanisms. Cup wear-pattern was not centrally contained, indicating this patient had experienced repetitive edge-wear during gait. Thinning of the cup rim by 350- 400μm indicated that posterior impingement with repetitive anterior subluxation of the head had created this edge-wear.
{"title":"Biomechanical Alignment of Main Wear-Pattern on MOM Total Hip Replacement","authors":"P. Burton, E. Medina, M. Burgett-Moreno, T. Donaldson, I. Clarke","doi":"10.15438/RR.5.2.111","DOIUrl":"https://doi.org/10.15438/RR.5.2.111","url":null,"abstract":"In the majority of retrievals, femoral heads and cups are sent for analysis with no designation as to positioning in-vivo. In addition, when patients retain the femoral prosthesis, evidence of neck impingement damage is lost. In this case report we studied head and cup wear-patterns and stripe damage in a novel case that included a large diameter metal-on-metal THA that was retrieved with the head still fused to the stem. This provided anatomical positioning of head wear-pattern and stripe damage as represented by the orientation of the femoral stem in radiographic images. We investigated (1) size, shape and location of head and cup wear-patterns, (2) cup-to-stem impingement damage, and (3) head stripe-wear. The head wear-pattern was elliptical in shape, 40mm diameter with area covering 2200 sq.mm. Its hemispherical ratio was 56% with aspect ratio 1.2 and typical of large-diameter MOM retrievals. Wear-pattern extended from 12° above superior head-margin to approximately 40° inferior to polar axis. Centroidal vector in coronal plane was 13° posterior to polar axis and in transverse plane was 19° superior to polar axis. These vector data corresponded well with biomechanical predictions of resultant load axes in gait studies. Stripe damage was identified on the head, and the cup rim could thereby be aligned to verify neck impingement and also head subluxation mechanisms. Cup wear-pattern was not centrally contained, indicating this patient had experienced repetitive edge-wear during gait. Thinning of the cup rim by 350- 400μm indicated that posterior impingement with repetitive anterior subluxation of the head had created this edge-wear.","PeriodicalId":20884,"journal":{"name":"Reconstructive Review","volume":"5 1","pages":"19-23"},"PeriodicalIF":0.0,"publicationDate":"2015-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67681539","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}
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