The Journal of Arthroplasty - Articles in Press

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.

Long-Term Outcomes of Patellofemoral Arthroplasty - Corrected Proof

Hans-Peter W. van Jonbergen, Dirk M. Werkman, Lex F. Barnaart, Albert van Kampen — 2010-01-07

Abstract: The purpose of this study was to correlate the long-term survival of patellofemoral arthroplasty with primary diagnosis, age, sex, and body mass index. One hundred eighty-five consecutive Richards type II patellofemoral arthroplasties were performed in 161 patients with isolated patellofemoral osteoarthritis. Diagnoses included primary patellofemoral osteoarthritis, posttraumatic patellofemoral osteoarthritis, and patellofemoral osteoarthritis with a previous realignment procedure for patellar subluxation or trochlear dysplasia. Median time to follow-up was 13.3 (range, 2.0-30.6) years. Patellofemoral arthroplasty survival was 84% at 10 years and 69% at 20 years. Primary diagnosis, sex, or age at patellofemoral arthroplasty did not significantly affect the rate of revision (P = .35, P = .24, and P = .65, respectively). The rate of revision in obese patients (body mass index >30 kg/m2) was higher than that in nonobese patients (P = .02).

The Birmingham Hip Resurfacing Prosthesis: An Independent Single Surgeon's Experience at 7-Year Follow-Up - Corrected Proof

2010-01-07

Abstract: An independent single surgeon's 7-year experience with Birmingham hip resurfacing is presented. The study also involved investigation of the significance of pedestal sign in patients requiring revision. A consecutive 117 hips in 101 patients (59 male and 42 female patients) operated on by the senior author (VGJ) were assessed at a mean follow-up of 7 years (range, 5-9.4 years). Mean age at surgery was 54 years (range, 20-74 years). Seventy-three hips had a preoperative diagnosis of primary osteoarthritis, and secondary osteoarthritis was seen in 44 hips. Failure was defined as revision for any reason. Revision of the femoral component alone was undertaken in 8 hips (6.8%): 5 within first year for periprosthetic fracture neck of femur and in 3 hips after 5 years of follow-up. In 2 patients who were known to have osteonecrosis of the femoral head preoperatively, the femoral component progressively collapsed into varus after 5 years of follow-up. Pedestal sign was the earliest radiologic sign noted in these 2 patients and progressed rapidly within 1 year on serial radiographs well before the onset of clinical symptoms. Kaplan-Meier survival with revision as end point at 7 years was 91.5% (95% confidence interval, 97.6%-85.4%).

Unexpected Finding of a Fractured Metal Prosthetic Femoral Head in a Nonmodular Implant During Revision Total Hip Arthroplasty - Corrected Proof

Nicholas J. Giori — 2009-12-21

Abstract: Though there are many reports of fractured femoral components after total hip arthroplasty; there are no reports of a fractured metal femoral head. This is a report of a fractured metal femoral head in a nonmodular total hip replacement discovered unexpectedly during revision total hip arthroplasty for acetabular failure. This surprise finding, which was not appreciated on preoperative x-rays, required unplanned extraction of a well-ingrown, fully porous coated cylindrical femoral stem. Though rare, fracture of the metal femoral head in a DePuy (Warsaw, Ind.) monoblock Anatomic Medullary Locking (AML) component is possible, and one cannot expect the fracture to be apparent on preoperative radiographs as the 2 pieces may not necessarily dissociate. As usual, the surgeon performing revision arthroplasty should be prepared to revise all components.

