Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Symposium: Papers Presented at the Hip Society Meetings 2009 36 articles


Hip Resurfacing Data from National Joint Registries: What Do They Tell Us? What Do They Not Tell Us?

Kristoff Corten MD, Steven J. MacDonald MD, FRCSC Current-generation metal-on-metal hip resurfacing implants (SRAs) have been in widespread global use since the 1990s, and in the United States, specific implants have recently been approved for clinical use. Many recent publications describe short-term survivorship achieved by either implant-designing surgeons or high-volume centers. National joint replacement registries (NJRRs) on the other hand report survivorship achieved from the orthopaedic community at large. We therefore reviewed SRA survivorship from national registry data and compared with that reported from individual centers. Additionally, we compared SRA survivorship reported by registries and compared prognosticators for failure with those of conventional total hip arthroplasty (THA). Although resurfacing was associated with an overall increased failure rate in comparison to THA (Australian registry 5-year cumulative revision rate [CRR], 3.7% and 2.7%, respectively), there were exceptions to this. Male patients younger than 65 years with primary osteoarthritis had equivalent results with SRA and THA (Australian registry 5-year CRR, 2.5% and 2.8%, respectively). Head size over 50 mm in diameter was a predictor of surface replacement arthroplasty survivorship and only females with a head diameter of 50 mm or greater (14% of females) had a comparable survivorship to males. Diagnoses other than primary osteoarthritis bear a higher risk of early revision of SRA as compared with THA. Revision of SRA does not lead to reproducible results with rerevision rates of 11% at 5 years. Given these predictors of failure, our review of data from the NJRR suggests stringent patient selection criteria might enhance the survival rates of SRA.

High Stress Conditions Do Not Increase Wear of Thin Highly Crosslinked UHMWPE

Natalie H. Kelly BS, Amar D. Rajadhyaksha MD, Timothy M. Wright PhD, Suzanne A. Maher PhD, Geoffrey H. Westrich MD Introduction of highly crosslinked polyethylene has increased interest in large femoral heads, because thin acetabular liners can be used while maintaining low wear rates and larger heads decrease the incidence of instability. However, crosslinking and subsequent thermal treatments can cause decreased mechanical properties that might obviate the reduced wear under extreme conditions. To examine whether increased contact pressures would adversely affect wear in thin liners, we tested thin and thick highly crosslinked liners (3.8 mm thickness/44-mm head and 7.9 mm thickness/36-mm head, respectively) to 5 million cycles on a hip simulator under near impingement conditions. Conventional polyethylene liners (7.9 mm thickness/36-mm head) served as controls. Large femoral heads with highly crosslinked polyethylene liners as thin as 3.8 mm in thickness do not wear at a higher rate than a thicker liner of the same material, even when subjected to large contact pressures such as occur under near-impingement conditions. Crosslinked polyethylene may allow for liners that are thinner than has been traditionally accepted. This conclusion, however, is based solely on wear test results with idealized cup position, no intentional edge loading, no head subluxation, and no artificial aging. Continued monitoring will be necessary to elucidate the clinical efficacy of these devices.

Open Treatment of Femoroacetabular Impingement is Associated with Clinical Improvement and Low Complication Rate at Short-term Followup

Christopher L. Peters MD, Kathryn Schabel MD, Lucas Anderson PA-C, Jill Erickson PA-C

Since the modern description of femoroacetabular impingement (FAI) a decade ago, surgical treatment has become increasingly common. Although the ability of open treatment of FAI to relieve pain and improve function has been demonstrated in a number of retrospective studies, questions remain regarding predictability of clinical outcome, the factors associated with clinical failure, and the complications associated with treatment.

Femoral Revision Hip Arthroplasty: A Comparison of Two Stem Designs

Corey J. Richards MD, MASc, FRCSC, Clive P. Duncan MD, MSc, FRCSC, Bassam A. Masri MD, FRCSC, Donald S. Garbuz MD, MHSc, FRCSC

For various reasons the tapered, fluted, modular titanium (TFMT) stem has become our component of choice over cylindrical, nonmodular cobalt chrome (CNCC) components for THA revision. We therefore asked whether the TFMT femoral components better achieved three important goals of revision arthroplasty than CNCC stems: (1) improving quality of life; (2) avoiding complications; and (3) preserving or restoring femoral bone stock. We compared patients undergoing femoral component revision hip arthroplasty with either a CNCC (N = 105) component or a TFMT (N = 95) component to determine if the increased use of TFMT components is justified. We retrospectively reviewed all patients undergoing revision total hip arthroplasty between January 2000 and March 2006. All eligible patients completed outcome questionnaires (WOMAC, SF-12, Oxford-12, UCLA Activity Score, and Satisfaction Scores). Radiographs were evaluated for loosening and preservation or restoration of the proximal femur host bone. The TFMT and CNCC cohorts were comparable with respect to age, gender, diagnosis, and comorbidities. The TFMT cohort had worse preoperative bone defects (65% Paprosky 3B and 4). The TFMT cohort had higher outcome scores (WOMAC pain, WOMAC stiffness, Oxford-12, and Satisfaction), fewer intraoperative fractures, and better restoration of the proximal femur host bone. Our data suggest the TFMT stem provided improved clinical outcomes (improved quality of life, decreased complications, and preservation of bone stock) than the CNCC stem.,[object Object]

Delta Ceramic-on-Alumina Ceramic Articulation in Primary THA: Prospective, Randomized FDA-IDE Study and Retrieval Analysis

