The Journal of Arthroplasty - Articles in Press

Influence of Prosthetic Design on Squeaking After Ceramic-on-Ceramic Total Hip Arthroplasty - Corrected Proof

2010-07-20

Abstract: Squeaky ceramic-on-ceramic (COC) total hips have received much recent publicity, and implant design may be implicated. We reviewed 270 consecutive COC total hip arthroplasties in 233 patients comparing 4 implant combinations representing 4 manufacturers. A cohort (n = 45) of Stryker Trident acetabular cups paired with Stryker Accolade femoral stems showed a dramatically higher incidence of “problem squeaking”—defined as always audible to others and occurring at least once per week—with a 35.6% incidence of squeaking and 11.1% incidence of problem squeaking. The 3 non-Stryker designs (n = 225) revealed 3.6% squeaking (P < .0001) and 0.44% problem squeaking (P = .006). The Stryker system has a unique design and metallurgy. Our results suggest that although the genesis of squeaking in COC total hips is multifactorial, prosthetic design plays a key role.

Tibial Shaft Stress Fractures Resulting from Placement of Navigation Tracker Pins - Corrected Proof

David Hoke, S. Mehdi Jafari, Fabio Orozco, Alvin Ong — 2010-07-20

Abstract: The use of navigation during joint arthroplasty is believed to allow better placement of components. Gross fracture or stress fracture through navigation tracker pin placement is a complication reported in the literature. This case series presents details of stress fracture of tibial shaft through navigation pin track in 3 patients of 220 cases who underwent total knee arthroplasty at our institution. All the fractures eventually healed after a course of protected weight bearing. As a result, we use smaller-diameter self-tapping and self-drilling pins routinely and avoid placement of pins in the diaphysis and ensure that pins are inserted in different plains during insertion into metaphysis.

Revision Total Hip Arthroplasty for a Vancouver Type B3 Periprosthetic Fracture Using an Allograft-Cemented Stem Composite by the Telescoping Technique - Corrected Proof

Hiroyasu Ogawa, Yoshiki Ito, Iori Takigami, Katsuji Shimizu — 2010-07-20

Abstract: We describe a case of successful revision total hip arthroplasty for a Vancouver type B3 periprosthetic femoral fracture with extensive bone stock deficiency and osteoporotic diaphyseal bone. The femur was reconstructed with an allograft-cemented stem composite using a telescoping technique and a drainage hole for surplus cement. This procedure facilitated stable stem fixation to the host femur without cement interference and bony fusion between the allograft and host bone, as revealed by bone scintigraphy. This technique provides a surgical option for a severe periprosthetic femoral fracture in which the femoral diaphyseal bone is too osteoporotic to support the fixation of an allograft-cementless stem composite.

Complete 180° Rotatory Dislocation in a Mobile-Bearing Knee Prothesis - Corrected Proof

Hussein W. Turki, Lorence Trick — 2010-07-20

Abstract: Dislocation of the rotator platform in mobile-bearing total knee arthroplasty is a well-documented, albeit uncommon, phenomenon. A review of the literature has revealed multiple case reports describing spin out to 90° or complete extrusion of the polyethylene component. Closed reduction may be attempted in the acute presentation followed by revision if instability persists. We present a case of a 57-year-old woman who had a partial rotatory subluxation of her polyethylene component and underwent closed reduction resulting in a full 180° spinout. To our knowledge, this has not been described in the literature and should be considered as a possibility after closed reduction attempts. She was treated successfully with open exploration and poly exchange using a larger component.

Does An Enhanced Surface Finish Improve Acetabular Fixation in Revision Total Hip Arthroplasty? - Corrected Proof

Miranda L. Jamieson, Robert D. Russell, Stephen J. Incavo, Philip C. Noble — 2010-07-20

Abstract: High-porosity “cancellous metal” coatings have been introduced to increase the fixation and biologic incorporation of acetabular cups. The strength of initial fixation provided by a cancellous metal cups vs conventional alternatives in the deficient revision acetabulum was investigated. Cancellous, plasma-sprayed, and beaded cups (n = 9) were implanted under controlled conditions into a validated model of the revision acetabulum. The greatest differences were seen in resistance to catastrophic (spin-out) failure that, for the cancellous shell, averaged 1076 ± 265 N, which was 25% greater than the plasma-sprayed implant (859 ± 214 N, P = .04) and 218% greater than the beaded implant (338 ± 123 N, P < .01). The cancellous coating also provided greater resistance to ultimate failure. These results suggest that these new cancellous metal coatings may represent a promising alternative for fixation in revision total hip arthroplasty.

Causes and Patterns of Aborting a Robot-Assisted Arthroplasty - Corrected Proof

2010-07-20

Abstract: For a successful robot-assisted arthroplasty, every step should be executed harmoniously. However, when we encounter serious obstacles during surgery, it is sometimes better to abort the procedure in a timely manner. This study investigated the possible causes and patterns of aborted robot-assisted arthroplasties. Of 100 consecutively planned robot-assisted arthroplasties, 22 cases were aborted. Most involved total knee arthroplasty (21/22 cases). We classified the causes according to the stage at which they occurred and the type of error. Abortions after starting the milling procedure and abortions due to an interactive factor were the most common. We believe that this study can guide surgeons to effective decision making during robot-assisted arthroplasty.

Factory-Assembled Polyethylene Linings in Metal Backing Show Higher Wear Rates Compared to Equisized All-Polyethylene Sockets - Corrected Proof

Matthias W. Jentschke, Wolfgang Schultz, Gottfried H. Buchhorn — 2010-07-20

Abstract: Two series of cementless total hip arthroplasty with acetabular sockets of a threaded truncated cone design were compared regarding volumetric wear rates. The first series included all-polyethylene acetabular sockets of the type Endler (E-PE); in the second series, a nonmodular titanium metal-backed polyethylene (E-MB) socket with an identical outer shape to E-PE was implanted. Bearings were articulated with alumina 32-mm diameter ball heads. Ninety-five retrieved devices were examined with a modified fluid displacement method using dental self-polymerizing precision casts. The sockets had to be revised mainly because of wear-induced osteolysis: E-PE after 10.6 years on average and E-MB after 7.8 years (P = .002). Comparison with unused sockets showed mean wear rates of 63 mm3/y for E-PE and 120 mm3/y for E-MB (P = .0008). Increased contact stress and load deformation due to reduction of polyethylene thickness in E-MB compared to E-PE were identified as predominant reasons for higher wear rates.