Gait Analysis of Knee Arthritis Treated With Hyaluronic Acid - Corrected Proof

Don Kevin Lester, Kuan Zhang — 2009-12-21

Abstract: Self-reported studies have demonstrated efficacy of hyaluronic acid (HA) therapy. Gait analysis may objectively demonstrate changes associated with HA therapy. Fifty-three consecutive patients with unilateral osteoarthritis (OA) of the knee were evaluated with a validated and sensitive gait laboratory previously used for gonarthrosis. Two 100-meter walks were performed before and after HA therapy. Nineteen parameters were measured. In addition, the subjective response to treatment was correlated with changes in gait parameters. Single-limb support time, velocity, fatigability, and swing phase were not improved. Only double-limb support time was found to be significantly different (P = .04). The remaining gait variables were not changed. Separately, the subset of patients that achieved greater than 70% subjective pain relief had no objective improvements in gait parameters. Hyaluronic acid therapy may result in a placebo effect for the treatment of gonarthrosis.

Efficacy of Periarticular Injection of Bupivacaine, Fentanyl, and Methylprednisolone in Total Knee Arthroplasty: A Prospective, Randomized Trial - Corrected Proof

Arun Mullaji, Raj Kanna, Gautam M. Shetty, Vipul Chavda, D.P. Singh — 2009-12-21

Abstract: We evaluated the efficacy of periarticular infiltration of corticosteroid, opioid, and a local anesthetic by comparing pain scores, knee flexion, and quadriceps function on the day of surgery, first postoperative day, day of discharge, and 2 and 4 weeks after surgery between the infiltrated and the noninfiltrated knee in 40 patients undergoing simultaneous bilateral computer-assisted total knee arthroplasty who were randomized to receive the injection in the right or left knee. In comparison to the noninfiltrated side, the infiltrated knee showed significantly lower pain scores, significantly greater active flexion up to 4 weeks, and superior quadriceps recovery up to 2 weeks after surgery. This simple and inexpensive technique can significantly reduce pain and hasten functional recovery in the first month after total knee arthroplasty.

Randomized Controlled Trial of Radiographic and Patient-Assessed Outcomes Following Fixed Versus Rotating Platform Total Knee Arthroplasty - Corrected Proof

Wael A. Rahman, Donald S. Garbuz, Bassam A. Masri — 2009-12-21

Abstract: This prospectively blinded randomized controlled study evaluated the difference in the functional and radiological outcomes in patients who received a press-fit condylar Sigma cemented cruciate-substituting total knee arthroplasty with either a rotating platform (RP) or a fixed bearing (FB). There were 51 joints in 49 patients: 24 joints in the RP group (mean follow-up, 43 months) and 27 joints in the FB group (mean follow-up, 40 months). At baseline, there was no significant difference in age, body mass index, preoperative diagnosis, Charnley class, range of motion, clinical and functional scores, between the RP and FB groups. At mid-term follow up both the RP and FB give equivalent results, but patients with the RP tended to have a higher activity level score.

Common Errors in the Execution of Preoperative Templating for Primary Total Hip Arthroplasty - Corrected Proof

2009-12-21

Abstract: We reviewed 75 primary total hip arthroplasty preoperative and postoperative radiographs and recorded limb length discrepancy, change in femoral offset, acetabular position, neck cut, and femoral component positioning. Interobturator line, as a technique to measure preoperative limb length discrepancy, had the least amount of variance when compared with interteardrop and intertuberosity lines (Levene test, P = .0527). The most common error in execution of preoperative templating was excessive limb lengthening (mean, 3.52 mm), primarily due to inferior acetabular cup positioning (Pearson correlation coefficient, P = .036). Incomplete medialization of the acetabular component contributed the most to offset discrepancy. The most common errors in the execution of preoperative templating resulted in excessive limb lengthening and increased offset. Identifying these errors can lead to more accurate templating techniques and improved intraoperative execution.

