The correlation between activity level, serum-ion concentrations and pseudotumours in patients with metal-on-metal hip articulations and metal-on-polyethylene total hip articulations.

PURPOSE: Young and physically active patients have mainly received metal-on-metal (MoM) total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA). However, the correlation between daily physical activity (PA) levels, serum-ion concentrations of chromium and cobalt and pseudotumours formation of patients who underwent MoM THA/RHA is insufficiently explored. METHODS: Ninety-nine patients with 134 hip articulations, 71 MoM THA/RHA and 63 MoP THA participated in a cross-sectional study at XXX University Hospital, Denmark, at mean 7.3 (range: 0.4-21.7) years after surgery. Patients' daily PA was monitored during a two-week period using a triaxial accelerometer. Metal artefact reduction sequence magnetic resonance imaging scans, estimation of serum-ion concentrations of chromium and cobalt and the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire were completed on Day 14. RESULTS: Patients with a pseudotumour who underwent MoM THA/RHA had a higher average cadence of median 101.4 [interquartile range (IQR: 95.5-105)] steps/min than patients without a pseudotumor, median 96.7 (IQR: 92.2-103) steps/min (p = 0.02). Serum-ion concentrations of chromium and cobalt were higher in patients with a pseudotumour who underwent MoM THA/RHA, median 2.57 (IQR: 1.4-3.4) µg/L and 1.80 (IQR: 1.2-2.6) µg/L, respectively, than in patients without a pseudotumour, median 1.85 (IQR: 1.1-3.2) µg/L and 1.34 (IQR: 0.9-2.2) µg/L in MoM THA/RHA (p = 0.04 and p = 0.03). There was no statistical difference in these parameters between patients with and without a pseudotumour who underwent MoP THA. Daily PA levels of patients who underwent MoM THA/RHA were significantly correlated with serum-ion concentrations of chromium (p = 0.0002, r = 0.44) and cobalt (p = 0.005, r = 0.34), whereas no correlations were seen among patients who underwent MoP THA (p > 0.12). CONCLUSION: The daily PA level of patients who underwent MoM THA/RHA influences the serum-ion concentrations of chromium and cobalt and the risk of pseudotumour formation. TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Results of this article add important knowledge on potential recommendations of prosthesis selection for patients with a high level of physical activity.

Physical Activity Is Associated With the Level of Chromium but Not With Changes in Pseudotumor Size in Patients With Metal-on-Metal Hip Arthroplasty.

BACKGROUND: Metal-on-metal (MoM) total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA) were previously considered an excellent option for young and physically active patients. However, the relationship between MoM THA/RHA patients' daily physical activity (PA), metal ion measurements of chromium and cobalt, and pseudotumor dynamic is insufficiently explored. METHODS: One hundred eleven patients with 148 hip articulations, 77 MoM THA/RHA and 71 MoP THA, participated in a prospective cohort study, with 5 cross-sectional analyses during a 1-year follow-up. Baseline follow-up was at mean 7.1 (range: 0.2-21.5) years postoperative. At baseline and every 3 months thereafter, patients' daily PA was monitored during a 2-week period using a triaxial accelerometer, and next metal artifact reducing sequence magnetic resonance imaging scans, metal ion measurements of chromium and cobalt, and the Copenhagen Hip and Groin Outcome Score questionnaire were completed. RESULTS: We found a statistically significant relationship between daily PA and metal ion measurements of chromium at all follow-ups in MoM THA/RHA patients (P ≤ .03) but not in MoP THA patients (P > .35). Patients' daily PA was not related to changes in pseudotumor size at any follow-up (P > .30). Ten of 26 (38%) pseudotumors in MoM THA/RHA and 8 of 29 (28%) pseudotumors in MoP THA changed classification according to the Anderson grading. No pseudotumors transformed in appearance or changed anatomical location. CONCLUSION: The daily PA of MoM THA/RHA patients is associated with metal ion measurements of chromium but not with changes in pseudotumor size. This is new and important knowledge, which may be useful for hip surgeons in recommendation and monitoration of the consequences of PA in active patients with MoM THA/RHA.