Pseudotumor in Large-Diameter Metal-on-Metal Total Hip Articulation - Corrected Proof

Cambize Shahrdar — 2010-07-20

Abstract: Large-diameter metal-on-metal hip arthroplasties have incited renewed interest because of the advantages of decreased wear and increased stability. These new designs have not had significant long-term or midterm performance results, and we are reporting the case of pseudotumor in a patient with a painful metal-on-metal hip arthroplasty.

Changes in the Medial and Lateral Posterior Condylar Offset in Total Knee Arthroplasty - Corrected Proof

2010-07-20

Abstract: The purpose of this study was to clarify the changes between preoperation and postoperation in each posterior condylar offset (PCO) using computed tomography (CT) and to compare them to conventional radiographic (x-ray) evaluation in total knee arthroplasty. One hundred nine knees in 97 patients were evaluated. The medial PCO was significantly larger before surgery. The lateral PCO was significantly larger after surgery. Changes in the PCO on x-ray showed no significant correlation with the changes observed in the CT-evaluated medial (R = 0.028) and lateral PCO (R = 0.190). Changes in PCO observed by x-ray did not reflect those of the medial or lateral condyles on CT. We recommend CT-based evaluation of PCO by condyle when assessing the influence of PCO on range of motion following total knee arthroplasty.

The Results of a Press-Fit-Only Technique for Acetabular Fixation in Hip Dysplasia - Corrected Proof

2010-07-20

Abstract: The purpose of the present study was to evaluate the 6- to 11-year follow-up results of hemispherical porous-coated cups implanted into dysplastic hips using press-fit technique without screws focusing on the amount of host bone coverage. There were 87 patients who underwent 98 primary total hip arthroplasties. Bony coverage was measured as the angle between the vertical line and the line drawn from the cup center to the lateral edge of the acetabulum, which was named the cup center-edge angle (cup-CE angle). All 98 cups were judged to be bone ingrown. The minimum cup-CE angle was 8.4° (mean, 26.3°). Bone-cup contact of more than 8.4° of the cup-CE angle was large enough for press-fit cups to resist superior directed loads during this follow-up period.

Management of Polyethylene Wear Associated With a Well-Fixed Modular Cementless Shell During Revision Total Hip Arthroplasty - Corrected Proof

2010-07-20

Abstract: We identified 128 revision total hip arthroplasties from 1993 to 2005 involving a well-fixed Harris-Galante Porous (HGP)-I or HGP-II acetabular component with minimum 2-year post-revision follow-up. Three treatment cohorts were identified. Of the hips that underwent modular liner exchange at revision, 14 hips (25%) required re-revision of the acetabular component, 8 for liner dislodgement, 3 for osteolysis and poly-wear, 2 for dislocation, and 1 for aseptic loosening. Of the hips that underwent revision of the well-fixed shell, 4 (15%) required subsequent re-revision of the acetabular component; 2 for dislocation and 2 for aseptic loosening. Six hips (27%) in the cemented liner group were re-revised; 4 for dislocation and 2 for loosening. Complete revision of a well-fixed HGP acetabular component is more reliable than liner exchange or liner cementation.

Relationship Between Femoral Component Rotation and Total Knee Flexion Gap Balance on Modified Axial Radiographs - Corrected Proof

2010-07-20

Abstract: Using modified axial radiographs, we investigated the relationship between femoral component rotation and flexion gap balance in 70 consecutive knees with varus osteoarthritis 1 year after they underwent cruciate-ligament–retaining total knee arthroplasty with the measured resection technique. We measured (1) the condylar twist angle, defined as the angle between the posterior condylar axis and the clinical epicondylar axis, and (2) the liftoff angle (LOA), defined as the angle between the posterior condylar axis and the tibial cutting surface. There was a significant positive correlation between the postoperative condylar twist angle (mean, 2.6°) and the postoperative LOA (mean, 1.8°). Our data suggest that a more accurate method of identifying the clinical epicondylar axis would lead to a smaller LOA as measured on modified axial radiographs.

Dermatitis Associated With Chromium Following Total Knee Arthroplasty - Corrected Proof

Xiang Gao, Rong-xin He, Shi-gui Yan, Li-dong Wu — 2010-07-20

Abstract: All metal implants release metal ions because of corrosion. Although 20% to 25% of patients develop metal sensitivity after total joint arthroplasty, which is 10% higher than that in the general population, only very few highly susceptible patients exhibit symptoms. Even patients with known metal allergy often do not react to their metal prosthesis. Systemic allergic contact dermatitis is particularly uncommon with total knee arthroplasty because there is no metal-on-metal contact between the femoral and tibial components. We present a case report of 62-year-old man with dermatitis most likely caused by chromium after total knee arthroplasty and review the relevant literature. Although this complication is very rare, it sometimes can be painful enough for the patient to undergo revision surgery.