Adolph V. Lombardi MD, Keith R. Berend MD, Brian E. Seng DO, Ian C. Clarke PhD, Joanne B. Adams BFA Wear and osteolysis continue to be major reasons for revision surgery in THA. Ceramic-on-ceramic bearings eliminate polyethylene wear debris. The newest generation of these bearings incorporate nanosized, yttria-stabilized tetragonal zirconia particles producing an alumina matrix composite. We asked whether this new material would perform as well as a conventional bearing in terms of functional hip scores, radiographic migration and osteolysis, complications and survival. As part of a US FDA investigational device exemption study (G000075), we conducted an initial prospective safety study of 21 alumina matrix composite femoral heads articulating on alumina liners followed by a prospective, randomized study with 44 more of these articulations and 45 zirconia femoral heads on polyethylene liners. The minimum followup for all patients was 26 months (mean, 73 months; range, 26–108 months). Harris hip scores and radiographic findings were similar in the two groups as was survivorship (trial 95% versus control 93%). There were three reoperations in the trial group and three in the control group. A fractured head retrieval showed a 33% monoclinic transformation with an increase in surface roughness from 3 to 5 nm at the main wear zone. While our numbers were insufficient to compare device-related complications, the trial device performed as well as the control device in terms of reoperation, and clinical and radiographic outcome. The alumina matrix composite femoral head on an alumina liner provided high survivorship.,[object Object]

Iliopsoas Bursa Injections Can be Beneficial for Pain after Total Hip Arthroplasty

Ryan M. Nunley MD, Joyce M. Wilson MD, Louis Gilula MD, John C. Clohisy MD, Robert L. Barrack MD, William J. Maloney MD Impingement of the iliopsoas tendon is an uncommon cause of groin pain after total hip arthroplasty (THA). We asked whether selective steroid and anesthetic injections for iliopsoas tendonitis after THA would relieve pain and improve function. We retrospectively reviewed 27 patients with presumed iliopsoas tendinitis treated by fluoroscopically guided injections of the iliopsoas bursa. Pre- and immediately postinjection, questionnaires and telephone followup questionnaires were administered to determine patient outcomes. Four patients were lost to followup and we were unable to obtain information from relatives on an additional four; the questionnaire was administered to the remaining 19 patients, including six who subsequently had surgery at an average of 44.6 months (range, 25–68 months) after their first injection. The average modified Harris hip score in the 19 patients improved from 61 preinjection to 82 postinjection and the average pain improved from 6.4 preinjection to 2.9 postinjection, but eight patients (30%) required a second injection at an average of 8.2 months after the first injection. Ultimately, six patients (22%) had an additional surgical procedure to address the underlying cause of the iliopsoas irritation. Iliopsoas tendonitis is uncommon after THA but should be considered in the differential diagnosis of all patients who present with groin pain after THA. Selective steroid and anesthetic injections of the iliopsoas bursa give adequate pain relief in the majority of patients and should be considered part of the nonoperative treatment plan before surgical release of the iliopsoas tendon or component revision.,[object Object]

Surgical Treatment of Femoroacetabular Impingement: A Systematic Review of the Literature

John C. Clohisy MD, Lauren C. St John BS, Amanda L. Schutz PhD The surgical treatment of femoroacetabular impingement has become more common, yet the strength of clinical evidence to support this surgery is debated. We performed a systematic review of the literature to (1) define the level of evidence regarding hip impingement surgery; (2) determine whether the surgery relieves pain and improves function; (3) identify the complications; and (4) identify modifiable causes of failure (conversion to total hip arthroplasty). We searched the literature between 1950 and 2009 for all studies reporting on surgical treatment of femoroacetabular impingement. Studies with clinical outcome data and minimum two year followup were analyzed. Eleven studies met our criteria for inclusion. Nine were Level IV and two were Level III. Mean followup was 3.2 years; range (2–5.2 years). Reduced pain and improvement in hip function were reported in all studies. Conversion to THA was reported in 0% to 26% of cases. Major complications occurred in 0% to 18% of the procedures. Current evidence regarding femoroacetabular impingement surgery is primarily Level IV and suggests the various surgical techniques are associated with pain relief and improved function in 68–96% of patients over short-term followup. Long-term followup is needed to determine survivorship and impact on osteoarthritis progression and natural history.,[object Object]

Incidence of Groin Pain After Metal-on-Metal Hip Resurfacing

Ahmad Bin Nasser MD, FRCSC, Paul E. Beaulé MD, FRCSC, Michelle O’Neill MD, FRCSC, Paul R. Kim MD, FRCSC, Anna Fazekas MA Metal-on-metal hip resurfacing is offered as an alternative to traditional THA for the young and active adult with advanced osteoarthritis. However, patients undergoing hip resurfacing may be predisposed to persistent groin pain due to insufficient head/neck offset, an uncovered acetabular component, or both. We therefore determined the incidence of groin pain after metal-on-metal hip resurfacing, its impact on patient function, and possible risk factors contributing to groin pain. We evaluated 116 patients with a followup of at least 12 months after surgery (mean, 26 months; range, 12–61 months). The mean age was 48.8 years (range, 24.0–66.3 years), with 21 women (18%) and 95 men (82%). All patients were evaluated clinically and radiographically and had a Harris hip score, WOMAC, UCLA Activity Rating Scale, and the RAND-36 General Health measure; they were specifically asked if they experienced groin pain currently or since their surgery. Although all patients had functional improvements postoperatively, 21 of 116 of the patients (18%) reported groin pain; 12 of these (10% of the total) stated the pain limited their activities of daily living and 11 (10%) required medication for pain. Female patients were at greater risk of having groin pain. Of the patients with groin pain, three patients had muscle atrophy with a joint effusion on CT; one of these patients had revision surgery for the pain. Patients with metal-on-metal resurfacing may have a higher incidence of pain than those with conventional THA.,[object Object]

