Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Symposium: Papers Presented at the Hip Society Meetings 2008 30 articles

Articles

Combined Anteversion Technique for Total Hip Arthroplasty

Lawrence D. Dorr MD, Aamer Malik MD, Manish Dastane MD, Zhinian Wan MD Combined cup and stem anteversion in THA based on femoral anteversion has been suggested as a method to compensate for abnormal femoral anteversion. We investigated the combined anteversion technique using computer navigation. In 47 THAs, the surgeon first estimated the femoral broach anteversion and validated the position by computer navigation. The broach was then measured with navigation. The navigation screen was blocked while the surgeon estimated the anteversion of the broach. This provided two estimates of stem anteversion. The navigated stem anteversion was validated by postoperative CT scans. All cups were implanted using navigation alone. We determined precision (the reproducibility) and bias (how close the average test number is to the true value) of the stem position. Comparing the surgeon estimate to navigation anteversion, the precision of the surgeon was 16.8° and bias was 0.2°; comparing the navigation of the stem to postoperative CT anteversion, the precision was 4.8° and bias was 0.2°, meaning navigation is accurate. Combined anteversion by postoperative CT scan was 37.6° ± 7° (standard deviation) (range, 19°–50°). The combined anteversion with computer navigation was within the safe zone of 25° to 50° for 45 of 47 (96%) hips. Femoral stem anteversion had a wide variability.,[object Object]

Imaging and Navigation Measurement of Acetabular Component Position in THA

Zhinian Wan MD, Aamer Malik MD, Branislav Jaramaz PhD, Lisa Chao BS, Lawrence D. Dorr MD There are six different definitions of acetabular position based on observed inclination and anteversion made in either the (1) anterior pelvic plane or (2) coronal planes and based on whether each of the observations made in one of these two planes is (1) anatomic, (2) operative, or (3) radiographic. Anteroposterior pelvic tilt is the angle between the anterior pelvic plane and the coronal plane of the body. The coronal plane is a functional plane and the anterior pelvic plane is an anatomic pelvic plane. A cup may be in the “safe zone” by one definition but may be out of the “safe zone” by another definition. We reviewed published studies, analyzed the difference in varying definitions, evaluated the influence of the anterior pelvic tilt, and provided methods to convert from one definition to another. We recommend all inclination and anteversion measurements be converted to the radiographic inclination and anteversion based on the coronal plane, which is equivalent to the inclination and anteversion on the anteroposterior pelvic radiograph.

Revision of the Deficient Proximal Femur With a Proximal Femoral Allograft

Oleg Safir MD, FRCSC, Catherine F. Kellett BSc, BM, BCh, FRCS(Tr & Orth), Michael Flint BHB, MB, ChB, FRACS, David Backstein MD, MEd, FRCS(C), Allan E. Gross MD, FRCS(C), O.Ont Substantial bone loss is frequently encountered with revision hip arthroplasty. A proximal femoral allograft may be used to reconstitute bone stock in the multiply revised femur with segmental bone loss of greater than 5 cm. We retrospectively reviewed 92 patients (93 hips) who underwent such proximal femoral allografts. The average age at the surgery was 61 years. The average number of previous revision procedures was 2.5. Six patients were lost to followup. Thirty-four of 36 deceased patients had the original proximal femoral allograft at the time of death. The minimum followup for the 50 remaining patients was 15 years (average, 16.2 years; range, 15–22 years). Analysis included survivorship and radiographic assessment. Of the 50 patients reviewed, two had a failed reconstruction due to infection, six for aseptic loosening, three for nonunion, and four for dislocation. Revision of the proximal femoral allograft for all reasons excluding the acetabulum was performed in seven patients. At last followup, 42 patients (84%) had a well-functioning construct. Proximal femoral allograft for revision hip arthroplasty in femoral segmental bone loss is a durable alternative in most patients for a complex problem.,[object Object]

