Michael E Berend

Spokane Joint Replacement Center, Spokane, Washington, United States

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Publications (90)175.21 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Uncemented stems have been used in THA for well over two decades, but there are relatively few studies reporting on the results after 20 years.
    Clinical Orthopaedics and Related Research 07/2014; · 2.79 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the use for screws and cement, and primary and revision specific prosthesis for revision TKR. Between July 1989 and February 2010, 839 consecutive revision TKAs were performed, with 609 knees meeting inclusion criteria. At 17 years followup, Kaplan-Meier survivorship was .9859 for revision specific prosthesis with screws and cement, .9848 for revision prosthesis with no screws, 0.9118 for primary prosthesis with screws, and .9424 for primary prosthesis with no screws. Revision TKRs using screws had greater defects (p < .0001). Use of revision prosthesis along with screws and cement to correct largely defective revision TKRs is highly recommended.
    The Journal of Arthroplasty. 01/2014;
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    ABSTRACT: Return to sexual activity is important to patients, but there is limited information regarding sexual function following total hip arthroplasty (THA) and total knee arthroplasty (TKA). A multicenter study of 806 THA, 542 TKA, and 181 control patients less than 60 years of age was conducted using an independent survey center to question subjects about their sexual function. Only 1.3% of THA and 1.6% of TKA patients stated they were not sexually active due to their operation. No statistically significant differences were noted in any sexual function outcome categories based on the bearing surface, femoral head size, or use of surface replacement arthroplasty in the hip cohort. Multivariate analysis revealed no difference in the percentage of patients sexually active following a THA or TKA (OR 1.19, p = 0.38). Most young active patients return to their baseline or higher level of sexual activity after hip and knee arthroplasty.
    The Journal of Arthroplasty. 01/2014;
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    ABSTRACT: The purpose of this study was to investigate screws and cement for large tibial bone defects during primary TKA. Of 14,686 consecutive primary TKAs performed between December 1988 and February 2010, 256 received screws and cement for tibial defects. Cox regression was used for the analysis. 20-year survival probability was 0.9897 (screws) and 0.9339 (no screws) (P=.4225 log-rank). Tibial bone condition was significantly worse in knees receiving screws (P<.0001) with 73.0% having defects in the screws group and 3.4% (P<.0001) for non-screws. Radiolucency appeared in 13.7% (screws) and 6.4% (no screws) postoperatively. Screws were $137 each, wedges $910 to $2240. Knees with tibial defects and screws performed similarly if not better than knees without defects at substantially lower cost than alternatives.
    The Journal of arthroplasty 12/2013; · 1.79 Impact Factor
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    ABSTRACT: Limited experimental data exist comparing the mechanical response of the tibial cortex between fixed and rotating platform (RP) total knee arthroplasty (TKA), particularly in the revision setting. We asked if RP-TKA significantly affects tibiofemoral torque and cortical stain response in both the primary and revision settings. Fixed and RP tibial trays were implanted into analogue tibias and biomechanically tested under axial and torsional loading. Torque and strain response were analyzed using digital image correlation. Fixed bearing designs exhibited 13.8 times greater torque (P<0.01), and 69% (P<0.01) higher cortical strain than RP designs. Strain response was similar in the primary and revision cohorts. The decrease in torque transfer could act as a safeguard to reduce stress, micromotion and torsional fatigue in scenario of poor bone stock.
    The Journal of arthroplasty 11/2013; · 1.79 Impact Factor
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    ABSTRACT: Revision knee data from six joint arthroplasty centers were compiled for 2010 and 2011 to determine mechanism of failure and time to failure. Aseptic loosening was the predominant mechanism of failure (31.2%), followed by instability (18.7%), infection (16.2%), polyethylene wear (10.0%), arthrofibrosis (6.9%), and malalignment (6.6%). Mean time to failure was 5.9years (range 10 days to 31years). 35.3% of all revisions occurred less than 2years after the index arthroplasty, 60.2% in the first 5years. In contrast to previous reports, polyethylene wear is not a leading failure mechanism and rarely presents before 15years. Implant performance is not a predominant factor of knee failure. Early failure mechanisms are primarily surgeon-dependent.