Effect of Balanced Gap Total Knee Arthroplasty on Intraoperative Laxities and Femoral Component Rotation - Corrected Proof

Dam-Seon Lee, Eun-Kyoo Song, Jong-Keun Seon, Sang-Jin Park — 2010-07-20

Abstract: The gap technique could lead to undesirable rotation of the femoral component in some knees. Using a navigation system, femoral component external rotations and varus-valgus laxities at 0° and 90° of flexion were measured intraoperatively in 44 patients. Significant improvements were observed at a minimum follow-up of 4 years with regard to clinical and radiologic outcomes. The balanced gap technique in total knee arthroplasty provided good intraoperative alignments and laxities of knees at 0° and 90°. However, increased femoral component external rotation was found to be correlated with increased varus alignment at 90° of knee flexion. This study shows that excessive external rotation of the femoral component during flexion gap balancing using the balanced gap technique in total knee arthroplasty can be avoided by additional soft tissue balancing guided by navigation.

Soft Tissue Tension in Cruciate-Retaining and Posterior-Stabilized Total Knee Arthroplasty - Corrected Proof

2010-07-20

Abstract: Using a tensor for total knee arthroplasty (TKA) designed to facilitate soft tissue balance measurements with a reduced patellofemoral joint, we intraoperatively compared the soft tissue tension of cruciate-retaining (CR) and posterior-stabilized (PS) TKAs performed at 0°, 10°, 45°, 90°, and 135° of flexion, with the patella both everted and reduced in 40 osteoarthritic patients. Although balance of soft tissue tension with a reduced patella of PS TKA slightly increased in varus from extension to flexion, these values slightly decreased for CR TKA from extension to flexion. Accordingly, we conclude that soft tissue tension patterns differ between everted and reduced patellae, as well as between PS and CR TKA.

Incorrect Use of the Student t Test in Randomized Trials of Bilateral Hip and Knee Arthroplasty Patients - Corrected Proof

Rajiv Gandhi, Holly N. Smith, Nizar N. Mahomed, Randy Rizek, Mohit Bhandari — 2010-07-20

Abstract: The statistical analysis of a study's results is critical to its interpretation. Often confused, 2 types of t tests exist for dependent or independent samples. We reviewed randomized controlled trials that included patients undergoing bilateral total hip or knee arthroplasty (dependent samples) that used the t test for analysis. Our inclusion criteria resulted in 40 studies for review, 10 of which combined both unilateral and bilateral patients. Of the 30 studies that compared a pure sample of only bilateral patients, 18 (60%) incorrectly used the independent t test. Of the 10 studies with mixed samples, 8 (80%) used the independent t test. The extent to which the incorrect use of this statistical test led to misleading conclusions is uncertain; however, our findings highlight the misuse of statistical tests in the arthroplasty literature.

Clinical Outcome of Total Knee Arthroplasty With Medial Pivot Prosthesis: A Comparative Study Between the Cruciate Retaining and Sacrificing - Corrected Proof

Dae Kyung Bae, Sang Jun Song, Sung Do Cho — 2010-07-16

Abstract: The purpose of this study is to evaluate results after total knee arthroplasty using a medial pivot prosthesis with the posterior cruciate ligament (PCL)-retaining and PCL-sacrificing techniques. The PCL was retained in 67 knees and sacrificed in 70 knees. The mean Knee Society knee score increased from 59.6 before surgery to 91.5 at the last follow-up, and the mean function score increased from 53.6 to 85.4. The mean preoperative femorotibial angle was varus 4.1°, which corrected to valgus 5.8° after surgery. The increased knee and function score did not vary significantly between the cruciate-retaining and cruciate-sacrificing groups (P > .108), nor did the mean preoperative and postoperative femorotibial angle (P > .140). The clinical results of total knee arthroplasty with a medial pivot prosthesis were satisfactory, whether the PCL was retained or sacrificed.

Revision Hip Arthroplasty for Ceramic-on-Ceramic Squeaking Hips Does Not Compromise the Results - Corrected Proof

2010-07-16

Abstract: Squeaking is a complication that may occur after ceramic-on-ceramic total hip arthroplasty (THA) that can be intolerable enough for some patients to seek revision THA. This prospective case series of 11 hips is the first to report on the results of these patients. All patients underwent isolated head and liner exchange to a metal-on-highly cross-linked polyethylene using the direct lateral approach. Mean age was 45.5 years, and body mass index was 30.0 kg/m2. Hips were revised at an average of 40.1 months postindex THA. Retrieval analysis showed 7 of 7 liners/heads with edge loading wear and 5 of 7 liners with signs of neck-rim impingement. Short Form-36 mental dimension, Western Ontario McMaster Osteoarthritis Index, and Harris Hip Score (HHS) showed a statistically significant improvement (P < .05). All squeaking was eliminated after revision THA. There were no morbidities or complications after the revision surgery rendering isolated head-and-liner exchange to a metal-on-highly cross-linked polyethylene a relatively benign procedure.

Hyperbaric Oxygen Therapy in Femoral Head Necrosis - Corrected Proof

2010-07-16

Abstract: We evaluated hyperbaric oxygen (HBO) therapy on a cohort of patients with femoral head necrosis (FHN). This double-blind, randomized, controlled, prospective study included 20 patients with unilateral FHN. All were Ficat stage II, treated with either compressed oxygen (HBO) or compressed air (HBA). Each patient received 30 treatments of HBO or HBA for 6 weeks. Range of motion, stabilometry, and pain were assessed at the beginning of the study and after 10, 20, and 30 treatments by a blinded physician. After the initial 6-week treatment, the blind was broken; and all HBA patients were offered HBO treatment. At this point, the study becomes observational. Pretreatment, 12-month. and 7 year-follow-up magnetic resonance images were obtained. Statistical comparisons were obtained with nonparametric Mann-Whitney U test. Significant pain improvement for HBO was demonstrated after 20 treatments. Range of motion improved significantly during HBO for all parameters between 20 and 30 treatments. All patients remain substantially pain-free 7 years later: none required hip arthroplasty. Substantial radiographic healing of the osteonecrosis was observed in 7 of 9 hips. Hyperbaric oxygen therapy appears to be a viable treatment modality in patients with Ficat II FHN.