The Learning Curve for Adopting Hip Resurfacing Among Hip Specialists

Ryan M. Nunley MD, Jinjun Zhu MD, PhD, Peter J. Brooks MD, C. Anderson Engh MD, Stephen J. Raterman MD, John S. Rogerson MD, Robert L. Barrack MD Patient demand and surgeon interest in hip resurfacing has recently increased, but surgeons in the United States are relatively inexperienced with this procedure. We determined the learning curve associated with hip resurfacing and compared the rate of early complications of the first 650 hip resurfacings between five experienced hip surgeons and a national safety survey database study we previously published, which included 89 surgeons and 537 hip resurfacings. Patient demographics and adverse events were recorded. Specific features on pre- and postoperative radiographs were measured in a blinded fashion by a single observer. There were 13 major complications (2.0%), which is 3.7 times lower than our national safety survey complication rate of 7.4%. All fractures occurred in the first 25 cases performed. The complication rate was higher for the first 25 procedures (5.6%) compared with the second 25 procedures (1.6%). For experienced hip surgeons, the learning curve for avoiding early complications was short, 25 cases or less. The learning curve for achieving the desired component positioning radiographically was much longer, 75 to 100 cases or more. If achieving some ideal component position proves important for long-term function and implant survival, improved instrumentation and surgical techniques would be necessary to shorten the learning curve.,[object Object]

Outcomes of Isolated Acetabular Revision

Bryan M. Lawless MD, William L. Healy MD, Sanjeev Sharma MD, Richard Iorio MD Isolated acetabular revision can be associated with variable patient outcomes; there is a risk of hip instability. We evaluated 42 isolated acetabular revision operations and investigated the impact of patient age, diagnosis, bone stock, bone loss, bone augmentation, and obesity on pain and the Harris hip score. Preoperative radiographs were graded according to Paprosky et al. Postoperative radiographs were graded according to Moore et al. and for implant position, prosthetic fixation, and osteolysis. Complications, patient outcome, reoperations, and acetabular rerevisions were recorded. All patients had complete clinical and radiographic followup with a minimum followup of 2 years (mean, 6.4 years; range, 2–13 years). The mean pain score and the mean Harris hip score improved postoperatively. There was one infection 6 months after operation. There were no dislocations. There were three acetabular rerevisions (7%) for aseptic loosening. Patient age, preoperative diagnosis, bone loss, and pelvic bone augmentation had no influence on pain or Harris hip scores. Before operation, obese patients tended to have less pain than nonobese patients but at followup obese patients had less improvement in pain scores than nonobese patients.,[object Object]

Fear in Arthroplasty Surgery: The Role of Race

Carlos J. Lavernia MD, Jose C. Alcerro MD, Mark D. Rossi PhD, PT, CSCS Understanding the difference in perceived functional outcomes between whites and blacks and the influence of anxiety and pain on functional outcomes after joint arthroplasty may help surgeons develop ways to eliminate the racial and ethnic disparities in outcome. We determined the difference in functional outcomes between whites and blacks and assessed the influence of fear and anxiety in total joint arthroplasty outcomes in 331 patients undergoing primary hip and knee arthroplasty. WOMAC, Quality of Well Being, SF-36, and Pain and Anxiety Symptoms Scale (PASS) were administered pre- and postoperatively (average 5-year followup). For the SF-36 General Health Score, blacks reported having worse perceived general health than whites before surgery. Regardless of time, blacks scored worse than whites for all measures except for the SF-36 physical function and general health scores. Blacks had a greater fear score (ie, that associated with the procedure) and total PASS score. For both races, there was a low association between the fear dimensions and dependent measures before and after surgery. Black patients undergoing hip and knee arthroplasty had lower scores than whites in most outcome measures regardless of time of assessment. We found higher fear levels before joint arthroplasty in blacks compared with whites. After surgery, blacks had much higher associations of the fear subscale, cognitive subscale, and total PASS score with the WOMAC physical function, pain, and total scores.,[object Object]

Osseous Remodeling After Femoral Head-neck Junction Osteochondroplasty

Nader A. Nassif MD, Murat Pekmezci MD, Gail Pashos BS, Perry L. Schoenecker MD, John C. Clohisy MD Femoral head-neck junction osteochondroplasty is commonly used to treat femoroacetabular impingement, yet remodeling of the osteochondroplasty site is not well described. We therefore describe bony remodeling at the osteochondroplasty site and analyze clinical outcomes and complications associated with femoral osteochondroplasty. We retrospectively reviewed 135 patients (150 hips) who underwent femoral head-neck osteochondroplasty combined with hip arthroscopy, surgical hip dislocation, periacetabular osteotomy, or proximal femoral osteotomy. The minimum clinical followup was 10 months (mean, 22.3 months; range, 10–65 months). We assessed the femoral-head neck offset, head-neck offset ratio, alpha angle, and cortical remodeling. We used the Harris hip score to determine hip function. We observed an increase in the head-neck offset, offset ratio, and decrease in the alpha angle postoperatively and at latest followup. Ninety-eight of 113 (87%) hips had partial or complete recorticalization at the osteochondroplasty site. The mean Harris hip score improved from 64 to 85. We excised heterotopic bone in one hip. There were no femoral neck fractures. The deformity correction achieved with femoral head-neck osteochondroplasty is maintained and recorticalization occurs in the majority of cases during the first two years.,[object Object]