The Position of the Tibial Component Affecting the Postoperative Mechanical Axis in Total Knee Arthroplasty - Corrected Proof

Dae Kyung Bae, Sang Jun Song, Kyoung Ho Yoon, Seung Mok Shin — 2009-12-21

Abstract: The purpose is to identify whether the position of the tibial component in relation to the anatomical axis affects the postoperative mechanical axis in total knee arthroplasty for Korean patients. Preoperatively, 30 patients with varus deformity lesser than 10° were classified as group A, and 30 patients greater than 10° were classified as group B. Postoperatively, the distance between the midline of the tibial stem and anatomical axis (medial offset) was measured. The medial offsets were 2.5 ± 1.9 mm in group A and 3.9 ± 2.7 mm in group B (P = .021). The postoperative mechanical axes were varus 1.3 ± 1.2° in group A and varus 2.5 ± 2.0° in group B (P = .004). We think that the medial position of tibial component in relation to the anatomical axis affects the measurement of postoperative mechanical axis in total knee arthroplasty.

Guidelines for Implant Placement to Minimize Impingement During Activities of Daily Living After Total Hip Arthroplasty - Corrected Proof

2009-12-21

Abstract: Impingement, both prosthetic and bony, precedes the vast majority of dislocations after total hip arthroplasty and may adversely impact component wear. Reconstructed computer hip models of 8 subjects were used to evaluate hip range of motion for activities of daily living (ADLs) associated with posterior instability and anterior instability. Variables examined included acetabular position, femoral offset, and head size. The majority of flexion ADLs (associated with posterior instability) encountered prosthetic impingement, whereas extension ADLs demonstrated bony impingement with the 45/20 cup placement position. Cup placement in natural anteversion and adduction allowed normal joint motion in anterior and posterior impinging activities. Insufficient femoral offset and smaller head size negatively impacted range of motion. Any anterior cup and posterior cup protrusions greater than 5 mm should be avoided.

Cup Anteversion in Hip Resurfacing: Validation of EBRA and the Presentation of a Simple Clinical Grading System - Corrected Proof

2009-12-21

Abstract: The use of large metal on metal bearings has led to a reduction in the risk of dislocation post hip arthroplasty. Because of this, and also because of the technical difficulties associated with resurfacing surgery in particular, it could be argued that a less meticulous approach to acetabular cup placement has developed in comparison with conventional metal on polyethylene arthroplasty. Resurfacing cups may produce significant clinical problems when placed at the extremes of version, including increased production of metal debris and psoas tendonitis. Presented in this article is evidence that EBRA software (Einzel-Bild-Roentgen-Analysis, University of Innsbruck, Austria) can be used to reliably assess the version of resurfacing cups, when radiographs are of sufficient quality. The cups have characteristic appearances when placed at the extremes of version. These characteristics can allow the surgeon to identify poorly positioned cups without the use of software.

Extensive Osteolysis Caused By Polyethylene Particle Migration in an Anatomical Hydroxyapatite-Coated Hip Prosthesis: 10 Years' Follow-Up - Corrected Proof

2009-12-21

Abstract: We report our 10-year follow-up results of 630 consecutive Anatomique Benoist Giraud I hip prostheses implanted between June 1990 and December 1995. At this time, 520 were satisfactory and 25 had been revised. Although the majority of patients remained asymptomatic at the end of follow-up, the real survivorship of the implant was less than 91% (33 patients who were in the waiting list for revision due to osteolysis at that time were revised by December 2007). On the other hand, radiographic outcomes were of concern: around 90% of patients showed progressive stress shielding and large granulomatous lesions in the proximal femur, and more than 82% of patients exhibited polyethylene wear in excess of 1 mm (mean = 1.69 mm).

Metal-on-Metal Cups Cemented Into Reinforcement Rings: A Possible New Acetabular Reconstruction Procedure for Young and Active Patients - Corrected Proof

Julien Girard, Antoine Combes, Stephane Herent, Henri Migaud — 2009-12-21

Abstract: The purpose of this study was to evaluate the clinical and radiological results of Metasul cups cemented into reinforcement rings for young and active patients. Twenty-three total hip arthroplasties with Metasul cups were cemented into Muller reinforcement rings. Mean follow-up was 6.1 years (5-10). At final follow-up, the Harris hip score increased from 62.2 (39-85) to 95.2 (84-100, P = .01): no revision was undertaken for aseptic loosening or fixation failure. Considering reoperation and bearing revision as end points, survival rates were 95.8% and 100%, respectively. The mean blood concentrations of chromium, cobalt, and titanium were 1.85 μg/L, 1.24 μg/L, and 9.62 μg/L, respectively. A longer follow-up is mandatory, but it seems possible to use hard-on-hard bearings with metallic rings in young patients during hip revisions or in dysplastic cases with encouraging intermediate follow-up results.