Robert Merle d’Aubigné, 1900–1989

David J. Biau MD, Richard A. Brand MD [object Object]

Survivorship of 2000 Tapered Titanium Porous Plasma-sprayed Femoral Components

Adolph V. Lombardi MD, Keith R. Berend MD, Thomas H. Mallory MD, Michael D. Skeels DO, Joanne B. Adams BFA Tapered titanium porous plasma-sprayed components have performed well in primary THA. To confirm the literature at longer followup we retrospectively reviewed all 1639 patients who underwent 2000 THAs in which a specific porous femoral component was used. One hundred fourteen patients (134 hips) were lost to followup leaving a cohort of 1525 patients (1866 THAs). The component is a tapered titanium plasma spray-coated design that remained relatively unchanged since its first implantation except for circumferential proximal porous coating added in 1986 and an offset option added in 1999. Minimum followup was 24 months (average, 119 months; range, 24 to 275 months). To date there have been 39 femoral revisions for an implant survival of 98%. Using the Kaplan-Meier method, cumulative survival with any stem revision as the end point was 98.6% at 5 years, 98.4% at 10 years, 97.1% at 15 years, and 95.5% at 20 years. Using aseptic revision for failure of ingrowth as the endpoint, stem survival was 99.1%. Kaplan-Meier cumulative survival with aseptic revision for failure of ingrowth as the endpoint was 99.4% at 5 years, 99.3% at 10, 15 and 20 years. Harris hip pain and total scores improved. This titanium, porous plasma spray-coated femoral component continues to demonstrate high long-term survival with a low rate of component revision for any reason or aseptic failure of ingrowth.,[object Object]

Why Revision Total Hip Arthroplasty Fails

Bryan D. Springer MD, Thomas K. Fehring MD, William L. Griffin MD, Susan M. Odum M.Ed., CCRC, John L. Masonis MD Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision THAs. The minimum followup was 2 years (mean, 6 years; range, 0–20.4 years). Eighty-seven percent of revision total hips required no further surgery; however, 141 hips (13%) underwent a second revision at a mean of 3.7 years (range, 0.025–15.9 years). Seventy percent (98 hips) had a second revision for a diagnosis different from that of their index revision, while 30% (43 hips) had a second revision for the same diagnosis. The most common reasons for failure were instability (49 of 141 hips, 35%), aseptic loosening (42 of 141 hips, 30%), osteolysis and/or wear (17 of 141 hips, 12%), infection (17 of 141 hips, 12%), miscellaneous (13 of 141 hips, 9%), and periprosthetic fracture (three of 141 hips, 2%). Survivorship for revision total hip arthroplasty using second revision as endpoint was 82% at 10 years. Aseptic loosening and instability accounted for 65% of these failures.,[object Object]

Initial American Experience with Hip Resurfacing Following FDA Approval

Craig J. Della Valle MD, Ryan M. Nunley MD, Stephen J. Raterman MD, Robert L. Barrack MD In May 2006, the US Food and Drug Administration approved the first metal-on-metal total hip resurfacing. Surgeons wanting to implant this device were required to undergo formal industry-sponsored training before performing their first case and a technical specialist attended their initial 10 cases. Safety surveys were completed on the first 537 cases performed and included patient age, gender, diagnosis, and occurrence of any unexpected events perioperatively or postoperatively. Intraoperative data were available for all 537 cases (100%), hospital discharge and six-week data were available for 524 cases (97.6%), three-month data were available for 523 cases (97.4%), six-month data were available for 509 cases (94.3%) and one-year data were available for 449 cases (83.6%); the mean followup was 10.4 months. We documented adverse events in 40 (32 major, 8 minor) of the 537 cases including nine nerve injuries and eight dislocations. There were 14 component revisions (7.4%) within the first year, including 10 for femoral neck fracture, two for dislocations, and two for acetabular component loosening. Complications were frequently seen among patients older than 55 years of age and in women, emphasizing the importance of appropriate patient selection for the procedure.,[object Object]