A Biomechanical Investigation of Implant Alignment and Femoral Neck Notching with the Birmingham Mid-Head Resection - Corrected Proof

Michael Olsen, Peter M. Lewis, James P. Waddell, Emil H. Schemitsch — 2010-07-16

Abstract: The Birmingham Mid-Head Resection (BMHR) is a bone-conserving, short-stem alternative to hip resurfacing for patients with compromised femoral head anatomy. The current study examined the effect of coronal implant alignment and femoral neck notching on proximal femoral strength with the BMHR. Neither relative valgus nor varus implant alignment had a significant impact on femoral strength compared to neutrally aligned, matched, paired cadaveric specimens. A 5-mm superior neck notch significantly weakened BMHR-implanted synthetic femurs compared to unnotched controls, whereas a 2-mm notch did not significantly affect ultimate failure load. Relative valgus alignment had a protective effect on a full-cortical-thickness superior neck notch. Mid-head resection arthroplasty may be more forgiving to minor preparatory errors than a typical hip resurfacing.

Cementless Bipolar Hemiarthroplasty Using a Hydroxyapatite-Coated Long Stem for Osteoporotic Unstable Intertrochanteric Fractures - Corrected Proof

2010-07-16

Abstract: Treating senile osteoporotic patients with unstable hip fractures remains a challenge. We evaluated the results of 87 cementless bipolar hemiarthroplasties using an extensively hydroxyapatite-coated long stem for unstable intertrochanteric fractures in senile patients. Sixty-one hips were followed for a minimum of 2 years (mean, 36 months) postoperatively. The mean Merle d'Aubigne and Postel hip score was 14.7 points (12-18). Two hips were reoperated because of infection. Of the remaining 59 hips, 48 were included in the radiographic analysis. Although cortical porosis around the stem was seen in 18 hips, there was no loosening or osteolysis. Cementless bipolar hemiarthroplasty using an extensively hydroxyapatite-coated long stem is a useful option for the treatment of unstable intertrochanteric fracture in senile patients with severe osteoporosis.

Mobile-Bearing Total Knee Arthroplasty: A Meta-Analysis - Corrected Proof

Joshua T. Carothers, Raymond H. Kim, Douglas A. Dennis, Carleton Southworth — 2010-07-15

Abstract: An extensive database search was completed to perform a meta-analysis of outcomes of mobile-bearing total knee arthroplasty. Nineteen manuscripts encompassing 3506 total knee arthroplasty met criteria for analysis (average follow-up, 8.6 years). Data were subdivided based on design type and included rotating platform, meniscal bearing, and anterior-posterior glide-rotation subgroups. Fifteen-year survivorship of rotating platform designs (96.4%) was greater than meniscal bearing implants (86.5%). Mean component loosening (0.33%) and bearing instability (<1%) for all subgroups were uncommon. Implants placed prior to 1995 exhibited higher rates of bearing complications (1.6% vs 0.1%). Excellent results were obtained with mobile-bearing TKA over 2 decades. Loosening and bearing instability were uncommon. Bearing complications lessened after 1995, possibly secondary to improved surgical technique.

Analyses of Prosthesis Stem Failures in Noncemented Modular Hip Revision Prostheses - Corrected Proof

Turgay Efe, Jan Schmitt — 2010-07-15

Abstract: In recent years, hip prosthesis stem revision by means of modular revision systems has reached an essential role in revision prosthetics. It is an extremely successful technique. Reports about mechanical failure in nonmodular revision stems have already been published. This complication is rare, but feared. We report about mechanical failure of four non-cemented modular revision stems over a period of 28 months. All failures became clinically apparent because of severe inguinal or thigh pain and were confirmed by conventional x-ray imaging. All stem failures occurred just below the interface between prosthesis stem and neck, which is a biomechanically stressed area. Distal of the failure, all stems were still firmly fixed. In all cases, there was obvious evidence of loosening at the proximal component. Metallographic and energy-dispensive x-ray analysis of one stem showed a fatigue fracture due to dynamic stress. If new pain arises after revision surgery with modular non-cemented prosthesis systems, the possibility of an implant failure should be kept in mind. Patients should be informed accordingly about the risk of implant failure.

Treatment of a Well-Fixed Modular Fully Porous Coated Stem after Fracture Using a Custom Rescue Sleeve - Corrected Proof

Matthew D. Beal, Anthony Marchie, Eric Black, Henrik Malchau, Dennis Burke — 2010-07-15

Abstract: We report a novel technique for the treatment of a fractured fully porous-coated modular stem. The fracture of the stem occurred at the taper of the stem-body junction. In both cases, the stem was well-fixed distally making the reconstruction difficult. Previously, authors have reported the use of an extended trochanteric osteotomy or multiple cortical windows for removal of this type of prosthesis. The technique we describe uses a custom-made “rescue sleeve” that takes advantage of the distal ingrowth. The rescue sleeve is fitted onto the existing stem obviating the need for an extended trochanteric osteotomy. The rescue sleeve's geometry makes up for the loss in height and accepts the modular body components to give the surgeon the length options to optimize stability.

No Clear Advantage to Use of Wound Drains After Unilateral Total Knee Arthroplasty: A Prospective Randomized, Controlled Trial - Corrected Proof

Cao Li, Ablimit Nijat, Mamtimin Askar — 2010-07-15

Abstract: We conducted a prospective randomized, controlled trial in 100 patients to compare the postoperative use of wound drains with the use of no drains in patients who underwent unilateral primary total knee arthroplasty to determine differences in blood loss, range of motion, wound healing, complications (deep vein thrombosis, wound infection), and need for blood transfusions. The patients, who underwent surgery between February 2006 and February 2007, were randomly divided into 2 groups of 50 each: group A, treated without a drain, and group B, treated with a drain. The between-group difference in total blood loss was significant: 535 ± 295 mL in group A and 853 ± 331 mL in group B. Group A needed comparatively less blood transfused than group B did. Differences in wound infection, incidence of deep vein thrombosis, and range of motion were not statistically significant between groups. We found no clear advantage to the use of wound drains in unilateral total knee arthroplasty.

