Highly Cross-linked Polyethylene Provides Decreased Osteolysis and Reoperation at Minimum 10-Year Follow-Up.

BACKGROUND: Highly cross-linked polyethylene was introduced to decrease periprosthetic osteolysis and reoperation, but this has not been conclusively proven. METHODS: One surgeon performed 513 consecutive primary total hip arthroplasties (450 patients) using 1 modern, cementless, titanium-mesh acetabular component with screw fixation. This study analyzed the differences in the rate of reoperation and incidence of osteolysis between 133 hips with standard and 112 hips with highly cross-linked polyethylene at minimum 10-year follow-up time. RESULTS: Of the entire cohort of 513 hips, no acetabular component was removed or revised for aseptic loosening. There were significantly more reoperations in the cohort with standard polyethylene (11 of 133, 8%) than highly cross-linked polyethylene (1 of 112, 1%; P = .03). Osteolysis was seen in 24% (32 of 133 hips) with standard polyethylene, compared with 13% (15 of 112 hips) with highly cross-linked polyethylene (P = .02). These differences occurred despite the presence of patients with greater BMI and higher activity in the cohort with highly cross-linked polyethylene. CONCLUSION: We continue to use this acetabular component with highly cross-linked polyethylene. Longer follow-up is required to determine the progression of osteolysis.

Wear and Osteolysis of Highly Crosslinked Polyethylene at 10 to 14 Years: The Effect of Femoral Head Size.

BACKGROUND: Highly crosslinked polyethylene (XLPE) was introduced to decrease periprosthetic osteolysis related to polyethylene wear, a major reason for revision of total hip arthroplasty. However, there are few reports of wear and osteolysis at 10 years postoperatively. QUESTIONS/PURPOSES: (1) What are the linear and volumetric wear rates of XLPE at 10 to 14 years? (2) What is the relationship among linear wear, volumetric wear, and femoral head size? (3) What proportion of hips developed osteolysis and was there a relationship between osteolysis and femoral head size or polyethylene wear? METHODS: We evaluated a previously reported cohort of 84 hips (72 patients) with one design of an uncemented acetabular component and one electron beam 10-kGy irradiated and remelted XLPE at a mean followup of 11 years (range, 10-14 years). The choice of femoral head size was based on several factors, including the outer diameter size of the acetabular component implanted, the perceived risk of dislocation (including the history of alcohol abuse and patient age), and liner availability from the manufacturer. The femoral head sizes used were 26 mm in 10 hips (12%), 28 mm in 31 hips (37%), 32 mm in 31 hips (37%), 36 mm in eight hips (10%), and 40 mm in four hips (5%). Measurements of linear and volumetric wear were performed in one experienced laboratory by the Martell method and analyzed using the first-to-last method. Standard radiographs, with additional Judet views, were used to detect periprosthetic osteolysis. Statistical analysis of wear and osteolysis compared with head size was performed. RESULTS: For the entire cohort, the median linear wear rate as 0.024 mm/year (95% confidence interval [CI], 0.016-0.030) and the median volumetric wear rate was 12.19 mm(3)/year (95% CI, 6.6-15.7). With the numbers available, we found no association between femoral head size and linear wear rate. However, larger femoral heads were associated with more volumetric wear; 36/40-mm femoral heads had higher volumetric wear (median 26.1; 95% CI, 11.3-47.1) than did 26-mm heads (median 3.1; 95% CI, 0.7-12.3), 28-mm heads (median 12.3; 95% CI, 3.0-19.3), and 32-mm heads (median 12.9; 95% CI, 6.6-16.8; p = 0.02). Small osteolytic lesions were noted in 12 hips (14%), but with the numbers available, there was no association with head size or volumetric wear rates. CONCLUSIONS: This uncemented acetabular component and this particular XLPE had low rates of linear and volumetric wear. Small osteolytic lesions were noted at 10 to 14 years but were not related to femoral head size or linear or volumetric wear rates. We recommend additional longer-term clinical followup studies and perhaps alternative imaging studies of patients with XLPE and osteolysis. LEVEL OF EVIDENCE: Level III, therapeutic study.

Is There a Benefit to Highly Crosslinked Polyethylene in Posterior-stabilized Total Knee Arthroplasty? A Randomized Trial.