Proximally Versus Fully Porous-coated Femoral Stems: A Multicenter Randomized Trial

Steven J. MacDonald MD, FRCSC, Seth Rosenzweig MD, Jeffrey S. Guerin BMath, Richard W. McCalden MD, FRCSC, Eric R. Bohm MD, FRCSC, Robert B. Bourne MD, FRCSC, Cecil H. Rorabeck MD, FRCSC, Robert L. Barrack MD There are two broad-based categories of cementless femoral component designs: proximally porous-coated and fully porous-coated. While both have been widely used, there remains debate regarding differences in clinical outcome scores, relative incidence of thigh pain, and development of stress shielding. We investigated these variables in a multicenter prospective randomized blinded clinical trial of 388 patients from three centers: 198 patients had a proximally porous-coated tapered cementless femoral component and 190 patients had a fully porous-coated cementless femoral component. A minimum followup of 2 years (mean, 6.7 years; range, 2.0–8.65 years) was available in 367 of the 388 patients (95%). We observed no differences in age at surgery, body mass index, or preoperative clinical outcome scores (WOMAC, SF-12, Harris hip score, UCLA activity, thigh pain) with the two groups. We determined serial bone density changes in a subcohort of 72 patients from two of the three centers. The postoperative clinical outcome scores were similar at all followup intervals, and we observed no differences in the incidence of thigh pain at any time. Bone density reduction in Gruen Zone 7 was greater with the fully coated stem than the proximally coated stem (24% versus 15% reduction, respectively). Both fully and proximally coated stems performed well, with no clinical differences at 2 years’ followup, except in bone mineral density evaluations.,[object Object]

THA With Delta Ceramic on Ceramic: Results of a Multicenter Investigational Device Exemption Trial

William G. Hamilton MD, James P. McAuley MD, Douglas A. Dennis MD, Jeffrey A. Murphy MS, Thomas J. Blumenfeld MD, Joel Politi MD Although the published studies on the outcomes of total hip arthroplasty (THA) performed with currently available ceramic components show high survivorship and low bearing wear at midterm followup, concern over ceramic fracture and squeaking persist. For these reasons, the use of ceramic is limited. Recently, a new alumina matrix composite material (Delta ceramic) with improved material properties was developed to address these concerns. We report the early outcomes and complications of a prospective, randomized, multicenter trial of 263 patients (264 hips) at eight centers, comparing a Delta ceramic-on-ceramic (COC) articulation with a Delta ceramic head-crosslinked polyethylene bearing combination (COP). There were 177 COC hips and 87 COP hips. Complications were reported for all patients, whereas clinical and radiographic results were provided for the 233 patients with minimum 2-year followup (average, 31.2 months; range, 21–49 months). The Harris hip scores and clinical, radiographic, and survivorship outcomes were similar in both groups. There were four (2%) revisions in the COC group and two (2%) in the COP group. We encountered three intraoperative ceramic liner-related events. In addition, one patient receiving the COC underwent revision for chipping of the ceramic liner, and a second had ceramic fragmentation on followup radiographs but has not undergone revision. These liner related complications remain a concern. No patient reported squeaking in either group; this leaves us hopeful the new material will lessen the frequency of squeaking. In the short term, the Delta COC articulation provided similar functional scores and survivorship and complication rates with the ceramic head mated with crosslinked polyethylene.,[object Object]

Do Tantalum and Titanium Cups Show Similar Results in Revision Hip Arthroplasty?

S. Mehdi Jafari MD, Benjamin Bender MD, Catelyn Coyle BA, Javad Parvizi MD, FRCS, Peter F. Sharkey MD, William J. Hozack MD Porous surfaces are intended to enhance osteointegration of cementless implants. Tantalum has been introduced in an effort to enhance osseointegration potential of uncemented components. We therefore compared the clinical outcome of acetabular components with two different porous surfaces. We retrospectively reviewed 283 patients (295 hips) who underwent cementless revision hip arthroplasty with either an HA-coated titanium cup (207 patients, 214 hips) or porous tantalum cup (79 patients, 81 hips). The minimum followup was 24 months in both groups (titanium: average 51.8 months, range, 24–98 months; tantalum: average, 35.4 months, range, 24–63 months). The titanium and tantalum groups had a mechanical failure rate (clinical plus radiographic) of 8% and 6%, respectively. In hips with minor bone deficiency (type 1, 2A, 2B using the classification of Paprosky et al.), 6% of titanium cups and 4% of tantalum cups failed. In hips with major bone deficiency (type 2C, 3), 24% of titanium cups and 12% of tantalum cups developed failure. In the major bone deficiency group, the tantalum cups had fewer numbers of lucent zones around the cup. Eighty-two percent of titanium cups that failed did so at 6 months postoperatively or later, whereas 80% of tantalum cups that failed did so in less than 6 months. Radiographically in the major group, tantalum cups yielded better fixation.,[object Object]