Computer-assisted versus Manual Alignment in THA: A Probabilistic Approach to Range of Motion

Anthony J. Petrella PhD, Joshua Q. Stowe MS, Darryl D. D’Lima MD, PhD, Paul J. Rullkoetter PhD, Peter J. Laz PhD Dislocation remains a major complication after THA, and range of motion before impingement is important in joint stability. Variability in implant alignment affects resultant range of motion. We used a probabilistic modeling approach to assess the effects of implant alignment variability based on manual and computer-assisted surgical (CAS) techniques on resultant range of motion after THA. We implemented a contact detection algorithm within a probabilistic analysis framework. The normally distributed alignment variables (mean ± 1 standard deviation) were cup abduction (manual = 45° ± 7.6°, CAS = 45° ± 5.7°), cup anteversion (manual = 20° ± 9.6°, CAS = 20° ± 4.5°), and stem anteversion (manual and CAS = 10° ± 1.5°). The outcomes of the probabilistic analysis were range of motion distributions with 1% and 99% bounds. The upper bounds of motion for manual and CAS alignment were similar because bony impingement was the limiting factor. The lower bounds of range of motion were substantially different depending on the type of surgical alignment; manual alignment produced a smaller range of motion in 3% to 5% of cases. CAS implant alignment produced range of motion values above minimum acceptable levels in all cases simulated.

Is Patient Selection Important for Hip Resurfacing?

Ryan M. Nunley MD, Craig J. Della Valle MD, Robert L. Barrack MD The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration approval of two devices. Recent studies indicate satisfactory short- and midterm clinical results (1- to 10-year followup) with low complication rates, but there is a learning curve associated with this procedure, a more extensive surgical approach is necessary, and long-term results have yet to be determined. Proper patient selection may help avoid complications and improve patient outcomes. Patient selection criteria in the literature appear based predominantly on theoretical considerations without any consensus on stratifying patient risk. The most commonly reported complications encountered with hip resurfacing include femoral neck fracture, acetabular component loosening, metal hypersensitivity, dislocation, and nerve injury. At the time of clinical evaluation, patient age; gender; diagnosis; bone density, quality, and morphology; activity level; leg lengths; renal function; and metal hypersensitivity are important factors when considering a patient for hip resurfacing. Based on our review, we believe the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology.,[object Object]

Late Remodeling Around a Proximally HA-coated Tapered Titanium Femoral Component

William N. Capello MD, James A. D’Antonio MD, Rudolph G. Geesink MD, PhD, Judy R. Feinberg PhD, Marybeth Naughton BS Most bone remodeling is thought to occur within the first few years after THA. Loss of bone density later may be associated with stress shielding or normal bone loss of aging. We evaluated remodeling changes over time with a proximally hydroxyapatite-coated tapered titanium stem. We evaluated plain radiographs of 143 hips for cancellous condensation, cortical hypertrophy, cortical porosis, cortical index, and canal fill at early postoperative, 5, 10, and 15 years. Average age was 51 years at THA; 69 patients (77 hips) (53%) were women; and 102 hips (71%) had primary osteoarthrosis. Based on radiographic findings at 15 years, hips were divided into three subgroups: 43 (30%) demonstrated minimal remodeling changes; 53 (37%) demonstrated cortical hypertrophy evident before 5 years; and 47 (33%) demonstrated additional late remodeling and cortical porosis, most often after 10 years. Hips with poorer bone (Dorr Types B or C) and, when including only hips with osteoarthrosis, more female hips had cortical porosis at 15 years. Late radiographic changes in patients with porosis appear more similar to that associated with an extensively rather than proximally coated stem. Whether continued bone adaptation and bone loss of aging will eventually threaten implant stability is unknown, but at 15 years, all 143 implants remained well fixed and clinically asymptomatic.,[object Object]

