Conversion Total Knee Arthroplasty After Failed Osteochondral Allograft Reconstruction: Similar Functional Performance With Lower Patient Satisfaction.

BACKGROUND: This study presents surgical techniques used in conversion total knee arthroplasty (cTKA) following early failure of large osteochondral allograft joint replacement and compares postoperative patient reported outcomes measures (PROMs) and satisfaction scores with a contemporary primary total knee arthroplasty (pTKA) cohort. METHODS: We retrospectively evaluated 25 consecutive cTKA patients (26 procedures) to define the utilized surgical techniques, radiographic disease severity, preoperative and postoperative PROMs (visual analog scale [VAS] pain, knee injury and osteoarthritis outcome score for joint replacement [KOOS-JR], University of California Los Angeles Activity), expected improvement and postoperative satisfaction (5-point Likert), and reoperations in comparison with an age and body mass index propensity matched cohort of 50 pTKA performed for osteoarthritis (52 procedures). RESULTS: Revision components were used in 12 cTKA cases (46.1%), with 4 cases requiring augmentation (15.4%), and 3 cases utilizing varus-valgus constraint (11.5%). While no significant differences were noted in expectation level or in other PROMs, mean patient reported satisfaction was lower in the conversion group (4.4 ± 1.1 versus 4.8 ± 0.5 points, P = .02). High cTKA satisfaction was associated with a higher postoperative KOOS-JR (84.4 versus 64.2 points, P = .01) and a trend towards higher University of California Los Angeles activity (6.9 versus 5.7 points, P = .08). Four patients in each group underwent manipulation (15.3 versus 7.6%, P = .42), and 1 pTKA patient was treated for early postoperative infection (0 versus 1.9%, P = 1.0). CONCLUSION: cTKA following failed biological replacement was associated with similar postoperative improvement as in pTKA. Lower patient-reported cTKA satisfaction was associated with lower postoperative KOOS-JR scores.

The porcine accessory carpal bone as a model for biologic joint replacement for trapeziometacarpal osteoarthritis.

Given its complex shape and relatively small size, the trapezium surface at the trapeziometacarpal (TMC) joint is a particularly attractive target for anatomic biologic joint resurfacing, especially given its propensity to develop osteoarthritis, and the limited and sub-optimal treatment options available. For this to advance to clinical translation, however, an appropriate large animal model is required. In this study, we explored the porcine accessory carpal bone (ACB) as a model for the human trapezium. We characterized ACB anatomy, geometry, joint and tissue-scale mechanics, and composition across multiple donors. We showed that the ACB is similar both in size, and in the saddle shape of the main articulating surface to the human trapezium, and that loads experienced across each joint are similar. Using this information, we then devised a fabrication method and workflow to produce patient-specific tissue-engineered replicas based on CT scans, and showed that when such replicas are implanted orthotopically in an ex vivo model, normal loading is restored. Data from this study establish the porcine ACB as a model system in which to evaluate function of engineered living joint resurfacing strategies. STATEMENT OF SIGNIFICANCE: Biologic joint resurfacing, or the replacement of a joint with living tissue as opposed to metal and plastic, is the holy grail of orthopaedic tissue engineering. However, despite marked advances in engineering native-like osteochondral tissues and in matching patient-specific anatomy, these technologies have not yet reached clinical translation. Given its propensity for developing osteoarthritis, as well as its small size and complex shape, the trapezial surface of the trapeziometacarpal joint at the base of the thumb presents a unique opportunity for pursuing a biologic joint resurfacing strategy. This work establishes the porcine accessory carpal bone as an animal model for the human trapezium and presents a viable test-bed for evaluating the function of engineered living joint resurfacing strategies.