Biomedical subjects

Cecil H Rorabeck

Publications and source records attributed to Cecil H Rorabeck.

At least 19 recordsLinked to original sources

PubMed2007

Wear and osteolysis around total knee arthroplasty.

Osteolysis induced by wear debris of ultra-high-molecular-weight polyethylene has emerged as a significant problem after total knee arthroplasty. The generation of polyethylene wear and the development of osteolysis around total knee arthroplasty are caused by a combination of patient, implant, and surgical factors. Activity level over time may be the most important patient factor affecting the loads placed on a total knee replacement, but it is the most difficult to manage. Multiple factors related to the manufacturing of the polyethylene implant influence the extent of wear, and surgeons should be cautious in considering enhanced polyethylenes pending results of further investigations. The optimal design of the articular bearing surface remains controversial but needs to be considered with respect to the stresses imparted on component-bone and modular tibial backside interfaces. Surgical factors, including restoration of alignment and ligament balance, are important for long-term durability of the implant. Methods of measuring the wear of total knee implants are still evolving. Thus, when confronted with a worn total knee implant and developing osteolysis, the surgeon should consider each of these factors in selecting the best management option to eliminate the source of debris and minimize the potential for wear and osteolysis following revision.

Arthroplasty, Replacement, Knee↗

PubMed2006

Tapered hydroxyapatite-coated press-fit stems: any added value?

This study compares the efficacy of hydroxyapatite (HA)-coated press-fit stems versus porous coated press-fit stems with a minimum 2-year follow up. Of the 1152 patients in the study, 69 had an HA-coated grit blasted cemented stem inserted (6%), whereas 1083 (94%) had a porous coated stem inserted. A detailed clinical and radiographic analysis demonstrated that there was no clinical difference at an average 4-year follow up. Similarly, there was no radiographic difference when the HA group was compared with the porous coated group. Thus, there is no need for HA coating on a tapered titanium stem in primary total hip arthroplasty in patients with osteoarthritis.

Arthroplasty, Replacement, Hip↗

PubMed2006

Cost effectiveness of revision total knee arthroplasty.

UNLABELLED: Total knee arthroplasty now exceeds total hip arthroplasty as the most commonly performed joint replacement. Projections suggest the need for revision knee arthroplasty in the future will produce an immense economic burden. The excellent cost effectiveness of primary knee arthroplasty has been well established. This article explores the cost effectiveness of revision knee arthroplasty, and makes a comparison of costs between different international health care systems. While revision knee arthroplasty is more costly, technically difficult, and complicated than primary knee arthroplasty, it is still a cost effective means of improving function, pain relief, and quality of life. The role of national arthroplasty registries will be important in guiding decision making toward reducing the requirements for revision surgery. LEVEL OF EVIDENCE: Prognostic study, level II-1 (prospective study). See Guidelines for Authors for complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗

PubMed2006

Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial.

BACKGROUND: Postoperative analgesia with the use of parenteral opioids or epidural analgesia can be associated with troublesome side effects. Good perioperative analgesia facilitates rehabilitation, improves patient satisfaction, and may reduce the hospital stay. We investigated the analgesic effect of locally injected drugs around a total knee prosthesis. METHODS: Sixty-four patients undergoing total knee arthroplasty were randomized either to receive a periarticular intraoperative injection containing ropivacaine, ketorolac, epimorphine, and epinephrine or to receive no injection. The perioperative analgesic regimen was standardized. All patients in both groups received patient-controlled analgesia for twenty-four hours after the surgery, and this was followed by standard analgesia. Visual analog scores for pain, during activity and at rest, and for patient satisfaction were recorded preoperatively and postoperatively and at the six-week follow-up examination. The consumption of patient-controlled analgesia at specific postoperative time-points and the overall analgesic requirement were measured. RESULTS: The patients who had received the injection used significantly less patient-controlled analgesia at six hours, at twelve hours, and over the first twenty-four hours after the surgery. In addition, they had higher visual analog scores for patient satisfaction and lower visual analog scores for pain during activity in the post-anesthetic-care unit and four hours after the operation. No cardiac or central nervous system toxicity was observed. CONCLUSIONS: Intraoperative periarticular injection with multimodal drugs can significantly reduce the requirements for patient-controlled analgesia and improve patient satisfaction, with no apparent risks, following total knee arthroplasty.

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PubMed2006

Managing bone loss in revision total hip arthroplasty: the acetabulum.

