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Inter-surgeon variability in the identification of clock face landmarks when placing suture anchors in arthroscopic
Massimo Petrera1, Darrell J Ogilvie-Harris2, John S Theodoropoulos3
1Division of Orthopaedic Surgery, University of Ottawa, Ottawa, Canada.
Background:
The accuracy of surgeons in utilizing the clock face method for anchor placement has never been investigated. Our hypothesis was that shoulder arthroscopy surgeons would be able to place suture anchors at predetermined positions with accuracy and reliability.
Methods:
Ten cadaveric shoulders were used. Five fellowship-trained shoulder arthroscopy surgeons were directed to place a suture anchor at 3:30, 4:30, and 5:30 clock in two shoulders each. The position of the anchors was determined with computed tomography. The accuracy of placement was calculated and data analyzed with one-way analysis of variance. The intraclass correlation coefficients were calculated.
Results:
The overall accuracy was 57%. The accuracy of anchor placement at the 3:30 position was 40% (average position 2:24 o'clock), it was 50% at the 4:30 position (average position 3:42 o'clock) and 80% at the 5:30 position (average position 5:03 o'clock). No statistical difference in accuracy between the placement of the superior, middle, and inferior anchors (p = 0.145) was seen. The intraclass correlation coefficient for inter-surgeon reliability was 0.4 (fair) while the intraclass correlation coefficient for intra-surgeon reliability was 0.6 (moderate).
Discussion:
The findings of this study suggest a moderate degree of accuracy and fair to moderate inter- and intra-surgeon reliability when using the clock face system to guide anchor placement.