BACKGROUND: Polyethylene wear and osteolysis remain a concern with the use of modular, fixed-bearing total knee arthroplasty (TKA). A variety of highly crosslinked polyethylenes (XLPs) have been introduced to address this problem, but there are few data on the results and complications of this polyethylene in posterior-stabilized knee prostheses. QUESTIONS/PURPOSES: In a randomized prospective study design comparing standard polyethylene (SP) tibial inserts with XLP inserts, we asked the following questions: (1) Are there any differences in the clinical results (as measured by the classic Knee Society scoring system) and radiographic results (as measured by an evaluation for radiolucencies and osteolysis) between these groups? (2) What is the frequency of reoperation in these two groups? (3) Are there any specific complications related to XLP liners? METHODS: These are preliminary data from a single surgeon of a planned interim analysis of a prospective randomized study of one modular posterior-stabilized TKA. One hundred ninety-two patients (236 knees) were randomized to receive a SP compression-molded liner or a XLP (6.5 CGy electron beam-irradiated and remelted) polyethylene liner. There was no difference in the number of knees who were lost or refused followup (14 knees [13%] with XLP and 21 knees [17%] with SP). Patients were evaluated clinically using the original Knee Society scores, Lower Extremity Activity Score (LEAS), presence of knee effusion, and by standard radiographs for radiolucent lines and osteolytic lesions. This analysis was performed at a mean followup of 4.5 years (range, 2-8 years). RESULTS: There were no clinical differences between 99 knees with SP and 94 knees with XLP in original Knee Society total score (SP mean 95, SD 5; XLP mean 94, SD 7 [p = 0.16]); change in total score (SP mean 41, 95% confidence interval [CI], 39-41; XLP mean 43, 95% CI, 39-48 [p = 0.56]); knee function score (SP mean 64 [SD 25]; XLP mean 64 [SD 24] p = 0.98; change in function score (SP mean 22, 95% CI, 17-27; XLP mean 21, 95% CI, 17-27 [p = 0.79]); LEAS score (both SP and XLP 9 [SD 2]; p = 0.88); and change in LEAS (both SP and XLP mean 1, 95% CI, 1-2 [p = 0.0.38]). There were no differences, with the numbers available, in the presence of effusion (two of 94 XLP and five of 99 SP) with 2 years minimum followup. There were no differences in the frequency of radiolucent lines (13 knees with SP and 15 with XLP) or of osteolysis (two knees with SP and none with XLP). There was no difference in frequency of reoperation between the two groups (three infections in 110 knees allocated to the XLP group and five (two infections, one femoral loosening, one instability, one fracture plating) in 122 knees allocated to the standard group. There were no complications related to the XLP liner. CONCLUSIONS: In this interim analysis, with the numbers available, there were no complications, but no advantages, related to the use of this XLP tibial liner. Additional enrollment has continued, and longer followup of these patients will be necessary to determine whether long-term wear characteristics differ between the groups. LEVEL OF EVIDENCE: Level I, therapeutic study.

A 30-mm cemented stem extension provides adequate fixation of the tibial component in revision knee arthroplasty.

BACKGROUND: The optimal stem length and method of fixation for the tibial component in revision knee arthroplasty remains controversial. The use of a cemented 30-mm stem extension provides certain advantages compared with other methods of fixation, but there are few published results. QUESTIONS/PURPOSES: We therefore asked (1) what is the survivorship (with respect to loosening and repeat revision) of tibial component revisions when a 30-mm stem extension is used; and (2) what factors are associated with the appearance tibial radiolucent lines? METHODS: We retrospectively reviewed 54 patients (58 knees) with fixation of the revision tibial component with a 30-mm cemented stem extension; another seven patients died and 11 patients had these components but were lost to followup. These implants represented 74% of our tibial revisions during the period in question (76 of 103); general indications for using them were need for a varus-valgus constrained liner or proximal bone loss requiring a metaphyseal cone or metal augment with an intact diaphysis. The Anderson Orthopaedic Research Institute tibial defect was Grade 1 in 37, 2A in 10, 2B in four, and Grade 3 in seven knees; constrained liners were used in 34% (20 of 58 knees). Patients were evaluated and followed for a mean of 5 years (range, 2-12 years). RESULTS: There were no revisions for tibial component loosening. One patient had débridement and liner exchange for late infection. Radiolucent lines were seen in 25 tibial components but only eight knees had radiolucencies in four or more zones. There were significantly fewer radiolucencies in revisions that used metaphyseal cones (20 in eight knees with cones compared with 53 in 17 without, p=0.013). CONCLUSIONS: The cemented 30-mm tibial stem extension provided excellent fixation in knee revision arthroplasty, even with metaphyseal defects and constrained polyethylene liners, although this series included relatively few patients with severe tibial defects. Longer followup is required for patients with radiolucent lines to confirm that the fixation will remain durable. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

