The Journal of Arthroplasty - Articles in Press

Intrapelvic Displacement of a Trial Femoral Head During Total Hip Arthroplasty and a Method to Retrieve It - Corrected Proof

Kunal Kalra, Michael D. Ries, Kevin J. Bozic — 2010-03-08

Abstract: We describe a technique to retrieve a dislodged femoral trial during total hip arthroplasty. During a revision total hip arthroplasty performed through a direct lateral approach, the femoral trial head was dislodged deep into the pelvis, superior and anterior to the hip joint and behind the anterior pelvic rim. This was retrieved via a posterior approach through the same incision by manipulating the trial head through the pelvis from the anterior to posterior direction. To our knowledge, this technique has not been described previously.

Lateral and High-Angle Oblique Radiographs of the Pelvis Aid in Diagnosing Pelvic Discontinuity After Total Hip Arthroplasty - Corrected Proof

Nicholas J. Giori, Adam O. Sidky — 2010-03-08

Abstract: Diagnosis of a pelvic discontinuity before revision total hip arthroplasty is critical for adequate preoperative planning. The lateral view of the pelvis or high-angle oblique views can aid in visualizing the posterior column when hip hardware obscures the view on standard anteroposterior and Judet views of the pelvis. These views are easy to obtain and can provide valuable information when planning revision total hip arthroplasty.

Torque Measures of Common Therapies for the Treatment of Flexion Contractures - Corrected Proof

Timothy L. Uhl, Cale A. Jacobs — 2010-03-08

Abstract: Efficacy of knee flexion contracture treatment protocols is dependent on the torque applied to the joint, but to date, no published reports have evaluated the torque applied by the available treatment options. The purpose of this study was to measure the torque applied by physical therapists (PTs), home exercises, and mechanical therapy devices. An instrumented test leg recorded peak torque applied by 14 PTs performing knee extension mobilization, 2 home exercises, and 3 types of mechanical therapy (dynamic splint, static progressive stretch, and patient-actuated serial stretch). Physical therapists applied 68.0 N m, patient-actuated serial stretch mechanical therapy applied 53.0 N m, and the other therapies ranged between 4.6 and 12.4 N m. The reported torque values can be used to help improve the efficacy of flexion contracture treatment protocols.

Repeat 2-Stage Revision for Recurrent Infection of Total Hip Arthroplasty - Corrected Proof

Kunal P. Kalra, Kirk K. Lin, Kevin J. Bozic, Michael D. Ries — 2010-03-08

Abstract: Eleven patients who developed reinfection after 2-stage revision for infected total hip arthroplasty (THA) were treated with a repeat 2-stage rerevision. Of the 11 rerevisions, 4 were successful, with no recurrent infection at mean follow-up of 44 months. Reinfection occurred in 7 patients of whom 6 involved either a significantly compromised host or poor local wound status. Clinical symptoms of infection were controlled in 4 of the 7 reinfected cases with antibiotic therapy in 2, irrigation and debridement in 1, and a third 2-stage revision THA in 1. Repeat 2-stage treatment of infected THA is associated with a high failure rate. However, successful results can be achieved particularly if the host is not immunocompromised and healthy soft tissue coverage is present.

Metal Ion Release With Large-Diameter Metal-on-Metal Hip Arthroplasty - Corrected Proof

2010-03-08

Abstract: Preoperative and postoperative ion concentrations were measured in 29 metal-on-metal, large-diameter head total hip arthroplasty (LDH-THA) patients. Mean chromium, cobalt (Co), and titanium levels from LDH-THA were 1.3, 2.2, and 2.7 μg/L at 12 months. The open femoral head design showed significantly higher Co concentrations than the closed design (3.0 vs 1.8 μg/L, P = .037). Compared with previously published ion levels from a hip resurfacing system presenting the same bearing characteristics, Co levels were significantly higher in LDH-THA (2.2 vs 0.7 μg/L, P < .001). This study has demonstrated that the addition of a sleeve with modular junctions and an open femoral head design of LDH-THA causes more Co release than bearing surface wear (157% and 67%, respectively). Even if no pathologic metal ion threshold level has been determined, efforts should be made to minimize its release. We recommend modification or abandonment of the modular junction and femoral head open design for this specific LDH-THA system.

Human Knee Joint Anatomy Revisited: Morphometry in the Light of Sex-Specific Total Knee Arthroplasty - Corrected Proof

Jens Dargel, Joern W.P. Michael, Janna Feiser, Roland Ivo, Juergen Koebke — 2010-03-08

Abstract: This study investigates differences in the anatomy of male and female knee joints to contribute to the current debate on sex-specific total knee implants. Morphometric data were obtained from 60 human cadaver knees, and sex differences were calculated. All data were corrected for height, and male and female specimens presenting with an identical length of the femur were analyzed as matched pairs. Male linear knee joint dimensions were significantly larger when compared with females. When corrected for differences in height, medial-lateral dimensions of male knees were significantly larger than female; however, matched paired analysis did not prove these differences to be consistent. Although implant design should focus interindividual variations in knee joint anatomy, our data do not support the concept of a female-specific implant design.

Results of Isolated Femoral Component Revision With Well-Fixed Acetabular Implant Retention - Corrected Proof

Kyung Soon Park, Taek Rim Yoon, Eun Kyoo Song, Keun Bae Lee — 2010-03-02

Abstract: The present study was undertaken to evaluate the clinical and radiological results of isolated femoral revisions conducted while retaining well-fixed cementless acetabular sockets. Thirty-nine patients that underwent isolated femoral stem revisions were reviewed. Mean age at time of surgery was 60.5 years, and mean follow-up duration was 4.2 years. Decisions to retain acetabular sockets were based on clinical and radiographic findings and intraoperative stabilities. During revisions, polyethylene liners were exchanged for metal-inlay polyethylene liners to have a metal-on-metal bearing surface in 23 cases. Mean Harris hip score improved from 58 points preoperatively to 85 points at final follow-up (P < .001). With the exception of one patient, no increases in acetabular radiolucent line numbers or thicknesses were observed during follow-up visits. Isolated femoral stem revisions with acetabular socket retention were found to provide excellent clinical and radiographic results.

