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Biomedical subjects

R B Bourne

Publications and source records attributed to R B Bourne.

At least 19 recordsLinked to original sources
PubMed2006

Factors affecting survival of uncemented total hip arthroplasty in patients 50 years or younger.

Providing a long-lasting total hip arthroplasty for patients younger than 50 years remains one of the greatest challenges for modern arthroplasty surgery. We retrospectively reviewed 221 patients younger than 50 years who underwent 299 uncemented total hip arthroplasties from 1983 to 2000. We assessed 5- to 15-year survival with revision as the endpoint. Femoral stem survival was 99.3% (range, 98.4-100%), 98.9% (range, 97.7-100%), and 96.8% (92.5-100%) at 5, 10, and 15 years, respectively. Including all component designs acetabular survival was 98.7% (range, 97.4-100%), 84.6% (78.8-90.4%), and 52.5% (40.7-64.3%) at 5, 10, and 15 years, respectively. Overall survival was 46.8% (33.5-58.1%) at 15 years. Total hip arthroplasties performed for hip dysplasia had lower 10-year and 15-year survival. Zirconium-on-polyethylene articulations had lower acetabular revision rates compared with cobalt-chrome-on-polyethylene. Sixty-nine revisions were performed, most commonly for polyethylene wear. Uncemented femoral stems resulted in 90% survival at 15 years followup in patients younger than 50 years at index operation. Contemporary bearing surfaces in association with such stems may provide long-lasting total hip arthroplasties, even in young, active patients.

Adolescent↗
PubMed2005

Fractures of distally-fixed femoral stems after revision arthroplasty.

We identified five (2.3%) fractures of the stem in a series of 219 revision procedures using a cementless, cylindrical, extensively porous-coated, distally-fixed femoral stem. Factors relating to the patients, the implant and the operations were compared with those with intact stems. Finite-element analysis was performed on two of the fractured implants. Factors associated with fracture of the stem were poor proximal bone support (type III-type IV; p = 0.001), a body mass index > 30; (p = 0.014), a smaller diameter of stem (< 13.5 mm; p = 0.007) and the use of an extended trochanteric osteotomy (ETO 4/5: p = 0.028). Finite-element analysis showed that the highest stresses on the stem occurred adjacent to the site of the fracture. The use of a strut graft wired over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stresses on the stem by 48%.We recommend the use of a strut allograft in conjunction with an extended trochanteric osteotomy in patients with poor proximal femoral bone stock.

Adult↗
PubMed2004

The fate of augments to treat type-2 bone defects in revision knee arthroplasty.

We report the five- to-ten year results of Anderson Orthopaedic Research Institute type-2 bone defects treated with modular metal augments in revision knee surgery. A total of 102 revision knee arthroplasties in patients with type-2 defects treated with augments and stems were prospectively studied. Seven patients (seven knees) had incomplete follow-up and 15 patients (16 knees) died with the arthroplasty in situ. The mean follow-up of the 79 remaining knees was 7 +/- 2 years (5 to 11). The presence of non-progressive radiolucent lines around the augment in 14% of knees was not associated with poorer knee scores, the range of movement, survival of the component or the type of insert which was used (p > 0.05). The survival of the components was 92 +/- 0.03% at 11 years (95% CI, 10.3 to 11.2). We recommend the use of modular augmentation devices to treat type-2 defects in revision knee surgery.

Adult↗
PubMed2004

Retrieval of a well-functioning extensor mechanism allograft from a total knee arthroplasty. Clinical and histological findings.

We present the histological findings of an extensor mechanism allograft which was used in a total knee arthroplasty two years after implantation. Analysis of the graft was undertaken at four distinct anatomical levels and it was found to be incorporated into host tissue at each level. A wedge of fibrinoid necrosis, probably related to impingement of the graft on the tibial polyethylene insert, was seen. Impingement may play a role in the injury and necrosis of an allograft and may be one mode of failure in an extensor mechanism allograft.

Amputation, Surgical↗
PubMed2003

The fate of cementless jumbo cups in revision hip arthroplasty.