Constrained Acetabular Liners Cemented Into Cages During Total Hip Revision Arthroplasty - Corrected Proof

John I. Khoury, Arthur L. Malkani, Edward M. Adler, David C. Markel — 2010-07-12

Abstract: The combination of acetabular bone loss and hip instability is challenging. Sixteen patients underwent revision total hip arthroplasty using constrained acetabular liners cemented into cages. The average follow-up was 28 months (range, 24-60 months). Clinical evaluation was obtained using the Harris hip score along with radiographic data. At latest follow-up, 13 patients were available for evaluation. Although the average postoperative Harris hip score was 62 points, which was better than the preoperative score of 27 points, the overall radiographic failure rate was 23%. The combination of poor acetabular bone stock and altered stresses from the increased constraint likely led to the poor outcome. We would only recommend use of a cemented, constrained acetabular liner in combination with a protrusio cage as a bail out or salvage procedure.

Revision Total Knee Arthroplasty for Stiffness - Corrected Proof

2010-07-12

Abstract: Few studies have evaluated the results of revision of well-fixed components for stiffness, and some authors have recommended against this intervention based on poor reported results. Thirty-five consecutive patients underwent revision of both femoral and tibial components for stiffness. At a mean of 54.5 months (range, 25-134), the mean arc of motion improved by 44.5° from a preoperative mean of 53.6° to a postoperative mean of 98.1° (P < .0001). The arc of motion improved by more than 30° in 75% (24/32) of patients evaluated at a minimum of 2 years. Seventeen (49%) of the 35 patients required a further intervention for stiffness or sustained a complication. These results suggest that revision total knee arthroplasty for stiffness can be performed with a reasonable expectation of improvement, although the risk of complications and additional operative procedures is substantial.

“Asymptomatic” Pseudotumors After Metal-on-Metal Hip Resurfacing Arthroplasty: Prevalence and Metal Ion Study - Corrected Proof

2010-06-30

Abstract: Symptomatic abnormal periprosthetic soft-tissue reactions (“pseudotumors”) have been reported after metal-on-metal hip resurfacing arthroplasty (MoMHRA). The aims of this study were (1) to determine the prevalence of asymptomatic pseudotumors after MoMHRA and (2) to measure metal ion levels in these patients. A total of 201 hips in 158 patients were evaluated at a mean follow-up of 61 months (range, 36-88) using ultrasound/magnetic resonance imaging and serum/hip aspirate cobalt and chromium measurements. Pseudotumors found in 7 patients (4%) were associated with significantly higher cobalt and chromium levels and inferior functional scores. Elevated levels of cobalt and chromium ions suggest that pseudotumors are associated with increased wear generated from metal-on-metal articulations. Clinicians need to be aware of pseudotumors as a differential diagnosis during clinical evaluation of MoMHRA patients, and further imaging such as ultrasound or magnetic resonance imaging is recommended to confirm the diagnosis.

Thirty-Year Follow-Up of Patient With Gorham Disease (Massive Osteolysis) Treated With Hip Arthroplasty - Corrected Proof

James A. Browne, Thomas C. Shives, Robert T. Trousdale — 2010-06-28

Abstract: Gorham disease (also known as massive osteolysis or disappearing bone disease) is an exceedingly rare, peculiar entity of uncertain cause and unpredictable prognosis. There is no proven mode of therapy or consensus on treatment. We present 30-year follow-up on a patient successfully treated with resection, total hip arthroplasty, and radiation with no recurrence of disease. Our observations in this case suggest that surgical treatment and reconstruction can lead to good long-term function and disease-free survival.

Variability in Physician Opinions About the Indications for Knee Arthroplasty - Corrected Proof

Toronto Arthroplasty Research Group Writing Committee — 2010-06-28

Abstract: To determine how much of variability in physician opinion about the indications for knee arthroplasty is due to inconsistency in individual physicians' opinions. We surveyed 201 orthopedic surgeons, 141 rheumatologists, and 455 family physicians. Physicians were asked how 34 patient characteristics affected their decision to perform or refer for knee arthroplasty. Surgeons and referring physicians agreed on how 4 and 2 of 34 patient characteristics affected their decision about knee arthroplasty, respectively. Half of the variability in opinion among physicians could be accounted for by inconsistency in their individual responses to the survey 6 weeks apart (mean intraclass correlation coefficient = 0.49). Although surgeons and referring physicians vary in their opinion, half of the variability could be attributed to individual physician inconsistency.

Ceramic-on-Ceramic Hip Outcome at a 5- to 10-Year Interval: Has it Lived Up to Its Expectations? - Corrected Proof

2010-06-28

Abstract: This study reports revision and complication rates of a single cementless double-wedged tapered stem with an alumina-alumina bearing over 10 years since the beginning of premarket clinical trials. Of 930 hips (848 patients) implanted by 9 surgeons, there were 19 revisions at mean follow-up of 5.9 years compared to 10 revisions in the 123 hips implanted with the polyethylene control group at mean 7.8 years. The ongoing safety of alumina-alumina bearings is demonstrated through excellent (96.8%) survivorship at 10 years. Twenty-one patients reported 23 incidences of noise described as clicking, squeaking, popping, or creaking. Eight patients with 9 hips described the noise as squeaking, most occurring rarely and only 1 occurring frequently in a patient subsequently revised for a reason aside from the squeaking.