Femoral Nerve Block vs Fascia Iliaca Block for Total Knee Arthroplasty Postoperative Pain Control: A Prospective, Randomized Controlled Trial - Corrected Proof

Brisbane Orthopaedic & Sports Medicine Centre Writing Committee — 2010-02-24

Abstract: Femoral nerve block (FNB) is an accepted mode of analgesia for lower limb procedures but has a documented complication rate. This study compared femoral nerve and fascia iliaca regional anesthesia for total knee arthroplasty (TKA), using fentanyl consumption as the primary outcome measure. Ninety-eight primary unilateral TKA patients were blinded and randomized into fascia iliaca block (FIB) (n = 51) or FNB (n = 47) groups. No significant differences were found in analgesia use (fentanyl and tramadol) at 12 and 36 hours in pain, nausea and range of motion between the groups. There was one case of paresthesia in the femoral nerve in the FNB group. Fascia iliaca block is as effective as FNB as part of a multimodal anesthetic regimen for TKA.

Distal Femoral Arthroplasty for the Treatment of Periprosthetic Fractures After Total Knee Arthroplasty - Corrected Proof

2010-02-22

Abstract: Periprosthetic fractures after total knee arthroplasty present substantial challenge if associated with poor bone stock, fracture comminution, and loose or damaged components. Revision total knee arthroplasty with distal femoral arthroplasty is often necessary in these injuries. We reviewed 20 patients (22 knees) with a mean age of 69.5 years who underwent revision with distal femoral arthroplasty fracture. Patients were followed for an average of 58.6 months. At the latest follow-up, the mean Knee Society knee and functional score were 82.8 and 40, and the Short Form 36 mean physical functioning and mental functioning scores were 55.8 and 65.6, respectively. There were 10 postoperative complications with 5 patients requiring additional surgery. Distal femoral arthroplasty seems to be a viable option for complex periprosthetic femoral fractures after total knee arthroplasty. However, considering the relatively high rate of complications, this procedure should be reserved for patients where alternative treatments are not possible.

In Reply - Corrected Proof

2010-02-22

The authors wish to thank Dr White and his colleagues for pointing out a potential flaw in our study design. Based on their suggestion and concerns, we reran the analysis without the V12.51 code. As shown in , the results of our analysis did not change. Even when the V code was excluded from the analysis, there was no difference in the odds of any venous thromboembolic (VTE) event among total knee arthroplasty (TKA) patients who received aspirin, warfarin, or injectable drugs (low–molecular-weight heparin or synthetic pentasaccharides) for VTE chemoprophylaxis.

Modification of the Explant System for the Removal of Well Fixed Hip Resurfacing Sockets - Corrected Proof

2010-02-22

Abstract: A major concern during revision hip arthroplasty is acetabular bone loss during the extraction of well-fixed acetabular components. Despite the good early survivorship of resurfacing prostheses, revision surgery may be necessary. We recommend the use of the Explant acetabular extraction system (Zimmer, Warsaw, Ind) with a trial liner to preserve acetabular bone stock. We present 2 cases of revised resurfacings using this technique, demonstrating minimal interference to the remaining acetabular bone.

Whole Blood Metal Ion Concentrations in Correlation With Activity Level in Three Different Metal-On-Metal Bearings - Corrected Proof

Christophe A. Pattyn, Sofie N. Lauwagie, René C. Verdonk — 2010-02-22

Abstract: Seventy consecutive osteoarthritis patients younger than 65 years undergoing a hip arthroplasty were included. Three different metal bearings were used (2 different resurfacing systems and one 28-mm metal bearing) and compared with a ceramic control group. Whole blood cobalt and chromium levels were analyzed preoperatively, at 3 months, 6 months, 1 year, and 2 years. Patients with steep cups (abduction >55°) were excluded. No significant differences in functional scores and activity level were found between either groups. Ion levels were significantly lower with one type of resurfacing. No correlation was found between ion and activity level. In conclusion, although the current second-generation metal bearings may show differences in ion release, more attention should be paid to the correlation between ion release and implant positioning.

Patients With Bilateral Procedures Can Be Included in Total Hip Arthroplasty Research Without Biasing Results - Corrected Proof

2010-02-22

Abstract: We explored the influence of bilaterality on the results of a trial of cemented vs uncemented acetabular components. Harris hip scores after 6 months, 2 years, 5 years, and 10 years were analyzed in 240 arthroplasties in 215 patients. Thus, 190 cases in 190 patients were compared to 50 cases in 25 patients. The group of 190 patients were further split into a group of 90 patients who had contralateral hip impairment, knee or spine problems, or significant comorbidities and into a group of 100 patients who had unilateral hip arthropathy. There was no significant difference between the cemented and uncemented groups or between any of these groups and the total group on Harris hip score, indicating that the inclusion of bilateral cases did not alter the outcome.

Tranexamic Acid to Reduce Blood Loss After Bilateral Total Knee Arthroplasty: A Prospective, Randomized Double Blind Study - Corrected Proof

Robin G. MacGillivray, Samih B. Tarabichi, Marwan F. Hawari, Nayzak T. Raoof — 2010-02-22

Abstract: The effects of 2-dosage regimens of tranexamic acid (10 mg/kg and 15 mg/kg) on blood loss and transfusion requirement were compared to saline placebo in 60 patients undergoing concurrent bilateral total knee arthroplasty, with additional reinfusion autotransfusion from intraarticular drains. Mean blood loss was 462 mL in 15 mL/kg group, 678 mL in 10 mg/kg group, and 918 mL in controls (P < .01 vs 15 mg/kg). Blood available for autotransfusion was greatest in controls and least in 15 mg/kg group. Combined autologous and allogenic transfusion volumes were similar in the treatment groups and significantly less than controls (P < .01). With use of an autologous reinfusion strategy, the lower dose is sufficient to lead to a lesser allogenic transfusion requirement.