We report 5-year minimum results of cementless over-sized cups used in revision hip arthroplasty, with significant associated bone defects. Forty-three porous-coated jumbo cups were used to treat acetabular defects in revision hip arthroplasty in 42 patients with a mean age of 63 (range, 25-86). Morsellized allograft only was used in 27 hips, and bulk allograft was used in 8 cases. Two patients were lost to follow-up, and 5 died after a mean 7 years' follow-up, with retention of their prostheses. In the remaining 36 cases, the mean follow-up was 10 years (range, 6-14 years). Two acetabular components were revised for aseptic loosening and graft resorption. Two cases were complicated by dislocation. A satisfactory 92% Kaplan Meier shell survival rate was seen at 14 years.

Adult↗
PubMed2003

Metal-on-metal versus polyethylene in hip arthroplasty: a randomized clinical trial.

A prospective, randomized, blinded clinical trial was done to evaluate polyethylene versus metal bearing surfaces in total hip replacement. Forty-one patients were randomized to receive either a metal (23 patients) or a polyethylene (18 patients) insert. The femoral and acetabular components were identical with the acetabular insert the only variable. Patients were assessed preoperatively and postoperatively using radiographs, multiple outcome measures (Western Ontario MacMaster University Score, Harris hip score, Short Form-12), erythrocyte metal ion analysis (cobalt, chromium, titanium), and urine metal ion analysis (cobalt, chromium, titanium). Patients were followed up for a minimum of 2 years (mean 3.2 years; range, 2.2-3.9 years). There were no differences in radiographic outcomes or outcome measurement tools between patients. Patients receiving a metal-on-metal articulation had significantly elevated erythrocyte and urine metal ions compared with patients receiving a polyethylene insert. Patients who had metal-on-metal inserts had on average a 7.9-fold increase in erythrocyte cobalt, a 2.3-fold increase in erythrocyte chromium, a 1.7-fold increase in erythrocyte titanium, a 35.1-fold increase in urine cobalt, a 17.4-fold increase in urine chromium, and a 2.6-fold increase in urine titanium at 2 years followup. Patients receiving a polyethylene insert had no change in erythrocyte titanium, urine cobalt, or urine chromium and a 1.5-fold increase in erythrocyte cobalt, a 2.2-fold increase in erythrocyte chromium, and a 4.2-fold increase in urine titanium. Forty-one percent of patients receiving metal-on-metal articulations had increasing metal ion levels at the latest followup.

Arthroplasty, Replacement, Hip↗
PubMed2002

The effectiveness of dual offset stems in restoring offset during total hip replacement.

Commonly, total hip prostheses have had a higher neck-shaft angle than the host bone and thus a tendency to reduce the femoral offset. Restoration of the femoral offset may be important as it has been shown to enhance hip stability and to improve the range and strength of abduction. The purpose of this study was to determine which of two designs was best able to restore femoral offset in comparison to the contralateral normal hip. Two hundred and two primary total hip patients were included in a radiographic study. Measurements were taken from a postoperative anteroposterior radiograph of the pelvis. The Synergy femoral component with a more varus neck-shaft angle of 131 degrees and a standard or high offset option tended to restore the femoral offset more reliably than did the Mallory-Head femoral component with a neck shaft angle of 135 degrees.

Aged↗
PubMed2001

Factors affecting range of flexion after total knee arthroplasty.

Many factors affect postoperative range of flexion after total knee arthroplasty (TKA). The purpose of this study was to identify the most important factors that affect range of knee flexion after TKA. Sixty-five patients (73 knees) were treated with Genesis II knee replacements. Minimum follow-up was 2 years. Patient demographics (sex, age, body mass index, previous surgery, component type, patella resurfacing, preoperative Knee Society score preoperative range of motion) and radiographic measurements (preoperative tibiofemoral varus/valgus angle, height of the joint line, length of the patellar tendon, shift and tilt angle of the patella) were analyzed statistically. Among these factors, preoperative range of flexion, positively, and preoperative varus/valgus tibiofemoral angle, negatively, affected postoperative range of flexion. The tilt angle of the patella and the tilt angle of the patellar button approached statistical significance in revealing a negative relation with postoperative range of flexion. TKAs in which the patella was not resurfaced tended to lose range of flexion, whereas TKAs in which the patella was resurfaced tended to have no loss of flexion, although the number of TKAs in which the patella was not resurfaced was small. In conclusion, preoperative range of flexion and preoperative varus/valgus tibiofemoral angle affected postoperative range of flexion. The tilt angle of the patella and tilt angle of the patellar button may be factors that affect postoperative range of flexion.

