Symposium: Papers Presented at the Annual Meetings of The Hip Society 54 articles
Adverse local tissue reactions (ALTR) around metal-on-metal (MOM) hip arthroplasties are increasingly being recognized as a cause of failure. These reactions may be associated with intraoperative tissue damage and complication rates as high as 50% after revision. Although MRI can identify ALTR in MOM hips, it is unclear whether the MRI findings predict those at revision surgery.
Smoking is considered a risk factor for surgical complications in total hip arthroplasty (THA) and has been linked to a higher rate of aseptic loosening in uncemented acetabular components. Acetabular reconstruction with newer ultraporous metals in both complex primary and revision THA has increased survivorship but it is unclear whether smoking affects survival of these implants.
Femoroacetabular impingement has been proposed as a cause of early osteoarthritis, but it is not known how this develops over time or whether the shape of the proximal femur influences this risk.
Press-fit acetabular component seating in hip resurfacing can be challenging as a strong interference fit is required. It has not been established whether reducing the acetabular underream minimizes incomplete component seating or leads to increased acetabular loosening.
A number of reconstructive procedures are available for the management of hip osteoarthritis. Hip resurfacing arthroplasty is now an accepted procedure, with implant survivorship comparable to THA at up to 10 years’ followup in certain series. Most reports focus on implant survivorship, surgeon-derived results, or complications. Fewer data pertain to patient-reported results, including validated measures of quality of life (QoL) and satisfaction and baseline measures from which to determine magnitude of improvement. Validated patient-reported results are essential to guide patients and surgeons in the current era of informed and shared decision making.
The 2012 John Charnley Award: Clinical Multicenter Studies of the Wear Performance of Highly Crosslinked Remelted Polyethylene in THA
Highly crosslinked polyethylene (HXLPE) in THA was developed to reduce particle-induced periprosthetic osteolysis. A series of clinical studies were initiated to determine the clinical efficacy as judged by patient-reported scores, radiographic osteolysis, and wear analysis of one form of HXLPE.
Outcomes of Minimally Invasive Anterolateral THA Are Not Superior to Those of Minimally Invasive Direct Lateral and Posterolateral THA
There has been considerable interest in minimally invasive surgical (MIS) THA in recent years. The MIS anterolateral approach, or the MIS Watson-Jones approach, is a novel intermuscular abductor-sparing technique. Early reports from case series suggest the potential for superior function and reduced complications; however, the available information from clinical reports is inadequate to suggest surgeons should change from their accepted standard approach.
Prevalence and Treatment of Intraarticular Pathology Recognized at the Time of Periacetabular Osteotomy for the Dysplastic Hip
The indication for hip arthrotomy accompanied by intraarticular work during periacetabular osteotomy (PAO) has not been precisely defined. To validate a role for routine hip arthrotomy accompanied by intraarticular work, frequent intraarticular pathology must exist, and the adjunct procedures must not be associated with inferior relief of pain, reduced function, radiographic osteoarthritis progression, or conversion to THA.
Two-stage Treatment of Hip Periprosthetic Joint Infection Is Associated With a High Rate of Infection Control but High Mortality
Periprosthetic infection after total hip arthroplasty (THA) is a devastating complication. Reported rates of infection control range from 80% to 95% but mortality rates associated with treatment of infected THA are also substantial and we suspect underreported.
While surgical navigation offers the opportunity to accurately place an acetabular component, questions remain as to the best goal for acetabular component positioning in individual patients. Overall functional orientation of the pelvis after surgery is one of the most important variables for the surgeon to consider when determining the proper goal for acetabular component orientation.
Hypothesized risk factors for fracture of ceramic liners include impingement, edge-loading, and cup malpositioning. These risk factors are similar to those for generation of stripe wear. However, it is unclear whether the biomechanical conditions contributing to stripe wear generation also increase the risk for ceramic liner fracture
Despite dislocation being the most frequent complication after revision THA, risk factors for its occurrence are not completely understood.
Dislocation remains common after total hip arthroplasty. Efforts have been made to identify and minimize risk factors. One such factor, jump distance, or the distance the femoral head must travel before dislocating, has been poorly characterized with respect to three-dimensional kinematics.
Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased torsional friction and micromotion. Specifically, however, it remains unclear how cup diameter, design, and time from implantation affect shell deformation.
Currently, the two most commonly used options for the revision of femoral components in North America are: cylindrical, nonmodular, cobalt-chromium stems and tapered, fluted, modular, titanium (TFMT) stems. Previous reports have cited high failure rates with cylindrical cobalt chrome stems in large femoral defects but the longer term survival of the fluted stems is unknown.
The Articular Surface Replacement™ (ASR™) metal-on-metal hip arthroplasty system (DePuy Orthopaedics, Inc, Warsaw, IN, USA) reportedly has a higher than anticipated early failure rate leading to a voluntary recall. This prompted us to evaluate all ASR™ components implanted at our center.
