Biomechanical Study of Patellar Component Fixation with Varying Degrees of Bone Loss.

BACKGROUND: The decision as to whether or not to resurface the patella in revision total knee arthroplasty (TKA) is affected by the amount of patellar bone stock remaining; however, the impact of the cancellous bone status on patellar component fixation has not been studied. Therefore, we conducted a biomechanical study of patellar component fixation with varying degrees of cancellous bone loss. METHODS: Sixty pairs of cadaveric patellae were randomly assigned between 3 groups and prepared in similar manner to a TKA with the standard 3-hole configuration. A control patella and an experimental patella were designated in each pair. To simulate bone loss in the experimental patellae, 1, 2, and 3 of the standard drill holes were uniformly enlarged to 12 mm in group 1, group 2, and group 3, respectively. Afterward, an all-polyethylene patellar component was cemented to each patella, as done intraoperatively. Patellar components were then sheared off using a materials testing system. The resulting mean offset yield force was analyzed within each group using paired t-tests. RESULTS: The mean offset yield force for the control patellae was greater than the experimental patellae in group 1. In groups 2 and 3, the experimental patellae produced a greater mean offset yield force than the control patellae. Comparison within each group did not demonstrate a statistically significant difference. CONCLUSION: Bone loss with enlargement of the patellar fixation holes, as is frequently seen in revision TKA, with holes up to 12 mm, does not significantly decrease patellar component fixation shear strength in this biomechanical cadaveric study.

Reimbursement for Hip Fractures: The Impact of Varied Current Procedural Terminology Coding Using Relative Value Units.

BACKGROUND: Many orthopedic practices routinely code hip fracture hemiarthroplasty as Current Procedural Terminology (CPT) 27125 even though 27236 is the correct CPT code. Our objective is to determine the financial impact this simple mistake has on surgeon reimbursement. METHODS: Our data comprised cases assigned International Classification of Diseases, Tenth Revision code S72.001A through S72.035A and CPT code 27125 or 27236 within the American College of Surgeons National Surgical Quality Improvement Program 2016-2017 database. Relative value units (RVUs) per CPT code and the Centers for Medicare and Medicaid Services reported that RVU conversion factor of $36.0896 per 1 RVU was used to calculate reimbursement per case. The dollar difference and percent difference per case was then calculated between cases assigned CPT code 27125 and those assigned 27236. RESULTS: Our total sample consisted of 12,287 National Surgical Quality Improvement Program cases. Of those, 4185 (34%) were cases of a hip fracture treated with hemiarthroplasty that were incorrectly coded as CPT code 27125. That error in coding results in a decrease in reimbursement of $35.01 per case, a 5.51% difference. CONCLUSION: Since the current healthcare reimbursement model relies solely on CPT codes to determine RVUs, it is imperative that orthopedic surgeons understand the financial impact of incorrect coding. Although correct coding of hemiarthroplasty procedures for hip fractures is an easy task to fix in the future, we hope that through this study a greater emphasis is placed on coding in orthopedic surgery.

Novel Investigation of the Deep Band of the Lateral Plantar Aponeurosis and Its Relationship With the Lateral Plantar Nerve.

BACKGROUND: We describe a thick fascial band arising from the medial aspect of the lateral plantar aponeurosis diving deep into the forefoot crossing over a branch of the lateral plantar nerve. Because a review of current literature resulted in limited and outdated sources, we sought to first determine the frequency of this fascial band and the location where it crosses the lateral plantar nerve and, second, discuss the clinical applications these anatomical findings could have. METHODS: 50 pairs of cadaveric feet (n = 100) were dissected to investigate for presence of the fascial band and its interaction with the lateral plantar nerve. Images were taken of each foot with the fascial band. ImageJ was used to take 2 measurements assessing the relationship of the tuberosity of the base of the fifth metatarsal to where the nerve crossed deep to the fascial band. RESULTS: Overall, 38% of the feet possessed the fascial band. It was found unilaterally in 10 pairs and bilaterally in 14 pairs. On average, the point at which the lateral plantar nerve passed deep to the fascial band was 2.0 cm medial and 1.7 cm anterior to the tuberosity of the base of the fifth metatarsal. CONCLUSION: When present, the deep band of the lateral plantar aponeurosis (PA) was consistently found to be crossing the lateral plantar nerve. The discovery of the location where this most commonly occurs has not been previously reported and adds an interesting dimension that elevates an anatomical study to one that has clinical potential. CLINICAL RELEVANCE: The established target zone gives a precise location for where the relationship between the deep band of the lateral PA and the lateral plantar nerve exists when evaluating the foot. The target zone provides a potential springboard for future investigations concerning said relationship clinically.