Porous-Coated Cementless Acetabular Components Without Bulk Bone Graft in Revision Surgery - Corrected Proof

2009-12-21

Abstract: We previously reported the average 9.3-year (range, 5-13 years) results of 74 patients (83 hips) with porous-coated acetabular components that were placed without bulk bone graft at revision surgery. Since the previous report, 7 patients (7 hips) died before the minimum follow-up of 10 years, and 1 patient (1 hip) was lost to follow-up. We now report the average 15.6-year (range, 10-20 years) results for 66 patients (75 hips). Three additional acetabular components were removed or revised again: 2 for infection and 1 for dislodgement of the polyethylene liner from the metal shell. Overall, 7 (7%) components required removal or repeat revision. No shell was revised for aseptic loosening, and none was categorized as loose during the entire follow-up period.

Effect of Alendronate on Pseudomembrane Cytokine Expression in Patients with Aseptic Osteolysis - Corrected Proof

Graeme Holt, James Reilly, R.M. Dominic Meek — 2009-12-07

Abstract: Aim: To determine whether alendronate alters the pseudomembrane inflammatory cytokine profile in patients with established aseptic osteolysis.Methods: A prospective, double-blind, randomized, controlled trial was conducted. Ten individuals listed for revision surgery for aseptic failure of a primary cemented arthroplasty were randomly assigned placebo/alendronate 70 mg once weekly for 8 weeks before revision surgery. Formalin-preserved pseudomembrane samples were paraffin-sectioned for immunohistochemical analysis to assess inflammatory cytokine protein expression. Polymerase chain reaction was carried out to assess expression of relevant mRNA.Results: No significant difference was detected in the inflammatory cytokine protein or mRNA expression between groups.Conclusion: Alendronate 70 mg administered for an 8-week period before surgery did not alter the pseudomembrane inflammatory cytokine profile in patients with established aseptic osteolysis. Any potential biological effects may occur due to downstream effects on osteoclast and osteoblast function.

A Painful Metal-on-Metal Total Hip Arthroplasty: A Diagnostic Dilemma - Corrected Proof

Thomas J. Blumenfeld, William L. Bargar, Pat A. Campbell — 2009-12-07

Abstract: Infection, loosening, osteolysis, or other causes can lead to the development of pain about a previously well-functioning total hip arthroplasty. An inflammatory reaction unique to metal on metal arthroplasty can lead to a painful total hip. A synovial biopsy is needed to make this specific diagnosis, and included in the differential diagnosis is infection. The workup of infection includes obtaining a C-reactive protein and erythrocyte sedimentation rate. Elevations of both the C-reactive protein and erythrocyte sedimentation rate are felt to indicate possible infection. This case report describes both of these findings and the treatment rendered in a painful subluxing metal-on-metal total hip arthroplasty presenting with ongoing pain and a large effusion.

Measuring Patellofemoral Forces and Pressures in a Simulated Operating Room Environment - Corrected Proof

Norman A. Johanson, Douglas L. Cerynik, Maria Pasquale — 2009-11-09

Abstract: The purpose of this study was to use a validated capacitive pressure (Novel Electronics, Inc, St Paul, Minn) in the measurement and distribution of patellofemoral forces and pressures during simulated operative procedures. Six fresh frozen cadaver knees were evaluated through a range of motion and observations recorded in native knees (NKNP) with sequential resurfacing of tibiofemoral (RKNP) and patellofemoral (RKRP) articulations with standard and gender (GKRP) components. Significant lateral-medial maximum force differentials were observed for all conditions. Significant lateral-medial peak pressure differentials were observed in RKNP and RKRP. A significant decrease in lateral maximum force from RKRP to GKRP (P = .01) was observed. Significant increases in lateral peak were seen from NKNP to RKNP (P = .04) and RKNP to RKRP (P = .047), whereas a significant decrease was seen from RKRP to GKRP (P < .01). Achieving a quantitative intraoperative assessment of patellar tracking and soft tissue balancing may offer benefits in terms of intraoperative decision making. This is the first reported study to simulate quantitative, intraoperative assessments of patellofemoral pressure and force.

