Abstract and Introduction
Abstract
Introduction: Aseptic loosening remains one of the most common indications for revision total knee arthroplasty (TKA). Given the demographic shift to a younger and more active TKA patient population, some surgeons have revisited noncemented fixation given its potential for lower rates of long-term aseptic loosening. The purpose of this study was to compare the demographics and complications between patients undergoing noncemented and cemented TKA.
Methods: Using the MKnee subset of the PearlDiver database, diagnosis and procedure codes were used to identify patients who had undergone cemented or noncemented TKA for osteoarthritis with a minimum 2-year follow-up. Propensity score matching was done to compare risk-adjusted medical and surgical complication profiles at 90 days, 1 year, and 2 years.
Results: Of 203,574 patients identified, 3.2% underwent noncemented TKA and 96.8% underwent cemented TKA. Using propensity-matched analysis, there was no difference in 90-day medical complications. Noncemented TKA was associated with a greater risk of periprosthetic joint infection throughout the study (90-day odds ratio [OR] 1.34, 1-year OR 1.27, 2-year OR 1.27, P < 0.05). Noncemented TKA was associated with a greater risk of periprosthetic fracture at 1 year and 2 years (1 year OR 2.19, 2 years OR 1.89, P < 0.05). No notable difference was observed in risk of aseptic loosening between the two groups.
Discussion: Noncemented TKA is associated with a higher rate of periprosthetic joint infection and periprosthetic fracture. Additional studies are needed to compare long-term rates of aseptic loosening between noncemented and cemented TKA.
Level of Evidence: Level III
Introduction
Although total knee arthroplasty (TKA) implant fixation can be cemented, noncemented, or hybrid, cemented TKA is the most widely conducted technique and has historically been considered the industry standard.[1–4] However, the cement is found to have weak resistance to shear force and can undergo gradual degradation and deformation over time. This combined with the concern for osteolytic activity at the cement-bone interface has raised concerns over its long-term durability.[2,5] This may not be an issue for the elderly population, but it poses a potential concern for younger and more active patients who require stable long-term fixation.[6,7] Increased participation in physical activity, direct-to-consumer advertising, and greater experience and comfort with TKA in both surgeons and patients have played a role in the demographic shift to a younger and more active TKA population.[3,8,9] Given the concern for prosthesis longevity and aseptic loosening in younger and more active patients, some surgeons have begun to revisit noncemented fixation for TKA.[3,10]
Noncemented TKAs were historically known for their failing designs with poorly osteoconductive surfaces and inadequate immediate stable fixation properties resulting in early catastrophic failures.[11–16] Whiteside et al[17] reported a unique complication of femoral implant fatigue fractures in an early series of noncemented TKAs. These most commonly occurred along the disproportionately thin regions, including the anterior flange and posterior condyles. Lewis et al reported screw track osteolysis from polyethylene wear along the tibial baseplate.[18] Other issues include patellar polyethylene wear from an incongruous trochlea,[19] polyethylene dissociation from a mismatch between a thick metal endoskeleton and thin polyethylene modular junction,[20] and failure of osseointegration leading to early subsidence.[12] Mid-term survivorships were reported as low as 74% in some series dating back to the 1980s and 1990s.[18]
More recently, improved surface coatings, such as highly porous surfaces and better polyethylene properties, have renewed interest in the use of noncemented TKA.[1,10,21] Second generation modern noncemented TKA designs feature several changes. They commonly have included more bone-conserving prosthesis designs with a focus on early biologic fixation using improved porous metal along the tibial baseplate and more robust femoral and tibial pegs and keels to prevent micromotion and subsidence.[22] Newer biomaterials, such as porous titanium and tantalum,[23,24] hydroxyapatite,[25] and plasma spray coatings, have facilitated earlier mechanical stability with consistent biologic osseointegration. Highly cross-linked polyethylene has also mitigated the role of catastrophic polyethylene wear seen in the first generation of implants.[26]
Most previous studies that demonstrated unequivocally worse results in noncemented TKA were written before these advancements seen today.[27–30] More recently, multiple studies have already demonstrated favorable functional results with the use of more modern noncemented prostheses.[1,3,23,31,32] However, there is debate about the relative advantages and disadvantages of cemented and noncemented fixation for TKA. The purpose of this study was to determine the current utilization of noncemented TKA in the United States and to compare medical and surgical complications between cemented and noncemented primary TKA. Our initial hypothesis was that complication profiles would not be different between noncemented and cemented TKA.
J Am Acad Orthop Surg. 2022;30(6):273-280. © 2022 American Academy of Orthopaedic Surgeons