    The Journal of arthroplasty 08/2013; · 1.79 Impact Factor
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    ABSTRACT: Many previous biomechanical studies of bone and bone substitutes have estimated strains in these materials using strain gages. The purpose of this study was to compare digital image correlation (DIC) strain measurements to those obtained from strain gages in order to assess the applicability of DIC technology to common biomechanical testing scenarios. Compression and bending tests were conducted on aluminum alloy, polyurethane foam, and laminated polyurethane foam specimens. Results showed no significant differences in the principal strain values (or the variances) between strain gage and DIC measurements on the aluminum alloy and laminated polyurethane foam specimens. There were significance differences between the principal strain measurements of the non-laminated polyurethane foam specimens, but the deviation from the theoretical results was similar for both measurement techniques. In summary, DIC techniques provide similar results to those obtained from strain gages and also provide full field strain results.
    ASME 2013 Summer Bioengineering Conference; 06/2013
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    ABSTRACT: BACKGROUND: Potential advantages suggested but not confirmed for surface replacement arthroplasty (SRA) over THA include lower frequency of limp, less thigh pain, less limb length discrepancy, and higher activity. QUESTIONS/PURPOSES: We therefore determined whether patients having SRA had a limp, thigh pain, or limb length discrepancy less frequently or had activity levels higher than patients having THA. METHODS: In a multicenter study, we surveyed 806 patients aged 18 to 60 years with a premorbid UCLA activity score of 6 or more who underwent hip arthroplasty for noninflammatory arthritis at one of five orthopaedic centers. Patients had either a cementless THA with an advanced bearing surface (n = 682) or an SRA (n = 124). The patients were demographically comparable. Specific telephone survey instruments were designed to assess limp, thigh pain, perception of limb length, and activity levels. Minimum followup was 1 year (mean, 2.3 years; range, 1.1-3.9 years). RESULTS: When controlled for age, sex, and premorbid activity level, patients with SRA had a higher incidence of complete absence of any limp, lower incidence of thigh pain, lower incidence of perception of limb length discrepancy, greater ability to walk continuously for more than 60 minutes, higher percentage of patients who ran after surgery, greater distance run, and higher percentage of patients who returned to their most favored recreational activity. CONCLUSIONS: When interviewed by an independent third party, patients with SRA reported higher levels of function with fewer symptoms and less perception of limb length discrepancy compared to a similar cohort of young, active patients with THA. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 03/2013; · 2.79 Impact Factor
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    ABSTRACT: With increased precision in alignment offered by new generations of instrumentation and customized guides, this study was designed to establish a biomechanically-based target alignment for the balance of tibial loading in order to diminish the likelihood of pain and subsidence related to mechanical overload post-UKA. Sixty composite tibias were implanted with Oxford UKA tibial components with varied sagittal slope, resection depth, rotation and medial shift using patient matched instrumentation. Digital image correlation and strain gage analysis was conducted in static loading to evaluate strain distribution as a result of component alignment. In this model, minimal distal resection and most lateral positioning, neutral component rotation, and 3°of slope (from mechanical axis) exhibited the most balanced strain response to loading following UKA.