Chronic Expanding Hematoma of the Lateral Thigh and Massive Bony Destruction After a Failed Total Hip Arthroplasty - Corrected Proof

Maria S. Goddard, Jeffrey J. Vakil, Edward F. McCarthy, Harpal S. Khanuja — 2010-02-22

Abstract: Pseudotumors have been described around both stable and failed total hip arthroplasties. The causes are varied and include polyethylene debris and masses associated with metal-on-metal bearings. We present a patient with a massive tumor of the thigh that grossly and pathologically was associated with recurrent bleeding and extensive bony destruction. The characteristics of this tumor most resemble those of a chronic expanding hematoma. To our knowledge, this has not previously been reported in association with a total hip arthroplasty.

Changes in Cobalt and Chromium Levels After Metal-on-Metal Hip Resurfacing in Young, Active Chinese Patients - Corrected Proof

Jing Yang, Bin Shen, ZongKe Zhou, Fuxing Pei, PengDe Kang — 2010-02-22

Abstract: Metal-on-metal resurfacing arthroplasty is increasingly being performed in young, active patients. Serum and urine metal ion levels are monitored in these patients to assess the physiologic effects of metal-on-metal wear on them. The aim of our prospective study was to evaluate the serum and urine levels of cobalt (Co) and chromium (Cr) in young (age, ≤50 years), active Chinese patients who had undergone metal-on-metal hybrid resurfacing arthroplasties. Levels were measured preoperatively using atomic absorption spectrometry and then sequentially at 3, 6, 9, 12, and 24 months after surgery. For both serum and urine Co and Cr, there was an initial increase to a peak at 6 months, followed by a gradual decline after 6 months, whereas renal function was normal during the study the 2-year study period. There was no radiographic evidence of component loosening. All implants were functioning well. Further long-term studies are needed to observe clinical outcomes and to determine the physiologic effects of the wearing process.

Total Hip Arthroplasty With an Uncemented Tapered Femoral Component in Patients Younger than 50 Years - Corrected Proof

Jeffrey R. McLaughlin, Kyla R. Lee — 2010-02-22

Abstract: The purpose of the present study was to evaluate the outcome of primary uncemented total hip arthroplasty in patients younger than 50 years using the Taperloc (Biomet, Warsaw, Ind) femoral component. We evaluated 94 hips in 79 patients at a mean follow-up of 16 years (range, 11-18.5 years). The average age of the patients at the time of surgery was 36 years (range, 20-49 years). Three femoral components had been revised, none for aseptic loosening. Complete clinical and radiographic follow-up was obtained on the 91 hips that had not undergone femoral component revision. The mean Harris hip score increased from 54 points (range, 20-72) before surgery to 93 points (range, 68-100) at the time of this review. Radiographically, 89 stems (98%) were determined to have fixation by bone ingrowth, 2 (2%) demonstrated stable fibrous ingrowth, and no femoral component was loose. Distal femoral osteolysis was identified in 1 hip (1%). These findings indicate that excellent clinical and radiographic results can be achieved in young patients with the Taperloc femoral component at a mean follow-up of 16 years.

Margin of Error in Alignment: A Study Undertaken When Converting From Conventional to Computer-Assisted Total Knee Arthroplasty - Corrected Proof

Rajesh N. Maniar, Ajay C. Johorey, Chandrashekhar T. Pujary, Akhilesh N. Yadava — 2010-02-22

Abstract: We analyzed alignment of 300 knees, divided equally into groups according to total knee arthroplasty technique: Conventional, CAS-Early (computer-assisted surgery during the surgeon's learning curve), and CAS-Late (after experience with CAS). With the margin of error for alignment of the mechanical axis and femoral and tibial components each within ±3°, the Conventional group's success rate was only 66%; but the rate for the CAS-Early group was 94%. The CAS-Late group's rate was 100%, with no outliers; moreover, the margin of error was reduced to within ±2° in 92% of patients and within ±1° in 52%. For the Conventional group's success rate to be 100%, the margin of error would have to be statistically relaxed to an unacceptable ±8°. Computed-assisted surgery improves alignment even early in the learning curve.

Body Mass Index and the Impact on Hospital Resource Use in Patients Undergoing Total Knee Arthroplasty - Corrected Proof

2010-02-22

Abstract: We identified all total knee arthroplasty patients between 1996 and 2004 and classified them by preoperative body mass index (BMI) as normal (BMI, 18.5-24.9 kg/m2), overweight (BMI, 25.0-29.9 kg/m2), obese (30-34.9 kg/m2), or morbidly obese (≥ 35.0 kg/m2). Of 5521 patients, 769 had a normal BMI, 1938 were overweight, 1539 were obese, and 1275 were morbidly obese. Adjusted length of stay was no different between normal (4.85 days), overweight (4.84 days), obese (4.86 days), or morbidly obese patients (4.93 days) (P = .30). Overall costs were similar among normal ($15 386), overweight ($15 430), obese ($15 646), or morbidly obese patients ($15 752) (P = .24). Postsurgical costs were no different among normal ($9860), overweight ($9889), obese ($10 063), or morbidly obese patients ($10 136) (P = .44). Our results suggest that increased BMI does not lead to increased hospital resource use for total knee arthroplasty.