Modular Tantalum Augments for Acetabular Defects in Revision Hip Arthroplasty

Alexander Siegmeth MD, Clive P. Duncan MD, MSc, Bassam A. Masri MD, Winston Y. Kim MBChB, Donald S. Garbuz MD, MHSc Large acetabular defects can be reconstructed with various methods depending on size and location of the defect. We prospectively followed our first 37 patients in whom we reconstructed the acetabulum with a trabecular metal augment combined with a trabecular metal shell. Three patients died before completing the minimum 24 months followup while the remaining 34 were followed a minimum of 24 months (mean, 34 months; range, 24–55 months). All defects were classified according to Paprosky. Radiographic signs of osseointegration were classified according to Moore. Quality of life was measured with the SF-12, WOMAC, and Oxford Hip Score. There were 15 men and 19 women with an average age of 64 years. At a minimum of two years followup 32 of the 34 patients required no further surgery for aseptic loosening, while two had rerevision. Of the 32 patients who had not been revised, all had stable cups radiographically. All quality-of-life parameters improved. The early results with tantalum augments are promising but longer followup is required.,[object Object]

Wear Analysis in THA Utilizing Oxidized Zirconium and Crosslinked Polyethylene

Kevin L. Garvin MD, Curtis W. Hartman MD, Jimmi Mangla MBBS, M Surg (ortho), Nathan Murdoch BS, John M. Martell MD Oxidized zirconium, a material with a ceramic surface on a metal substrate, and highly cross-linked polyethylene are two materials developed to reduce wear. We measured in vivo femoral head penetration in patients with these advanced bearings. We hypothesized the linear wear rates would be lower than those published for cobalt-chrome and standard polyethylene. We retrospectively reviewed a select series of 56 THAs in a relatively young, active patient population utilizing oxidized zirconium femoral heads and highly cross-linked polyethylene acetabular liners. Femoral head penetration was determined using the Martell computerized edge-detection method. All patients were available for 2-year clinical and radiographic followup. True linear wear was 4 μm/year (95% confidence intervals, ± 59 μm/year). The early wear rates in this cohort of relatively young, active patients were low and we believe justify the continued study of these alternative bearing surfaces.,[object Object]

2008 Otto Aufranc Award: Component Design and Technique Affect Cement Penetration in Hip Resurfacing

Paul E. Beaulé MD, FRCSC, Wadih Y. Matar MSc, MD, Philippe Poitras BASc, Kevin Smit BSc, Olivier May MSc, MD Either excessive or insufficient cement penetration within the femoral head after hip resurfacing influences the risk of femoral failures. However, the factors controlling cement penetration are not yet fully understood. We determined the effect of femoral component design and cementation technique on cement penetration. Six retrieved femoral heads were resurfaced for each implant (BHR®, ASR®, Conserve Plus®, DuROM®, ReCAP®) using the manufacturers’ recommendations for implantation. In addition, the BHR was implanted using the Conserve Plus® high-viscosity cementation technique, “BHR/hvt,” and vice versa for the Conserve, “Conserve/lvt.” The average cement penetration was highest with BHR (65.62% ± 15.16%) compared with ASR® (12.25% ± 5.12%), Conserve Plus® (19.43% ± 5.28%), DuROM® (17.73% ± 3.96%), and ReCAP® (26.09% ± 5.20%). Cement penetration in BHR/hvt remained higher than all other implants equaling 36.7% ± 6.6%. Greater femoral component design clearance correlated with cement mantle thickness. Femoral component design in hip resurfacing plays a major role in cement penetration.