Incidence of ‘Squeaking’ After Ceramic-on-Ceramic Total Hip Arthroplasty

Kenny Mai MD, Christopher Verioti DO, Kace A. Ezzet MD, Steven N. Copp MD, Richard H. Walker MD, Clifford W. Colwell MD The incidence of hip “squeak” associated with ceramic-on-ceramic bearings has been variably reported, ranging from 0.7% to 20.9%. We determined the patients’ perception of squeaking in 306 patients (336 hips) in whom ceramic-on-ceramic total hip arthroplasties (THAs) were performed between 1997 and 2005. A questionnaire regarding hip noise was obtained by telephone. With a minimum followup of 2 years (mean, 3.9 years; range, 2–10 years), 290 patients (320 or 95% of the THAs) completed the questionnaire. Patients reported hip noise in 55 of the 320 THAs (17%); noise was perceived as squeak in 32 of the 320 (10%). Most squeaking hips (29 of 32) were pain-free and symptom-free. One patient was unhappy with his squeaking hip without pain. Our data suggest a much higher incidence of squeak as perceived by patients than previously reported.,[object Object]

Hip Resurfacing Results for Osteonecrosis Are as Good as for Other Etiologies at 2 to 12 Years

Harlan C. Amstutz MD, Michel J. Duff MA A bone-conserving prosthetic solution, such as hip resurfacing arthroplasty, is desirable for patients with osteonecrosis (ON) of the femoral head because of their young age. However, many surgeons are reluctant to perform hip resurfacing for ON because of large femoral head defects. To ascertain whether this reluctance is warranted, we determined the mid- to long-term effects of ON on the survivorship, radiographic implant fixation, and disease-specific and quality-of-life scores of hip resurfacing. We compared the results of metal-on-metal resurfacing performed for ON of the hip (including large lesions) with those of resurfacing performed for other causes. The ON group had 70 patients (85 hips) and the control group 768 patients (915 hips) including all other etiologies operated on during the same period. The ON group was younger and had a greater incidence of femoral defects, a smaller component size, and a lower body mass index, three variables previously shown to reduce survivorship in hip resurfacing. We observed no difference in survivorship between the ON group and the control group even after adjusting for head size, body mass index, and defect size. Pain relief, walking, and function scores were comparable postoperatively. The activity level was lower in the ON group. Our data suggest ON is not a contraindication for resurfacing even with large femoral head defects.,[object Object]

Is There Faster Recovery With an Anterior or Anterolateral THA? A Pilot Study

Virginia Klausmeier MS, Vipul Lugade MS, Brian A. Jewett MD, Dennis K. Collis MD, Li-Shan Chou PhD Surgical technique is an important factor affecting recovery of hip function after total hip arthroplasty (THA). We therefore asked whether short-term recovery of hip strength and motion would differ between the anterior and anterolateral THA approaches. We presumed that although both approaches would improve hip function by 16 weeks postsurgery when compared with presurgery, a slower recovery would be demonstrated by the anterolateral group at 6 weeks when compared with the anterior group as a result of division and reattachment of the abductor muscles. We observed hip kinematics and kinetics during walking and isometric hip abductor strength for the involved limb. Hip abductor strength of all patients was lower than controls at all three testing times. Compared with presurgery, all patients demonstrated improved abductor strength at 16 weeks postsurgery. At 6 weeks, the patients with an anterior approach had improved late stance peak abductor moment postsurgery and reached the level of controls, but those with an anterolateral approach did not. Although the anterior approach was associated with improved gait velocity and peak flexor moments at 6 weeks compared to before surgery, we observed no differences between the two approaches for most of the isometric strength and dynamic gait measures at 6 or 16 weeks. Neither approach provided faster recovery.

The Otto Aufranc Award: Identification of a 4 Mb Region on Chromosome 17q21 Linked to Developmental Dysplasia of the Hip in One 18-member, Multigeneration Family

George Feldman PhD, DMD, Chelsea Dalsey BA, Kasia Fertala BA, David Azimi BS, Paolo Fortina MD, Marcella Devoto PhD, Maurizio Pacifici PhD, Javad Parvizi MD, FRCS [object Object]

Failure of the Durom Metasul® Acetabular Component

William T. Long MD, Manish Dastane MD, Michael J. Harris MD, Zhinian Wan MD, Lawrence D. Dorr MD Large-diameter metal-on-metal articulations reportedly provide better stability and range of motion than smaller diameter bearings. We therefore asked whether a large-diameter (44- to 50-mm) metal-on-metal articulation (Durom®) would eliminate dislocation and provide similar functional scores and clinical and radiographic failure rates as those with 28-mm articulation. We prospectively followed 181 patients (207 hips) who had a large-diameter articulation implanted between May 2006 and November 2007. We compared these patients with a historical control of 54 patients who had a small-diameter (28-mm Metasul®) articulation. All patients had a Harris hip score and a self-assessment of outcome and radiographic followup. The minimum followup was 1 year (mean, 1.6 years; range, 1–2 years). During the followup period, we performed revisions on 29 patients (30 hips [15%]) with 21 of 29 (72%) having radiographic criteria of loosening. Thirteen retrieved cups and acetabular tissue were examined histologically. Twenty-eight of 151 unrevised patients had radiographic impending failure; 12 without revision had clinical failure. Eight patients (nine hips) had both clinical failure and impending radiographic failure. Cup inclination was 41.3° ± 5.4° and anteversion was 20.2° ± 7°. The revision rate and quality of clinical results were unacceptable as compared with our historical controls. We do not recommend use of the Durom® implant.,[object Object]

Metal-on-Metal Hip Arthroplasty: Does Early Clinical Outcome Justify the Chance of an Adverse Local Tissue Reaction?

