Background
Dual-mobility (DM) cups were introduced to minimize the risk of THA dislocation. The overall rate of dislocation of DM cups (including both large and small articulations) is controversial ...and ranges from 0% to 5% in previous studies.
Questions/purposes
We therefore recorded (1) the dislocation rate, (2) loosening and osteolysis, and (3) subsequent related revisions with DM cups.
Methods
Between 1998 and 2003, 2480 primary THAs with DM cups were undertaken in 2179 patients. The mean age was 69 years (range, 19–94 years). This group underwent specific clinical and radiographic evaluation at a minimum followup of 0.17 years (mean, 7 years; range, 0.17–11 years) to assess dislocation, reoperation, osteolysis, and cup fixation.
Results
There were 22 dislocations (0.88%): 15 dislocations of large articulations (0.6%), with two (0.08%) recurring but only one requiring revision (0.04%), and seven intraprosthetic small articulation dislocations (0.28%), all needing revision surgery. At last followup, mean Harris hip score was 91 (range, 60–100); 2439 cups (98%) showed no signs of loosening; and 141 patients (145 hips) had osteolysis (6%). Osteolysis and cup loosening were more frequent in patients younger than 50 years at the time of surgery. The 10-year survivorship considering revision for any reason was 93% (95% CI, 91%–95%).
Conclusions
DM cups had a low dislocation rate in primary THA, with a limited frequency of adverse effects. We recommend DM cups to minimize dislocation in populations at high risk for instability, but they should be avoided in younger, active patients at higher risk for osteolysis.
Level of Evidence
Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
Patient-reported outcome measures such as the Oxford-12 Hip Score and Hip Disability and Osteoarthritis Outcome Score (HOOS) are used in daily orthopaedic practice to evaluate patients. Because ...different studies use different scores, it would be important to build conversion tables between scores (crosswalk) to compare the results of one study with those of another study. Various mapping methods can be used to develop crosswalk tables that convert Oxford-12 scores to the HOOS (and its derivatives, including the HOOS physical function short form, HOOS joint replacement, and HOOS-12) and vice versa. Although prior studies have investigated this issue, they are limited to short forms of the HOOS score. Consequently, they cannot be applied to hip preservation surgery and do not include quality-of-life items, whereas the Oxford-12 Hip Score is used for all hip evaluations.
We prospectively studied the Oxford-12 and HOOS and its derivatives to (1) determine which version of the HOOS has the best mapping with the Oxford-12, (2) define the most-appropriate mapping method using selected indicators, and (3) generate crosswalk tables between these two patient-reported outcome measures.
The study enrolled 500 adult patients before primary THA (59% men 294 of 500 patients) with hip osteoarthritis or avascular necrosis of the femoral head who completed the HOOS and Oxford-12. Patients were recruited from January 2018 to September 2019 in a tertiary-care university hospital, and we included all primary THAs in patients older than 18 years with a BMI lower than 35 kg/m2 and greater than 18 kg/m2. After a minimum of 6 months of follow-up, 39% (195 of 500) of the patients were assessed using the same tools. To determine which version of the HOOS mapped best to the Oxford-12 and what the most-appropriate mapping method was, we used preoperative data from all 500 patients. Because there is no consensus on the method to establish crosswalk, various mapping methods (linear regression, tobit regression, and quantile regression) and equating methods (linear equating and equipercentile method) were applied along with cross-validation to determine which method was the most suitable and which form of the HOOS provided the best result according to different criteria (mean absolute error, r2, and Kolmogorov-Smirnov distance).To generate crosswalk tables, we created a conversion table (between the Oxford-12 and the HOOS form that was chosen after answering our first research question and the method chosen after answering our second question) using preoperative and postoperative data (n = 695). This table was meant to be simple to use and allows easy conversions from one scoring system to another.