Proximal Femoral Allograft: Prognostic Indicators - Corrected Proof

Pedro J. Roque, Henry J. Mankin, Henrik Malchau — 2009-11-02

Abstract: Between 1972 and 1999, the Orthopedic Oncology Service treated 150 patients with resection and allograft transplantation of the proximal femur. Of the group, 121 patients had malignant tumors of the proximal femur and 29 had benign disorders. Four types of allografts were used: osteoarticular (46 patients), allograft-prosthesis (73), intercalary (20), and allograft-arthrodesis (5). Only 16% of the patients died of disease and 3% required amputation. The overall success rate for the series was 77% with the best results for the allograft prosthetic (82%) and intercalary procedures (87%). Graft infection (15 patients), allograft fracture (26 patients), and local recurrence (11 patients) most markedly affected outcome. With the exception of deaths of disease, no significant outcome difference occurred between the patients with malignant and benign disorders. In conclusion, allograft implantation especially for aggressive or malignant tumors of the proximal femur appears to be a competent system for therapy.

Fat Emboli in Total Knee Arthroplasty: A Prospective Randomized Study of Computer-Assisted Navigation vs Standard Surgical Technique - Corrected Proof

2009-11-02

Abstract: A prospective exploratory study of fat emboli in patients undergoing total knee arthroplasty was performed in patients randomly assigned to surgery with computer-assisted navigation or standard technique. Transesophageal echocardiography of the right atrium was recorded for 5 consecutive 1-minute intervals after tourniquet deflation. Emboli were graded on a scale of 0 to 3 based on embolism size, amount of atrium filled, and duration of embolic shower, creating an overall score of 0 to 9. The mean (SD, range) of the 5 overall scores for each total knee arthroplasty was 6.00 (0.76, 4.6-7.4) for computer-assisted navigation (22 patients) and 6.42 (0.97, 4.6-7.9) for standard technique (22 patients) (P = .14), with a 95% confidence interval for the difference of −0.11 to 0.95. We conclude that any difference in extent of emboli between the 2 surgical techniques is unlikely to be of clinical significance.

Impact of Body Mass Index on Functional Performance After Total Knee Arthroplasty - Corrected Proof

2009-11-02

Abstract: The purpose of this investigation was to determine whether functional performance and self-report outcomes are related to body mass index (BMI) after total knee arthroplasty (TKA). We hypothesized that higher BMIs would negatively affect functional performance as assessed by the timed up-and-go test, stair climbing test, 6-minute walk test, and self-report questionnaires. A total of 140 patients with BMIs ranging from 21.2 to 40.0 kg/m2 were followed over the first 6 months after unilateral TKA. Hierarchical linear regression was used to evaluate the impact of BMI on functional performance at 1, 3, and 6 months after TKA, while taking into account preoperative functional performance. There were no meaningful relationships between BMI and functional performance in the subacute (1 and 3 months) and intermediate (6-month) stages of recovery.

Incidence and Risk Factors for Deep Surgical Site Infection After Primary Total Hip Arthroplasty: A Systematic Review - Corrected Proof

2009-11-02

Abstract: Although deep surgical site infection (SSI) is a major complication of primary total hip arthroplasty (THA), there are conflicting data regarding the incidence of deep SSI, and no comprehensive evaluation of the associated risk factors has been undertaken. We performed a systematic review of the literature; undertaking computer-aided searches of electronic databases, assessment of methodological quality, and a best-evidence synthesis. The incidence of SSI ranged from 0.2% before discharge to 1.1% for the period up to and including 5 years post surgery. Greater severity of a pre-existing illness and a longer duration of surgery were found to be independent risk factors for deep SSI. There is a need for high-quality, prospective studies to further identify modifiable risk factors for deep SSI after THA.