Charles A. Engh MD, Henry Ho MS, Charles A. Engh MD Larger diameter metal-on-metal (MOM) bearing hips offer the possibility of low wear and reduced risk of dislocation. We reviewed the first 126 patients (131 hips) who had a large-head (36-mm) MOM bearing surface to report the early clinical outcome and especially to determine the occurrence of dislocation and wear-related concerns. The minimum followup was 5 years (mean, 5.6 years; range, 5–7 years). We found a 98% survivorship free of component revision. No hips had been revised for dislocation. Three hips (2%) had small femoral osteolytic lesions. Because this series of patients did not completely represent our experience with this bearing surface, we queried our database for the 828 patients (945 hips) that had the same bearing surface from April 2001 to December 2008. Three patients (0.3%) had a local reaction to the MOM bearing surface on revision-retrieved tissue. All three patients presented with elevated inflammatory indices, and a purulent-appearing joint effusion at revision. The possibility of infection and the delay in diagnosing a reaction to the MOM bearing with pathology complicated management of these three patients. We continue to use this bearing surface because the 5-year results are comparable to other bearing surfaces, however, we counsel patients that a local adverse reaction to the MOM bearing surface may be a factor contributing to reoperation.,[object Object]

Durability of Second-generation Extensively Porous-coated Stems in Patients Age 50 and Younger

Jennifer A. Moyer BS, Catherine M. Metz MD, John J. Callaghan MD, David W. Hennessy BS, Steve S. Liu MD Early versions of uncemented femoral total hip stems were often associated with thigh pain thought to be due to micromotion between the implant and bone in the distal uncoated regions. An extensively coated stem was introduced in 1992 to reduce that risk. We therefore asked whether second-generation extensively porous-coated cementless femoral stems in patients younger than 50 years of age would (1) be durable in terms of revisions; (2) provide high functional scores and reduce thigh pain; and (3) show radiographic signs of durability, including a reduction in stress shielding. We prospectively followed all 100 patients (115 hips) age 50 and younger treated with primary cementless total hip arthroplasties using a second-generation extensively porous-coated femoral stem between June 1994 and December 1999. The average age was 39.6 years (range, 17–50 years). The stems were mated to cementless acetabular components. Ninety patients were followed for a minimum of 5 years (mean, 8.6 years; range, 5–10 years). One stem was revised after a periprosthetic fracture. None were revised for loosening and all stems demonstrated bony ingrowth at last followup. No acetabular shell was revised for loosening and none was radiographically loose. Six acetabular liners were revised for wear (three each were 22-mm and 26-mm heads). This second-generation extensively porous-coated stem was durable at 5- to 10-year followup in this young active population.,[object Object]

A Three-dimensional Method for Evaluating Changes in Acetabular Osteolytic Lesions in Response to Treatment

Hiroshi Egawa MD, Henry Ho MS, Cathy Huynh BS, Robert H. Hopper PhD, C. Anderson Engh MD, Charles A. Engh MD [object Object],[object Object]

Comparing Patient Outcomes After THA and TKA: Is There a Difference?

Robert B. Bourne MD, FRCSC, Bert Chesworth PhD, Aileen Davis PhD, Nizar Mahomed MD, FRCSC, Kory Charron DipMET Both primary total hip (THA) and knee (TKA) arthroplasty relieve pain, restore function, and increase mobility. Despite these successes, there is controversy as to whether THA or TKA provides greater or similar improvement. We therefore compared primary THA and TKA patient results in terms of (1) willingness to have surgery again; (2) WOMAC change score; (3) whether expectations were met; and (4) satisfaction. Patients undergoing primary THA were more willing to undergo their surgery again (THA 96%, TKA 89%), demonstrated greater WOMAC change scores, more frequently reported their expectations were met (THA 78%, TKA 70%), and expressed greater overall satisfaction (THA 89%, TKA 81%). In addition, patients undergoing THA expressed higher satisfaction with pain reduction while performing activities (ie, walking, stairs, and sitting/lying) and their ability to perform daily activities (ie, stairs, transportation, getting up, lying in bed, and light domestic duties) when compared with patients undergoing TKA. Our data suggest primary THA offers superior short-term outcomes when compared with primary TKA.,[object Object]

Femoral Anteversion in THA and its Lack of Correlation with Native Acetabular Anteversion

William L. Bargar MD, Amir A. Jamali MD, Amir H. Nejad BA Several studies support the concept that, for optimum range of motion in THA, the combined femoral and acetabular anteversion should be some constant or fall within some “safe zone.” When using a cementless femoral component, the surgeon has little control of the anteversion of the component since it is dictated by native femoral anteversion. Given this constraint, we asked whether the surgeon should use the native anteversion of the acetabulum as a target for implant position in THA. Forty-six patients scheduled for primary THA underwent CT scanning and preoperative planning using a computer workstation. The native acetabular anteversion and the native femoral anteversion were measured. Prosthetic femoral anteversion was measured on the workstation by three-dimensional templating of a straight-stemmed tapered implant. The mean of the sum of the native acetabular anteversion and native femoral anteversion was 28.9°; however, 17% varied by 10° to 15° and 11% by more than 15°. The mean of native femoral anteversion and prosthetic femoral anteversion was 13.8° (range, −6.1°–32.7°) and 22.5° (range, 1°–39°), respectively. Based on our data, we believe the surgeon should not use the native acetabular anteversion as a target for positioning the acetabular component.