Letter to The Editor - Corrected Proof

Z. Deniz Olgun, Bülent Atilla — 2010-02-22

We have greatly benefited from reading the article published in the Journal of Arthroplasty, titled “A Randomized Controlled Trial Comparing “High-Flex vs Standard Posterior Cruciate Substituting Polyethylene Tibial Inserts in Total Knee Arthroplasty,” by McCalden and MacDonald, Vol. 24, No. 6, Suppl. 1.

Are Current Total Knee Arthroplasty Implants Designed to Restore Normal Trochlear Groove Anatomy? - Corrected Proof

Kartik M. Varadarajan, Harry E. Rubash, Guoan Li — 2010-02-22

Abstract: Biomechanical studies have shown that external rotation of the femoral TKA component improves patellar tracking but does not restore it to physiologic values. We hypothesized that this could be due to differences in the trochlear groove geometry of TKA and normal knees. This was investigated via a virtual TKA procedure that mounted femoral components on to 3-dimensional models of healthy femurs, followed by measurement of the trochlear geometry before and after the simulated TKA. The results showed that (1) external rotation of the component brought the trochlear groove closer to normal anatomy than no external rotation; (2) however, even with external rotation, the trochlear anatomy was only partially restored to normal. Further work is needed to determine implications for patellofemoral complications observed with current TKA designs.

Femoral Anterior Tangent Line of the Osteoarthritic Knee for Determining Rotational Alignment of the Femoral Component in Total Knee Arthroplasty - Corrected Proof

2010-02-22

Abstract: Several reference axes have been used to establish femoral rotational alignment during total knee arthroplasty. The current study examined the configuration of the anterior surface of the femur immediately proximal to the trochlea as an alternative rotational landmark. An analysis of computed tomographic images of 150 knees with osteoarthritis indicated that the configuration of the surface is mostly flat or slightly depressed, and the line tangential to the surface (femoral anterior tangent line; FAT line) was consistently determined to be 12.2° ± 3.6° internally rotated to the transepicondylar axis. This value was relatively constant and as reliable as the femoral anteroposterior axis for determining rotational alignment. In addition, the FAT line was not affected by the degree of the varus-valgus deformity of the osteoarthritic knees.

Corrected Proof

Yuan-Ya Liao, Yu-Min Lin — 2010-02-19

We read with interest with the well-written article entitled “Comparison of the Early Results of Minimally Invasive Vs Standard Approaches to Total Knee Arthroplasty: A Prospective, Randomized Study” by Karpman and Smith . Their eligible patients were randomized into 3 groups: a quad sparing, mini midvastus, or standard approach to total knee arthroplasty. The authors used repeated t tests to compare continuous variables among 3 groups, and significance levels were not adjusted for multiple testing, which are not appropriate. The authors set the significance level at .05, the probability of a type I error. If the 3 comparisons can be assumed to be independent, then the chance of not committing a type I error in any one of them is (1 − .05)3 = .857. The chance of committing a type I error in at least one of the comparisons is 1 − .857 = .143, which is the overall type I error rate, although for each individual test the type I error rate is .05. We have to use analysis of variance (ANOVA) to avoid this problem . When a significance has been found by ANOVA, it is necessary to do post hoc comparisons that maintains a low overall type I error, such as Bonferroni correction, Tukey test, Scheffé test, Duncan test, and many other procedures .

Influence of Acetabular Cup Rim Design on the Contact Stress During Edge Loading in Ceramic-on-Ceramic Hip Prostheses - Corrected Proof

Mathew Mak, Zhongmin Jin, John Fisher, Todd D. Stewart — 2010-02-10

Abstract: The purpose of the study was to investigate the contact stresses in 3 different acetabular cup rim designs (new, worn, chamfer) during edge loading, after microseparation of ceramic on ceramic hip prostheses. A 3-dimensional finite element analysis was conducted for a 28-mm diameter alumina ceramic bearing with a radial clearance of 40 μm using a normal load of 2500 N under edge loading. At a separation distance of 250 μm, the maximum tensile stress in the “new” design was of similar magnitude to the flexural strength of the alumina material that supports the localized breakdown (stripe wear) of the acetabular cup surface observed clinically. Introducing a 2.5-mm radius chamfer should reduce the maximum tensile stress in the region of 60%.

Wound Drainage After Metal-On-Metal Hip Arthroplasty Secondary to Presumed Delayed Hypersensitivity Reaction - Corrected Proof

Mark D. Earll, Patrick G. Earll, Russell S. Rougeux — 2010-02-10

Abstract: An emerging concern with metal-on-metal total hip arthroplasty is metal-induced hypersensitivity. Currently, this is a diagnosis of exclusion in patients with groin pain after metal-on-metal total hip arthroplasty. We describe a patient presenting nearly a year after arthroplasty with incisional drainage. Infection was presumed; but preoperative studies were nondefinitive, and the wound was explored. The operative cultures were negative; the histology revealed lymphocytic vasculitis. The patient recovered uneventfully after exchange to a metal polyethylene bearing couple. We believe that metal-induced hypersensitivity should be considered with draining wounds with this bearing couple if infection cannot be proven.

Magnetic Resonance Imaging Findings in Painful Metal-On-Metal Hips: A Prospective Study - Corrected Proof

2010-02-10

Abstract: Metal artifact reduction sequence magnetic resonance imaging findings are reported in a prospective series of 31 patients with unexplained painful metal-on-metal (MOM) hips. The abnormalities identified were fluid collection (20 patients), solid mass (2 patients), moderate to severe muscle atrophy (23 patients), and muscle edema (8 patients). In conclusion, soft tissue lesions and muscle atrophy appear to be prevalent in unexplained painful MOM hips. Metal artifact reduction sequence magnetic resonance imaging may be useful to diagnose and monitor at-risk hips but requires validation in well-functioning MOM hips before it can guide clinical decision making.