Osteolysis is the greatest threat to the viability of modern acetabular implants. The etiology and natural history of osteolysis remain unknown. Patients with cementless implants who have osteolysis are challenging to treat. There are no standards for follow-up methods or frequency, and there is little evidence to support timing of the decision to begin treatment in these patients. The natural history of proposed treatment options is also unknown. Reconstruction of the acetabulum in the presence of bone loss is difficult. Classifications have been developed to guide management. Multiple options exist for revision acetabular surgery, and it is important to understand the rationale and data in support of these options. A review of the literature was undertaken and algorithms were developed to help address acetabular bone loss in patients undergoing revision surgery.

Acetabulum↗

PubMed2005

The mini-incision direct lateral approach in primary total hip arthroplasty.

UNLABELLED: Patients are inquiring about mini-incision primary total hip arthroplasty with increasing frequency. There are no published randomized controlled trials to substantiate claims that the mini-incision direct lateral approach is better than a standard approach. The purpose of our study was to review our initial experience with the mini-incision technique through the direct lateral approach, with the intent of implementing a randomized controlled trial if the approach could be shown as safe and effective. Of importance was determining if there is any difference in component positioning and if there is any difference in intraoperative or postoperative complications between the two groups. We retrospectively compared a consecutive series of 87 primary total hip arthroplasties. Thirty-four total hip arthroplasties were done using a mini-incision direct lateral approach. The mean abduction angle was 45 degrees for both groups. The femoral stem alignment was within five degrees of neutral in 97% of the mini group and 94% of the standard group. There were no dislocations, infections, neurologic or wound complications. There were no differences in medical complications or blood transfusions. A significant decrease was found regarding body mass index, which reflects the bias in patient selection and lack of randomization. We conclude that it is safe to continue further study with this approach because as there was no increase in complications or component malpositioning. LEVEL OF EVIDENCE: Therapeutic study, Level III (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

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PubMed2005

Arthroplasty options for the young patient: Oxinium on cross-linked polyethylene.

Our purpose was to determine whether metal femoral heads scratch with in vivo use, to characterize the scratching that occurs, and to determine whether this scratching affected polyethylene wear. Assessment of 133 consecutive retrieved femoral heads showed that metal femoral heads do scratch with in vivo use, that cobalt-chromium femoral heads are more scratch resistant than titanium alloy heads, and that scratching seems to be time dependent. Profilmetry studies showed that all roughness parameters (average roughness, maximum peak to lowest valley distance, mean peak height above the mean surface line, estimate of small peaks above the main plateau of the surface, and estimate of the depth of the valleys below the mean plateau of the surface with the exception of the symmetry of the profile about its mean line) showed increased roughness with time of use. Cobalt-chromium and Oxinium femoral heads were damaged in a dislocation model. Assessment of these femoral heads in a wear simulator revealed that against conventional polyethylene, a damaged Oxinium femoral head had no more wear than a new cobalt-chromium articulation on the same polyethylene (36.5/million cycles versus 38.4 mm/million). Against cross-linked polyethylene, a damaged Oxinium femoral head had minimal wear (1.5 mm cubed per Mc).

Adult↗

PubMed2005

Soft-tissue balancing of the hip: the role of femoral offset restoration.

Inadequate soft-tissue balancing is a major yet often underemphasized cause of failure for primary and revision total hip arthroplasty. Accordingly, contemporary cemented and cementless hip prostheses have been designed with consideration of this issue, and this has substantially increased the long-term survival of total hip replacements. Therefore, it is important for orthopaedic surgeons to be familiar with the rationale, biomechanical principles, and clinical implications associated with soft-tissue balancing of the hip as well as strategies to avoid inadequate soft-tissue balancing and systematic techniques to restore adequate soft-tissue tensioning during total hip arthroplasty.

Arthroplasty, Replacement, Hip↗

PubMed2004

A quantitative analysis of bone support comparing cementless tapered and distal fixation total hip replacements.

The purpose of this study was to develop a technique to accurately assess cementless femoral stem-bone contact. Using this technique, differences in contact patterns between tapered (Synergy) and cylindrical distal fixation (Prodigy) cementless stems were explored. Femurs were prepared and the 2 types of femoral stems were implanted. After implantation, the femurs were imaged in a spiral computed tomography scanner and analyzed using novel custom-developed imaging software. This analysis used a geometric deformable-model UNIX-based software that determined bone-prosthesis contact area. The tapered stem features proximal, cancellous bone contact and a 3-point fixation pattern. The cylindrical distal fixation stem demonstrates cortical support in the distal aspect of the stem.

Algorithms↗

PubMed2004

Isolated liner exchange in revision total hip arthroplasty: clinical results using the direct lateral surgical approach.