Lessons Learned From Managing a Prospective, Private Practice Joint Replacement Registry: A 25-year Experience
In 1984, we developed a private practice joint replacement registry (JRR) to prospectively follow patients undergoing THA and TKA to assess clinical and radiographic outcomes, complications, and implant survival. Little has been reported in the literature regarding management of this type of database, and it is unclear whether and how the information can be useful for addressing longer-term questions.
Excessive alcohol consumption has been associated with adverse health measures after elective surgery. The effects of low or moderate consumption remain unclear.
The 2012 Otto Aufranc Award: The Interpretation of Metal Ion Levels in Unilateral and Bilateral Hip Resurfacing
The interpretation of metal ion concentrations and their role in clinical management of patients with metal-on-metal implants is still controversial.
Disclosure of Financial Conflicts of Interest: An Evaluation of Orthopaedic Surgery Patients’ Understanding
Industry and orthopaedic surgeons often partner to develop new technology, which can lead to orthopaedic surgeons having financial conflicts of interest (FCOI). It is essential these FCOI be conveyed clearly to patients. It is unclear, however, whether and to what degree patients understand the ramifications of physician FCOI.
The 2012 Frank Stinchfield Award: Decreasing Patient Activity With Aging: Implications for Crosslinked Polyethylene Wear
Patient activity influences polyethylene wear. However, it is unclear how individual activity changes with patient aging after THA.
Low Early and Late Dislocation Rates with 36- and 40-mm Heads in Patients at High Risk for Dislocation
Large (36- and 40-mm) femoral heads with highly crosslinked polyethylene liners were introduced to reduce the risk of dislocation after primary total hip arthroplasty (THA), but it is unclear whether the risk is reduced and whether there is osteolysis or liner fracture.
While the primary objective of joint arthroplasty is to improve patient quality of life, pain, and function, younger active patients often demand a return to higher function that includes sporting activity. Knowledge of rates and predictors of return to sports will help inform expectations in patients anticipating return to sports after joint arthroplasty.
Ceramic liner fracture is a concern in THA. However, it is unclear what factors influence the risk of facture. To study these factors under controlled conditions, we created a laboratory model to avoid fractures in vitro.
Initial reports with short-term followup of porous tantalum acetabular components and augments for Paprosky IIIA acetabular defects demonstrate high hip scores, low rates of aseptic loosening, and low rates of complications. However, longer-term followup with a larger cohort is needed to determine the durability of these reconstructions.
Few large series of hard bearing surfaces have reported on reasons for early failure. A number of unique mechanisms of failure, including fracture, squeaking, and adverse tissue reactions, have been reported with these hard bearing surfaces. However, the incidence varies among the published studies.
Numerous cementless femoral stem design variations are in clinical use. Because initial implant instability and micromotion are associated with aseptic loosening of the femoral component, migration analysis provides an early assessment of implant survivorship.
Does Previous Reconstructive Surgery Influence Functional Improvement and Deformity Correction After Periacetabular Osteotomy?
The Bernese periacetabular osteotomy (PAO) is commonly used to surgically treat residual acetabular dysplasia. However, the degree to which function and radiographic deformity are corrected in patients with more severe deformities that have undergone previous reconstructive pelvic or femoral osteotomies is unclear.
The Frank Stinchfield Award: Dislocation in Revision THA: Do Large Heads (36 and 40 mm) Result in Reduced Dislocation Rates in a Randomized Clinical Trial?
Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA.
Pelvic discontinuity is an increasingly common complication of THA. Treatments of this complex situation are varied, including cup-cage constructs, acetabular allografts with plating, pelvic distraction technique, and custom triflange acetabular components. It is unclear whether any of these offer substantial advantages.
Surgical Technique: A Simple Soft-tissue-only Repair of the Capsule and External Rotators in Posterior-approach THA
Posterior soft tissue repair after posterior THA reportedly decreases the risk of dislocation. Previously described techniques often require drill holes through the greater trochanter, do not include both the short external rotators and the capsule, or require a complex series of multiple sutures. We therefore describe a technique to address these issues.
Currently more than 200,000 THAs are performed annually in the United States. In patients with bilateral disease, the chance of subsequent contralateral THA reportedly ranges from 16% to 85%. Factors influencing contralateral THA are not completely understood.
Overdiagnosis of Pulmonary Embolism: Evaluation of a Hypoxia Algorithm Designed to Avoid This Catastrophic Problem
We observed a substantial increase in the incidence of pulmonary embolism (PE) after total joint arthroplasty (TJA) when multidetector computerized tomography (MDCT) replaced ventilation-perfusion (V/Q) scans as the diagnostic modality of choice. We questioned whether this resulted from the detection of clinically unimportant PE with the more sensitive MDCT and in 2007 instituted a hypoxia protocol to enhance the detection of PE.