Minimum 5-Year Follow-Up of a Cementless, Modular, Tapered Stem in Hip Revision Arthroplasty - Corrected Proof

2010-02-10

Abstract: Hip revision surgery with a cementless tapered femoral component can provide axial and rotational stability in patients with compromised proximal bone stock. This study includes 90 cases revised with the Link MP (Waldemar Link, Hamburg, Germany) prosthesis. The median age at surgery was 72 (38-89) years. Aseptic loosening (70%) and periprosthetic fracture (22%) were common indications for surgery. Sixty-three patients (70%) were followed clinically with a median of 6 (5-11) years of follow-up. All other patients were followed through the Swedish Hip Register. The 5-year survival rate was 98% with stem removal and 90% with any reoperation as the end point. Complications included hip dislocation in 17 (19%) patients. The median Harris hip score was 78 (16-100) points, and the median radiographic stem migration was 2.7 mm at follow-up.

Visual Loss After Orthopedic Procedures - Corrected Proof

Pierre-François Kaeser, François-Xavier Borruat — 2010-02-10

Abstract: Perioperative visual loss (PVL) is a very rare and unpredictable complication of surgery performed at distance from the visual pathways, mostly after spine or cardiac procedures. We report 6 consecutive patients with PVL after routine orthopedic procedures (osteosynthesis for complex fracture of the femur [2], total hip arthroplasty [2], hip prosthesis arthroplasty [1], bilateral simultaneous total knee arthroplasty [1]) and reviewed the literature on the subject. An ischemic optic neuropathy was diagnosed in all cases, and visual loss was bilateral in 5 of 6 patients. Partial visual improvement occurred in only 3 of 11 eyes. No specific therapy is available for PVL. Postoperative visual disturbances should prompt without delay an ophthalmic evaluation because emergent correction of anemia, systemic hypotension, or hypovolemia might improve visual prognosis of PVL.

Differences of Knee Anthropometry Between Chinese and White Men and Women - Corrected Proof

2010-02-10

Abstract: Whether there are differences in knee anthropometry between Asian and white knees remains unclear. Three-dimensional knee models were constructed using computed tomography or magnetic resonance imaging of healthy Chinese and white subjects. The morphologic measurements of the femur included mediolateral, anteroposterior dimensions, and aspect ratio. The tibial measurements included mediolateral, medial/lateral anteroposterior dimension, aspect ratio, and posterior slope of medial/lateral plateau. The results showed that Chinese knees were generally smaller than white knees. In addition, the femoral aspect ratio of Chinese females was significantly smaller than that of white females (1.24 ± 0.04 vs 1.28 ± 0.06). Tibial aspect ratio differences between Chinese and white males (1.82 ± 0.07 vs 1.75 ± 0.11), though significant, were likely a reflection of differences in knee size between races. These racial differences should be considered in the design of total knee arthroplasty prosthesis for Asian population.

Complications After Minimally Invasive Total Knee Arthroplasty as Compared With Traditional Incision Techniques: A Meta-Analysis - Corrected Proof

Rajiv Gandhi, Holly Smith, Kelly A. Lefaivre, J. Rod Davey, Nizar N. Mahomed — 2010-02-10

Abstract: The primary objective of our meta-analysis was to compare the incidence of complications between minimally invasive surgery and standard total knee arthroplasty (TKA) approaches. We reviewed randomized controlled trials comparing minimally invasive TKA to standard TKA. After testing for publication bias and heterogeneity, the data were aggregated by random effects modeling. Our primary outcome was the number of complications. Our secondary outcomes were alignment outliers, Knee Society Function scores, and Knee Society Knee scores. The combined odds ratios for complications for the minimally invasive surgery group and alignment outliers were 1.58 (95% confidence interval, 1.01-2.47; P < .05) and 0.79 (95% confidence interval, 0.34-1.82; P = .58), respectively. The standard difference in means for Knee Society scores was no different between groups. Minimally invasive knee surgery should be approached with caution.

Retrieval Analysis of Femoral Zirconium Components in Total Knee Arthroplasty: Preliminary Results - Corrected Proof

2010-02-10

Abstract: Safety of oxidized zirconium (OxZr) in total knee arthroplasty (TKA) has been supported by biomechanical, clinical, and radiologic data. Retrieved OxZr femoral components and corresponding polyethylene (PE) inserts were examined to rule out patterns leading to early failure. Sixteen retrieved TKA with an OxZr femoral component were included. The PE inlays were analyzed applying an established scoring system for wear and surface damage. Femoral components were screened for scratching, pitting, delamination, and striations. The prostheses were in situ for 16.4 ± 11.9 months. The average wear and damage score for the tibial PE inserts was 36.0 ± 12.7. The average score in the visual analysis of the OxZr femoral components was 1.3 ± 1.3. The data presented in this study did not show major wear of the PE in TKA using OxZr components. In this cohort, there were no failures directly related to this implant.

A Prospective Evaluation of 2 Different Pain Management Protocols for Total Hip Arthroplasty - Corrected Proof

2010-02-10

Abstract: Pain management after total hip arthroplasty has improved dramatically in the past decade. However, most protocols use opioid medications for pain control. In the current study, 100 patients were prospectively selected to receive a traditional narcotic-based patient-controlled analgesia protocol or a nonnarcotic oral protocol for pain management after primary total hip arthroplasty. Therapy programs were similar for both groups. Postoperatively, patients were followed daily for opioid use, medication adverse effects, pain control, and overall satisfaction. The nonnarcotic oral group showed lower mean pain scores during the first 24 hours after surgery. The satisfaction rate was high in both groups. Both protocols provided adequate pain control after total hip arthroplasty; the nonnarcotic pain management protocol resulted in significantly decreased opioid consumption and fewer adverse effects.

