Influence of patellar thickness on patellar tracking and patellofemoral contact characteristics after total knee arthroplasty

Horng Chaung Hsu, Zong Ping Luo, James A. Rand, Kai Nan An

Research output: Contribution to journalArticle

110 Scopus citations

Abstract

Although total knee arthroplasty (TKA) has become a very common procedure, patellar problems remain a major cause of disability. Patellar thickness is one of the most challenging factors. The influence of patellar thickness on patellofemoral kinematics and contact characteristics following TKA was investigated. Seven unembalmed whole-lower-extremity cadaveric specimens were used. The kinematics was measured with a magnetic tracking device (3Space Tracker System, Polhemus Navigation Sciences Division, Colchester, VT). Contact area was calculated from the kinematic data and the digitized joint surface geometries based on a theoretical method. The patellofemoral joint contact force was measured directly using a uniaxial force transducer. Kinematically, the influence of patellar thickness on patellar flexion, rotation, and proximodistal shift was not significant. Orthopaedic surgeons are often challenged by derangement of the patellofemoral joint, especially following TKA. It is commonly assumed that restoration of overall patellar thickness is most desirable. A thin patella can reduce the contact force, but it also poses the potential risks of stress fracture and anteroposterior instability. Increasing patellar thickness might be expected to increase the effective quadriceps moment arm at low flexion angles of the knee, but potentially reduces the range of motion of the knee and predisposes to patellar subluxation. Either a thicker or a thinner patella had a smaller contact area than intact and normal-thickness patella. Therefore, the surgical technique of patellar resurfacing during TKA should attempt to reproduce the original patellar thickness.

Original languageEnglish (US)
Pages (from-to)69-80
Number of pages12
JournalJournal of Arthroplasty
Volume11
Issue number1
DOIs
StatePublished - Jan 1 1996

Keywords

  • patellar thickness
  • patellar tracking
  • patellofemoral contact characteristics
  • total knee arthroplasty

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

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