Abstract
BackgroundLow-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses. Radiological analysis shows radiolucent lines (RLL) appearing immediately or two years after primary implantation, indicative of poor seat. Investigations proved RLL to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau, but their association with clinical findings and patients discomfort and knee pain is still unknown.Methods553 patients with 566 low-contact-stress (LCS) total knee prostheses were screened for continuous moderate knee pain. We compared tibial stress shielding classified by Ewald in patients suffering from pain with a matched, pain-free control group on blinded X-rays. We hypothesized a positive correlation between pain and radiolucency and higher frequency of such radiolucent lines in the most medial and most lateral zones of the tibial plateau.ResultsTwenty-eight patients suffered from knee pain in total. Radiolucencies were detected in 27 of these cases and in six out of 28 matched controls without knee pain. We could demonstrate a significant correlation of knee pain and radiolucencies, which appeared significantly more frequently in the outermost zones of the tibial plateau.ConclusionOur findings suggest that radiolucent lines, representing poor implant seat, about the tibial plateau are associated with knee pain in LCS patients. Radiolucencies are observed more often in noncemented LCS, and cementing the tibial plateau might improve implant seat and reduce both radiolucent lines and associated knee pain.
Highlights
Low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses
Earlier studies demonstrated radiolucent lines (RLL) to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau [16,17], yet the potential and likely association between clinical findings and radiolucencies was never formally assessed [10,11,18,19]
The relative distribution of affected tibial zones in pain-free patients and patients with continual moderate knee pain is shown in Figure 1, 2, and 3
Summary
Low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses. Low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analysis [1,2,3,4]. Earlier studies demonstrated RLL to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau [16,17], yet the potential and likely association between clinical findings and radiolucencies was never formally assessed [10,11,18,19] This multicenter study screened 553 patients with 566 low-contact-stress total knee prostheses for continual moderate knee pain determined by the Knee Society Score [20]. Selected patients were further tested for tibial stress shielding, evaluated by the classification of Ewald et al [21] and compared to a pain-free, ageand sex-matched control group selected from the same population of 566 patients
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