Twenty-four hips (23 patients) underwent isolated polyethylene liner exchange (modular and nonmodular liners) via the direct lateral surgical approach for a preoperative diagnosis of polyethylene wear and acetabular osteolysis. Accessible osteolytic lesions were bone grafted with cancellous allograft. Patients were followed up clinically and radiographically, with a mean follow-up time of 36 months (range, 12-100 months). A computer-assisted method measured lesional area from the radiographs of the 18 hips that presented with osteolysis. Seventeen of 18 lesions either regressed or resolved since the procedure. Two patients required repeat revisions, and no dislocations were noted. Clinically, both Harris Hip and Western Ontario and McMaster Universities Osteoarthritis Index scores improved postoperatively. In selected patients, isolated liner exchange with or without bone grafting is effective for treating polyethylene wear and associated osteolysis. Dislocation rates with revision may be reduced using a surgical approach that preserves an adequate capsular layer for closure in liner exchange surgery.

Adult↗

PubMed2004

Radiographic changes in the patella following quadriceps turndown for revision total knee arthroplasty.

Quadriceps turndown is a technique that may be used to enhance exposure of the tight total knee arthroplasty (TKA), particularly in the revision scenario. This technique does, however, compromise the vascularity of the patella, with avascular necrosis (AVN) being a possible sequela. A modified Coonse-Adams quadriceps turndown was performed in 29 revision TKAs in 27 patients. Immediate preoperative and sequential postoperative radiographs were analyzed for changes in the patella, including sclerosis, flattening, fracture, and fragmentation, as evidence of possible AVN, and clinical scores were collected prospectively. Eight patellae had such radiographic changes. Despite a lack of corresponding worsening in clinical outcome in these patients, quadriceps turndown is shown to have a high risk of subsequent changes consistent with patellar AVN, and should be avoided when other available techniques can achieve satisfactory exposure.

Aged↗

PubMed2004

Intraoperative complications of revision hip arthroplasty using a porous-coated, distally slotted, fluted femoral stem.

Intraoperative complications of 175 cementless revision total hip arthroplasties done at four institutions using a porous-coated, uncemented, distally slotted, fluted femoral stem were reviewed. Three types of complications were recorded: eccentric reaming, femoral perforation, and femoral fracture. Intraoperative complications occurred in 16 patients (9.1%). There was no statistically significant association between complication rate and type of surgical approach, stem length, stem diameter, or host bone quality. This complication rate is comparable to or lower than that reported with the use of similar uncemented long femoral revision stems.

Adult↗

PubMed2004

Revision total hip arthroplasty with use of a cemented femoral component. Results at a mean of ten years.

BACKGROUND: Revision of the femoral component of a total hip replacement with use of cement has been associated with early mechanical failure due to aseptic loosening. The purpose of the present study was to determine the long-term survival after revision of the femoral component with cement and to identify factors that were predictive of failure. METHODS: The results of 129 revision total hip arthroplasties that had been performed with use of a cemented femoral stem were reviewed to determine component survival. Ninety-seven hips that had been followed for a minimum of five years were included in survival analysis and tests of significance. Harris hip scores were used to quantify clinical outcomes. Clinical and surgical factors were analyzed to determine whether they were predictive of failure. RESULTS: The mean Harris hip score improved from 52 points preoperatively to 71 points at the time of the most recent follow-up (p < 0.001). The ten-year survival rate was 91% with rerevision of the femoral component because of aseptic loosening as the end point and 71% with mechanical failure as the end point. Patients who were more than sixty years old had greater long-term component survival and less pain than younger patients did (p < 0.05). A good-quality postoperative cement mantle was associated with better long-term radiographic signs of fixation (p < 0.001). Poor femoral bone quality was associated with an increased rate of rerevision for aseptic loosening (p = 0.021). CONCLUSIONS: Revision with use of a cemented femoral component remains an option for selected patients, with an acceptable ten-year survival rate and fair radiographic evidence of fixation. Our patients had acceptable clinical outcomes at ten years, and few had notable pain. The best results may be achieved in older patients (those who are sixty years old or more) with adequate bone stock who are managed with modern cementing techniques.

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PubMed2004

Medial unicompartmental knee arthroplasty with the Miller-Galante prosthesis.

