Our intention was to investigate if the highly porous biological fixation surfaces of a new 3D-printed total knee arthroplasty (TKA) achieved adequate fixation of the tibial and patellar components to the underlying bone. A total of 29 patients undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate and metal-backed patella. Patient-reported outcomes measures were recorded and implant migration was assessed using radiostereometric analysis.Aims
Patients and Methods
Uncemented highly porous titanium implants have been shown to promote osseointegration, and may result in a durable construct for total knee arthroplasty (TKA). Given the mixed results of uncemented TKA, it is important to evaluate the early stability for this product. The objective of the following study was to use radiostereometric analysis (RSA) to assess early fixation of a highly porous tibial baseplate and metal backed patella. Twenty-seven patients (mean age 64 years, 30% female) undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate, a metal backed patella and tantalum RSA bone markers. Implant migration was assessed using model-based RSA at 1.5, 3, 6, 12 and 24 months post-operative. Patient reported outcome measures were captured using the same follow-up schedule, and compared to pre-operative measures.Introduction
Methods
Radiostereometric Analysis (RSA) is a well developed imaging technique used to estimate implant fixation of orthopaedic implants in randomized clinical trials. The precision of RSA depends on a number of factors including image quality related to the individual modality properties. This study assesses the precision of RSA with a novel Digital Radiography (DR) system compared to a CR imaging system using different imaging techniques. Additionally, the study assesses the precision of locating beads embedded in a modified spine pedicle screw. A modified titanium spinal pedicle screw 4.5 mm diameter, 35 mm length, marked with two 1.0 mm tantalum beads, one inside the head and one near the screw tip was inserted into a bovine tibia segment. Six additional 1.0 mm tantalum beads were inserted into the bone segment – superiorly, distally and adjacent to the pedicle screw. The phantom was placed on a standard clinical diagnostic imaging bed above a custom RSA carbon fiber calibration cage (Halifax Biomedical Inc.). A pair of DR or CR imaging plates were placed below the calibration cage and irradiated 15 times at 100, 125 kV at 2.5 mAs. To determine precision, the standard deviation of 3D vector distances between beads was determined using RSA for each of the different imaging parameters.Purpose
Method
Radiostereometric Analysis (RSA) is an imaging method that is increasingly being utilized for monitoring fixation of orthopaedic implants in randomized clinical trials. Extensive RSA research has been conducted over the last 35+ years using standard clinical x-ray acquisition modalities that irradiate screen/film media or Computed Radiography (CR) plates. The precision of RSA can depend on a number of factors including modality image quality. This study assesses the precision of RSA with a novel Digital Radiography (DR) system compared to a CR imaging system using different imaging techniques. Additionally, the study assesses the precision of locating beads embedded in a modified spine pedicle screw.Introduction
Objective