High Survival of Uncemented Proximally Porous-coated Titanium Alloy Femoral Stems in Osteoporotic Bone

John B. Meding MD, Matthew R. Galley, Merrill A. Ritter MD Because the initial fixation of an uncemented stem may be compromised in patients with osteoporotic bone (Class C, Dorr et al.), many surgeons prefer a cemented stem in this setting. We therefore determined the survival of an uncemented, proximally porous-coated, straight-stemmed, titanium alloy femoral component in patients with Class C bone when compared with Class A and B bone. We implanted proximally plasma-sprayed, straight-stemmed titanium alloy stems in 1994 patients (2321 hips). Of these, 625 hips (27%), 1569 hips (67%), and 127 hips (6%) were classified as Classes A, B, and C, respectively. Minimum followup was 2 years (mean, 5.9 years; range, 2–19.5 years). We identified no differences in Harris hip scores, pain, radiolucencies, or osteolysis among Classes A, B, and C hips. Stem survival at 5, 10, and 15 years for aseptic loosening (failure) was 100% in all patients with Class A bone; 99+% in all patients with Class B bone; and 100% in all patients with Class C bone. Initial stability and durable fixation can be achieved with the use of this uncemented stem in patients in whom a cemented stem traditionally has been preferred as a result of poor bone quality.,[object Object]

Does Femoral Component Loosening Predispose to Femoral Fracture?: An In Vitro Comparison of Cemented Hips

Barton Harris MD, John R. Owen BS, Jennifer S. Wayne PhD, William A. Jiranek MD The incidence of femur fracture around total hip arthroplasties continues to increase at substantial cost to society. These fractures are frequently associated with a loose femoral component. Consequently, we sought to test whether femoral component loosening predisposes to periprosthetic femoral fracture. Because many periprosthetic femoral fractures are spiral in nature, we evaluated the torsional characteristics of the implanted femur in which the only design variable was instability of the femoral component. We used synthetic (polyurethane) (n = 15) and paired cadaveric femora (n = 10) with specimens divided into two groups: well-fixed and loose cemented stems. Each specimen was tested mechanically in internal rotation until failure. For the synthetic specimens, torque to failure was reduced by 38%, whereas stiffness was decreased 54% for the loose group compared with the well-fixed group. For the cadaveric specimens, torque to failure was reduced by 58%, whereas stiffness decreased 70% for the loose group compared with the well-fixed group. Fracture patterns were similar between synthetic and cadaveric femora with a proximal spiral pattern in loose specimens and more distal fracture patterns with well-fixed stems. Based on our data, patients with loosened femoral components are at risk for fracture at a substantially lower torque than those with well-fixed components.

The John Charnley Award: Metal-on-Metal Hip Resurfacing versus Large-diameter Head Metal-on-Metal Total Hip Arthroplasty: A Randomized Clinical Trial

Donald S. Garbuz MD, MHSc, Michael Tanzer MD, Nelson V. Greidanus MD, MPH, Bassam A. Masri MD, Clive P. Duncan MD, MSc

Resurfacing arthroplasty has become an attractive option for young patients who want to maintain a high activity level. One recent study reported modestly increased activity levels for patients with resurfacing compared to standard total hip arthroplasty (THA). We conducted a prospective randomized clinical trial to compare clinical outcomes of resurfacing versus large-head metal-on-metal total hip arthroplasty. We randomized 107 patients deemed eligible for resurfacing arthroplasty to have either resurfacing or standard THA. Patients were assessed for quality-of-life outcomes using the PAT-5D index, WOMAC, SF-36, and UCLA activity score. The minimum followup was 0.8 years (mean, 1.1 years; range, 0.8–2.2 years). Of the 73 patients followed at least one year, both groups reported improvement in quality of life on all outcome measures. There was no difference in quality of life between the two arms in the study. Serum levels of cobalt and chromium were measured in a subset of 30 patients. In both groups cobalt and chromium was elevated compared to baseline. Patients receiving a large-head metal-on-metal total hip had elevated ion levels compared to the resurfacing arm of the study. At 1 year, the median serum cobalt increased 46-fold from baseline in patients in the large-head total hip group, while the median serum chromium increased 10-fold. At 1 year, serum cobalt was 10-fold higher and serum chromium 2.6-fold higher than in the resurfacing arm. Due to these excessively high metal ion levels, the authors recommend against further use of this particular large-head total hip arthroplasty.,[object Object]

Survivorship of a Low-stiffness Extensively Porous-coated Femoral Stem at 10 Years

Mark A. Hartzband MD, Andrew H. Glassman MD, Victor M. Goldberg MD, Louis R. Jordan MD, Roy D. Crowninshield PhD, Kevin B. Fricka MD, Louis C. Jordan MD A novel low-stiffness extensively porous-coated total hip femoral component was designed to achieve stable skeletal fixation, structural durability, and reduced periprosthetic femoral stress shielding. In short- to intermediate-term clinical review, this implant achieved secure biologic fixation and preserved periprosthetic bone. We retrospectively reviewed all 102 prospectively followed patients (106 implants) with this implant to document the longer-term implant survivorship, clinical function, fixation quality, and periprosthetic bone preservation. Ninety-seven patients with 101 implants had current followup or were followed to patient death (range, 1–14 years; average, 10 years). Eighty-six living patients were followed for an average implant survivorship of 10 years. There were no known femoral implant removals. The average Harris hip score at 10-year followup was 98. Radiographs demonstrated secure implant fixation and maintenance of periprosthetic bone. These data suggest this implant design provided long-term function characterized by extensive fixation, structural durability, and radiographic appearance of maintained periprosthetic cortical thickness and density.,[object Object]