    The Journal of arthroplasty 03/2013; · 1.79 Impact Factor
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    ABSTRACT: Implant survival after total knee arthroplasty has historically been dependent on postoperative knee alignment, although failure may occur when alignment is correct. Preoperative knee alignment has not been thoroughly evaluated as a possible risk factor for implant failure after arthroplasty. The purpose of this study was to analyze the effect of preoperative knee alignment on implant survival after total knee arthroplasty. We performed a retrospective review of 5342 total knee arthroplasties performed with use of cemented Anatomic Graduated Component implants from 1983 to 2006. Each knee was independently measured preoperatively and postoperatively for overall coronal alignment. Neutral ranges for preoperative and postoperative alignment were defined by means of Cox proportional hazards regression. The overall failure rate was 1.0% (fifty-four of 5342 prostheses); failure was defined as aseptic loosening of the femoral and/or tibial component. The average preoperative anatomical alignment (and standard deviation) was 0.1° ± 7.7° of varus (range, 25° of varus to 35° of valgus), and the average postoperative anatomical alignment (and standard deviation) was 4.7° ± 2.5° of valgus (range, 12° of varus to 20° of valgus). The failure rate in knees in >8° of varus preoperatively (2.2%; p = 0.0005) or >11° of valgus preoperatively (2.4%; p = 0.0081) was elevated when compared with knees in neutral preoperatively (0.71%). Knees with preoperative deformities corrected to postoperative neutral alignment (2.5° through 7.4°) had a lower failure rate (1.9%) than undercorrected or overcorrected knees (3.0%) (p = 0.0103). Knees with postoperative neutral alignment, regardless of preoperative alignment, had a lower failure rate (0.74%) than knees with postoperative alignment of <2.5° or >7.4° of anatomic valgus (1.7%) (p < 0.0001). Patients with excessive preoperative alignment (>8° of varus or >11° of valgus) have a greater risk of failure (2.3%). Neutral postoperative alignment (2.5° through 7.4° of valgus) improves (1.9% for preoperatively deformed knees) but does not completely eliminate the risk of failure (0.5% for knees that were neutral both preoperatively and postoperatively). Careful attention should be paid to knee alignment during total knee arthroplasty, especially for patients with severe preoperative deformities. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 01/2013; 95(2):126-31. · 3.23 Impact Factor
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    ABSTRACT: Initial stability with limited micromotion in uncemented total hip arthroplasty acetabular components is essential for bony attachment and long-term biomechanical fixation. This study compared porous titanium fixation surfaces to clinically established, plasma-sprayed designs in terms of interface stability and required seating force. Porous plasma-sprayed modular and metal-on-metal (MOM) cups were compared to a modular, porous titanium designs. Cups were implanted into polyurethane blocks with1-mm interference fit and subsequently edge loaded to failure. Porous titanium cups exhibited 23% to 65% improvement in initial stability when compared to plasma-sprayed cup designs (P=.01): a clinically significant increase, based on experience and prior literature. The results of this study indicate increased interface stability in porous titanium-coated cups without significantly increasing the necessary force and energy required for full seating.
    The Journal of arthroplasty 11/2012; · 1.79 Impact Factor
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    ABSTRACT: BACKGROUND: Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased torsional friction and micromotion. Specifically, however, it remains unclear how cup diameter, design, and time from implantation affect shell deformation. QUESTIONS/PURPOSES : We asked whether (1) changes in component geometry and material altered maximum shell deformation and (2) time-dependent deformational relaxation processes occurred. METHODS: Diametral deformation was quantified after press-fit implantation of metal shells into a previously validated polyurethane model. Experimental groups (n = 6-8) consisted of 48-, 54-, 60-, and 66-mm MOM cups of 6-mm wall thickness, 58-mm cups of 10-mm wall thickness, and CoCrMo and Ti6Al4V 58-mm modular cups. RESULTS : Greater cup diameter, thinner wall construction, and Ti6Al4V modular designs generated conditions for maximum shell deformation ranging from 0.047 to 0.267 mm. Relaxation (18%-32%) was observed 120 hours postimplantation in thin-walled and modular designs. CONCLUSIONS : Our findings demonstrate a reduction of shell deformation over time and suggest, under physiologic loading, early component deformation varies with design. CLINICAL RELEVANCE : Component deformation should be a design consideration regardless of bearing surface. Designs neglecting to adequately address deformational changes in vivo could be susceptible to diminished cup survival, increased wear, and premature revision.
    Clinical Orthopaedics and Related Research 09/2012; · 2.79 Impact Factor
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    ABSTRACT: Acetabular cup orientation has been shown to influence dislocation, impingement, edge loading, contact stress, and polyethylene wear in total hip arthroplasty. Acetabular implant stiffness has been suggested as a factor in pelvic stress shielding and osseous integration. This study was designed to examine the combined effects of acetabular cup orientation and stiffness and on pelvic osseous loading. Four implant designs of varying stiffness were implanted into a composite hemipelvis in 35° or 50° of abduction. Specimens were dynamically loaded to simulate gait and pelvic strains were quantified with a grid of rosette strain gages and digital image correlation techniques. Changes in the joint reaction force orientation significantly altered mean acetabular bone strain values up to 67%. Increased cup abduction resulted in a 12% increase along the medial acetabular wall and an 18% decrease in strain in inferior lateral regions. Imbalanced loading distributions were observed with the stiffer components, resulting in higher, more variable, and localized surface strains. This study illustrates the effects of cup stiffness, gait, and implant orientation on loading distributions across the implanted pelvis.