The Use of Navigation to Obtain Rectangular Flexion and Extension Gaps During Primary Total Knee Arthroplasty and Midterm Clinical Results - Corrected Proof

Jong-Keun Seon, Eun-Kyoo Song, Sang-Jin Park, Dam-Seon Lee — 2010-06-28

Abstract: The authors evaluated 112 knees treated by total knee arthroplasty (TKA) using a navigation-assisted modified gap balancing technique. Initial mediolateral gap differences in extension and in 90° of flexion were measured after proximal tibia bone cutting. Final flexion and extension gaps were measured by checking distances under equal tension before prosthesis insertion. Amount of femoral bone cutting and external rotations of femoral components were found to depend on initial gaps. Patients with a final rectangular gap had greater knee flexion angles preoperatively and at 1 year after TKA. However, no differences were observed between the clinical and radiologic outcomes of knees with rectangular and nonrectangular gaps at 1 or 4 years after TKA. The study shows that the navigation-assisted modified gap balancing technique provides an effective means of achieving rectangular flexion and extension gaps during TKA.

Is Deep Vein Thrombosis a Good Proxy for Pulmonary Embolus? - Corrected Proof

2010-06-28

Abstract: It is assumed that prevention of deep venous thrombosis (DVT) is likely to lead to a reduction in the incidence of pulmonary embolus (PE). This study examines the association between symptomatic DVT and PE in patients undergoing orthopedic procedures. We reviewed medical records of 1495 patients who underwent evaluation for DVT or PE within 90 days of an index orthopedic procedure at our institution between 2004 and 2008. Only 27 cases were positive for both DVT and PE (1.7% of the total cohort, 10.8% of cases scanned for both DVT and PE). Tests of association, performed across the entire cohort and within specific subsets of patients, did not demonstrate that patients were more likely to have both DVT and PE than to have either DVT or PE. The high association between DVT and PE that is assumed to exist does not seem to hold true for orthopedic surgery patients.

Current Practice Patterns in Primary Hip and Knee Arthroplasty Among Members of the American Association of Hip and Knee Surgeons - Corrected Proof

Daniel J. Berry, Kevin J. Bozic — 2010-06-28

Abstract: A poll was conducted at the 2009 Annual Meeting of the American Association of Hip and Knee Surgeons to determine current practices among its members in primary total hip arthroplasty and total knee arthroplasty. This article summarizes the audience responses to a number of multiple choice questions concerning perioperative management and operative practice patterns and preferences including anesthetic choices, blood management, surgical approaches, implant selection, implant fixation, bearing surface choice, postoperative rehabilitation, recommended postoperative activity restrictions, and antibiotic prophylaxis.

Prevalence and Management of Obstructive Sleep Apnea in Patients Undergoing Total Joint Arthroplasty - Corrected Proof

2010-06-28

Abstract: Obstructive sleep apnea (OSA) may be a risk factor for complications after total joint arthroplasty (TJA). We sought to determine the prevalence of OSA in patients undergoing TJA, and the safety and effectiveness of intrathecal narcotic (IN) in these patients. We retrospectively reviewed 1255 consecutive patients undergoing 1463 TJA at one hospital. All patients underwent routine screening for OSA and IN anesthesia, with 109 patients (134 TJA) identified with OSA (8.7%). Compared with 127 randomly selected patients (141 TJA) without OSA, OSA patients were significantly heavier and had higher American Society of Anesthesiologists scores, more comorbidities, longer length of stay, more transient hypoxia, more transfusions, and more medical variances. Despite more minor variances, with appropriate screening and management, OSA patients did not have a higher rate of significant or major complications. Length of stay, although longer, was only 2.3 days in OSA patients, demonstrating the safety and efficacy of IN anesthesia in these patients.

Reduction in Narcotic Use After Primary Total Knee Arthroplasty and Association with Patient Pain Relief and Satisfaction - Corrected Proof

Patricia D. Franklin, John A. Karbassi, Wenjun Li, Wenyun Yang, David C. Ayers — 2010-06-28

Abstract: We examined the prevalence of narcotic use before and after total knee arthroplasty (TKA) and its association with post-TKA pain relief and satisfaction. Data on 6364 primary, unilateral TKA patients in a national registry were analyzed. Before TKA, 24% of patients were prescribed one form of narcotic. Of these, 14% reported continued narcotic use at 12 months after TKA, whereas the majority discontinued use. Only 3% of patients who did not use narcotics before TKA had a narcotics prescription at 12 months. Patients who used narcotics before TKA were more likely to have a narcotic prescription at 12 months post-TKA, reported greater pain at 12 months, and were more likely to be dissatisfied with TKA outcome. These findings have implications for patient pre-TKA counseling.

Arterial Injury in Total Knee Arthroplasty - Corrected Proof

2010-06-28

Abstract: Arterial complications associated with knee arthroplasty are relatively rare, although probably underreported, complications of knee arthroplasty that carry a risk of significant morbidity. Thorough preoperative assessment and close liaison with a vascular surgeon, combined with an appreciation of common anatomical variants or distorted anatomy, may help prevent both thromboembolic and direct injuries from occurring. Clinical features of arterial complications following knee arthroplasty may vary significantly from acute hemorrhage or ischemia in the immediate postoperative period to chronic pain and swelling presenting even months following the procedure. There is potential for diagnostic confusion and delay that may adversely affect outcome. Early diagnosis along with vascular surgical review and intervention is key to successful management.

Improved Antibiotic Impregnated Cement Prosthesis for Treating Deep Hip Infection: A Novel Design Using Hip Compression Screw - Corrected Proof

Kuo-Ti Peng, Wei-Hsiu Hsu, Robert Wen-Wei Hsu — 2010-06-24

Abstract: A 2-stage revision arthroplasty has been suggested as the optimal treatment for deep infections in the hip joint. Improvement of the surgical technique to increase the interim function is subject to investigation. From 2004 to 2007, we collected a cohort of 15 consecutive patients who were treated by a novel design augmented with a modified hip compression screw. No fracture of the cement spacer occurred. We believe the modified hip compression screw is a good alternative for the functional endoskeleton of an antibiotic loaded cement prosthesis in the treatment of deep hip infection.

