Custom Triflange Cups: 20-Year Experience.

BACKGROUND: The custom triflange acetabular component is used during revision THA to address severe acetabular bone loss. Midterm results are promising, with low rates of loosening and triflange revision reported. However, reoperation and overall complication rates remain high. We aim to investigate our institution's custom triflange experience over 20 years by evaluating implant survivorship, reoperations, complications, and clinical outcomes. METHODS: Prospectively collected data were reviewed for 50 patients undergoing revision THA with the use of a triflanged component from January 2000 to December 2018. 94% among these cases had a known outcome or minimum two year follow-up. Outcomes related to the triflange component were recorded, including revisions, reoperations, surgical complications, medical complications, Harris hip scores, and patient satisfaction. Phone interviews were conducted with patients whose recent follow-up exceeded 2 years. Radiographic review was performed to define implants as either stable or unstable. RESULTS: The average Harris hip scores improved 24 points (49 to 73; P < .001). 91% of eligible patients were satisfied at follow-up. One patient was scheduled for revision at an outside institution during the study period. There were 2 reoperations (1 acute infection and 1 screw removal). One patient died due to pulmonary thromboembolism. A Trendelenberg gait was present in 46% (23/50) of patients. There were 14 major complications (28%). Dislocation (12%) was the most common complication. CONCLUSION: Custom triflange components provide a reliable solution for managing complex acetabular defects in revision THA. Patients should be counseled on magnitude of surgery and the high incidence of complications, specifically infection and dislocation.

Results of the First U.S. FDA-Approved Hip Resurfacing Device at 10-Year Follow-up.

BACKGROUND: The BIRMINGHAM HIP Resurfacing (BHR) system is a metal-on-metal hip implant system approved by the U.S. Food and Drug Administration in 2006. The approval required a multicenter, prospective, post-market-approval study. Our purpose is to report the current results at 10 years of follow-up. METHODS: Between October 2006 and December 2009, 280 primary BHR procedures were performed at 5 sites. Outcome measures included Kaplan-Meier survivorship, reasons for revision, radiographic component stability and osteolysis, Harris hip scores, and metal levels including cobalt and chromium. The mean age at the time of the procedure was 51.3 ± 7.1 years, 74% (206) of 280 BHRs were implanted in male patients, the mean body mass index was 27.8 ± 4.4 kg/m2, and 95% (265) of 280 hips had a primary diagnosis of osteoarthritis. The mean follow-up among all 280 hips was 9.0 ± 2.5 years. Prior to 10-year follow-up, 20 hips were revised and 5 patients representing 5 hips had died. Among the remaining 255 hips, 218 (85%) met the minimum follow-up of 10 years. RESULTS: The 10-year survival free from all-cause component revision was 92.9% (95% confidence interval [CI], 89.8% to 96.1%) for all hips and 96.0% (95% CI, 93.1% to 98.9%) among male patients <65 years old at the time of the procedure. Reasons for revision included femoral loosening (n = 5), femoral neck fracture (n = 3), pseudotumor (n = 3), osteolysis (n = 2), and acetabular loosening (n = 1), as well as 6 revisions for a combination of pain, noise, or metal levels. Among unrevised hips, the median Harris hip score improved from preoperatively (59) to 1 year postoperatively (99; p < 0.001) and remained stable through 10 years postoperatively (99; p = 0.08). Radiographically, 5% (10) of 218 unrevised hips had osteolysis with no component migration. Median metal levels had increased at 1 year postoperatively (cobalt: from 0.12 ppb preoperatively to 1.5 ppb at 1 year postoperatively, p < 0.001; chromium: from 0.6 ppb preoperatively to 1.7 ppb at 1 year postoperatively, p < 0.001), then remained stable through 5 years before slightly decreasing at 10 years postoperatively (cobalt: 1.3 ppb, p < 0.001; chromium: 1.4 ppb, p < 0.001). CONCLUSIONS: This prospective, multicenter, post-market-approval study demonstrated that the BHR implant system is safe and effective through 10 years of follow-up, particularly among young male patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A lower threshold for revision of aseptic unicompartmental vs total knee arthroplasty.