    The Journal of arthroplasty 07/2012; · 1.79 Impact Factor
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    ABSTRACT: Partial knee arthroplasty has enjoyed renewed interest during the past decade. It is helpful to be familiar with the classic and current indications, contraindications, and technical aspects of partial knee arthroplasty, including patellofemoral, medial unicompartmental, and lateral unicompartmental knee arthroplasty. Various implant choices for partial knee arthroplasty can be compared and evaluated based on patient characteristics, design qualities, and reported outcomes. It is also helpful to review the indications and techniques for performing medial or lateral unicompartmental knee arthroplasty in combination with arthroscopically assisted reconstruction of the anterior cruciate ligament.
    Instructional course lectures 01/2012; 61:347-81.
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    ABSTRACT: Large-diameter metal-on-metal articulations reportedly improve stability and wear in THAs. However, some reports suggest some patients have unexplained hip and early failures with these implants. Thus, the potential benefits may be offset by these concerns. However, the incidence of these problems is not clearly established. We therefore assessed hip pain, function, osteolysis, and complications in patients with large-diameter metal-on-metal THA. We retrospectively reviewed 611 patients who had 681 large-diameter metal-on-metal THAs with the same cup and head design. The average age at operation was 62 years, 53% of the THAs were in men, and the average body mass index was 32 kg/m(2). The diagnosis was osteoarthritis in 92% of the THAs. The minimum followup was 24 months (mean, 37 months; range, 24-60 months). Nine of the 611 patients (1.5%) experienced moderate or severe pain in the hip region that we considered to be coming from an extraarticular source in each case. Harris hip scores for pain averaged 42 points. Total Harris hip scores averaged 93 points. Cup abduction averaged 42°, and cup anteversion averaged 26°. There were no infections. Three cups (0.4%) were considered radiographically loose. All were secondary to inadequate seating of the shell. Our observations suggest with this implant the concerns of higher incidences of groin pain, early failures, and adverse tissue reactions were not confirmed. Early successes or failures with large-diameter metal-on-metal articulations may be implant specific. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 09/2011; 470(2):388-94. · 2.79 Impact Factor
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    ABSTRACT: The purpose of this study was to determine the effect of tibiofemoral alignment, femoral and tibial component alignment, and body-mass index (BMI) on implant survival following total knee replacement. We retrospectively reviewed 6070 knees in 3992 patients with a minimum of two years of follow-up. Each knee was classified on the basis of postoperative alignment (overall tibiofemoral alignment and alignment of the tibial and the femoral component in the coronal plane). Failures (defined as revision for any reason other than infection) were analyzed with use of Cox regression; patient covariates included overall alignment, component alignments, and preoperative BMI. Failure was most likely to occur if the orientation of the tibial component was <90° relative to the tibial axis and the orientation of the femoral component was ≥8° of valgus (failure rate, 8.7%; p < 0.0001). In contrast, failure was least likely to occur if both the tibial and the femoral component were in a neutral orientation (≥90° and <8° of valgus, respectively) (failure rate, 0.2% [nine of 4633]; p < 0.0001). "Correction" of varus or valgus malalignment of the first implanted component by placement of the second component to attain neutral tibiofemoral alignment was associated with a failure rate of 3.2% (p = 0.4922) for varus tibial malalignment and 7.8% (p = 0.0082) for valgus femoral malalignment. A higher BMI was associated with an increased failure rate. Compared with patients with a BMI of 23 to 26 kg/m2, the failure rate in patients with a BMI of ≥41 kg/m2 increased from 0.7% to 2.6% (p = 0.0046) in well-aligned knees, from 1.6% to 2.9% (p = 0.0180) in varus knees, and from 1.0% to 7.1% (p = 0.0260) in valgus knees. Attaining neutrality in all three alignments is important in maximizing total knee implant survival. Substantial "correction" of the alignment of one component in order to compensate for malalignment of the other component and thus produce a neutrally aligned total knee replacement can increase the risk of failure (p = 0.0082). The use of conventional guides to align a total knee replacement provides acceptable alignment; however, the surgeon should be aware that the patient's size, as determined by the BMI, is also a major factor in total knee replacement failure.