Survivorship of Polyethylene Liner Exchanges Performed for the Treatment of Wear and Osteolysis Among Porous-Coated Cups - Corrected Proof

William G. Hamilton, Robert H. Hopper, C. Anderson Engh, Charles A. Engh — 2010-06-17

Abstract: For the past 17 years, we have favored treating patients with polyethylene wear and osteolysis by performing a liner exchange with retention of the old shell when possible. Using our institutional database, we identified 187 acetabular revisions in which we had retained the old shell. Among this group, we found 25 rerevisions. These included 10 for hip instability, 9 for cup loosening, 3 for recurrence of excessive wear or osteolysis, 2 for infection, and 1 for dissociation of the replaced liner. The need for rerevision varied with the different retained shell designs. We rerevised 17% of the total hip arthroplasties with old spiked shells, 21% with Arthropor shells, 13% with Triloc shells and 5% with Duraloc shells. Before making a decision to retain or remove a well-fixed old acetabular shell, we recommend consideration of the design's past track record and careful inspection of the condition of the existing shell.

The Effect of Fixation Technique on the Stiffness of Comminuted Vancouver B1 Periprosthetic Femur Fractures - Corrected Proof

2010-06-17

Abstract: The purpose of this study was to evaluate the stiffness of 3 different constructs for the fixation of comminuted Vancouver B1 periprosthetic femoral shaft fractures: a single lateral locking plate, a single lateral locking plate plus an anterior strut allograft, and a lateral locking plate plus an anterior locking plate. The axial stiffness, lateral bending stiffness, and torsional stiffness of 10 synthetic periprosthetic femur fracture models were tested. Differences in stiffness between constructs were determined with a 1-way repeated-measures analysis of variance. Fixation technique was found to have a significant effect for all loading modalities (P < .0001). A lateral locked plate plus an anterior locked plate was significantly stiffer than the allograft that in turn was significantly stiffer than the single plate (P < .0001).

Temporal Relationship Between Knee Arthroscopy and Arthroplasty: A Quality Measure for Joint Care? - Corrected Proof

2010-06-14

Abstract: This study examined the incidence and rates of knee arthroscopy in patients older than 65 years and the risk of subsequent knee arthroplasty. Medicare claims data (1997-2006, 5% sample) were used to identify 78 137 knee arthroscopy patients. Performance of arthroscopy increased 56.1%. Prevalence increased 44.6% from 362.2 to 523.7 per 100 000 Medicare patients. The prevalence was greater for women and white patients. Prevalence of knee arthroscopy was greater in the South. Within 1 year after arthroscopy, 10.2% of arthropathy patients and 8.5% of injury patients underwent knee arthroplasty. A progressive increase was seen in the rates of use of knee arthroscopy in elderly Medicare patients for a 10-year period. A 10.2% failure rate 1 year after knee arthroscopy may be a reasonable benchmark against which performance of knee arthroscopy in patients older than 65 years can be measured.

Recurrent Hematomas Within the Iliopsoas Muscle Caused by Impingement After Total Hip Arthroplasty - Corrected Proof

Robert B. Bartelt, Rafael J. Sierra — 2010-06-14

Abstract: Impingement of the iliopsoas muscle after total hip arthroplasty is a potential cause of postoperative groin pain. In addition, hematoma within the iliopsoas sheath has been documented as a cause of groin pain in patients on long-term anticoagulation. We present the case of a patient on long-term anticoagulation presenting after total hip arthroplasty with recurrent, symptomatic iliopsoas sheath hematomas. We believe this was due to iliopsoas impingement caused by a malpositioned acetabular component. His pain was relieved after revision of the acetabular component and debridement of the inflamed psoas tendon.

Mini-Midvastus vs Standard Medial Parapatellar Approach: A Prospective, Randomized, Double-Blinded Study in Patients Undergoing Bilateral Total Knee Arthroplasty - Corrected Proof

2010-06-14

Abstract: The purpose of this study was to determine whether the mini-midvastus approach to total knee arthroplasty (TKA) results in differences in quadriceps muscle strength as well as previously cited advantages in a double blind prospective randomized trial. Twenty-seven patients (54 TKAs) scheduled for bilateral TKA were randomized to undergo mini-midvastus approach on one knee and standard approach on the other. Incision lengths were the same. Postoperative strength was determined by isokinetic and isometric peak torque testing. Range of motion, pain Visual analog scale, side-preference, and gait analysis were assessed preoperatively and postoperatively. The only significant difference in strength testing was increased isokinetic and isometric extension torque at 3 weeks postoperatively for the mini-midvastus approach. No differences between the mini-midvastus and standard approach were observed for stride length, stance time, pain Visual analog scale, or knee range of motion. The mini-midvastus approach has limited benefit compared to the standard approach for TKA.

High Preoperative Range of Motion Is a Significant Risk Factor for Dislocation in Primary Total Hip Arthroplasty - Corrected Proof

2010-06-14

Abstract: Dislocation after total hip arthroplasty (THA) is multifactorial and is dependent on surgical, implant, and patient factors. We hypothesized that high preoperative hip range of motion is an important variable contributing to instability after THA. We retrospectively reviewed 3379 THAs performed during a 21-year period. Average follow-up was 6.6 years. We examined the effect of surgical approach, femoral head size, and preoperative range of motion on dislocation rates. Patients with a posterior approach and 115° or greater of combined preoperative flexion, adduction, and internal rotation dislocated at a significantly higher frequency than those with less than 115° of combined motion (odds ratio, 1.9; P = .007). High preoperative motion in conjunction with a posterior approach and femoral head size less than 32 mm had the highest dislocation rate in our sample (5.9%). Preoperative range of motion is an important variable that should be taken into consideration during operative planning to help reduce the risk of dislocation.