AIMS: It has been hypothesized that a unicompartmental knee arthroplasty (UKA) is more likely to be revised than a total knee arthroplasty (TKA) because conversion surgery to a primary TKA is a less complicated procedure. The purpose of this study was to determine if there is a lower threshold for revising a UKA compared with TKA based on Oxford Knee Scores (OKSs) and range of movement (ROM) at the time of revision. METHODS: We retrospectively reviewed 619 aseptic revision cases performed between December 1998 and October 2018. This included 138 UKAs that underwent conversion to TKA and 481 initial TKA revisions. Age, body mass index (BMI), time in situ, OKS, and ROM were available for all patients. RESULTS: There were no differences between the two groups based on demographics or time to revision. The top reasons for aseptic TKA revision were loosening in 212 (44%), instability in 88 (18%), and wear in 69 (14%). UKA revision diagnoses were primarily for loosening in 50 (36%), progression of osteoarthritis (OA) in 50 (36%), and wear in 17 (12%). Out of a maximum 48 points, the mean OKS of the UKAs before revision was 23 (SD 9.3), which was significantly higher than the TKAs at 19.2 (SD 9.8; p < 0.001). UKA patients scored statistically better on nine of the 12 individual OKS questions. The UKA cases also had a larger pre-revision mean ROM (114°, SD 14.3°) than TKAs (98°, SD 25°) ; p < 0.001). CONCLUSION: At revision, the mean UKA OKSs and ROM were significantly better than those of TKA cases. This study suggests that at our institution there is a difference in preoperative OKS between UKA and TKA at the time of revision, demonstrating a revision bias. Cite this article: Bone Joint J 2020;102-B(6 Supple A):91-95.

The Lawrence D. Dorr Surgical Techniques & Technologies Award: "Running Two Rooms" Does Not Compromise Outcomes or Patient Safety in Joint Arthroplasty.

BACKGROUND: Scrutiny from the federal government and the media regarding the safety of 1 surgeon doing cases in 2 operating rooms (ORs) on the same day, prompted us to examine our own institutional data. Over the past 11 years, surgeons at our facility have operated consecutively in 1 OR on a given day or used 2 alternating ORs. This study compares these cases with a focus on revisions and complications in both groups. METHODS: Six surgeons performed a total of 16,916 primary hip and knee arthroplasties from 2006-2016. 7002 cases (41%) were consecutive cases (CCs) and 9914 cases (59%) were overlapping cases (OCs). Intraoperative complications, component revisions, and postoperative complications within 90 days of surgery were compared between the CC and OC groups. RESULTS: There was no difference in intraoperative complication rates between the two groups (CC 1.6% vs. OC 1.7%, relative risk 1.082, 95% confidence interval 0.852 to 1.375, P = .52). There was no difference in 90-day component revision rates among the CC and OC groups (0.66% vs. 0.85% respectively, relative risk = 1.290, 95% confidence interval 0.901 to 1.845, P = .19). There was also no difference in 90-day complication rates among the CC and OC groups (1.33% vs. 1.45% respectively, relative risk = 1.094, 95% confidence interval 0.844 to 1.417, P = .54). CONCLUSION: This large study of a single institution with multiple surgeons over an 11-year period shows no compromise in patient safety or outcomes when comparing cases done in either consecutive or overlapping rooms.

No Difference in Reoperations at 2 Years Between Ceramic-on-metal and Metal-on-metal THA: A Randomized Trial.

BACKGROUND: Hard-on-hard bearings for total hip arthroplasty continue to warrant analysis even though crosslinked polyethylene is performing very well. Ceramic-on-metal (CoM) has low in vitro wear and did well in an early clinical trial. We report on a prospective, randomized, multicenter investigational device trial comparing CoM with metal-on-metal (MoM). QUESTIONS/PURPOSES: (1) Is there a difference in the number or type of revisions comparing CoM with MoM? (2) Are cobalt and chromium metal levels different for CoM and MoM THA? METHODS: Between August 2005 and October 2006, of 1015 patients screened, 390 patients were enrolled at 11 centers and randomized to 194 CoM and 196 MoM bearings. There was no difference in the preoperative patient demographics between the study groups. Mean followup was 50 months (range, 22-75 months). Seventy-two patients from two centers had metal level analysis. RESULTS: With the numbers available, there was no difference in the proportion of patients undergoing revisions between the MoM and the CoM cohorts (MOM: 3% [six of 196]; COM: 1.5% [three of 194]; p = 0.50). Four MoM revisions were unrelated to the bearing surface. Two had bearing surface-related reoperations, one for an aseptic lymphocyte-dominated vasculitis-associated lesion and one for elevated metal levels with acetabular malposition. None of the CoM revisions were related to the bearing surface. The metal level analysis revealed that in contrast to the CoM, the MoM bearing group had increasing values of erythrocyte and serum cobalt from 1 to 5 years (CoM erythrocyte 0.45-0.55 ppb, p = 0.11 and CoM serum 0.88-0.85, p = 0.55, and MoM erythrocyte 0.32-0.51 ppb, p < 0.01 and MoM serum 0.65-1.01 ppb, p < 0.01). In addition, the MoM cobalt levels in erythrocytes and serum at 5 years were more variable than at 1 year (erythrocyte interquartile range [IQR], 0.26-0.44 to 0.31-1.21 ppb and serum IQR, 0.42-0.80 to 0.64-2.20 ppb, p < 0.02 for both). CONCLUSIONS: Although both bearings performed well at short-term followup, the CoM bearing group had no wear-related revisions and maintained consistently low metal levels. The MoM cobalt elevations may be important considering recent reports of taper corrosion. This CoM bearing was approved by the FDA but withdrawn from the market because of low sales. If it were available, the authors would not use CoM until long-term data were available. The bearing would have to outperform crosslinked polyethylene because it is unlikely that CoM metal levels will return to normal. LEVEL OF EVIDENCE: Level I, therapeutic study.