Aged↗
PubMed2001

Prevalence of abductor mechanism tears of the hips in patients with osteoarthritis.

In a prospective study of 176 consecutive patients who underwent total hip arthroplasty for osteoarthritis, we identified 34 (20%) with degenerative pathology of the abductor mechanism. These degenerative tears were commoner in elderly women. The hip capsule usually was involved, but in 6 patients (16%), the gluteus minimus or medius tendons were involved in isolation. These abductor mechanism tears are progressive in nature and the result of degenerative processes.

Aged↗
PubMed2001

Patellar infera after high tibial osteotomy.

Forty-six knees in 41 patients that had undergone high tibial osteotomy (HTO) were evaluated to assess the potential correlation between alteration in the inclination of the proximal tibial articular surface and subsequent patellar height. Of the knees examined, 61% lost > or =5 degrees of posterior tibial inclination after HTO, whereas 54% of knees showed a relative lowering of patellar height of >10%, as measured by the Insall-Salvati ratio. The loss of the normal posterior tibial inclination was found to have a statistically significant association with the subsequent loss of the patellar height. Clinically, these results suggest that careful preservation of the posterior tibial inclination at the time of HTO could minimize the risk of subsequent patellar infera and alteration in patellofemoral mechanics.

Adult↗
PubMed2001

Polyethylene wear of the porous-coated anatomic total hip arthroplasty with an average 11-year follow-up.

The purpose of this study was to identify the factors that affect polyethylene wear of 55 porous-coated anatomic total hip arthroplasties after 9 to 14 years selected from a study population of 311 implants. The average three-dimensional linear, two-dimensional linear, and volumetric wear rates were 0.096 mm/y, 0.052 mm/y, and 34 mm3/y. Negative wear was noted in 7 patients using two-dimensional techniques. Significantly higher volumetric wear rate was observed for men (48 mm3/y) compared with women (24 mm3/y; P<.01), for patients <60 years old (45 mm3/y) compared with patients >60 years old (25 mm3/y; P<.01), and for 32-mm femoral heads (54 mm3/y) compared with 26-mm femoral heads (29 mm3/y; P<.01). Volumetric wear rate for patients having small (39 mm3/y) and large (65 mm3/y) areas of osteolysis were 2 and 3 times greater than for patients having no osteolysis (21 mm3/y) (P<.01).

Analysis of Variance↗
PubMed2001

Long-term followup of cementless versus hybrid fixation for total knee arthroplasty.

In a prospective trial, 99 patients (100 knees) with osteoarthritis were randomized to either cementless or hybrid fixation of cruciate-retaining Miller-Galante-I total knee arthroplasties between January 1987 and December 1988. Thirty-one patients died during the study period and two additional patients were lost to followup, leaving 67 total knee arthroplasties for analysis. Thirty-nine patients underwent revision surgery at an average of 6.9 years postoperatively. The main reason for revision surgery was failure of metal-backed patellas with 25 knees revised at an average of 7.4 years, and the second most common reason was tibial polyethylene failure. Survival curves showed 60% survival at 14 years for all knees, and 85% survival at 14 years when failures for metal-backed patellas and infection were excluded, with no significant difference between the two groups. Failure of metal-backed patellas was significantly higher in the cementless group. Tibial polyethylene failure occurred in five of the hybrid group and none of the cementless group, but this was not a significant difference. Surviving prostheses were assessed at an average of 12.8 years (range, 11.5-13.5 years). Average clinical scores were 94.8 points preoperatively, and 143 points at the latest followup, with significantly higher scores in the hybrid group. Differences in outcome between the two groups were not sufficiently significant to recommend one method of fixation over another. With elimination of poor design features related to the patellofemoral articulation and thin tibial polyethylene, cruciate-retaining total knee arthroplasties can yield good durable results, whether cementless or hybrid fixation is used.