The Oxford-12 and HOOS were strongly correlated (Pearson correlation coefficient range 0.586-0.842) for the HOOS subcategories and HOOS physical function, HOOS joint replacement, and HOOS-12. The correlation between the HOOS-12 and Oxford-12 was the strongest (r = 0.825). According to the three different criteria and five methods, the HOOS-12 was the best suited for mapping. The goal was to minimize the mean absolute error (perfect model = 0), have a Kolmogorov-Smirnov distance as close as possible to 0, and have the r2 as close as possible to 1. Regarding the most-suitable method for the crosswalk mapping (research question 2), the five methods generated similar results for the r2 (range 0.63-0.67) and mean absolute error (range 6-6.2). For the Kolmogorov-Smirnov distance, the equipercentile method was the best (Kolmogorov-Smirnov distance 0.04), with distance reduced by 43% relative to the regression methods (Kolmogorov-Smirnov distance 0.07). A graphical comparison of the predicted and observed scores showed that the equipercentile method provided perfect superposition of predicted and observed values after mapping. Finally, crosswalk tables were produced between the HOOS-12 and Oxford-12.
The HOOS-12 is the most complete and suitable form of the HOOS for mapping with the Oxford-12, while the equipercentile method is the most suitable for predicting values after mapping. This study provides clinicians with a reliable tool to crosswalk between these scores not only for joint arthroplasty but also for all types of hip surgeries while also assessing quality of life. Our findings should be confirmed in additional studies.
The resulting crosswalk tables can be used in meta-analyses, systematic reviews, or clinical practice to compare clinical studies that did not include both outcome scores. In addition, with these tools, the clinician can collect only one score while still being able to compare his or her results with those obtained in other databases and registries, and to add his or her results to other databases and joint registries.
Background
Despite widespread use of ceramic-on-ceramic (CoC) in total hip arthroplasty (THA) during the past 10 years, little is known about why revisions are performed in hips with this bearing or ...the time elapsed before revision.
Questions/purposes
The purposes of this study were: (1) Do the reasons for first revision differ between CoC bearings and other bearing couples? (2) Does the time to revision differ between CoC and other bearing couples? (3) Are there unique reasons for revisions of CoC bearings?
Methods
All members of the Société Française de Chirurgie Orthopédique et Traumatologique (SoFCOT) who performed ≥ 30 revisions per year were invited to participate in this multicenter, prospective, observational study. Our data represent 12% of the revision procedures performed in France. A total of 2107 first revisions of THA (from January 2010 to December 2011) were done in 2107 patients (1201 females 57% and 906 males 43%; median age, 73 years; age range, 17–104 years) at the time of surgery after a median of 11 years (range, 0 day–42 years) after the primary THA. There were 238 of 2107 (11%) CoC, 148 of 2107 (7%) metal-on-metal (MoM), and 1721 of 2017 (82%) metal-on-polyethylene (MoP) bearings.
Results
The reasons for reoperation differed according to the bearing component: (1) for the MoP reference bearing (odds ratio OR; 95% confidence interval), cup loosening occurred in 698 of 1721 hips (41%), periprosthetic fracture in 220 of 1721 hips (13%), and osteolysis in 213 of 1721 hips (12%); (2) for CoC, cup loosening occurred in 41 of 238 hips (17%) (OR, 0.31 0.22–0.43; p < 0.001), infection in 39 of 238 hips (16%) (OR, 1.63 1.12–2.37; p = 0.01), and dislocation in 23 of 238 hips (10%) (OR, 0.9 0.57–1.42; p = 0.9); (3) for MoM, cup loosening occurred in 28 of 148 hips (19%) (OR, 0.34 0.22–0.52; p < 0.001), adverse reaction to metallic debris in 26 of 148 hips (18%) (OR, 18.12 9.84–33.4; p < 0.001), and infection in 16 of 148 hips (11%) (OR, 1 0.59–1.73; p = 0.9). In comparison with MoP, osteolysis was rarely the reason for revision in CoC (four of 238 hips 2%; OR, 0.12 0.05–0.33; p < 0.001), but this bearing was frequently revised because of iliopsoas irritation (18 of 238 hips 8%; OR, 4.9 2.7–9; p < 0.001). The time elapsed before revision differed between bearings: median of 3 years (range, 3 days to 28 years) for CoC and 4 years (range, 14 days to 37 years) for MoM versus a median 13 years (range, 0 day to 42 years) for MoP (p < 0.001). Thirty-seven of the 238 revisions (16%) were directly related to ceramic use (ceramic breakage n = 23, squeaking n = 6, impingement n = 7, incorrect ceramic insert insertion n = 1). No factors were identified that contributed to breakage of the 12 bulk ceramic components (eight heads, four inserts, four of 12 Delta ceramic). No factors were associated with squeaking, iliopsoas irritation, or impingement, but component orientation was not assessed.