Short-term Results of Birmingham Hip Resurfacing in the United States.

Previous data on the survivorship of the Birmingham Hip Resurfacing (BHR) implant have come from design surgeons and large national databases outside of the United States, and there is a lack of reported outcomes of surface replacement arthroplasty from US centers. A retrospective study was undertaken of 1271 hips treated with a BHR system (Smith & Nephew, Memphis, Tennessee) between June 2006 and September 2008 at 6 high-volume total joint centers in the United States. Demographic features, Harris Hip Score (HHS), and radiographic findings were recorded. Patients who did not have a 2-year follow-up visit were contacted by telephone. All patients were asked about complications, reoperations, or failure of the implants. Of the treated hips, 1144 (90%) had a minimum of 2 years of clinical follow-up (mean, 2.9 years; range, 1.8-4.2 years). Mean age was 52.3 years, and 75% of patients were men. Mean HHS improved from 55.8 preoperatively to 97.4 at the most recent follow-up (P<.001). There were 16 (1.4%) revisions to total hip arthroplasty (THA) for fracture (7), early dislocation (3), acetabular component malpositioning with pain (3; 1 with metallosis), infection (1), femoral loosening (1), and pseudotumor (1). There were 9 additional complications (0.8%) that did not require revision, including 3 dislocations treated with closed reduction, 2 fractures, 3 nerve injuries, and 1 pseudotumor. At 2 to 4 years of follow-up, the revision rate and the major complication rate with the BHR system were similar to those in previous reports of primary THA. Excellent clinical results were observed, but further follow-up is necessary to assess mid- and long-term results with the BHR system in US patients.

Greater Trochanteric Fragmentation After Failed Metal-on-Metal Hip Arthroplasty.

Adverse reaction to metal debris (ARMD) involving the hip joint has emerged as an important reason for failure and revision among patients with metal-on-metal (MOM) hip arthroplasty. To the authors' knowledge, there are no reports of adverse radiographic sequelae in the greater trochanter subsequent to revision for ARMD. The authors describe clinical and radiographic findings in 2 patients who developed greater trochanteric fragmentation 1 to 2 years after conversion of their failed MOM hips to polyethylene bearings. Both patients had solid pseudotumors with tissue necrosis. Several reports describe various clinical features of ARMD. Although poor outcomes have been demonstrated after some MOM revisions, to the authors' knowledge, no reports document greater trochanter fragmentation in ARMD. The current patients highlight the fact that tissue damage occurring with MOM bearing hips can involve bone in addition to soft tissue even after a pseudotumor has been removed and serum metal levels have decreased to normal levels after revision. Unlike the greater trochanteric fractures historically associated with polyethylene wear and osteolysis, no evidence of bone cysts or lesions was found prior to the fractures and neither fracture healed with conservative treatment. For these 2 patients, the authors believe the tissue necrosis included both soft tissue and bone. The necrotic bone resorbed gradually after removal of the MOM bearing, resulting in bone fragmentation with ongoing symptoms. These patients emphasize and remind us that damage is not only limited to soft tissues, but also includes bone. Surgeons should be aware of this radiographic finding and the associated clinical symptoms.

Five year results of the first US FDA-approved hip resurfacing device.