Tibial Component Alignment After Total Knee Arthroplasty with Intramedullary Instrumentation: A Prospective Analysis - Corrected Proof

Carl T. Talmo, Andrew J. Cooper, Tom Wuerz, Jason E. Lang, James V. Bono — 2009-11-02

Abstract: The best operative technique for achieving appropriate postoperative alignment following total knee arthroplasty (TKA) remains controversial, with proponents of extramedullary, intramedullary and computer-assisted techniques. One hundred ninety-two consecutive patients undergoing TKA were prospectively evaluated with full-length lower extremity radiographs. Patients underwent cemented TKA using femoral and tibial intramedullary instrumentation. Digital radiographs were analyzed using PACS (AGFA Healthcare, Ridgefield Park, NJ) software. Tibial component alignment was measured in the coronal and sagittal planes. Tibial component slope averaged 3.89° + 1.96 for the cruciate-retaining components and averaged 1.7° + 1.92 for PS components. The average coronal tibial component alignment was 90.00°, and 99% were within 3° of neutral mechanical alignment with only 2 (1%) outliers. Intramedullary instrumentation resulted in excellent postoperative tibial component and lower extremity alignment.

Use and Cost-Effectiveness of Intraoperative Acid-Fast Bacilli and Fungal Cultures in Assessing Infection of Joint Arthroplasties - Corrected Proof

2009-11-02

Abstract: The objective of this study is to determine a protocol for collecting acid-fast bacilli (AFB) and fungal intraoperative cultures during orthopedic procedures. An observational study was undertaken. Four hundred forty-six AFB cultures and 486 fungal cultures were processed over a 2-year period. The number of positive cultures was determined. A protocol specific to handling these types of specimens was developed. Cost analysis was completed to determine both the time and money saved if the new protocol was implemented. The infrequency of positive AFB and fungal cultures in this study suggests that it is only necessary to routinely request AFB and fungal cultures on 1 of 5 samples. Implementation of this protocol has potential to lead to substantial cost reduction and resource savings without diminishing patient outcomes.

Seven Years of Chronological Changes of Serum Chromium Levels After Metasul Metal-On-Metal Total Hip Arthroplasty - Corrected Proof

2009-11-02

Abstract: Although many authors have reported the serum concentrations of metal ions in patients who had metal-on-metal coupling prostheses, most of the studies were not longitudinal, and the follow-up periods were short. We evaluated the longitudinal changes of serum chromium levels in 44 patients who had undergone unilateral metal-on-metal total hip arthroplasty for a minimum of 7 years postoperatively. Although there was a consistent increase in the mean serum chromium level until 3 years after implantation, there was little difference in the levels from years 3 to 7 postoperatively. Although the serum chromium concentration was low throughout postoperative follow-up for 7 years in about 25% of patients, the serum chromium level stayed high or showed gradual elevation in 16.3% of our patients.

A Mechanical Analysis of Femoral Resurfacing Implantation for Osteonecrosis of the Femoral Head - Corrected Proof

Daigo Sakagoshi, Tamon Kabata, Yuichiro Umemoto, Jiro Sakamoto, Katsuro Tomita — 2009-11-02

Abstract: Hip resurfacing is becoming a popular procedure for treating osteonecrosis of the femoral head. However, the biomechanical changes that occur after femoral resurfacing have not been fully investigated with respect to the individual extent of the necrosis. In this study, we evaluated biomechanical changes at various extents of necrosis and implant alignments using the finite element analysis method. We established 3 patterns of necrosis by depth from the surface of femoral head and 5 stem angles. For these models, we evaluated biomechanical changes associated with the extent of necrosis and the stem alignment. Our results indicate that stress distribution near the bone-cement interface increased with expansion of the necrosis. The maximum stress on the prosthesis was decreased with stem angles ranging from 130° to140°. The peak stress of cement increased as the stem angle became varus. This study indicates that resurfacing arthroplasty will have adverse biomechanical effects when there is a large extent of osteonecrosis and excessive varus or valgus implantation of the prosthesis.