Higher Prevalence of Mixed or Solid Pseudotumors in Metal-on-Polyethylene Total Hip Arthroplasty Compared With Metal-on-Metal Total Hip Arthroplasty and Resurfacing Hip Arthroplasty.

BACKGROUND: Pseudotumors are a common finding in metal-on-metal (MoM) total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA). However, information on pseudotumors in metal-on-polyethylene (MoP) THA is limited. METHODS: One hundred eleven patients with 148 hip articulations-30 MoM THA, 47 MoM RHA, and 71 MoP THA-participated in a cross-sectional study at mean 7.1 (range: 0.2-21.5) years postoperatively. Patients were evaluated with metal artifact reducing sequence magnetic resonance imaging, measurements of metal ions, clinical scores of Harris Hip Score, Oxford Hip Score, the Copenhagen Hip and Groin Outcome Score, and conventional radiographs. RESULTS: Pseudotumors were present in 13 of 30 (43%) MoM THA, 13 of 47 (28%) MoM RHA, and 29 of 71 (41%) MoP THA patients, which was a similar prevalence (P = .10). The prevalence of mixed or solid pseudotumors was significantly higher in patients with MoP THA (n = 10) compared to MoM THA (n = 3) and MoM THA (n = 0), (P = .01). Hips with a mixed or solid pseudotumor had significantly poorer scores of Harris Hip Score (P = .01) and OHS (P = .002) and higher metal ion levels of cobalt (P = .0009) compared to hips without a pseudotumor or with a cystic pseudotumor. CONCLUSION: Pseudotumors have primarily been associated with MoM hip articulations, but we found a similar pseudotumor prevalence in MoP THA, which is the most common bearing worldwide. Mixed or solid pseudotumors were more often seen in MoP THA compared with MoM hip articulations, and patients with a mixed or solid pseudotumor had poorer clinical scores and higher metal ion levels than patients without a pseudotumor or with a cystic pseudotumor.

Position emission tomography with or without computed tomography in the primary staging of Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVES: In order to receive the most appropriate therapy, patients with Hodgkin's lymphoma (HL) must be accurately stratified into different prognostic staging groups. Computed tomography (CT) plays a pivotal role in the conventional staging. The aim of the present study was to investigate the value of positron emission tomography using 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) and combined FDG-PET/CT for the staging of HL patients, and the impact on the choice of treatment. DESIGN AND METHODS: Ninety-nine consecutive, prospectively included patients had FDG-PET and CT in their staging work-up. Sixty-one of the 99 patients had combined FDG-PET/CT. A standard of reference for each nodal region and organ was determined using all available information including scan results, histology and a minimum of one year's clinical follow-up data. The lack of a satisfactory diagnostic gold standard limits the reliability of accuracy calculations. RESULTS: FDG-PET would have upstaged 19% of patients and downstaged 5% of patients, leading to a different treatment in 9% of patients. For FDG-PET/CT, the corresponding figures are 17%, 5%, and 7%. In nodal regions, the sensitivity of FDG-PET and FDG-PET/CT seemed higher than that of CT (92% and 92% vs. 83%). FDG-PET identified more false positive nodal sites than did CT and FDG-PET/CT (1.6% vs 0.7% and 0.5%). FDG-PET and FDG-PET/CT were highly sensitive for evaluating organs (86% and 73%) while CT detected 37% of involved organs. INTERPRETATION AND CONCLUSIONS: FDG-PET and FDG-PET/CT have a substantial potential impact on staging and choice of treatment and the methods tend to upstage rather than downstage patients. FDG-PET and FDG-PET/CT seem to have a higher diagnostic accuracy than CT in the staging of HL. However, care should be taken so patients with an excellent prognosis and at risk of over-treatment do not receive more intensive treatment because of these staging methods.