2008 John Charnley Award: Metal Ion Levels After Metal-on-Metal Total Hip Arthroplasty: A Randomized Trial

C. Anderson Engh MD, Steven J. MacDonald MD, Supatra Sritulanondha MPH, Abigail Thompson RN, Douglas Naudie MD, Charles A. Engh MD Metal-on-metal bearing total hip arthroplasty is performed more commonly than in the past. There may be manufacturing differences such as clearance, roughness, metallurgy, and head size that affect performance. In a prospective, randomized trial, we compared 2-year postoperative ion levels for a 28-mm metal-on-polyethylene bearing with 28-mm and 36-mm metal-on-metal bearings. We measured serum, erythrocyte, and urine ion levels. We observed no difference in the ion levels for the 28-mm and 36-mm metal-on-metal bearings. The ion levels in these patients were lower than reported for most other metal-on-metal bearings. Although both erythrocyte and serum cobalt increased, erythrocyte chromium and erythrocyte titanium did not increase despite a four- to sixfold serum chromium and a three- to fourfold serum titanium increase. This may represent a threshold level for serum chromium and serum titanium below which erythrocytes are not affected.,[object Object]

Isolated Polyethylene Exchange versus Acetabular Revision for Polyethylene Wear

Camilo Restrepo MD, Elie Ghanem MD, Carrie Houssock MD, Mathew Austin MD, Javad Parvizi MD, FRCS, William J. Hozack MD Polyethylene wear and osteolysis are not uncommon in THA mid- and long-term. In asymptomatic patients the dilemma faced by the orthopaedic surgeon is whether to revise the cup and risk damage to the supporting columns and even pelvic discontinuity or to perform isolated polyethylene exchange and risk a high rate of postoperative recurrent instability and dislocation that will necessitate further surgery. We retrospectively reviewed 62 patients (67 hips) who underwent revision arthroplasty for polywear and osteolysis. Thirty-six hips had isolated polyethylene exchange, while 31 had full acetabular revision. The minimum followup was 2 years (mean, 2.8 years; range, 2–5 years). Three of 36 hips with a retained cup grafted through the cup holes failed within 5 years due to acetabular loosening. One of 31 hips with full revision underwent re-revision for aseptic cup loosening at 5 months postoperatively. Although we do not recommend prophylactic revision of all cups for polywear and osteolysis, the patient may be warned of the possibility of an approximate 10% failure rate when retaining the acetabular component. We do, however, advocate cup extraction in the following situations: damage to the locking mechanism, erosion of the femoral head through the liner and into the cup damaging the metal, and a malpositioned component that may jeopardize the stability of the revision.,[object Object]

Early Mortality after Modern Total Hip Arthroplasty

Michael Aynardi BA, Luis Pulido MD, Javad Parvizi MD, FRCS, Peter F. Sharkey MD, Richard H. Rothman MD, PhD Because of improvements in surgical technique, anesthesia, and rehabilitation, mortality after hip arthroplasty may be on the decline. The purpose of this study was to determine the 90-day mortality rate after uncemented total hip arthroplasty (THA) performed under regional anesthesia. We retrospectively reviewed 7478 consecutive patients undergoing cementless primary or revision THA between January 2000 and July 2006. Patient survivorship was established and causes of death were obtained by accessing the Social Security Death Index, Centers for Disease Control and Prevention National Death Index, and State Departments of Vital Statistics. There were two intraoperative deaths from cardiac arrest. The overall 30- and 90-day mortality rates were 0.24% (18 of 7478) and 0.55% (41 of 7478), respectively. Thirty-day mortality after primary THA was low at 0.13% (eight of 6272). The most common cause of death was cardiovascular-related. Mortality after modern THA seems to have remained very low despite the availability of this procedure to patients of all ages and comorbidities.,[object Object]

