Overall staining scores of tenascin-C in the interface tissue from aseptic loosening of total hip replacement (THR): comparison of interface tissue (median score 4.0, quartiles 3.8 and 4.0) to control synovial tissue (median score 2.0, quartiles 2.0 and 2.0) and fibrous capsule (median score 2.0, quartiles 1.0 and 2.3) from primary total hip replacement (THR)