Conclusions
The reasons and time to first revision differed between CoC and other bearings. CoC THAs are revised earlier and are sensitive to mechanical problems such as impingement, squeaking, and ceramic rupture that did not disappear with introduction of Delta ceramics and large-diameter (≥ 36 mm) bearings. CoC was rarely revised for osteolysis, but a high rate of iliopsoas irritation requires further investigation.
Level of Evidence
Level III, therapeutic study.
Non-traumatic osteonecrosis (ON) of the femoral head is a common disease affecting a young population as the peak age of diagnosis is in the 40 s. The natural history of non-traumatic ON leads to a ...collapse of the femoral head requiring prosthetic replacement in a 60% of cases. Although trabecular bone involvement in the collapse is suspected, the underlying modifications induced at a molecular level have not been explored in humans. Here, we examine changes in the molecular composition and structure of bone as evaluated by Raman spectroscopy in human end-stage ON. Comparing samples from femoral heads harvested from 11 patients and 11 cadaveric controls, we show that the mineral and organic chemical composition of trabecular bone in ON is not modified apart from age-related differences. We also show that the molecular composition in the necrotic part of the femoral head is not different from the composition of the remaining 'healthy' trabecular bone of the femoral head. These findings support that quality of trabecular bone is not modified during ON despite extensive bone marrow necrosis and osteocyte death observed even in the 'healthy' zones on histological examination.
Background
Numerous reports of THAs in patients younger than 30 years indicate a high risk of revision. Although risk factors for revision have been reported for older patients, it is unclear whether ...these risk factors are the same as those for patients younger than 30 years.
Questions/purposes
We therefore (1) determined function and survivorship of revision THAs performed in patients younger than 30 years, and (2) assessed the risk factors for revision THAs in this younger population by comparison with a group of patients younger than 30 years who did not undergo revision.
Patients and Methods
We retrospectively reviewed the clinical records and radiographs of 55 patients younger than 30 years (average age at revision, 24.3 years; range, 14–30 years) who underwent 77 hip revisions. Revision was performed, on average, 4.6 years (range, 0.4–12 years) after the primary THA. The results for these 55 patients (77 revision THAs) were compared with results for a nonrevised group, including 819 THAs in patients younger than 30 years. Minimum followup of the revision group was 1 year (mean, 6.2 years; range, 1–15 years).
Results
At followup after the revision, the Merle d’Aubigné-Postel score improved from 12.2 to 14.6. The rates of dislocation, neurologic lesions, and fractures were 15%, 7.8%, and 14%, respectively. The 10-year survival rate was 36% (95% confidence interval CI, 21%–51%). Compared with the nonrevised group, the independent revision risk factors were young age at primary THA (OR 1.14 1.07–1.19), high number of previous surgeries (OR 5.41 2.67–10.98), and occurrence of at least one dislocation (OR 3.98 1.74–9.07). Hard-on-soft bearings had a higher risk (OR 3.42 1.91–6.1) of revision compared with hard-on-hard bearings.
Conclusions
Revision THAs are likely in patients younger than 30 years, and the complication rate is high. The survivorship of hip revision in this population is low and alternative solutions should be advocated whenever possible.
Level of Evidence
Level III, therapeutic study, case control study. See the Guidelines for Authors for a complete description of levels of evidence.
This study aimed to evaluate in vitro susceptibility to ceftobiprole of clinical strains identified from prosthetic joint infections (PJIs) compared to that of the associations currently recommended ...for post-operative empirical antibiotic therapy (PEAT) (vancomycin with either cefepime, third-generation cephalosporin or piperacillin-tazobactam).
We performed a 1-year retrospective study on all the surgical procedures performed in our hospital for PJI. Susceptibility profiles of all the strains cultured from surgical samples were reviewed to compare ceftobiprole to current used associations.
During the study period (from January 2018 to December 2018), we identified 106 patients managed for PJI and a total of 216 surgical interventions. One hundred-fifty strains were identified from intraoperative samples, excluding redundant strains. Staphylococcus spp. represented 52.7% of all strains and Enterobacteriales 13.3%. Twenty-three patients had polymicrobial infection (22%). Among 149 surgical procedures with positive culture results, ceftobiprole covered the bacterial strains in 138 (92.6%) cases. In comparison, this percentage was 94.6% for vancomycin plus cefepime (p = 0.64), 92.6% for vancomycin plus a third-generation cephalosporin in 138 cases (p = 1) and 94.6% for vancomycin plus piperacillin-tazobactam) (p = 0.64).