The Role of Arthroscopy in Evaluation of Painful Hip Arthroplasty

Joseph C. McCarthy MD, Stefan R. Jibodh MD, Jo-Ann Lee NP Unexplained pain after hip arthroplasty is frustrating for patients and surgeons. We describe the use of hip arthroscopy in management of the painful hip arthroplasty, critically evaluate the outcomes of these patients, and refine indications for hip arthroscopy in this setting. We retrospectively reviewed 14 patients (16 hips) who underwent hip arthroscopy after joint replacement. One patient had suspected septic arthritis despite negative aspiration and one had known septic arthritis but was not a candidate for open arthrotomy; two had intraarticular migration of hardware. The remaining 10 patients (11 hips) had persistent pain despite negative diagnostic studies. The two patients (two hips) with infection were successfully treated with arthroscopic lavage and débridement plus intravenous antibiotics. Intraarticular metal fragments and a loose acetabular screw were successfully removed in two patients (three hips). Findings in the remaining 11 hips included a loose acetabular component (one); corrosion at the head-neck junction of a metal-on-metal articulation (one); soft tissue-scar impingement at the head/cup interface (four); synovitis with associated scar tissue (four); and capsular scarring with adhesions (one). Arthroscopy represented a successful treatment or directly led to a successful treatment in 12 of 16 hips. We observed no complications as a result of the arthroscopy. Arthroscopy may be of value in selected patients undergoing hip arthroplasty with unexplained pain after an inconclusive standard workup.,[object Object]

Acetabular Orientation: Anterolateral Approach in the Supine Position

Matthew S. Austin MD, Richard H. Rothman MD, PhD The anterolateral approach in the supine position provides excellent visualization of the acetabulum. The main advantage of the approach, a low dislocation rate, has been demonstrated in the literature, while the purported disadvantage of abductor dysfunction has not been clearly delineated in the literature. The technique requires meticulous attention to preservation of the gluteus medius and minimus tendons. Impingement and dislocation are avoided by careful attention to the preparation of acetabulum, critical assessment of the implanted components, and intraoperative trialing. Leg lengths are assessed through direct palpation of the malleoli. Routine use of postoperative hip precautions is not necessary when this approach is utilized. The anterolateral approach in the supine position allows for a reproducible result with a low dislocation rate.,[object Object]

Can the Volume of Pelvic Osteolysis be Calculated without Using Computed Tomography?

Hiroshi Egawa MD, Cara C. Powers MD, Sarah E. Beykirch BS, Robert H. Hopper PhD, C. Anderson Engh MD, Charles A. Engh MD [object Object],[object Object]

The 2008 Frank Stinchfield Award: Variation in Postoperative Pelvic Tilt May Confound the Accuracy of Hip Navigation Systems

Sebastien Parratte MD, Mark W. Pagnano MD, Krista Coleman-Wood PT, PhD, Kenton R. Kaufman PhD, Daniel J. Berry MD Most computer navigation systems used in total hip arthroplasty integrate preoperative pelvic tilt to calculate the anterior pelvic plane assuming tilt is constant; however, the consistency of pelvic tilt after THA has never been proven. Therefore, using a modern comprehensive gait analysis before and after arthroplasty we sought to compare (1) dynamic pelvic tilt changes and (2) pelvic flexion/extension range-of-motion changes. Twenty-one patients who underwent unilateral THA were prospectively studied. Quantitative pelvic tilt changes (in the sagittal plane) and pelvic range of flexion/extension motion relative to a laboratory coordinate system were compared using a computerized video motion system. Mean gait pelvic tilt was 13.9º ± 4.8º (range, 1.73º–23.1º) preoperatively, 12.5º ± 4.5º (range, 1.4º–18.7º) 2 months postoperatively, and 10.5° ± 5.5º (range, –2.36º–19.2º) 12 months postoperatively. A significant proportion (31%) of patients had more than a 5° difference between preoperative and 12-month postoperative measurements and the variability was spread over 20°. Significant dynamic changes in pelvic tilt occurred after THA. While navigation clearly improves the anatomical position of the component during THA, the functional position of the component will not always be improved because of the significant change between preoperative and postoperative pelvic tilt.