Periprosthetic Bone Remodeling Using a Triple-Taper Polished Cemented Stem in Total Hip Arthroplasty - Corrected Proof

2009-11-02

Abstract: The triple-taper cemented femoral stem was developed to promote proximal femoral and calcar loading to minimize periprosthetic bone loss and aseptic loosening. Periprosthetic changes in bone mineral density in Gruen zones 1 to 7 were analyzed in 103 patients over a 2-year period using dual x-ray absorptiometry. There was a statistically significant decrease in bone mineral density in all Gruen zones, but was most marked in zones 1 and 7. Periprosthetic bone density was reduced significantly in the first 3 to 9 months, after which recovery of bone density occurred. Greater calcar bone loss was seen in women, patients with a low preoperative bone density, and patients with poor postoperative mobility. Age at surgery did not effect calcar bone loss.

Morbid Obesity and Excessive Hospital Resource Consumption for Unilateral Primary Hip and Knee Arthroplasty - Corrected Proof

Sunny H. Kim — 2009-11-02

Abstract: Two objectives of this study were (i) to estimate the number of primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) performed on morbidly obese people in the United States, and (ii) to estimate the economic impact of morbid obesity on hospital resource use. In 2006, approximately 2.9% (6713 cases) of primary THA and 4.2% (20 964 cases) of primary TKA recipients were diagnosed as morbidly obese. Despite the controversy associated with increased infection risk and failure rate, a large number of morbidly obese people seem to consider that the benefits outweigh the risks. When sex, age, race, and primary payer were held constant, the hospital resource consumption for unilateral primary THA and TKA was 9% ($1432) and 7% ($1025) higher among morbidly obese patients than among nonobese patients, respectively.

Minimum Five-Year Follow-Up Wear Measurement of Longevity Highly Cross-Linked Polyethylene Cup Against Cobalt-Chromium or Zirconia Heads - Corrected Proof

2009-11-02

Abstract: We investigated the efficacy of combining highly cross-linked polyethylene with ceramic heads on further reduction in polyethylene wear compared with the combination with cobalt-chromium heads via PolyWare computer-assisted method. A prospective cohort study was performed on 102 cementless total hip arthroplasties using Longevity (Zimmer, Warsaw, Ind) highly cross-linked polyethylene liners. Either 26-mm zirconia heads or 26-mm cobalt-chromium heads were randomly used in 51 hips each. At a mean follow-up of 6.7 years, no significant differences were identified between the groups for total penetration rate and steady-state wear rate. Osteolysis was not observed in any hips in either group. In conclusion, no advantage was seen for the 26-mm zirconia head compared with the 26-mm cobalt-chromium head in this period.

Dabigatran Etexilate Prevents Venous Thromboembolism After Total Knee Arthroplasty in Japanese Patients, With a Safety Profile Comparable to Placebo - Corrected Proof

Takeshi Fuji, Satoru Fuijita, Toru Ujihira, Toru Sato — 2009-10-26

Abstract: We assessed the efficacy, safety, and dose-response of dabigatran etexilate (DAB) in preventing venous thromboembolism (VTE) in Japanese patients undergoing total knee arthroplasty (TKA). Five hundred twelve patients received DAB (110, 150, or 220 mg) or placebo once daily for 11 to 14 days, starting the day after surgery. The primary efficacy end point was the incidence of total VTE and all-cause mortality; the primary safety end point was incidence of major, clinically relevant, and minor bleeding events. Total VTE and all-cause mortality were lower in patients receiving DAB (39.6%, 32.7%, and 24.0%) than placebo (56.4%). There was no difference in the incidence of major bleeding between the DAB and placebo groups. Overall, DAB reduced the incidence of VTE in Japanese patients undergoing TKA, with a comparable safety profile vs placebo.

