Moritz M. Innmann

Sports and physical activity after cementless total hip arthroplasty with a minimum follow‐up of 10 years

The present retrospective cohort study was conducted to compare sporting activity levels before and a minimum of 10 years after primary cementless total hip arthroplasty (THA). A consecutive series of 86 patients with a mean age at surgery of 52 years (range, 21–60 years) was evaluated 11 years after surgery (range, 10–12 years). Pre‐ and post‐operative sporting activities were assessed at routine follow‐up using the University of California, Los Angeles activity score and the Schulthess Clinic sports and activity questionnaire. Post‐operative health‐related quality of life was measured using the Short‐Form 36 (SF‐36) questionnaire and compared with age‐matched reference populations from the SF‐36 database. Eleven years after THA, 89% of preoperatively active patients had returned to sport. Comparing sports activity preoperatively (before the onset of symptoms) and 11 years after THA, no significant difference was found for the mean number of disciplines or session length. A significant decline in high‐impact activities was observed, while participation in low‐impact activities significantly increased. Health‐related quality of life compared well against a healthy age‐matched reference population and was significantly higher than in a reference group of patients with osteoarthritis. The majority of patients were able to maintain their physical activity level in the long term after primary cementless THA, compared with the activity level before the onset of restricting osteoarthritis symptoms. However, a change in disciplines toward low‐impact activities was observed.

Early Migration Predicts Aseptic Loosening of Cementless Femoral Stems: A Long-term Study

BackgroundExcessive early migration of cemented stems and cups after THA has been associated with poor long-term survival and allows predictable evaluation of implant performance. However, there are few data regarding the relationship between early migration and aseptic loosening of cementless femoral components, and whether early migration might predict late failure has not been evaluated, to our knowledge. Einzel-Bild-Röntgen-Analyse-femoral component analysis (EBRA-FCA) is a validated technique to accurately measure axial femoral stem migration without the need for tantalum markers, can be performed retrospectively, and may be a suitable tool to identify poor performing implants before their widespread use.Questions/purposesWe asked: (1) Is axial migration within the first 24 months as assessed by EBRA-FCA greater among cementless stems that develop aseptic loosening than those that remain well fixed through the second decade; (2) what is the diagnostic performance of implant migration at 24 months postoperatively to predict later aseptic loosening of these components; and (3) how does long-term stem survivorship compare between groups with high and low early migration?MethodsWe evaluated early axial stem migration in 158 cementless THAs using EBRA-FCA. The EBRA-FCA measurements were performed during the first week postoperatively (baseline measurement) and at regular followups of 3, 6, and 12 months postoperatively and annually thereafter. The mean duration of followup was 21 years (range, 18–24 years). The stems studied represented 45% (158 of 354) of the cementless THAs performed during that time, and cementless THAs represented 34% (354 of 1038) of the THA practice during that period. No patient enrolled in this study was lost to followup. Multivariate survivorship analysis using Cox’s regression model was performed with an endpoint of aseptic loosening of the femoral component. Loosening was defined according to the criteria described by Engh et al. and assessed by two independent observers. Patients with a diagnosis of prosthetic joint infection were excluded. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance of axial stem migration 1, 2, 3, and 4 years postoperatively as a predictor of aseptic loosening. Survivorship of hips with high (≥ 2.7 mm) and low (< 2.7 mm) migration was compared using a competing-events analysis.ResultsFemoral components that had aseptic loosening develop showed greater mean distal migration at 24 months postoperatively than did components that remained well fixed throughout the surveillance period (4.2 mm ± 3.1 mm vs 0.8 mm ± 0.9 mm; mean difference, 3.4 mm, 95% CI, 2.5–4.4; p ≤ 0.001). Distal migration at 24 months postoperatively was a strong risk factor for aseptic loosening (hazard ratio, 1.98; 95% CI, 1.51–2.57; p < 0.001). The associated overall diagnostic performance of 2-year distal migration for predicting aseptic loosening was good (area under the ROC curve, 0.86; 95% CI, 0.72–1.00; p < 0.001). Sensitivity of early migration measurement was high for the prediction of aseptic loosening during the first decade after surgery but decreased markedly thereafter. Stems with large amounts of early migration (≥ 2.7 mm) had lower 18-year survivorship than did stems with little early migration (29% [95% CI, 0%–62%] versus 95% [95% CI, 90%–100%] p < 0.001).ConclusionsEarly migration, as measured by EBRA-FCA at 2 years postoperatively, has good diagnostic capabilities for detection of uncemented femoral components at risk for aseptic loosening during the first and early second decades after surgery. However, there was no relationship between early migration patterns and aseptic loosening during the late second and third decades. EBRA-FCA can be used as a research tool to evaluate new cementless stems or in clinical practice to evaluate migration patterns in patients with painful femoral components.Level of EvidenceLevel III, diagnostic study.

