Extensor tendon ruptures have been reported in up to 8.8% of patients after volar plating and long screws have been implicated. The dihedral dorsal surface of the distal radius hinders accurate screw length determination using standard radiographic views (lateral; pronation and supination). A ‘dorsal tangential’ view has recently been described, but has not been validated. To validate this view, we mounted a plate-instrumented sawbone onto a jig. Radiographs at different angles were reviewed independently by 11 individuals. Skyline views clearly demonstrated all screw tips, whereas only 69% of screw tips were identifiable on standard views. With screws 2mm proud of the dorsal surface, skyline views detected 67% of long screws (sensitivity). The best of the standard views achieved only 11% sensitivity. At 4mm long, skyline sensitivity was 85%, compared with 25% for standard views. At 6mm long, 100% of long screws were detected on skylines, but only 50% of 8mm long screws were detected by standard views. Inter and intra-observer variability was 0.97 (p=0.005). For dorsal screw length determination of the distal radius, the skyline view is superior to standard views. It is simple to perform and its introduction should reduce the incidence of volar plate-related extensor tendon rupture.
We assessed a new knotless anchor system (Opus AutoCuff, ArthroCare Sports Medicine), which was designed to repair torn rotator cuffs. This knotless anchor winches cuff tissue into the bone with a mattress suture that is cinched into place without the need for knots. We reviewed patients who underwent arthroscopic repair with this technique with a minimum follow up of one year. This is prospective study of a consecutive series of the first one hundred patients who underwent arthroscopic cuff repair with the Autocuff system in 2005. Nine were lost to follow-up leaving ninety-one were available for review. All sizes of cuff tear were addressed and in all one hundred and eighty anchors were deployed. There were thirty seven men and sixty seven women with an average age of 69.4 years (range 36–85 years) Follow-up was by clinical assessment, cuff ultrasound and plain radiographs one year after surgery (12–20 months). Pain relief was described as good to excellent in 93% of patients and Constant scores improved by an average of 34 points with 48.5% being good to excellent, 39.4% fair and 12.1% poor. Nine anchors (5%) in eight patients had pulled out at one year, of which three were symptomatic. Suture repair poses varied points of weakness; loose knots, suture attrition and screw toggle all contribute to failure. We have shown that cuff repair by this method appears to be effective up to one year. It is important, however, to spread the tension of the repair with more than one anchor when treating larger tears.
Introduced in 2005, the Opus Magnum (Arthrocare) anchor has been used in our unit for repair of rotator cuff tears. It is a non-screw type anchor which relies on the deployment of wings locked in the subchondral bone. In order to evaluate whether these anchors migrate after implantation we undertook radiographic examination of their placement at intervals. We attempted to assess whether loss of fixation could be secondary to osteoporosis. Between 2005 and 2006, 106 patients (59 female, 47 male) aged 35–84 years (average age 62 years) underwent arthroscopic repair of rotator cuff tears with a total of 229 anchors. A review of radiographs taken at six weeks and 12 months post-insertion was undertaken. Cortical index of the proximal humeral diaphysis was measured from the AP radiograph indicating bone density; this involved measuring humeral width and medullary cavity diameter at a fixed point of 10cm below the greater tuberosity of the humerus. At six weeks follow-up there were no anchor pull-outs seen on radiographs. At 12 months follow-up 10 of the 229 anchors were found to have pulled out of the bone, equating to a failure rate of 4%. Of these seven of the 10 patients were asymptomatic. The average cortical index was found to be significantly lower in the failure group. Bone quality at the greater tuberosity of the humerus can be insufficient to withstand the tensions developed in newer anchor technology, leading to anchor migration. We present evidence that radiographs may be sufficient to influence the clinician’s choice of anchorage device. An economic estimation of bone density would be a helpful predictor of pull-out strength of suture anchors, essentially a low cortical index would indicate that these anchors are more likely to fail. A routine radiograph at 12 months would also identify the asymptomatic anchor failures.