A prospective, multi-center postmarket approval study has been ongoing since May 2006 to assess safety and efficacy of the first US FDA approved hip resurfacing implant. 265 patients have been enrolled at five study sites. The average age of the patients is 51.3 years. There have been 7 revisions (2.4%) in the cohort to date. K-M survival curves for the cohort are 97.6% at 5 years. There is a trend toward a gender difference in implant survivorship, with 98.6% of men and 94.7% of women free from revision. Metal ion analysis revealed median cobalt and chromium levels of 1.5 ppb and 1.7 ppb at 1 year. In this prospective US study, the Birmingham Hip Resurfacing implant is demonstrating results comparable to those in the literature.

Do young, active patients perceive advantages after surface replacement compared to cementless total hip arthroplasty?

BACKGROUND: Potential advantages suggested but not confirmed for surface replacement arthroplasty (SRA) over THA include lower frequency of limp, less thigh pain, less limb length discrepancy, and higher activity. QUESTIONS/PURPOSES: We therefore determined whether patients having SRA had a limp, thigh pain, or limb length discrepancy less frequently or had activity levels higher than patients having THA. METHODS: In a multicenter study, we surveyed 806 patients aged 18 to 60 years with a premorbid UCLA activity score of 6 or more who underwent hip arthroplasty for noninflammatory arthritis at one of five orthopaedic centers. Patients had either a cementless THA with an advanced bearing surface (n = 682) or an SRA (n = 124). The patients were demographically comparable. Specific telephone survey instruments were designed to assess limp, thigh pain, perception of limb length, and activity levels. Minimum followup was 1 year (mean, 2.3 years; range, 1.1-3.9 years). RESULTS: When controlled for age, sex, and premorbid activity level, patients with SRA had a higher incidence of complete absence of any limp, lower incidence of thigh pain, lower incidence of perception of limb length discrepancy, greater ability to walk continuously for more than 60 minutes, higher percentage of patients who ran after surgery, greater distance run, and higher percentage of patients who returned to their most favored recreational activity. CONCLUSIONS: When interviewed by an independent third party, patients with SRA reported higher levels of function with fewer symptoms and less perception of limb length discrepancy compared to a similar cohort of young, active patients with THA.

The effect of poly sterilization on wear, osteolysis and survivorship of a press-fit cup at 10-year followup.

BACKGROUND: 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. QUESTIONS/PURPOSES: At minimum 10-year followup, we asked whether the fixation achieved by solely relying on a press-fit would be durable and how different liner sterilization methods affected radiographic wear, osteolysis, and survivorship. PATIENTS AND METHODS: We retrospectively reviewed 373 patients who underwent 398 primary THAs with a press-fit porous-coated cup between March 1995 and December 1996. Mean age at time of surgery was 61.5 ± 13.3 years and mean followup was 10.4 ± 3.7 years. We determined reasons for revision, survivorship, femoral head penetration, osteolysis, and wear-related complications. RESULTS: Among 20 revisions involving any component, seven were associated with wear and osteolysis. Kaplan-Meier survivorship, using component revision for any reason as an end point, was 95.7% (95% confidence interval, 93.6%-97.9%) at 10 years. Noncrosslinked liners sterilized with gas plasma demonstrated a mean head penetration rate of 0.20 ± 0.09 mm/year compared with 0.13 ± 0.07 mm/year for liners sterilized with gamma irradiation in air and 0.09 ± 0.04 mm/year for liners sterilized with gamma-irradiation with barrier packaging without oxygen. THAs with increased volumetric wear tended to demonstrate larger osteolytic lesions (r = 0.40) and there tended to be less osteolysis among the liners sterilized with gamma-irradiation with barrier packaging without oxygen. However, there was no difference in survivorship among the sterilization groups and there has been no cup or stem loosening associated with osteolysis. CONCLUSIONS: Durable biologic fixation through 10-year followup can be achieved by solely relying on an initial press-fit. Noncrosslinking gas plasma for terminal sterilization of the polyethylene liners was associated with greater head penetration rate than gamma irradiation. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Polyethylene quality affects revision knee liner exchange survivorship.