What is the survivorship of fully coated femoral components in revision hip arthroplasty?

BACKGROUND: Femoral revision using fully coated femoral components offers distinct advantages in patients with notable bone loss. With the increasing concerns being raised about the problems of stem modularity, the results and complications of revision arthroplasty using devices with limited modularity are important. QUESTIONS/PURPOSES: We therefore asked: (1) What is the frequency of infection, aseptic loosening, and reoperations after use of these components? (2) What is the frequency of intraoperative fracture of the femur when using these components and are there any identifiable factors related to these fractures? (3) What is the 10-year survivorship of these components, and are there any identifiable factors related to survival and rerevision? METHODS: We retrospectively reviewed prospectively obtained data on 96 patients undergoing 104 revisions with fully coated components of two different manufacturers; six patients had died (6%) and six were lost to followup (6%) before 2 years. Data on intraoperative fracture, aseptic loosening, and reoperation were analyzed. Ninety-two hips, with a minimum followup of 2 years (mean, 8 years; range, 2-16 years), were evaluated for radiographic evidence of loosening. Intraoperative fracture frequency and Kaplan-Meier survivorship was calculated to 10 years for the entire cohort of 104 hips. Demographic, radiographic, and operative factors associated with implant survival and intraoperative fracture were analyzed using chi-square and Wilcoxon tests. RESULTS: There were three infections, nine hips (10%) had femoral component loosening (six rerevised), and there were seven other reoperations. Intraoperative complications in 17 hips (17%; 11 diaphyseal fractures, four perforations, two proximal fractures) were treated with allograft strut and cable fixation in 14 hips. Intraoperative femoral complication was more likely with the use of a curved stem [17 of 76, 22% curved; 0 of 28 straight stems (p=0.005)]. With failure defined as femoral component revision for aseptic loosening or radiographic evidence of loosening, implant survival was 88% at 10 years. Those femurs with Paprosky Grades 3B and 4 defects had a higher risk of loosening (3 of 10 for Grades 3B and 4 versus 6 of 94 hips [6%] for Grades 1, 2, 3A; p=0.03). CONCLUSIONS: As concerns about stems with more modularity become more prominent, we find the durability of the approach using fully coated femoral components reassuring, but we will continue to follow these patients in the longer term. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Fixation, survival and osteolysis with a modern posterior-stabilized total knee arthroplasty.

Early failure of the NexGen prosthesis with a 3° fluted, 4 hole tibial component has been reported. We evaluated fixation, survival and osteolysis with the NexGen LPS prosthesis with a 7° fluted, solid tibial component at a mean of 10 years. Knees were evaluated using Knee Society and LEAS scores, survival analysis, and univariable modeling. No knee had tibial loosening or debonding. With the endpoint mechanical failure (132 knees), the 12 year survival was 88.8% (CI 61.5-97.1).With failure defined as any reoperation (132 knees), the 12 year survival was 88.1% (CI 62.3-96.7). Osteolysis occurred in 16 knees, associated with male gender and LEAS score>10. Loosening was not seen with this tibial component.

Liner exchange in total knee arthroplasty.

