Lenca Steinert, Abstract Co-Author: Nothing to Disclose

Marco Zanetti MD, Abstract Co-Author: Nothing to Disclose

Christian W.A. Pfirrmann MD, Abstract Co-Author: Nothing to Disclose

Juerg Hodler MD, Abstract Co-Author: Research Consultant, Smith & Nephew plc Research Consultant, Bayer AG

Claudio Dora, Abstract Co-Author: Nothing to Disclose

Nadja Saupe MD, Presenter: Nothing to Disclose

The aim of this study was to assess the predicitive value of trochanteric contour irregularities on conventional radiographs for abductor tendon abnormalities diagnosed on MRI.

150 consecutive patients (age range 21-88 yrs, mean age 58.7 yrs, 57 m, 93 f) were included in this study. Conventional radiographs and MR imaging of the hip were performed within 180 days (range 0-174d, mean interval 32.7d). Trochanteric contour was graded on conventional radiographs as: normal, irregularities of 1-2 mm or irregularities >2mm by two readers independently. Abnormalities of gluteus minimus and medius tendon were analyzed (normal, tendinopathy, partial tear, full thickness tear), fatty muscle infiltration of gluteus medius and minimus was assessed, the absence/presence of fluid in the bursal complex of the greater trochanter (trochanteric bursa, subgluteus medius or minimus bursa), avulsion injuries and peritendinous fluid were assessed on MRI by two different panel readers independently and in consensus. For statistical analysis a logistic regression and Fishers exact test was used. Sens, Spec, Accuracy, PPV and NPV and positive likelihood ratio were calculated. For interobserver agreement a kappa statistic was used.

In 90.2% (PPV) of patients with contour irregularities >2mm on conventional radiographs patho-logic findings (tendinopathy or partial/full thickness tear) on MRI was found. Sensitivity was 40.2%, specitifity 93.7%, accuracy 60.6%, NPV 49.5% and positive likelihood ratio (pos LR) 6.2. 97% of patients with contour irregularities >2mm presenting peritendinous fluid on MRI (Sens 38.4%, Spec 97.8%, PPV 97.6%, NPV 41.3%, Acc 56.6% and pos LR 17.5). Interobserver agreement on MRI ranged between 0.51 -0.78 and was for detection of trochanteric irregularities on X-rays 0.73.

90% of patients with trochanteric countour irregularities >2mm on conventional radiographs presenting also pathologic findings of abductor tendons on MR imaging and 97% patients with trochanteric contour irregularities >2mm presenting peritendinous fluid on MRI.

If trochanteric contour irregularities >2mm on X-rays are present the possibility of occurance of abductor tendon abnormalities on MRI is 6 times higher and of peritendinous fluid 17 times higher.

Steinert, L, Zanetti, M, Pfirrmann, C, Hodler, J, Dora, C, Saupe, N, Association between Abductor Tendon Abnormalities and Trochanteric Contour Irregularities on Conventional Radiographs.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6019605.html