Statistical Validation of the Grand Rapids Arch Collapse Classification

Transcription

1 Statistical Validation of the Grand Rapids Arch Collapse Classification David Burkard, BS Michelle Padley, CRTM John Anderson, MD Donald Bohay, MD John Maskill, MD Daniel Patton, MD Orthopaedic Associates of Michigan Grand Rapids, MI

2 Disclosure NO CONFLICT TO DISCLOSE Statistical Validation of the Grand Rapids Arch Collapse Classification David Burkard, BS Michelle Padley, CRTM John Anderson, MD Donald Bohay, MD John Maskill, MD Daniel Patton, MD Our disclosures are in the AOFAS mobile app. We have no potential conflicts with this presentation.

3 Introduction The Grand Rapids Arch Collapse Classification (GRACC) was devised as a tool for describing the mechanism of adult acquired flat foot and the pathologies associated with it types corresponding to the portion of the foot/ankle that are affected Gastrocnemius, forefoot, midfoot, hindfoot, ankle Intended to build upon the posterior tibial tendon dysfunction classification system 4-6. Simplistic design with potential for easy reproducibility Must be statistically validated with determination of reproducibility

4 Introduction Table 1. Grand Rapids Arch Collapse Classification Characteristics. This table demonstrates the various pathologies associated with each type of deformity along with the biomechanics driving the deformity.

5 Methods A priori power analysis determined 50 clinical cases needed to achieve significance 10 cases of each deformity type were randomly chosen from the extensive clinic EMR Cases were standardized to include de-identified pre-treatment radiographs (weight bearing AP, lateral foot, AP and lateral ankle views), pain location, and comorbid foot and ankle-specific conditions 26 physicians of varying experience completed the test at baseline 13 of these physicians completed the test again 8 weeks later Independent statistics group determined cohen s kappa for inter-rater and intra-rater reproducibility 7

6 Methods Figure 1. Example Test Question. Example of physical exam findings, pain location, and X-rays as presented to each physician.

7 Results Deformity Type [Kappa] value [Kappa] value Level of agreement I II III IV V Average Near perfect Substantial Moderate Fair Slight Table 2. Inter-rater reproducibility for each deformity type. Table 3. Level of agreement at different [kappa] values as recommended by Landis and Koch 8

8 Results [Kappa] value Level of agreement Near perfect Substantial Moderate Fair Slight Table 4. Intra-observer reproducibility for all 13 physicians who completed the test at baseline and at 8 weeks. Table 3. Level of agreement at different [kappa] values as recommended by Landis and Koch 8

9 Discussion GRACC provides an updated explanation for the biomechanics behind adult acquired arch collapse There is substantial inter-rater agreement between physicians of various experience levels There is also substantial intra-rater agreement This study, thus, demonstrates that the GRACC can be used as a beneficial tool among physicians when evaluating and treating adult acquired arch collapse

10 References 1. Anderson JG, Bohay DR, Eller EB, Witt BL. Gastrocnemius Recession. Foot Ankle Clin N Am 19: , Habbu R, Holthusen SM, Anderson JG, Bohay DR. Operative Correction of Arch Collapse With Forefoot Deformity: A Retrospective Analysis of Outcomes. Foot Ankle Intl. 32(8): , Maskill JD, Bohay DR, Anderson JG. Gastrocnemius recession to treat isolated foot pain. Foot Ankle Int. 31(1):19 23, Beals TC, Pomeroy GC, Manoli A. Posterior tibial tendon insufficiency: diagnosis and treatment. Journal of the American Academy of Orthopaedic Surgeons. 7(2):112-18, Johnson KA, Strom DE. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res. 239: , Myerson MS. Adult acquired flatfoot deformity: Treatment of dysfunction of the posterior tibial tendon. Instr Course Lect. 46: , Cohen J. A coefficient of agreement for nominal scales. Educational and Psychological Measurement. 20:37-46, Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics 1977;33:159 74