BACKGROUND: Options to treat patients with wear or osteolysis include full revision, partial (tibial or femoral) revision, and isolated polyethylene exchange. It is unclear whether one choice is superior to the other. Polyethylene quality reportedly influences the survivorship of primary TKA, but similar reports are not described for revision TKA. QUESTIONS/PURPOSES: We compared the failure rate for the three procedures and the influence of polyethylene quality on failure. PATIENTS AND METHODS: We retrospectively evaluated 123 patients with 135 TKAs in which wear or osteolysis was thought to have contributed to the need for surgery. Twenty-five percent had an isolated polyethylene exchange, 39% a single-component revision, and 36% a full revision. We determined survivorship of the revisions. The mean follow-up for the 123 patients was 6.2 years. Fifteen patients (16 knees, or 12%) were lost before 5-year evaluations leaving 108 patients (119 knees, or 88%) for comparison of rerevision rates. RESULTS: Five-year survivorship was similar for all three procedures: 82% ± 14% for polyethylene exchange, 89% ± 8% for partial revision, and 88% ± 10% for a full revision. Polyethylene sterilization had the strongest influence on rerevision. Survivorship was 73% ± 16% for knees revised with gamma-in-air polyethylene compared to 92% ± 6% for nongamma or gamma-in-barrier sterilization methods. CONCLUSIONS: The survival rates of isolated polyethylene exchange for wear or osteolysis are similar to those of a single-component or full revision when the components are well aligned and well fixed. Polyethylene sterilization influenced revision TKA survivorship in this study and should be reported in future studies.

Do patients return to work after hip arthroplasty surgery.

Improvements in total hip arthroplasty implant design and advances in bearing materials, including modern surface arthroplasty, have resulted in these procedures being performed in younger and more active patients. There is limited information in the literature to provide to patients, employers, and insurance companies about returning to work after hip arthroplasty surgery. We conducted a multicenter telephone survey on 943 patients younger than 60 years with a University of California, Los Angeles, activity score of 6 or higher (regularly participates in moderate activities) who underwent hip arthroplasty surgery between 2005 and 2007 at a minimum of 1 year after surgery. We found that most young, active patients employed before surgery can expect to return to work (90.4%), with the vast majority returning to their preoperative occupation, and very few (2.3%) were limited in their ability to return to work because of their operative hip.

Survivorship of polyethylene liner exchanges performed for the treatment of wear and osteolysis among porous-coated cups.

For the past 17 years, we have favored treating patients with polyethylene wear and osteolysis by performing a liner exchange with retention of the old shell when possible. Using our institutional database, we identified 187 acetabular revisions in which we had retained the old shell. Among this group, we found 25 rerevisions. These included 10 for hip instability, 9 for cup loosening, 3 for recurrence of excessive wear or osteolysis, 2 for infection, and 1 for dissociation of the replaced liner. The need for rerevision varied with the different retained shell designs. We rerevised 17% of the total hip arthroplasties with old spiked shells, 21% with Arthropor shells, 13% with Triloc shells and 5% with Duraloc shells. Before making a decision to retain or remove a well-fixed old acetabular shell, we recommend consideration of the design's past track record and careful inspection of the condition of the existing shell.

A three-dimensional method for evaluating changes in acetabular osteolytic lesions in response to treatment.

UNLABELLED: The treatment of asymptomatic osteolysis among well-fixed cementless cups remains controversial. To compare the effectiveness of different treatment strategies, an objective technique for evaluating bone remodeling would be useful. By matching and comparing serial CT images with the aid of a computer-assisted imaging program, we developed a method to evaluate three-dimensional mineralization changes within osteolytic defects. Preoperative, immediate postoperative, and followup CT images were normalized based on a phantom with known densities and matched using image registration so that the same region could be analyzed on each image. New bone mineralization within the preoperative osteolytic lesion volume was quantified based on a patient-specific trabecular bone density threshold. As a pilot study, we applied this technique in 10 patients treated by polyethylene liner exchange with débridement and grafting of periacetabular osteolytic lesions using a calcium sulfate bone graft substitute. Relative to the preoperative osteolytic lesion volume, an average of 43% (range, 8%-72%) of each defect was filled with graft at revision. After resorption of the graft, an average of 24% (range, 9%-44%) of the original defect volume demonstrated evidence of new mineralization at 1-year followup. The amount of new mineralization was directly proportional (r(2) = 0.70) to the defect filling achieved at revision. CT-based image analysis offers an objective method for quantifying three-dimensional bone remodeling and can be used to evaluate the effectiveness of osteolysis treatment strategies. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Learning curve with minimally invasive unicompartmental knee arthroplasty.