Incidence and Characteristics of Femoral Deformities in the Dysplastic Hip

John C. Clohisy MD, Ryan M. Nunley MD, Jack C. Carlisle MD, Perry L. Schoenecker MD Reorientation acetabular osteotomies can correct dysplastic deformities and provide marked improvement in hip function. Deformities of the proximal femur can produce suboptimal articulation or secondary impingement after acetabular reorientation, yet the incidence and characteristics of such deformities have not been well described. To describe the proximal femoral anatomy in patients with symptomatic acetabular dysplasia, we retrospectively analyzed the radiographs of 108 hips treated with periacetabular osteotomy. The radiographic findings were compared with those in 22 control hips. In the dysplastic group, 80 hips were in women and 28 in men, and the average age was 24.8 years. Of the 108 abnormal radiographs, 44% had coxa valga and 4% coxa vara. Seventy-two percent had an aspheric or deformed femoral head and the head-neck offset was insufficient in 75% of the hips. When compared with the control hips, dysplastic hips had differences in parameters of proximal femoral anatomy that we measured. These data demonstrate a high incidence of proximal femoral abnormalities associated with acetabular dysplasia. Identifying and treating these abnormalities may optimize joint congruency and minimize secondary impingement after acetabular reorientation.,[object Object]

Midterm to Long-term Followup of Staged Reimplantation for Infected Hip Arthroplasty

Joaquin Sanchez-Sotelo MD, PhD, Daniel J. Berry MD, Arlen D. Hanssen MD, Miguel E. Cabanela MD Most reports on two-stage reimplantation have focused on the short-term cure rate of infection, but little is known about long-term reinfection-free survival or mechanical durability. We retrospectively reviewed 168 patients (169 hips) with infected arthroplasty, all of whom had two-stage reimplantation for the treatment of an infected total hip arthroplasty between 1988 and 1998. In the second stage, the femoral component was fixed with antibiotic-loaded bone cement in 121 hips; the remaining femoral components and all acetabular components were uncemented. The minimum followup time was 2 years (mean, 7 years; range, 2–16 years). At most recent followup, 12 hips (7.1%) were reoperated on for reinfection and 13 hips (7.7%) were revised for aseptic loosening or osteolysis. Apparently aseptic loosening occurred on one or both sides of the joint in 24 hips (14.2%). The 10-year survivals free of reinfection and mechanical failure were 87.5% and 75.2% respectively. Nineteen hips dislocated and eight underwent revision surgery for instability. The method of femoral component fixation, either with or without cement, did not correlate with risk of infection, loosening, or mechanical failure. Based on these results, the method of fixation used for the femoral component during two-stage reimplantation surgery should be based on the surgeon’s preference for fixation combined with the assessment of femoral bone stock.,[object Object]

Acetabular Loosening Using an Extended Offset Polyethylene Liner

Michael J. Archibeck MD, Tamara Cummins RT(R) (ARRT), Daniel W. Junick MD, Richard E. White MD The use of extended offset femoral components and acetabular liners helps restore preoperative offset during hip arthroplasty. We report a relatively high acetabular component aseptic loosening rate with the use of offset polyethylene liners. We reviewed 1919 primary and 346 revision total hip arthroplasties (THAs). A 7-mm offset acetabular liner was used in 120 of the primary and 100 of the revision THAs. The aseptic loosening rate in the primary THA group was 0.12% in the standard offset and 4.2% in the extended offset groups at a minimum of 2 years (mean, 3.6 years; range, 2–9 years) followup. The aseptic loosening rate in the revision group was 1.7% in the standard and 7% in the extended offset groups at a mean of 4 years (range, 2–9 years) followup. Although extended offset acetabular liners help restore hip offset, torsional force applied to the implant-bone interface may have a detrimental effect on fixation. We found a relatively high failure rate in our primary and revision acetabular components used with an offset liner.,[object Object]