Based on antimicrobial susceptibility testing, our results suggest that ceftobiprole could be an interesting option for PEAT in PJIs, allowing the use of a single agent.
Background
Dual mobility (DM) cups of mobile polyethylene were introduced to prevent total hip arthroplasty (THA) dislocation, but no large series with this design to treat recurrent instability have ...been reported.
Purpose
Our retrospective investigation ascertained the efficiency of DM cups in correction of recurrent dislocation and assessed any adverse effects.
Methods
One hundred eighty THAs with recurrent instability were revised to DM cups in 180 patients (mean age, 67.4 ± 11.7 years; range, 19 to 92 years). Thirty-one patients (17.2%) underwent at least one earlier THA revision, and 15 (10.3%) incurred non-union of the greater trochanter. Of the initial group in 2009, 145 patients had completed evaluations which included assessment of the Harris Hip Score and a radiographic assessment at a mean follow-up of 7.7 ± 2.2 years (range, 4 to 14 years). The rate of survival was calculated considering any reason for revision as failure.
Results
At follow-up, Harris hip score was 83.9 ± 16.1 (range, 21 to 100). Dislocation of the large articulation occurred in seven hips (4.8%), and only two recurred (1.4%) (one requiring additional revision). In addition, two intra-prosthetic dislocations of the small articulation (1.4%) were observed and needed revision surgery. The large number of earlier surgeries and non-union of the greater trochanter were related to recurrent instability. Two cups (1.4%) showed signs of definite loosening; six (4.1%) presented signs of possible loosening. Twenty-nine hips manifested femoral or acetabular osteolysis (20%), but only three were severe. Eight-year survival rate considering revision for any reason was 92.6% (95% CI, 85.5–96.4%).
Conclusions
This series indicates that DM cups are a viable option to treat recurrent THA instability. Their design provides a low risk of recurrent instability without increasing mechanical complications.
Lateral wedge augmentation trochleoplasty (LWAT) was the earliest described trochleoplasty technique but was gradually replaced by other methods for the treatment of patello-femoral instability with ...trochlear dysplasia. Data on the outcomes of this procedure in adults are limited. We therefore performed a retrospective study in patients managed by LWAT to assess (1) clinical (recurrent instability and functional scores), (2) and radiological (patello-femoral osteoarthritis) outcomes.
LWAT is associated with a low long-term rate of recurrent patello-femoral dislocation and with no risk of progression to severe patello-femoral osteoarthritis.
Between 1988 and 1995, LWAT was performed on 66 knees in 58 patients to treat patello-femoral instability with trochlear dysplasia. Among them, 17 knees in 13 patients were re-evaluated 16 then 25 years after surgery and were included in the study. At both time points, the following were recorded: stability, pain, the Lille patello-femoral function score, and changes in radiographic and computed tomography findings. In addition to LWAT, Insall's realignment vastus medialis advancement was performed in 4 cases, sartorius muscle transposition in 9 cases, and anterior tibial tubercle osteotomy in 10 cases.
No episodes of patello-femoral dislocation were recorded during the 25-year follow-up. The mean Lille patello-femoral function score (0 worst to 100 highest) was 90±15 (range, 48–99) after 16 years and 86±23 (range, 33–94) after 25 years. After 16 years, 8/17 knees had evidence of patello-femoral osteoarthritis, which was Iwano stage 1 in 7 cases and Iwano stage 2 in 1 case. Patello-femoral osteoarthritis was noted in 12 of 13 knees after 25 years but was mild (Iwano stage 1 or 2) in 8 cases. After 25 years, arthroplasty had been performed for 4 of the 17 knees, with 2 cases each of patello-femoral arthroplasty and total knee arthroplasty.
LWAT is a reliable procedure that provides sustained protection against patello-femoral dislocation and good functional scores when used to treat patello-femoral instability due to trochlear dysplasia. Our results do not support claims that LWAT may be associated with high rates of severe osteoarthritis even after more than 20 years.
IV, retrospective observational study with no control group.
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