Exchange of the tibial liner in revision knee arthroplasty for wear and other indications is controversial. The purpose of the study was to determine the clinical success and reoperation rate for liner exchange performed for four groups of patients. Thirty-nine revisions were identified in which modular liner exchange was performed: polyethylene wear (12 knees), acute infection (11 knees), instability (4 knees), and a variety of other diagnoses (12 knees). The knees were evaluated using the systems of the Knee Society. The mean follow-up time was 4.3 years. Liner exchange for wear was successful in all 12 patients: for acute infection, in 9 of 11 patients; for instability, in 3 of 4 patients; for other diagnoses, in 10 of 12 patients. There were significant improvements in the pain score in all four groups and significant improvement in the function score in the infection and other diagnoses groups. With the use of six criteria, these observations suggest that liner exchange for wear is successful.

Fixation, survival, and dislocation of jumbo acetabular components in revision hip arthroplasty.

BACKGROUND: Acetabular revision of a total hip arthroplasty using jumbo components (Mayo definition, ≥62 mm in women and ≥66 mm in men) offers distinct advantages in patients with notable acetabular bone loss. However, there are little data on the long-term survival and complications associated with use of these components. METHODS: This retrospective study of prospectively collected data included 120 patients who underwent 129 revision total hip arthroplasties with jumbo cups. Data on infection, aseptic loosening, reoperation, and dislocation were analyzed. One hundred and one patients (108 hips) with a mean follow-up of 8.1 years (range, two to twenty years) were evaluated with use of the Harris hip score and radiographic evidence of loosening, radiolucent lines, and osteolysis. Kaplan-Meier survivorship was calculated at ten and fifteen years with use of three different end points. Demographic and operative factors associated with implant survival and dislocation were analyzed with use of chi-square and Wilcoxon tests. RESULTS: Four (3.1%) of the jumbo components were removed for infection and four hips (3.1%) had aseptic implant loosening. Reoperation for any reason was performed in twenty hips. With failure defined as cup revision for aseptic loosening or radiographic evidence of loosening, implant survival was 97.3% (95% confidence interval [CI], 89.6% to 99.3%) at ten years and 82.8% (95% CI, 59% to 97.6%) at fifteen years. With failure defined as cup removal for any reason, implant survival was 93.8% (95% CI, 83.4% to 97.2%) at ten years and 79.8% (95% CI, 61.1% to 95.4%) at fifteen years. There was no significant association between Paprosky type, component coating, or patient characteristics and failure. Dislocation occurred in twelve (9.3%) of the hips (10% of the patients) and three underwent reoperation. A femoral head size of ≥32 mm was associated with a significantly lower risk of dislocation compared with smaller sizes. CONCLUSIONS: Jumbo acetabular components with screw fixation were associated with low rates of infection and loosening after revision total hip arthroplasty and had high survival at fifteen years. Reoperation for wear and loosening increased in the second decade. Dislocation was the most common complication and was significantly associated with smaller femoral head sizes.

Low early and late dislocation rates with 36- and 40-mm heads in patients at high risk for dislocation.

BACKGROUND: 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. QUESTIONS/PURPOSES: We therefore determined (1) the incidence of early and late (> 5 years) dislocation; (2) the rate of femoral and acetabular component loosening and revision; and (3) the rate of liner fracture and pelvic osteolysis. METHODS: We retrospectively reviewed 112 patients presumed at high risk for dislocation who had 122 primary THAs: 108 with 36-mm and 14 with 40-mm femoral heads. The risk factors were: age > 75 years (80 hips); proximal femur fracture (18); history of contralateral dislocation (two); history of alcohol abuse (two); large acetabulum > 60 mm (six); and other (14). Patients were evaluated for early (< 1 year) and late (> 5 years) dislocation; rate of reoperation; clinical result with Harris hip score; and standard radiographic analysis for radiolucent lines and osteolysis. RESULTS: The rate of early dislocation was 4% (five of 122 hips), all with a 36-mm head. There were no late dislocations in 74 hips followed for 5 to 10 years, no revision for acetabular or femoral loosening, and no liner fractured. There were no hips with pelvic osteolysis and seven hips with an acetabular radiolucent line. CONCLUSIONS: The 36- and 40-mm femoral heads were associated with a low risk of dislocation in high-risk patients undergoing primary THA with no osteolysis or liner fracture. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.

Can tantalum cones provide fixation in complex revision knee arthroplasty?

