Metal ion release after hip resurfacing arthroplasty and knee arthroplasty: a retrospective study of one hundred ninety-five cases.

PURPOSE: Hip arthroplasty with metal-on-metal bearings like hip resurfacing results in the release of metallic ions. In parallel, like every metallic implant, knee arthroplasty implants undergo passive corrosion. We analyzed blood levels of cobalt and chromium ions in patients who have a hip resurfacing arthroplasty and compared them to patients who have undergone knee arthroplasty at a minimum follow-up of one year. The hypothesis was that there is no difference in the ion release between hip resurfacing and knee arthroplasty. METHODS: Sixty-three patients who underwent knee arthroplasty were compared to a cohort of 132 patients who underwent hip resurfacing. The blood levels of cobalt and chromium ions were determined preoperatively and at six and 12 months postoperatively and then compared between groups. We analyzed the relationship between ion release and the change in clinical outcome scores (Harris Hip score, Oxford Hip score, Merle D'Aubigné Postel score, Oxford Knee score, International Knee Society score), the BMI, sex, physical activity, implant size and inclination of the acetabular implant (hip resurfacing patients only). Mixed linear models were used to assess the changes in ion blood levels over time. RESULTS: The cobalt blood levels were higher in the first 6 months in the resurfacing group (0.87 ug/L vs 0.67 ug/L; p = 0.011), while it was higher in the knee arthroplasty group at 12 months (1.20 ug/L vs 1.41 ug/L; p = 0.0008). There were no significant differences in chromium levels during the follow-up period. CONCLUSION: The increase in metal ion release after knee arthroplasty is as high as after hip resurfacing at the one year follow-up. The monitoring of this parameter probably should not be recommended in case of good clinicals outcomes.

Association Between Potentially Inappropriate Medications and Frailty in the Early Old Age: A Longitudinal Study in the GAZEL Cohort.

OBJECTIVES: High-risk prescribing can have deleterious effects on the health of older people. This study aimed to assess the role of inappropriate prescribing on changes in frailty status over 3 years of follow-up. DESIGN, SETTING: This is a prospective observational study nested in the GAZEL cohort. PARTICIPANTS: The study sample included 12,405 community-dwelling people aged 58 to 73 in 2012, and followed for 3 years. MEASUREMENT: Polypharmacy and potentially inappropriate medications (PIMs) were assessed from reimbursement data by the French National Health Insurance. Frailty was evaluated each year with the Strawbridge questionnaire. PIMs were defined according to the Laroche list plus additional criteria dealing with inappropriate prolonged use of medications. The relationship between PIMs and changes in frailty status (incident frailty and recovery) was analyzed with Markov multistate modeling. RESULTS: The prevalence of frailty increased from 14% in 2012 to 17% in 2014, whereas the frequency of PIMs was 29% in 2012 and 23% in 2014. Polypharmacy (5-9 drugs: aHR 1.31, 95% CI 1.14-1.50; and 10 drugs or more: aHR 1.57, 95% CI 1.28-1.92) and potentially inappropriate use of nonsteroidal anti-inflammatory drugs (aHR 1.33, 95% CI 1.04-1.71) were significantly associated with incident frailty, when the presence of at least 1 PIM presented a small association with the risk of becoming frail (aHR 1.15, 95% CI 1.01-1.32). CONCLUSIONS/IMPLICATIONS: This study brings new elements to our knowledge regarding the association between inappropriate prescribing and frailty in older adults, which support research development to alert on inappropriate prescribing and to improve drug prescribing among old people, especially with polypharmacy.

Course of dislocated posterior hip arthroplasty: A continuous 232-patient series at a mean 10 years' follow up (range, 1-22 years).

BACKGROUND: Dislocation rates in posterior total hip arthroplasty (THA) range between 2% and 5%, but long-term course (recurrence of dislocation or revision surgery) is not known, most series having short follow-up or small populations. We therefore conducted a retrospective study on a large series, to determine long-term rates of recurrence and surgical revision and recurrence risk factors. HYPOTHESIS: Long-term follow-up of a large cohort of THA dislocations enables recurrence rate and factors to be determined. MATERIAL AND METHOD: Five hundred and nine cases of THA dislocation were admitted to our center between 1994 and 2008. A hundred and twenty seven incomplete files and 150 patients who had received their THA elsewhere were excluded, leaving 232 patients: 150 female, 82 male. Mean age at THA (163 primary, 69 revision) was 63 years (range, 15-90 years), and 65 years (range 20-90 years) at first dislocation, with a mean interval to dislocation of 25 months. Minimum follow-up was 8 years up to 2016, or 1 year taking account of deaths (111 deaths). There were 46 anterior, 185 posterior and 1 multidirectional dislocations. The following potential recurrence factors were assessed: gander, age, body-mass index (BMI), etiology, surgical history, bearing diameter and type, component fixation means, dislocation direction, and time to dislocation. RESULTS: A hundred and thirty three of the 232 patients (57%) showed at least 1 recurrence, at a mean 38 months (range, 0.5-252 months); 78 experienced a second and 32 a third recurrence. Ninety-nine (43%) had only 1 dislocation, without recurrence, but 17 of these (17%) underwent reoperation for other causes. The reoperation rate was 17/232 (7%) excluding recurrent instability, and 84/232 (36%) for instability. Fourty-eight months after the first dislocation, 84/133 cases of recurrence (63%) had been reoperated on: 16 complete replacements, 18 bearing replacements, 42 dual mobility cups, one large diameter cup, seven Lefèvre retentive cups. The rate of revision surgery for instability was high, at 84/232 (36%), and higher again in relation to recurrence (84/133: 63%). Only posterior dislocation emerged as a factor for recurrence (HR=1.774, 95% CI [1.020-3.083]), the other tested factors showing no correlation.14 of the 84 revision surgeries for instability (16.6%) were followed by recurrence, without identifiable risk factors. CONCLUSION/DISCUSSION: The recurrence rate was 57%, with posterior dislocation as the only risk factor. The rate of revision surgery for recurrence was 84/232 (36%), with 14/84 revision procedures (16.6%) followed by further recurrence. LEVEL OF EVIDENCE: IV, retrospective, without control group.