Failure of the Modular Neck in a Total Hip Arthroplasty - Corrected Proof

Chris J. Dangles, Carl J. Altstetter — 2009-10-19

Abstract: Modular femoral necks in total hip arthroplasty are promoted as giving the surgeon more options during surgery and as being safe. We report a case of fatigue fracture in the modular neck of a femoral implant 3 1/2 years after implantation. The probable design errors leading to product failure are discussed.

Are Acetabular Component Alignment Guides for Total Hip Arthroplasty Accurate? - Corrected Proof

2009-10-19

Abstract: The acetabular component orientation of total hip arthroplasty is of critical importance to the clinical results. Although navigation systems have recently been introduced, acetabular component alignment guides are still used in most of ordinary hospitals. However, the accuracy of alignment guides themselves has not been evaluated. Fifteen types of alignment guide were examined. In all the alignment guides, the angles actually indicated and those stated by manufacturers were different. Our results showed that usage of modern alignment guides inherently misleads anteversion into decrease by a mean of 6° (maximum, 12°) and inclination into increase by a mean of 2° (maximum: 4°). Such setting of alignment guides could be one of the factors of error in acetabular component orientation.

Low Incidence of Postoperative Complications Due to Pin Placement in Computer-Navigated Total Knee Arthroplasty - Corrected Proof

Richard F. Owens, Michael L. Swank — 2009-10-19

Abstract: Computer-navigated joint arthroplasty surgery using optical tracking systems requires arrays fixated to bone via pins. Reports of fractures at pin sites have raised concern about safety. We reviewed the postoperative complications occurring in a single-surgeon series of 984 consecutive primary total knee arthroplasties. All pins were placed unicortically and connected by a dual pin array. Femoral pins were placed into the medial epicondyle, and tibial pins were placed in the shaft 10 cm inferior to the joint line. There were no fractures. Seventeen (1.7%) patients had minor pin-related complications. Twelve patients had a superficial infection around the tibial pin sites, which resolved with antibiotics. None of the infections required readmission or reoperation. We believe pin placement to be safe and effective with proper technique.

Neuraxial Hematoma and Paralysis After Enoxaparin Administration 3 Days After Attempted Spinal Anesthesia for Total Knee Arthroplasty - Corrected Proof

David F. Bindelglass, David S. Rosenblum — 2009-10-19

Abstract: A 69-year-old man underwent a total knee arthroplasty. Spinal anesthesia was attempted, but when unsuccessful, a general anesthesia was given. The surgery and rehabilitation were uneventful until postoperative day 3 when a pulmonary embolism was diagnosed. He was placed on enoxaparin at a therapeutic dose that begun more than 72 hours after his attempted spinal. He developed a spinal hematoma and was paralyzed. The literature has no recommendations for using enoxaparin at therapeutic doses after regional anesthesia. There is no previous report to suggest that a patient 72 hours after surgery is still at risk from a neuraxial hematoma.

Navigated Percutaneous Screw Fixation of a Periprosthetic Acetabular Fracture - Corrected Proof

2009-10-19

Abstract: Periprosthetic fractures are severe complications of total hip arthroplasty with increasing incidence. Most fractures are localized around the femoral component of prosthesis, whereas periacetabular fractures are rare and their management is difficult. In most cases, an operative procedure with revision and exchange of the acetabular cup is necessary. The approaches are demanding and an increased risk of complications is reported. We present the case of a female patient with a cementless total hip arthroplasty due to severe arthritis, suffering of an infratectal transverse periprosthetic fracture. After an initial conservative treatment attempt, we performed a minimally invasive screw fixation using navigated 2-dimensional fluoroscopic guidance. In this report, the literature for treatment recommendations is reviewed and the chosen navigation technique discussed.