The prevalence of adverse reactions to metal debris (ARMD) associated with metal on metal (MoM) hip arthroplasty has been reported to be as high as 69%. Such findings promoted the development of metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) classifications, with the aim of stratifying soft lesions by severity of disease. The Modified Oxford Classification is a straightforward system that has been shown to correlate with disease progression. The aim of this study was to test the reliability of this classification between observers. Seven observers were recruited, all with a musculoskeletal background. Using the PACS image analysis system, 20 MARS-MRI scans were provided for interpretation. Observers reviewed these scans in random order at two separate intervals over the course of five weeks. They classified them according to the Modified Oxford Classification as: ‘normal’, ‘trochanteric fluid, ‘effusion’, ‘ARMD type 1’, ‘ARMD type 2’ and ‘ARMD type 3’.Introduction
Methods
Proximal Femoral Nail Antirotation (PFNA) I one of the implants commonly used to stabilise subtrochanteric fractures or communited inter/pertrochanteric fractures. The aim of this project was to assess the outcome of PFNA in a busy District General Hospital. Between November 2009 to November 2012, 76 patients underwent PFNA. These patients were identified from the local hip fracture database, which is prospectively collected. The mean age of the patients was 80.11 years (range of 26.83 to 98.53). 27 were male and 49 female. Right hip was involved in 36 cases and left hip in 40. 9 patients required revision surgery due to failure of the primary surgery. 2 patients died due to other causes. 5 out of the 9 patients who underwent revision surgery had their primary surgery performed by a trainee under consultant supervision and a consultant surgeon performed the other 4 cases. In our series failure rate was 11.8%. We conclude that although PFNA is an excellent device to fix subtrochanteric or communited intertrochanteric fractures of the proximal femur one needs to be cautious and follow the correct operative technique to avoid failures.
We investigated the changes seen on serial metal
artefact reduction magnetic resonance imaging scans (MARS-MRI) of
metal-on-metal total hip arthroplasties (MoM THAs). In total 155
THAs, in 35 male and 100 female patients (mean age 70.4 years, 42
to 91), underwent at least two MRI scans at a mean interval of 14.6
months (2.6 to 57.1), at a mean of 48.2 months (3.5 to 93.3) after
primary hip surgery. Scans were graded using a modification of the
Oxford classification. Progression of disease was defined as an
increase in grade or a minimum 10% increase in fluid lesion volume
at second scan. A total of 16 hips (30%) initially classified as
‘normal’ developed an abnormality on the second scan. Of those with
‘isolated trochanteric fluid’ 9 (47%) underwent disease progression,
as did 7 (58%) of ‘effusions’. A total of 54 (77%) of hips initially
classified as showing adverse reactions to metal debris (ARMD) progressed,
with higher rates of progression in higher grades. Disease progression
was associated with high blood cobalt levels or an irregular pseudocapsule
lining at the initial scan. There was no association with changes
in functional scores. Adverse reactions to metal debris in MoM THAs
may not be as benign as previous reports have suggested. Close radiological
follow-up is recommended, particularly in high-risk groups. Cite this article:
The PFNA is used routinely at the RUH for unstable peri-trochanteric and femoral fractures. Failure of operative treatment is associated with increased morbidity and financial burden. We analysed surgical and fracture factors, aiming to identify those associated with fixation failure. Retrospective analysis of 76 consecutive patients treated with a PFNA between 2009–2012 was performed. Patient demographics were assessed, along with fracture classification, adequacy of reduction, tip apex distance (TAD) and grade of surgeon. Failure was defined as metal work failure, non-union or need for repeat procedure. The mean age was 78.9 years (25.9–97.4). 21 were male and 49 female. There were 17 failures (24.3%) (7 required further surgery). 10 failures were per-trochanteric, 2 sub-trochanteric and 5 mid-shaft fractures. Complications included 4 broken and 6 backed-out distal locking screws, 2 blade cut-outs, 1 nail fracture and 4 non-unions. All per-trochanteric were adequately reduced with a TAD <25 mm. 11/17 had consultant supervision. A high rate of backed-out distal locking screws was identified. We found no concerns with adequacy of reduction, TAD or consultant supervision.