Early- and Late-Term Dislocation Risk After Primary Hip Arthroplasty in the Medicare Population - Corrected Proof

2010-06-14

Abstract: From 1998 to 2007 Medicare 5% national sample dataset, 39 271 primary total hip arthroplasty (THA) patients were identified. Dislocations within 2 years (early) and after 2 years (late) of primary THA were identified. Cox regression was used to evaluate patient, hospital, and procedure characteristics for risk of dislocation, and 1540 (3.92%) and 451 (1.15%) patients were diagnosed with early and late dislocations, respectively. Dislocation rate at 6 months' follow-up decreased steadily between 1998 and 2007 from 4.21% to 2.14%. Early and late dislocation risks were lower by 35% (P < .001) and 43% (P = .01), respectively, for patients operated during 2004 and 2007 compared with 1998 and 2003. Higher Charlson index scores (i.e., more comorbid conditions) and surgeon volume were significant risk factors (P ≤ .04). Decrease in dislocation risks after primary THA seems to coincide with increasing use of larger diameter femoral heads. An awareness of risk factors for dislocation can help surgeons identify high-risk patients so as to prescribe appropriate intervention strategies.

Reinfection After Prior Staged Reimplantation for Septic Total Knee Arthroplasty: Is Salvage Still Possible? - Corrected Proof

Aditya V. Maheshwari, Terence J. Gioe, Niraj V. Kalore, Edward Y. Cheng — 2010-06-14

Abstract: Although results of staged reimplantation for septic total knee arthroplasty (TKA) are well-known, the outcomes of a subsequent repeat infection are not well studied. We studied 34 patients (35 TKA), who were treated for reinfection after prior staged reimplantation for septic TKA. Successful outcome was defined an infection-free prosthetic joint at the time of the last follow-up or death. At a mean follow-up of 59.2 (24-168) months, success was achieved in 24 (68.6%) of 35 knees. Among the failures were 5 amputations, 2 arthrodeses, 1 resection arthroplasty, and 3 continued antibiotic cement spacers. Failure was significantly (P = .02) related to growth of resistant microorganisms. Success was achieved significantly more often (P = .002) with complete prosthetic removal and reimplantation rather than debridement and retention of component(s). Reinfection after prior reimplantation for septic TKA is challenging but success is possible, although less frequent as compared to first time infection after a primary TKA.

Reasons for Revision of First-Generation Highly Cross-Linked Polyethylenes - Corrected Proof

2010-06-14

Abstract: Over a 10-year period, we prospectively evaluated the reasons for revision of contemporary and highly cross-linked polyethylene formulations in a multicenter retrieval program. Two hundred twelve consecutive retrievals were classified as conventional gamma inert sterilized (n = 37), annealed (Crossfire, [Stryker Orthopedics, Mahwah, NJ] n = 72), or remelted (Longevity [Zimmer ,Warsaw, Ind], XLPE [Smith and Nephew, Memphis, Tenn], Durasul [Zimmer, Warsaw, Ind] n = 103) liners. The most frequent reasons for revision were loosening (35%), instability (28%), and infection (21%) and were not related to polyethylene formulation (P = .17). Annealed and remelted liners had comparable linear penetration rates (0.03 and 0.04 mm/y, respectively, on average), and these were significantly lower than the rate in conventional retrievals (0.11 mm/y, P ≤ .0005). This retrieval study including first-generation highly cross-linked liners demonstrated lower wear than conventional polyethylene. Although loosening remained as the most prevalent reason for revision, we could not demonstrate a relationship between wear and loosening. The long-term clinical performance of first-generation highly cross-linked remains promising based on the midterm outcomes of the components documented in this study.

Oblique Posterior Trochanteric Osteotomy in Revision Total Hip Arthroplasty - Corrected Proof

Steven A. Stuchin, Jennifer S. Millman — 2010-06-14

Abstract: Modular polyethylene failure and attendant revision play an increasing role in hip arthroplasty. In spite of well-fixed, well-aligned components, bearing exchange has a high risk of chronic instability, which may be attributed to the resection of stabilizing soft tissue structures to gain exposure. This creates a difficult situation for the surgeon and an inexplicable one for the patient with a previously well-functioning implant. The senior author modified a technique previously described by Shaw that included an osteotomy of the posterior one third of the greater trochanter and preservation of posterior soft tissues. Thirty-five patients underwent 47 revision procedures utilizing this approach, including 16 modular component and 31 more extensive procedures. There were no dislocations or significant complications and no loss of reduction or nonunion. The approach offers excellent exposure while preserving stabilizing soft tissues.

Periprosthetic Stress Fractures at the Sleeve/Stem Junction of the Sivash-Range of Motion Modular Femoral Stem - Corrected Proof

Turlough M.P. O'Donnell, Wui K. Chung, Michael J. Neil — 2010-06-14

Abstract: We report on 13 cases of periprosthetic stress fracture at the sleeve/stem junction using the Sivash-Range of Motion femoral prosthesis. Radioisotope bone scans confirmed the incidence of fracture, and review of the lateral radiographs revealed anteromedial notching of the distal sleeve on the metaphyseal throat of the femur. Treatment in all cases was expectant with full resolution of symptoms. However, there were 3 cases of recurrence, 1 of which needed revision to a more distally loading stem. This is a rare complication when using this prosthesis, but we recommend a slight alteration of the entry point for the femoral reamer when using this stem and advise nonsurgical management if it occurs, as the natural history is for the condition to settle.

Primary Hip Arthroplasty With 28-mm Metasul Articulation: Follow-Up Report - Corrected Proof

2010-06-14

Abstract: This follow-up study reports on 69 patients at mean 13 years with total hip arthroplasty using 28-mm Metasul (Zimmer, Winterthur, Switzerland) metal-on-metal articulation. These results are not transferable to large–diameter head metal-on-metal articulations. Four new revisions, 3 for disassociation of the liner and 1 for mechanical loosening of the acetabulum, occurred since the previous report of mean 7.3 years. The prevalent cause of late revision is disassociation, which suggests a high frictional torque or impingement in these articulation surfaces. No revision was done for osteolysis. Overall, of the original 127 hips, 116 (91%) were known to have maintained their original components.