BACKGROUND: Unicompartmental knee arthroplasty has become a popular treatment alternative for osteoarthritis that is confined to the medial part of the knee. Excellent intermediate-term results recently have been reported in association with the Miller-Galante unicompartmental implant. The purpose of the present study was to report on our longer-term experience with the Miller-Galante medial unicompartmental knee implant. METHODS: We evaluated the results of 113 medial unicompartmental knee arthroplasties that had been performed with use of the Miller-Galante implant in eighty-four patients between 1989 and 2000. The mean age of the patients at the time of surgery was sixty-eight years. Forty-five patients were men, and thirty-nine were women. Thirteen patients (sixteen knees) died at a mean of seven years after the index arthroplasty. No patient was lost to follow-up. The remaining seventy-one patients (ninety-seven knees) were followed for a mean of ten years and were evaluated with use of the Knee Society clinical and radiographic rating system. RESULTS: Eleven knees were revised at a mean of four years after the index procedure. The mean Knee Society knee and function scores for the sixty-one patients (eighty-six knees) who were living and who had not had a revision improved from 48 and 53 points preoperatively to 93 and 80 points at the time of the most recent evaluation. The five and ten-year rates of survival were 94% and 90%, respectively, with revision to tricompartmental knee arthroplasty as the end point and 93% and 86%, respectively, with revision or radiographic loosening as the end point. CONCLUSIONS: The Miller-Galante medial unicompartmental knee arthroplasty provided excellent pain relief and restoration of function in carefully selected patients and demonstrated durable implant survival at ten years.

Adult↗

PubMed2004

The dysplastic hip.

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Arthroplasty, Replacement, Hip↗

PubMed2004

Managing instability in total knee arthroplasty with constrained and linked implants.

Instability is a relatively common cause of failure of total knee arthroplasty. In the management of the unstable total knee, the need for constraint must be anticipated. Careful preoperative planning including history and physical examination of the ligamentous support of the knee is mandatory. A thorough study of current and previous radiographs is important to determine wear, component migration, and bone loss. As a general rule, it is recommended that the minimum amount of constraint necessary to achieve stability should be used. Most of the time, stability can be achieved using a posterior-stabilized or a nonlinked implant, such as a varus-valgus constrained or constrained-condylar knee implant. Occasionally, a hinge prosthesis may be indicated, particularly in a patient with an absent and nonreconstructable medial collateral ligament. Increasing constraint is not without its problems, however, as forces across the knee may be transmitted to the stem-bone interface, resulting in radiographic loosening of stemmed components. Fortunately, these observations of radiographic loosening around stems of revision components have not so far correlated with reports of clinical failure.

Arthroplasty, Replacement, Knee↗

PubMed2004

Sources of osteolysis around total knee arthroplasty: wear of the bearing surface.

Once mostly a problem in total hip arthroplasty, osteolysis has now emerged as a significant problem around total knee arthroplasty (TKA). The development of osteolysis is often related to wear of the polyethylene bearing surface with production of biologically active particulate debris. There are many structural and design factors related to the polyethylene bearing surface that have been shown to affect the extent of wear that occurs over time. For instance, the processing, manufacturing, and sterilization methods of polyethylene all are critical factors in determining its mechanical and wear-resistant properties. Cross-linking of polyethylene bearing surfaces in TKA, however, may not demonstrate the same degree of improved resistance to wear as seen in total hip arthroplasty. Optimization of polyethylene bearing surface thickness, with a goal to insert at least 8 mm of polyethylene, has been shown to minimize contact stresses and subsequent fatigue failure of total knee implants. Selecting a well-designed component with minimal counter surface roughness is also important in minimizing the generation of polyethylene wear debris and subsequent osteolysis. Finally, proper surgical technique, including restoration of mechanical axis and rotational alignment, is critical to minimizing wear and maximizing the longevity of TKA.

Arthroplasty, Replacement, Knee↗

PubMed2004

Patella resurfacing versus nonresurfacing in total knee arthroplasty: results of a randomized controlled clinical trial at a minimum of 10 years' followup.

Patellar resurfacing in total knee arthroplasty remains controversial. This study evaluates the results of resurfacing and nonresurfacing the patella in a randomized controlled, clinical trial at a minimum of 10 years followup. One hundred knees (90 patients) with osteoarthritis were enrolled in a prospective randomized clinical trial using a posterior-cruciate-retaining total knee arthroplasty. Patients were randomized to receive resurfacing or retention of the patella. Evaluations were done preoperatively and yearly, up to a minimum of 10 years (range, 10.1-11.5 years) postoperatively. Disease-specific (Knee Society clinical rating score) and functional (stair climbing, flexion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was done. No patients were lost to followup; 45 patients remained alive. Nine revisions (in nine of 90 knees; 10%) were done in seven patients in the nonresurfaced group (15% of knees) and in two patients in the resurfaced group (5% of knees). No significant difference was found between the groups regarding revision rates, Knee Society clinical rating scores, and functional, patient satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome. This study currently is the longest followup of a randomized controlled, clinical trial that examines patellar resurfacing in total knee arthroplasty. The results showed no significant difference between the groups for all outcome measures at a minimum of 10 years of followup.

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