Comparable Cumulative Incidence of Late Periprosthetic Femoral Fracture and Aseptic Stem Loosening in Uncemented Total Hip Arthroplasty—A Concise Follow-Up Report at a Minimum of 20 Years

BACKGROUND There is a lack of long-term studies into the third decade reporting on the incidence of periprosthetic femoral fracture (PPFF) and aseptic stem loosening (ASL) after cementless total hip arthroplasty (THA). The aim of the present retrospective, longitudinal cohort study was to compare the cumulative incidence of PPFF and ASL in a consecutive cohort of 326 patients with 354 primary uncemented THAs after 20-25 years and to identify risk factors being associated with PPFFs. METHODS Postoperative femoral fractures were investigated for timing, mechanism of injury, Vancouver classification, and subsequent treatment. The cumulative incidence of PPFF and ASL was estimated using Kaplan-Meier survival analysis. Risk factors for PPFFs were analyzed using a Cox proportional hazards regression model. RESULTS One hundred sixty-three patients (180 hips) were available for follow-up at a mean of 22 years. Twenty-one fractures occurred during the follow-up period. The cumulative incidence of PPFF was 1.6% at 10 years, 4.5% at 17 years, and 9.4% at 22 years after surgery. The cumulative incidence of PPFF and ASL after 22 years was comparable (9.4% [95% confidence interval, 5.9%-14.7%] and 6.9% [95% confidence interval, 4.5%-10.5%]). Gender, age at surgery, diagnosis, cup revision, and canal fill index of the stem in the proximal femur were no risk factors for the occurrence of a PPFF. CONCLUSION The cumulative incidence of PPFF after primary uncemented THA further increased in the second decade and reached the incidence of ASL in the third decade, while no risk factors for the occurrence of a PPFF could be identified.

Cumulative Long-Term Incidence of Postoperative Periprosthetic Femoral Fractures Using an Uncemented Tapered Titanium Hip Stem: 26- to 32-Year Results.

BACKGROUND Although falling is becoming a major problem in the elderly, little is known about the long-term incidence of postoperative periprosthetic femoral fractures (PFF) after total hip arthroplasty (THA) using uncemented stems with a minimum follow-up of 26 years postoperatively. METHODS In a consecutive series, the cumulative incidence of PFF after uncemented THA using a straight, collarless, tapered titanium stem was retrospectively reviewed in 354 hips (326 patients). After a mean follow-up of 28 (26-32) years postoperatively, 179 hips had died and 5 hips had been lost to follow-up. Kaplan-Meier survival analysis was used to estimate cumulative percentage probability of PFF. RESULTS At final follow-up, a total of 27 fractures in 27 patients had occurred. In 15 hips, the stem had to be revised, and in 10 the fracture was treated by open reduction and internal fixation. Two patients declined further surgery. The cumulative percentage probability of PFF was 1.6% (95% confidence interval, 0.7 to 3.8) at 10 years and 13.2% (95% confidence interval, 8.5 to 20.2) at 29 years after primary THA. There was no association between the occurrence of fracture and gender, age at primary THA, cup revision, or canal fill index. CONCLUSION Our findings indicate that PFF is the major mode of failure in the long term after uncemented THA using a tapered titanium stem. More research is needed to evaluate the reasons and risk factors for PFF after THA, thus providing better prophylaxis for those at risk and to compare the long-term incidence using different fixation methods and implants. LEVEL OF EVIDENCE IV.