BACKGROUND: The best method for managing large bone defects during revision knee arthroplasty is unknown. Metaphyseal fixation using porous tantalum cones has been proposed for severe bone loss. Whether this approach achieves osseointegration with low complication rates is unclear. QUESTIONS/PURPOSES: We therefore asked: (1) What is the risk of infection in revision knee arthroplasty with large bone defects reconstructed with porous tantalum cones? (2) What is the rate of osseointegration with these cones? (3) What is the rate of loosening and reoperation? (4) Is knee function restored? METHODS: We retrospectively reviewed 27 patients who had 33 tantalum cones (nine femoral, 24 tibial) implanted during 27 revision knee arthroplasties. There were 14 women and 13 men with a mean age of 64.6 years. Preoperative diagnosis was reimplantation for infection in 13 knees, aseptic loosening in 10, and wear-osteolysis in four. Patients were evaluated clinically and radiographically using the score systems of the Knee Society and followed for a minimum of 2 years (mean, 3.3 years; range, 2-5.7 years). RESULTS: One knee with two cones was removed for infection. All but one cone showed osseointegration. One knee was revised for femoral cone and component loosening. There was one reoperation for femoral shaft fracture and one for superficial dehiscence. The mean Knee Society pain score improved from 40 points preoperatively to 79 points postoperatively. The mean function score improved from 19 points to 47 points. CONCLUSIONS: Our observations suggest metaphyseal fixation with tantalum cones can be achieved. Longer-term followup is required to determine whether the fixation is durable.

Second-generation modular acetabular components provide fixation at 10 to 16 years.

BACKGROUND: 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. QUESTIONS/PURPOSES: We asked the following questions: (1) Is the risk of revision surgery for loosening, wear, or liner dissociation low with the second-generation acetabular component? (2) Is the rate of pelvic osteolysis low? (3) Can the liner be exchanged without bone cement? METHODS: We retrospectively reviewed prospectively collected data from 99 patients (118 hips) undergoing THAs with one second-generation modular titanium acetabular component with routine screw fixation and conventional polyethylene. The minimum followup was 10 years (mean, 12 years; range, 10-16 years). We obtained Harris hip scores and examined radiographs for loosening and osteolysis. RESULTS: At last followup, all acetabular components were well fixed and no titanium shell had been revised or removed. No liner had dissociation. At most recent followup, the mean Harris hip score was 89. We observed pelvic osteolysis in eight hips (7%). There were three reoperations for dislocation (head-liner exchange only) and three loose femoral components revised. Two liners (at 11 and 14 years) were exchanged for wear-pelvic osteolysis. CONCLUSIONS: This second-generation modular titanium fiber-metal-coated acetabular component with screw fixation had no loosening, no liner dissociation, and a low rate of pelvic osteolysis at 10 to 16 years. Liner exchange is practical without use of cement. We continue to use this component with highly crosslinked polyethylene liners. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Results of a second-generation constrained condylar prosthesis in primary total knee arthroplasty.

This is a prospective study of the results of a second-generation modular constrained condylar knee (CCK) prosthesis in primary total knee arthroplasty. Of 418 consecutive total knee arthroplasties performed by 1 surgeon, a second-generation modular CCK prosthesis was indicated for intraoperative stability in 30 knees (7.2%). Three knees were lost to follow-up, and 27 knees had a mean follow-up time of 5.4 years (range, 2-11.5 years). All tibial components had a cemented 35-mm stem extension, and 26 femoral components had a 100-mm uncemented stem extension. The indication for use of the CCK components was most commonly severe valgus deformity and incompetent medial collateral ligament. There were no revisions for loosening, patella problems, or tibial post fracture. A lateral retinacular release of the patella was performed in 6 knees (22%). An asymptomatic, minimally displaced patella fracture was noted in 2 knees (7.4%). Constrained condylar knees are used infrequently now but are successful for the treatment of the unstable primary knee that cannot be balanced. These results may be design specific.

Beta-blocker prophylaxis for total knee arthroplasty patients: a case series.