This study examined 445 consecutive minimally invasive unicompartmental knee arthroplasties (UKAs) from one institution to determine whether revision and reoperation rates would decrease as the number of cases performed increased, indicating the presence of a learning curve with this procedure. At a mean of 3.25 years, 26 knees required revision yielding an overall revision rate of 5.8%; survivorship at 2 years with revision as an end point was 96% +/- 1.7%. Both revisions and reoperations decreased over time but not significantly. For the first half of UKA cases performed vs the second half, revision rates fell from 5.0% to 2.5%, and reoperation rates fell from 8.1% to 5.4%. These data demonstrate that despite modifications made to improve surgical technique across time, a substantial complication rate with this procedure persists.

Influence of stem size on clinical outcome of primary total hip arthroplasty with cementless extensively porous-coated femoral components.

This study retrospectively evaluated the clinical outcome of primary total hip arthroplasty as a function of stem diameter in 1545 patients implanted with extensively porous-coated stems. Less than 2% of femoral components were loose or revised; femoral survivorship was 97.9% at 15 years. Of patients with stable components, 95 to 97% had increased function, decreased pain, and overall satisfaction. Although 17% of patients indicated activity-limiting pain, only 3% were dissatisfied with the results of their hip arthroplasty. Logistic regression demonstrated no statistical relationship between stem size and either revision, loosening, pain, or satisfaction. We conclude that patients with large-diameter, extensively porous-coated femoral components are no more likely to be revised, loose, or have thigh or activity-limiting pain than patients with smaller diameter stems.

Computed tomography assessment of pelvic osteolysis and cup-lesion interface involvement with a press-fit porous-coated acetabular cup.

We used computed tomography to investigate the 3-dimensional pattern of expansile osteolysis that occurs with a modular cementless acetabular component incorporating a central hole. We measured pelvic osteolysis volume and evaluated how much of the porous-coated surface area was involved with osteolytic defects. Among the 34 total hip arthroplasties we studied, osteolysis almost always originated from the dome hole and typically expanded inferiorly or superiorly without involving the anterior or posterior surfaces of the cup. Larger-volume lesions generally involved greater amounts of the cup surface area, but the cup-lesion interface involvement plateaued at 40% for radiographically stable cups without clinical complications. We hypothesize that the plateauing surface area involvement may explain the absence of cup loosening among these cases despite the presence of large osteolytic lesions.

Can the volume of pelvic osteolysis be calculated without using computed tomography?

UNLABELLED: The most common method to diagnose and monitor osteolysis is the standard anteroposterior radiograph. Unfortunately, plain radiographs underestimate the incidence and extent of osteolysis. CT scans are more sensitive and accurate but also more expensive and subject patients to more radiation. To determine whether the volume of pelvic osteolysis could be accurately estimated without a CT scan, we evaluated the relationships between CT volume measurements and other variables that may be related to the size of pelvic osteolytic lesions in 78 THAs. Only the area of pelvic osteolysis measured on radiographs, heavy patient activity level, and total volume of wear were associated with the pelvic osteolysis volume measured on CT in the context of the multivariate regression analysis. Despite a strong correlation (r = 0.93, r(2) = 0.87) between these three variables and the volume of pelvic osteolysis measured on CT, estimates of pelvic osteolysis volume deviated from the actual volume measured on CT by more than 10 cm(3) among eight of the 78 THAs in this study. CT images remain our preferred modality when accurate assessments of pelvic osteolysis volume are required. LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Results of the anatomic medullary locking total hip arthroplasty at a minimum of twenty years. A concise follow-up of previous reports.

Between October 1982 and December 1984, the senior author performed 223 total hip arthroplasties in 215 patients with use of the anatomic medullary locking hip stem and TriSpike cup. We now report on 119 of these hips at a mean of 22.0 years (range, 20.0 to 25.0 years) after surgery. Of the fifty-six hips with minimum twenty-year follow-up radiographs and the original acetabular component, seventeen (30.4%) had pelvic osteolytic lesions measuring larger than 1.5 cm(2). Of the sixty-eight hips with twenty-year radiographs and the original anatomic medullary locking stem, twenty-five (36.8%) had femoral osteolytic lesions measuring larger than 1.5 cm(2). Acetabular osteolysis was significantly associated with cup loosening (p = 0.006), but the presence of femoral osteolysis was not associated with stem loosening. Kaplan-Meier analysis, with revision for any reason as the end point, revealed that the survival rate at twenty years was 85.8% +/- 5.2% for the acetabular shell and 97.8% +/- 2.2% for the stem. The most common reoperation was polyethylene exchange because of wear or osteolysis.