The indications for surgical techniques for treatment of recurrent hip dislocation after THA differ, and their rates of achievement of stability may not be similar.
Factors affecting risk for impingement and dislocation can be related to the patient, implant design, or surgeon. While these have been studied independently, the impact of each factor relative to the others is not known.
Ceramic bearings were introduced to reduce wear and increase long-term survivorship of total hip arthroplasty. In a previous study comparing ceramic with metal-on-polyethylene at 5 to 8 years, we found higher survivorship and no osteolysis for the ceramic bearings.
Severe medial and/or superior defects encountered in revision THA are currently managed with jumbo (≥ 66 mm) acetabular components and modular augments, with reconstruction cages, or with the cup-cage technique. Preoperative planning can indicate when these techniques may not restore vertical and horizontal offset. Failure to restore offset can lead to impingement, leg length inequality, abductor weakness, and dislocation.
Large-diameter metal-on-metal articulations reportedly improve stability and wear in THAs. However, some reports suggest some patients have unexplained hip and early failures with these implants. Thus, the potential benefits may be offset by these concerns. However, the incidence of these problems is not clearly established.
While short-stem design is not a new concept, interest has surged with increasing utilization of less invasive techniques. Short stems are easier to insert through small incisions. Reliable long-term results including functional improvement, pain relief, and implant survival have been reported with standard tapered stems, but will a short taper perform as well?
Limitations of conventional uncemented femoral stems persist, including proximal-distal mismatch, nonideal load transfer, loss of bone, and difficulties with minimally invasive surgery. Metaphyseal-engaging short-stem implants have been designed to address these issues in THA. While these devices have been studied in younger patients, it is unclear whether they offer advantages in older patients.
The John Charnley Award: An Accurate and Extremely Sensitive Method to Separate, Display, and Characterize Wear Debris Part 2: Metal and Ceramic Particles
Metal-on-metal and ceramic-on-ceramic bearings were introduced as alternatives to conventional polyethylene in hip arthroplasties to reduce wear. Characterization of wear particles has been particularly challenging due to the low amount and small size of wear particles. Current methods of analysis of such particles have shortcomings, including particle loss, clumping, and inaccurate morphologic and chemical characterization.
The John Charnley Award: An Accurate and Sensitive Method to Separate, Display, and Characterize Wear Debris: Part 1: Polyethylene Particles
Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them.
The Effect of Poly Sterilization on Wear, Osteolysis and Survivorship of a Press-fit Cup at 10-Year Followup
During the mid-1990s when our institution was using a press-fit porous-coated cup without supplemental initial fixation for primary THA, the manufacturer transitioned from gamma irradiation to gas plasma for the terminal sterilization of their polyethylene liners.
Although surgeons use many procedures to preserve the femoral head in patients with hip osteonecrosis, there is no consensus regarding the best procedure.
The recent interest in hip resurfacing arthroplasty is motivated by its potential advantages over THA. One advantage of hip resurfacing arthroplasty is that it conserves bone on the femoral side; however, it is unclear whether it does so on the acetabular side.
The Otto Aufranc Award: Demineralized Bone Matrix Around Porous Implants Promotes Rapid Gap Healing and Bone Ingrowth
Noncemented revision arthroplasty is often complicated by the presence of bone implant gaps that reduce initial stability and biologic fixation. Demineralized bone matrix has osteoinductive properties and therefore the potential to enhance gap healing and porous implant fixation.
Preventing pulmonary embolism is a priority after major musculoskeletal surgery. The literature contains discrepant data regarding the influence of anticoagulation on the incidence of pulmonary embolism after joint arthroplasty. The American College of Chest Physicians guidelines recommend administration of oral anticoagulants (warfarin), aiming for an international normalized ratio (INR) level between 2 and 3. However, recent studies show aggressive anticoagulation (INR > 2) can lead to hematoma formation and increased risk of subsequent infection.
Acetabular component position is associated with joint function and bearing wear. Current techniques for determining acetabular component version on standard radiographs lack reliability. Other, more consistent techniques are time-consuming and require additional equipment or software.
With contemporary canal-filling press-fit stems, there is no adjustability of stem position in the canal and therefore the canal anatomy determines stem version. Stem version will affect head/neck impingement, polyethylene wear from edge loading, and hip stability, but despite this, the postoperative version of a canal-filling press-fit stem is unclear.
Surgical Technique: Transfer of the Anterior Portion of the Gluteus Maximus Muscle for Abductor Deficiency of the Hip
Loss of the abductor portions of the gluteus medius and gluteus minimus muscles due to THA causes severe limp and often instability.
Defining the epidemiology of adverse events after THA will aid in the development of strategies to enhance perioperative care.
First-generation modular titanium fiber-metal-coated acetabular components had high rates of wear, pelvic osteolysis, and liner dissociation. Second-generation components were designed to reduce the incidence of these problems but it is unclear whether the changes achieved these goals.