Cardiac complications are an infrequent yet undesirable cause of morbidity and mortality following total knee arthroplasty. Perioperative prophylaxis with beta-blocker medication has been shown to reduce in-hospital cardiac deaths in noncardiac surgical patients. This study evaluated the safety and in-hospital cardiac complications of a consecutive cohort of 267 total knee arthroplasties in patients who followed a perioperative beta-blocker prophylaxis institutional protocol. The patients were categorized into three groups: A, already on a beta-blocker; B, beta-blocker prescribed by orthopaedic surgeon; and C, not given the medication. The 90-day mortality and in-hospital cardiac complications were evaluated. Of the patients who had 267 procedures, 203 (76%) received beta-blocker prophylaxis perioperatively: 110 (41.2%) were already on the medication preoperatively, 93 (34.8%) were prescribed the medication by the surgeon, and 64 (24%) did not receive this medication. There were no deaths within the first 90 days. There were two nonfatal myocardial infarctions (0.7%) and six other cardiac complications (2.2%). With a beta-blocker prophylaxis protocol implemented by one surgeon, 76% of total knee arthroplasty patients were given the medication and it was prescribed in 34.8% by the orthopaedic surgeon. In-hospital cardiac complications were low.

Tantalum components in difficult acetabular revisions.

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

Value of preoperative templating for primary total knee arthroplasty.

The value of preoperative templating for primary total knee arthroplasty (TKA) has recently been questioned. In our clinical practice, preoperative templating is valuable for sizing components and achieving optimal coronal alignment. We preoperatively templated the size of femoral and tibial components, the distal femoral valgus cut, and the proximal tibial cut for 200 primary TKAs. Preoperative templating predicted the exact size of 165 (82.5%) femoral and 159 (79.5%) tibial components, with 194 (97%) femoral and 185 (92.5%) tibial components templated to within one size used. Postoperative tibiofemoral alignment was within +/- 3 degrees of the goal alignment in 189 (94.5%) knees. Postoperative femoral and tibial component coronal alignment was within +/- 3 degrees of the goal coronal alignment in 190 (95%) and 199 (99.5%) knees, respectively. The accuracy of component sizing in this study is greater than previously reported. The prevalence of alignment outliers in this study is less than previously reported for conventional techniques.

Femoral head size and wear of highly cross-linked polyethylene at 5 to 8 years.

UNLABELLED: Wear of highly cross-linked polyethylene is reportedly independent of head size. To confirm that observation we asked in our population whether head size related to wear with one type of electron beam highly cross-linked polyethylene. Of 146 hips implanted, we evaluated complete clinical and radiographic data for 90 patients (102 hips or 70%). The minimum followup was 5 years (mean, 5.7 years; range, 5-8 years). The head size was selected intraoperatively based on the size of the acetabular component and presumed risk of dislocation. Polyethylene wear measurements were performed in one experienced laboratory using the method of Martell et al. There was no hip with pelvic or femoral osteolysis. The median linear wear rate was 0.028 mm/year (mean, 0.04 mm/year), and the median volumetric wear rate was 25.6 mm(3)/year (mean, 80.5 mm(3)/year). Median total volumetric wear was 41.0 mm(3) (mean, 98.5 mm(3)). We found no association between femoral head size and the linear wear rate, but observed an association between larger (36- and 40-mm) head size and volumetric wear rate and total volumetric wear. Although the linear wear rate of polyethylene was not related to femoral head diameter, there was greater volumetric wear (156.6 mm(3)/year) with the 36- and 40-mm heads. Pending long-term studies of large head sizes, we advise caution in using larger femoral heads in young or active patients and in those with a low risk of dislocation. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fifteen-year survival and osteolysis associated with a modular posterior stabilized knee replacement. A concise follow-up of a previous report.

We report the results of a consecutive series of total knee arthroplasties with use of a modular posterior stabilized prosthesis after a mean follow-up of twelve years (range, ten to eighteen years). In the five years since the original publication of our study, two additional knees were revised; one was revised for aseptic loosening and one, for polyethylene wear with tibial osteolysis. With mechanical failure as an end point, the fifteen-year survival was 96.8%. With failure defined as any reoperation, the fifteen-year survival was 90.6%. Osteolysis occurred in eight of the 117 knees with a minimum ten-year follow-up. With the relatively small number of subjects, no significant association was identified between polyethylene thickness or sterilization method and osteolysis. A significant association was identified between younger patient age and osteolysis. We continue to routinely implant a similar modular posterior stabilized total knee prosthesis.