Aged↗
PubMed2001

The John Charnley Award: Three-dimensional analysis of the cement mantle in total hip arthroplasty.

Cemented fixation of the femoral stem is the gold standard for patients older than 60 years. The importance of reliably achieving an adequate cement mantle has been shown in many studies. Currently, inspection and grading of plain radiographs is the accepted method for study of the cement mantle. However, the reliability of plain radiographs for this purpose has been questioned. In addition, the interobserver agreement of current grading systems has been shown to be limited. A new in vitro method of cement mantle analysis is described. Plastic replicas of six contemporary stems were implanted into femurs from cadavers. The specimens were imaged with a computed tomography scanner. Detailed, computer-assisted analysis of mantle thickness was done. Comparisons were made between designs. A subset was compared with standard radiographs. Plain radiographs overestimated thickness and underestimated the deficiencies. There was significant variability in the mantle produced by the different designs. Commonly used designs had deficiencies in their mantles by standard criteria despite proper surgical technique. The importance of being fully acquainted with the particular implant one uses is emphasized by these results. This is a valuable technique for investigation of the effects on the cement mantle of implant design, surgical technique, and patient anatomy.

Arthroplasty, Replacement, Hip↗
PubMed2001

Instability in primary total hip arthroplasty with the direct lateral approach.

Instability after a total hip arthroplasty is a serious complication. Dislocation rates as much as 6.5% after posterior approaches have been reported within the past decade. For this reason, the authors use the direct lateral approach for primary and revision total hip arthroplasties. A review of the arthroplasty database yielded 1515 primary total hip arthroplasties done via a direct lateral approach in 1333 patients. These arthroplasties were done within a 10-year period and patients with followup data less than 12 months were excluded. At the most recent examination, 11.6% of the patients had a moderate or severe limp and 2.5% had severe heterotopic ossification. Only six hips (0.4%) had a dislocation or episode of instability. Three patients had more than one dislocation and required revision surgery. The results of the current study show that dislocation after primary total hip arthroplasty almost can be eliminated using the direct lateral approach. The associated risks of heterotopic ossification or limp are acceptable.

Aged↗
PubMed2001

Tibial post wear in posterior stabilized total knee arthroplasty. An unrecognized source of polyethylene debris.

BACKGROUND: With extensive use of posterior stabilized total knee arthroplasty implants, it is increasingly important to assess the mechanical performance of this design alternative. The purpose of this study was to examine the wear patterns at the femoral cam-tibial post interface in a series of posterior stabilized prostheses retrieved at revision arthroplasty. METHODS: Qualitative and quantitative wear analysis was performed over the surface of the stabilizing posts from twenty-three retrieved total knee components that had been implanted for a mean of 35.6 months (range, 2.3 to 107.2 months). The implants were designs from four different manufacturers. Digital images of the anterior, posterior, medial, and lateral surfaces of the tibial post were made for quantitative analysis and determination of a post wear score. Wear was characterized with a grading system that isolates adhesive, abrasive, and fatigue wear, inferring a weighted score from an estimation of generated polyethylene debris. RESULTS: Evidence of wear or damage was observed on all twenty-three of the stabilizing posts, including those revised because of infection. On the average, 39.9% (range, 18.5% to 60%) of the post surface demonstrated some form of deformation, with adhesive wear, or burnishing, being the predominant wear mechanism. Seven posts (30%) exhibited severe damage with gross loss of polyethylene. The wear caused premature failure and early revision of two components: one of these failures was related to isolated post wear and the other, to severe post wear and subsequent fracture. Overall, wear was primarily posterior, but wear over the anterior, medial, and lateral surfaces was also notable. CONCLUSIONS: The cam-post articulation in posterior stabilized implants can be an additional source of polyethylene wear debris. The variability in wear patterns observed among designs may be due to differences in cam-post mechanics, post location, and post geometry. The surgeon should be aware that the cam-post interface is not an innocuous articulation, and manufacturers should be motivated to produce implants that maintain the function of the post while limiting wear and surface damage.

Humans↗