Tantalum Components in Difficult Acetabular Revisions

Paul F. Lachiewicz MD, Elizabeth S. Soileau BSN Although porous-coated hemispherical components are usually successful in acetabular revisions, the rate of failure is increased in hips with severe bone loss. Tantalum acetabular implants are characterized by higher friction, higher porosity, and greater osteoconductivity than titanium mesh or chrome-cobalt beads. We asked whether these components would provide stable short-term fixation without radiographic loosening in revisions at higher risk for failure. We prospectively followed 37 patients (39 hips) who had an acetabular revision with tantalum acetabular components. The minimum followup time was 2 years (mean, 3.3 years; range, 2–7 years). The acetabular defects were classified as Paprosky et al. Type 3 in 26, Type 2 in 11, and Type 1 in two hips. The mean postoperative Harris hip score was 86. Thirty-eight of the 39 (97%) tantalum components were radiographically well fixed. There was one mechanical failure at 6 months, rerevised with a larger tantalum component. Bone ingrowth was apparent in 38 hips and four hips had a radiolucent line. There were six other reoperations, three recurrent dislocations (constrained liners leaving the shell in place), two infections that seeded to the hip from elsewhere and treated with drainage, and one supracondylar femur fracture, but the tantalum component was left in place. Tantalum acetabular components provide stable fixation in difficult acetabular revisions.,[object Object]

The John Charnley Award: The Functional Outcome of Hip Resurfacing and Large-head THA Is the Same: A Randomized, Double-blind Study

Martin Lavigne MD, MSc, Marc Therrien MSc, Julie Nantel MSc, Alain Roy MD, François Prince PhD, Pascal-André Vendittoli MD, MSc Better functional outcome is believed by some to occur after hip resurfacing (HR) than conventional 28-mm total hip arthroplasty (THA) in young and active patients with hip osteoarthritis. However, the postulated superior outcome of HR over THA may simply be the result of a bias in patient selection or the use of a larger femoral head. We therefore asked whether HR would demonstrate superior functional outcome when compared with a THA with a large-diameter femoral head in a randomized, double-blind study. Gait speed and postural balance evaluations, functional tests, and clinical data were analyzed preoperatively and at 3, 6, and 12 months after surgery. Gait speed was used as the primary outcome measure. Forty-eight patients were randomized in the study and a third group of 14 healthy subjects served as controls. The gait speed and postural balance evaluations, the performance at most functional tests, and clinical scores were similar in HR and large-head THA groups at each followup period. The operated patients reached most control group values at 3 months postoperatively. By these measures, HR did not provide better clinical function over large-head THA.,[object Object]

Salvage of Failed Acetabular Cages by Nonbuttressed Trabecular Metal Cups

Yona Kosashvili MD, Oleg Safir MD, FRCSC, David Backstein MD, FRCSC, Dror Lakstein MD, Allan E. Gross MD, FRCSC Acetabular revision of failed cages or rings may be facilitated by previously placed bone graft, enabling the use of highly porous cementless hemispheric cups. We retrospectively reviewed all 15 patients who had conversion of failed antiprotrusion cages (10 patients) or roof rings (five patients) to cementless cups. All patients had restoration of bone stock (three major column, eight morselized, four combined bone grafts) performed in conjunction with their index cage or ring reconstruction arthroplasty. The minimum followup was 24 months (average, 48.3 months; range, 24–72 months). Failure was defined as radiographic cup migration. In 12 of the 15 patients, there was no radiographic change in cup position at the last followup or symptoms indicative of loosening. The average Harris hip scores improved from 31 (range, 15–48) to 69 (range, 56–87) at latest followup. Cup failure occurred in three patients. In two patients, the failed cups were revised; the third patient refused additional surgery. Our experience suggests treatment of failed cages by highly porous cementless cups is a reasonable option. However, we recommend patients be followed closely to detect cup migration, which can occur until satisfactory bony ingrowth occurs.,[object Object]

The 2009 Frank Stinchfield Award: “Hip Squeaking”: A Biomechanical Study of Ceramic-on-ceramic Bearing Surfaces

Christophe Chevillotte MD, Robert T. Trousdale MD, Qingshan Chen PhD, Olivier Guyen MD, PhD, Kai-Nan An PhD We designed and implemented an in vitro bench test to simulate and identify potential biomechanical causes for hip squeaking with alumina ceramic-on-ceramic bearing surfaces. All bearings were third-generation alumina ceramic with a 32-mm head coupled with a 56-mm acetabular component with a 32-mm ceramic insert. Conditions for testing were normal gait, high load, stripe wear, stripe wear in extreme load, metal transfer, edge wear with extreme load, and microfracture. Each condition was tested two times in dry conditions and two times in a lubricated condition with 25% bovine serum. Squeaking was reproduced in all dry conditions. It occurred quickly with high load, stripe wear, or metal transfer. Once squeaking occurred, it did not stop. Squeaking disappeared for all conditions when a small amount of lubricant was introduced. In lubricated conditions, squeaking was only reproduced for the material transfer condition. Our observations suggest squeaking is a problem of ceramic-ceramic lubrication and that this noise occurs when the film fluid between two surfaces is disrupted. Material (metal) transfer was the only condition that led to squeaking in a lubricated situation.