Survival of polished compared with precoated roughened cemented femoral components. A prospective, randomized study.

BACKGROUND: The optimal surface finish for cemented femoral components remains controversial. The purpose of this randomized clinical trial was to compare the survival of two femoral components with similar geometry but substantially different surface finishes. METHODS: During a five-year period, 201 patients (219 hips) were prospectively randomized to be treated with a total hip arthroplasty with either a polished (Ra, 0.18 to 0.3 microm) or a precoated roughened (Ra, 1.8 to 2.3 microm) cemented femoral component with similar geometry. There were no significant differences between the patient groups in terms of age, sex, weight, preoperative diagnosis, component size, or cement grade. So-called third-generation cementing techniques were used. One hundred and thirteen polished components and 106 precoated roughened components were followed for a mean of 5.3 years. Complete clinical and radiographic data were available for 134 hips at a minimum of five years (mean, 6.1 years; range, five to ten years) postoperatively. RESULTS: In the entire cohort of 219 hips, there was no significant difference (log rank p = 0.66) in survival, with the end point defined as component removal for any reason or definite radiographic loosening, between the precoated components (96.2%; 95% confidence interval, 90.9% to 100%) and the polished components (97.1%; 95% confidence interval, 93.8% to 100%). There was a periprosthetic fracture in three hips with a polished component. Two precoated roughened components were revised because of loosening, and two polished components were revised: one because of loosening and one because of a nonunion of a periprosthetic fracture. There was no significant difference between the groups with regard to the Harris hip scores or the clinical results. There was also no significant difference with regard to the presence or number of bone-cement radiolucent lines. CONCLUSIONS: Kaplan-Meier survival analysis showed no significant differences between two types of cemented femoral components with similar geometry but substantially different surface finishes at seven years. In the patient population selected for treatment with a cemented femoral component, the surface finish may not be a crucial factor affecting component survival at a minimum of five years, provided that good cement technique is used.

Polyethylene wear and osteolysis with a new modular titanium acetabular component: results at 7 to 13 years.

The first-generation and second-generation modular titanium fiber-metal acetabular components were notable for high rates of pelvic osteolysis and liner dislodgment. This is a prospective, consecutive study of 111 new modular titanium-fiber metal acetabular components with a novel polyethylene locking mechanism at a mean follow-up of 9.5 years (range, 7-13 years). The polyethylene was gamma-irradiated in air in 58 hips and gamma-irradiated in nitrogen in 54 hips. No acetabular component migrated, none were revised, and there was no liner dislodgment. Pelvic osteolysis was seen in only 2 hips. The mean linear wear rate was 0.085 mm/y (range, 0.001-0.3 mm/y). There was a significantly lower rate of wear with polyethylene liners sterilized by gamma-irradiation in nitrogen (P = .0001). The high rate of success and low rate of polyethylene wear and pelvic osteolysis at this length of follow-up may be related to the new design features of this modular acetabular component.

Second-generation proximally coated titanium femoral component: minimum 7-year results.

It is unclear whether resurfacing or fully porous-coated or proximally coated stems are the best femoral components for young patients. First-generation proximally coated titanium fiber-metal femoral components had a high rate of failure. We prospectively followed 56 patients (70 hips) whom we believed were at high risk for loosening of a cemented femoral component; all patients were implanted with one second-generation proximally coated titanium femoral component. Ten patients (11 hips) died and three patients (four hips) were lost to minimum followup. Three models of titanium fiber-metal acetabular component were implanted with screws. Patients were clinically evaluated using the Harris hip score. We used standardized radiographs to assess fixation status and osteolysis. Forty-four patients (55 hips) with a mean age of 45 years were followed for a minimum of 7 years (mean, 10.5 years; range, 7-15 years). No femoral component had been revised for any reason. Bone ingrowth (spot welding) was seen in 41 hips (75%) and proximal femoral osteolysis in only four hips. Reoperations for polyethylene wear were performed in seven patients (12.7%) and two patients had liner exchange for recurrent dislocation. Even with an articulating surface with considerable polyethylene wear debris, these second-generation proximally coated titanium fiber-metal femoral components had a survival rate of 100% at a mean 10.5-year followup.