    The Journal of Bone and Joint Surgery 09/2011; 93(17):1588-96. · 3.23 Impact Factor
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    ABSTRACT: Clinical success of unicompartmental knee arthroplasty (UKA) is on the rise and is dependent on multiple patient, implant, and surgical factors. Tibial subsidence has been clinically reported as a cause of failure in UKA with an all-polyethylene tibial design in the absence of metal backing, yet the role of metal backing UKA tibial components on tibial loading is not fully understood. In this study, composite tibiae were implanted with medial all-polyethylene fixed-bearing or metal-backed UKA tibial components and a 1.5-kN load applied in 3 different contact positions simulating femoral translation during gait. All-polyethylene tibial components exhibited significantly higher strain measurements in each femoral position. This study demonstrates the role that metal backing plays on generating an even loading distribution while diminishing the development localized regions of excessive loading across the medial tibial cortex.
    The Journal of arthroplasty 08/2011; 26(5):777-82. · 1.79 Impact Factor
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    ABSTRACT: The influence of intramedullary (IM) and extramedullary (EM) femoral cutting guides on survivorship of total knee arthroplasty was studied in 6726 total knee arthroplasty guided by either an IM (4993 knees) or EM (1733 knees) system. Fifteen-year survivorship of the 2 cohorts showed no statistically significant difference (EM 97.9% vs IM 98.5%; P = .2500, log rank). Medial bone collapse comprised the highest proportion of all failure modes for both groups (0.35% vs 0.40%, respectively, P = .6731, Cox regression). Mean tibiofemoral (overall) anatomical alignment was statistically more accurate in the IM group (IM 4.6° [± 2.2°] valgus vs EM 5.1° [± 3.1°] valgus; P < .0001). The mean tibial alignment was 90.5° (± 3.0) and 90.3° (± 2.2) (P = .0077). The EM group had a significantly larger tibial component alignment variance (SD(2)) than the IM group. No statistical difference in postoperative Knee Society scores, pain, or stair-climbing abilities was found. The choice of either alignment system should be determined by the patient's anatomy; however, the overall alignment is not as precise using the extramedullary system.
    The Journal of arthroplasty 06/2011; 26(4):591-5. · 1.79 Impact Factor
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    ABSTRACT: Improvements in total hip arthroplasty implant design and advances in bearing materials, including modern surface arthroplasty, have resulted in these procedures being performed in younger and more active patients. There is limited information in the literature to provide to patients, employers, and insurance companies about returning to work after hip arthroplasty surgery. We conducted a multicenter telephone survey on 943 patients younger than 60 years with a University of California, Los Angeles, activity score of 6 or higher (regularly participates in moderate activities) who underwent hip arthroplasty surgery between 2005 and 2007 at a minimum of 1 year after surgery. We found that most young, active patients employed before surgery can expect to return to work (90.4%), with the vast majority returning to their preoperative occupation, and very few (2.3%) were limited in their ability to return to work because of their operative hip.
    The Journal of arthroplasty 05/2011; 26(6 Suppl):92-98.e1-3. · 1.79 Impact Factor
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    ABSTRACT: "Thin" modular polyethylene bearings have previously been associated with failure from wear. This study examined the influence of polyethylene thickness on survivorship in primary total knee arthroplasty (TKA). Do "thinner" or "thicker" bearings fail more? Six thousand seventy primary TKAs with a single implant design were reviewed. The failure rate in knees with bearings 14 mm or less was 0.7%, whereas the failure rate of knees with bearings 16 mm or greater was 2.3% (P < .0001; hazard ratio, 3.2). No knee was revised for polyethylene wear. Thicker bearings did not directly cause failure, but factors that lead to the insertion of a thicker bearing such as a deeper tibial resection and ligament imbalance may contribute to the observed increased failure. The significant influence of this often-unrecognized surgical variable has not been previously reported and must be carefully considered during TKA.
    The Journal of arthroplasty 09/2010; 25(6 Suppl):17-20. · 1.79 Impact Factor

Publication Stats

1k Citations
175.21 Total Impact Points


  • 2013
    • Spokane Joint Replacement Center
      Spokane, Washington, United States
    • Hip Knee Arkansas Foundation
      Little Rock, Arkansas, United States
  • 2002–2013
    • Saint Francis Hospital
      Tulsa, Oklahoma, United States
  • 2008
    • University of Missouri
      Columbia, Missouri, United States