Surface Replacement is Comparable to Primary Total Hip Arthroplasty

Mike S. McGrath MD, David R. Marker BS, Thorsten M. Seyler MD, Slif D. Ulrich MD, Michael A. Mont MD Conversion of a failed surface hip replacement to a conventional total hip arthroplasty is reportedly a straightforward procedure with excellent results. We compared perioperative parameters, complications, and clinical as well as radiographic outcomes of 39 hemi and total hip resurfacing conversions with conventional THAs. The hips were matched by diagnosis, gender, age, body mass index, preoperative Harris hip score, and followup time to a cohort of primary conventional THAs performed during the same time period by the same surgeon. The mean operative time was longer (by 19 minutes) for the conversions, but other perioperative parameters were similar. At a mean followup of 45 months (range, 24–63 months), the mean Harris hip scores were similar in the two groups (92 points versus 94 points for the conversion and conventional hips, respectively). Thirty-eight of 39 stems were well-aligned and appeared osseointegrated. When a resurfaced hip fails, conversion to conventional THA has similar early clinical and radiographic outcomes to primary conventional THA.,[object Object]

The First 50 Years of Total Hip Arthroplasty: Lessons Learned

William H. Harris MD, DSc Fifty years have passed since the first total hip arthroplasty of the modern era was performed. At this, the vantage point, it is reasonable to review these five decades, inquiring behind the single dominating observation that, in its current form, this operation is one of the most successful of all surgical procedures for the management of end-stage human disease. What are the generic lessons that can be derived from the experience? Succinctly, five major observations appear valuable. They are “skunk works,” “Pasteur’s motto,” “the totally unexpected,” “research solutions,” and “the role of alternatives.” “Skunk works,” an industrial management term, might be characterized as an innovative endeavor that is offline and off-budget resulting from the relentless pursuit of a vivid dream by creative zealots who eschew defeat. Pasteur’s motto dealt with serendipity, which was crucial to total hip arthroplasty progress. The totally unexpected is represented by an entirely new manmade disease, “periprosthetic osteolysis.” The research solutions are represented by the complex, sophisticated contemporary research that has unraveled periprosthetic osteolysis and suggested modes of correction. Finally, the application of “alternatives” has characterized major progress. Importantly, these, or similar generic observations, may provide insights into important progress in the future.

No Difference in Gender-specific Hip Replacement Outcomes

Timothy Kostamo MD, FRCSC, Robert B. Bourne MD, FRCSC, John Paul Whittaker FRCS (T&O), Richard W. McCalden MD, FRCSC, MPhil(Edin), Steven J. MacDonald MD, FRCSC Gender-specific total hip arthroplasty (THA) design has been recently debated with manufacturers launching gender-based designs. The purpose of this study was to investigate the survivorship and clinical outcomes of a large primary THA cohort specifically assessing differences between genders in clinical outcomes, implant survivorship, revisions as well as sizing and offset differences. We reviewed 3461 consecutive patients receiving 4114 primary THAs (1924 women, 1537 men) between 1980 and 2004 with a minimum of 2 years followup (mean, 11.33 ± 6.5 years). A subset of patients with complete implant data was reviewed for sizing and offset differences. Preoperative, latest, and change in clinical outcome scores as well as Kaplan–Meier analysis were performed. Men had higher raw clinical outcome scores preoperatively and postoperatively. Differences in change of clinical outcome scores were found only in the WOMAC pain score in favor of the female cohort (39.4 versus 36.1). Survivorship and revision rate were not significantly different. Men used larger stems with greater stem lengths, neck offset, and neck lengths. Current implant systems were sufficiently versatile to address the different size and offset needs of male and female patients. These data suggest there is no apparent need for a gender-designed THA system.,[object Object]

Resurfacing is Comparable to Total Hip Arthroplasty at Short-term Followup

Michael A. Mont MD, David R. Marker BS, Jonathan M. Smith BS, Slif D. Ulrich MD, Mike S. McGrath MD [object Object],[object Object]