Uncemented Total Knee Arthroplasty: 2-Year Follow-Up of 100 Knees With a Rotating Platform, Cruciate-Retaining Design - Corrected Proof

Joseph J. Signorelli, Philip M. Bernini, Thomas G. Shirreffs — 2010-02-10

Abstract: Review of the literature shows mixed results regarding uncemented total knee arthroplasty (TKA). To our knowledge, there are no reports of results for uncemented TKA that incorporates a cruciate-retaining and rotating platform design. It is theorized that these design features could decrease the stress at the bone-implant interface. This study reports results on 100 uncemented TKAs at a minimum of 2-year follow-up. Average Knee Society clinical score improved from 52.9 to 95.1; average Knee Society functional score improved from 60.5 to 82.0. Ninety-eight percent of patients had excellent and 2% had good results based on Knee Society scores. There was 99% implant survival; 1 patient required revision of a loose tibial component after a motor vehicle accident. The promising short-term results support the continued use of this implant and suggest a prospective randomized study comparing cemented vs uncemented TKA of this design is warranted.

Polyethylene Subluxation: a Radiographic Sign of Locking Mechanism Failure After Modular Total Knee Arthroplasty - Corrected Proof

Matthew S. Hepinstall, José A. Rodriguez — 2010-02-05

Abstract: Tibial insert locking mechanisms are intended to limit interface motion and “backside” wear in modular total knee arthroplasty (TKA). Nevertheless, anterior polyethylene subluxation is occasionally apparent on lateral radiographs after TKA, suggesting locking mechanism failure. We retrospectively identified 10 modular posterior-stabilized implants of a single design that were found to have failure of the locking mechanism at the time of revision surgery for osteolysis. Operative reports were reviewed for the presence of backside wear, and preoperative radiographs were inspected for polyethylene subluxation. All 10 implants demonstrated significant backside wear. Nine had anterior polyethylene subluxation evident on preoperative radiographs. Anterior polyethylene subluxation on the lateral radiograph is a subtle sign of failure of the locking mechanism in this modular posterior-stabilized TKA.

In Reply - Corrected Proof

Steven J. MacDonald, Robert B. Bourne, Julia T. Marr — 2010-02-05

Thank you for your interest in our article “A Randomized Controlled Trial Comparing “High-Flex” vs “Standard” Posterior Cruciate Substituting Polyethylene Tibial Inserts in Total Knee Arthroplasty,” published recently in the Journal of Arthroplasty. We agree that cultural differences, specifically, the differences in the importance of obtaining knee flexion after surgery between Western and Eastern societies, are important factors to consider. Unfortunately, we do not routinely measure the knee flexion of the contralateral limb (assuming it is normal) so we cannot comment on the premorbid flexion of the affected side. With the respect to the role of “necessity,” that we have performed a randomized control trial would make it unlikely that either group had a predisposition for achieving more postoperative flexion compared to the other. Of interest, we have recently published another article, “The Role Of Polyethylene Design On Post-Op TKR Flexion: An Analysis of 1534 Cases” that demonstrated a larger influence of component design to postoperative flexion after total knee arthroplasty.

An Unusual Case of Pigmented Villonodular Synovitis 14 Years After Total Hip Arthroplasty - Corrected Proof

Xiaomei Ma, Chunyan Xia, Liangzhe Wang, Liangyu Zhao, Huimin Liu, Jin He — 2010-02-04

Abstract: Pigmented villonodular synovitis (PVNS) is a rare benign proliferation lesion of the synovium of the joint, bursa, and the tendon sheath. We report here a case of PVNS in a 78-year-old woman 14 years after she underwent total arthroplasty of her right hip. Diffuse PVNS was detected in her right hip during surgery to replace her prosthesis, which had loosened. Macroscopically, the surface of the resected tissue was black and composed of papillae and nodules. Histologically, the tissue consisted of proliferative synoviocytes with black pigment in the cytoplasm. Beneath the synoviocytes were foamy cells. Pathologic analysis confirmed the diagnosis of PVNS with black pigment and the presence of hemosiderin. This indicates that implantation of the prosthesis might have caused the lesion or might have caused its proliferation.

A Rare Mode of Extensor Mechanism Failure in Total Knee Arthroplasty - Corrected Proof

Chi Ho Jason Fan, Chun Kwong Lo, Shu Hang Patrick Yung, Kai Ming Chan — 2010-02-01

Abstract: We reported a rare mode of extensor mechanism failure in total knee arthroplasty. The patellar tendon was elongated and thin instead of disruption at the bone-tendon junction. We also described the surgical technique for reconstruction of patellar tendon. Patellar tendon was shortened by a precalculated amount. It was then augmented by autologous semitendinosus tendon graft and protected by tension band wire. Active full knee extension could be achieved at postoperative 10 months after the removal of wire loop.

Effects of Provider Patient Volume and Comorbidity on Clinical and Economic Outcomes for Total Knee Arthroplasty: A Population-Based Study - Corrected Proof

Min-Hsiung Wei, Yi-Ling Lin, Hon-Yi Shi, Herng-Chia Chiu — 2010-01-29

Abstract: Our study examined how provider patient volume, postoperative infection rate, and perioperative complication affect length of stay, hospitalization charges, and adverse outcomes for patients undergoing total knee arthroplasty (TKA). The study sample included patients who had undergone total knee arthroplasty at all acute care hospitals in Taiwan between 2000 and 2003. Two economic indicators revealed linear associations with surgeon's patient volume, hospital's patient volume, and comorbidity score. Patients who developed postoperative infections remained hospitalized an average of 8.49 days longer than did patients with no infection. Postoperative infection was associated with surgeon experience. Our findings indicate that a surgeon's patient volume has a more significant effect than a hospital's patient volume on clinical outcomes. However, patient volumes for both surgeon and hospital are equally important in economic outcomes.

The Aquamantys System—An Alternative To Reduce Blood Loss in Primary Total Hip Arthroplasty? - Corrected Proof

Alexander Zeh, Jana Messer, John Davis, Attila Vasarhelyi, David Wohlrab — 2010-01-25

Abstract: To evaluate the effectiveness of the Bipolar Sealer 6.0-VT (BPS 6.0-VT) (Tissue Link Medical, Inc, Dover, NH) in reducing blood loss compared with a conventional electrocautery (Erbe ICC 350) (Erbe ICC 350 (ERBE Elektromedizin GmbH, Tübingen, Germany). A prospective randomized trial of 105 patients with primary total hip arthroplasty (Erbe ICC 350: 50 patients; BPS 6.0-VT: 55 patients). On the basis of the calculation of the preoperative blood volume the total and postoperative blood loss were calculated. No statistically significant difference could be shown for total intraoperative and postoperative blood loss (group A 1846 mL; group B 1740 mL) (t test). Due to the lack of reduction of blood loss and the high costs of the BPS 6.0-VT, its use is not recommended in primary total hip arthroplasty.

Femoral Periprosthetic Fracture in Osteoporotic Bone after a Total Knee Replacement: Treatment with Ilizarov External Fixation - Corrected Proof

2010-01-25

Abstract: We report 3 cases of periprosthetic fractures after total knee replacement treated with Ilizarov external fixator (Smith and Nephew plc, Memphis, Tenn) and a follow-up of at least 3 years. We used 2 rings in the supracondylar area distal to the fracture and 3 half pins proximally in all our cases leaving the knee free to move. In one patient apart from the 2-ring frame placed distal to the fracture site the fixator included another ring frame placed proximally just below the 3 half pins. Uncomplicated fracture healing with lower extremity excellent alignment was achieved in 12 weeks after surgery. In periprosthetic femoral fractures, especially in elderly patients, Ilizarov external fixator is a treatment option which provides stable fixation, prompt postoperative mobilization, and has no major complications.

Cementing Techniques for Hip Resurfacing Arthroplasty: In Vitro Study of Pressure and Temperature: Hip Resurfacing: Pressure and Temperature - Corrected Proof

Rudi G. Bitsch, Travis Loidolt, Christian Heisel, Thomas P. Schmalzried — 2010-01-25

Abstract: Cementing irregularities have been associated with femoral failures of resurfacing arthroplasties in retrieval studies. We used an in vitro model to measure pressure, temperatures, and cement penetration as a function of 6 different cementing techniques. Filling the component with cement can lead to overpenetration or increase the resistance to component seating with resultant polar cement mass. Both conditions result in high and long-lasting cement pressures, cement defects, as well as peak temperatures higher than 50°C. Manual application of cement provides complete penetration of the available fixation area with the lowest cement pressures, the smallest total cement mass, and a peak temperature of 36.0°C ± 4.1°C. Application of the principles elucidated by this study may reduce the risk of cement overpenetration and incomplete seating.

Five Duraloc Locking Ring Failures - Corrected Proof

Cara C. Powers, Kevin B. Fricka, Matthew S. Austin, Charles A. Engh — 2010-01-25

Abstract: We report on 5 cases that underwent revision for locking ring failure in the Duraloc product line (DePuy, Warsaw, Ind). All liner retrievals showed signs of posterior neck/liner impingement and superior edge loading or significant wear. In these cases, we believe superior head migration and neck/liner impingement due to cup anteversion contributed to these locking ring failures. More research is needed to determine the incidence of this complication. Patients with locking ring failures should be closely monitored. Full cup revision, face-changing liners, or cementing liners into well-fixed cups are all options to correct suboptimal cup positioning.

Total Hip Arthroplasty Using a Cylindrical Cementless Stem in Patients With a Small Physique - Corrected Proof

Yoshihide Nakamura, Hiromasa Mitsui, Akira Kikuchi, Satoshi Toh, Hiroshi Katano — 2010-01-25

Abstract: We performed total hip arthroplasty using an anatomic medullary locking cementless stem for small-physique patients from 1988 to 1995. We conducted a retrospective study of 50 joints in 44 cases, including 40 developmentally dysplastic hips followed for 12 to 20 years (average, 15.1 years). Average height and body weight were 152 cm and 56 kg (5.0 ft and 124 lb), respectively, with an average body mass index of 24.2. Twelve joints (24%) were revised for acetabular-sided failures. Forty-eight stems (96%) showed bone ingrowth fixation, and there were no unstable stems. The simple cylindrical shape of the distal portion of the AML stem was less affected by deformity of the proximal femur of developmental dysplasia of the hip in patients with a small physique, and both clinically and radiologically good results were confirmed at long-term follow-up.

Correlations Between Commonly Used Clinical Outcome Scales and Patient Satisfaction After Total Knee Arthroplasty - Corrected Proof

2010-01-25

Abstract: Patient satisfaction is becoming increasingly important as a crucial outcome measure for total knee arthroplasty. We aimed to determine how well commonly used clinical outcome scales correlate with patient satisfaction after total knee arthroplasty. In particular, we sought to determine whether patient satisfaction correlates better with absolute postoperative scores or preoperative to 12-month postoperative changes. Patient satisfaction was evaluated using 4 grades (enthusiastic, satisfied, noncommittal, and disappointed) for 438 replaced knees that were followed for longer than 1 year. Outcomes scales used the American Knee Society, Western Ontario McMaster University Osteoarthritis Index scales, and Short Form–36 scores. Correlation analyses were performed to investigate the relation between patient satisfaction and the 2 different aspects of the outcome scales: postoperative scores evaluated at latest follow-ups and preoperative to postoperative changes. The Western Ontario McMaster University Osteoarthritis Index scales function score was most strongly correlated with satisfaction (correlation coefficient = 0.45). Absolute postoperative scores were better correlated with satisfaction than the preoperative to postoperative changes for all scales. Level of evidence: Level IV (retrospective case series)

Corrected Proof

Richard H. White, John P. Meehan, Patrick S. Romano — 2010-01-25

In their recently published study, Bozic and colleagues analyzed the effect of 3 different thromboprophylaxis regimens on the 30-day incidence of acute venous thromboembolism (VTE) after total knee arthroplasty, using the proprietary Perspective database. The authors used a risk-adjusted multivariate model that included a propensity score (for aspirin use) to compare outcomes associated with 3 principal thromboprophylactic regimens: aspirin alone, low–molecular-weight heparins, and warfarin. Among the International Classification of Diseases, Ninth Revision, Clinical Modification codes they used to define the outcome of interest, VTE, they included the code V12.51 in their definition of both “any VTE” and “proximal DVT.” Unfortunately, this code is used to indicate a “personal history of venous thrombosis or embolism,” not acute VTE. To determine how frequently this code is used, we analyzed the records of 237 935 cases that underwent knee arthroplasty in the State of California and found that there were 3755 cases (1.55%) with a discharge code of V12.51 for the index surgical hospitalization. Assuming the Perspective cohort that was analyzed is similar to the California cohort, the effect of including V12.51 in the definition of VTE leads to 2 errors: a significantly higher observed incidence of acute VTE and, more importantly, a potential bias against warfarin and/or low–molecular-weight heparin thromboprophylaxis because physicians are more likely to use these agents rather than aspirin in patients with a history of VTE. We suggest that the authors repeat their otherwise comprehensive analysis after eliminating V12.51 as an outcome code for VTE.

Purse-String Capsule Repair to Reduce Proximal Femoral Arthroplasty Dislocation for Tumor—A Novel Technique With Results - Corrected Proof

2010-01-25

Abstract: Hip joint dislocation is the most common complication after proximal femoral arthroplasty with a large endoprosthesis. Average dislocation rates are around 15%. In an attempt to decrease dislocations after proximal femoral arthroplasty for tumor resections, we devised a novel closure of the hip capsule. This technique uses a 3-mm cottony Dacron suture placed about the hip capsule in a circumferential, purse-string manner. Thirty-nine patients received hip hemiarthroplasty with purse-string capsular closure. Seven patients were lost to follow-up, leaving 36 patients available for analysis. One patient dislocated (2.8%). We believe this technique is useful in preventing dislocation in patients undergoing proximal femoral arthroplasty for oncologic disease.

Corrosion at the Stem-Sleeve Interface of a Modular Titanium Alloy Femoral Component as a Reason for Impaired Disengagement - Corrected Proof

2010-01-25

Abstract: Modularity in sleeved femoral components allows the exchange of the stem without disruption of the fixation between the sleeve and the surrounding bone at revision surgery. Failure to disengage the stem from the sleeve would represent an unnecessary compromise from the intended usefulness of the modular design. We report the results of an examination of 22 modular titanium alloy femoral components retrieved after 0.0 to 8.8 years in vivo. In 7 implants, the stem-sleeve interface could not be disengaged without cutting through the components or using mechanical force. Moderate to severe corrosion was detected in all 7 of these cases. Corrosive surface changes were observed in an additional 6 interfaces. There was no correlation with the length of time that the devices had been implanted. When only the stem is to be revised, orthopedic surgeons should be aware of difficulties in disengagement and anticipate alternative surgical procedures.

Wear Comparison Between a Highly Cross-Linked Polyethylene and Conventional Polyethylene Against a Zirconia Femoral Head: Minimum 5-Year Follow-Up - Corrected Proof

2010-01-25

Abstract: Highly cross-linked polyethylene (HXLPE) was developed to reduce wear of articular bearing surface in total hip arthroplasty patients. Several studies have shown reduced wear of HXLPE compared with conventional polyethylene; however, these studies had used HXLPE in combination with a Co-Cr metal head. The purpose of this study was to compare the 5-year in vivo wear of HXLPE with that of conventional PE using a zirconia femoral head. Forty-five hips with a Trilogy HXLPE (Zimmer, Warsaw, Ind) were matched and compared with a control group of 20 conventional Trilogy PE hips. The 2-dimensional linear wear rate was significantly less in the HXLPE group between 1 and 5 years postoperation (P < .001). The results show that HXLPE reduces short-term polyethylene wear against not only a Co-Cr head but also a zirconia head.

Iliopsoas Tendonitis Caused by Overhang of a Collared Femoral Prosthesis - Corrected Proof

Christopher J. Brew, Ian Stockley, Andrew J. Grainger, Martin H. Stone — 2010-01-22

Abstract: Pain after total hip arthroplasty can be due to a variety of causes, one of the less common being iliopsoas tendonitis. We report an unusual case of iliopsoas tendonitis caused by overhang of the femoral calcar by a collared femoral prosthesis resulting in impingement on the iliopsoas tendon. An ultrasound-guided corticosteroid and local anesthetic diagnostic injection to the site of impingement confirmed the diagnosis with temporary symptom relief. Revision of the femoral stem to a collarless prosthesis resulted in immediate and complete resolution of symptoms.

Revision Total Knee Arthroplasty for Component Malrotation is Highly Beneficial: A Case Control Study - Corrected Proof

2010-01-21

Abstract: Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. We reviewed 24 patients who had TKA revision due to component malrotation as the only objective abnormality. Mean combined component rotation was 6.8° excessive internal rotation, as documented by computed tomography. Twenty-four matched control patients had TKA revision due to aseptic loosening. Mean follow-up was 37 months. Preoperative Knee Society Score improved by 49 points at 6 months postoperatively for the malrotation patients and by 39 for the loosening patients. At last follow-up, Knee Society Score was 80 for the malrotation group and 75 for the loosening group. We recommend the use of computed tomography scans in evaluation of all patients with early painful TKAs and no objective evidence of infection. When component malrotation is demonstrated, early revision should be considered.