Reliability and validity of a new caliper for measuring patellar thickness.

The process of patellar resurfacing during total knee arthroplasty involves measuring patellar thickness. The optimal residual patellar bone thickness has been questioned. The surgeon's ability to measure patellar thickness currently rests on a standard caliper. Standard methods involve use of a smooth-mouthed caliper, which can overestimate patellar thickness because of soft tissue interposition. This brief communication introduces a new spiked caliper design that can be used to measure patellar bone thickness more accurately. Improved accuracy in measuring patellar bone thickness allows the operating surgeon to assess more correctly a patient's patellar bony status. This knowledge may result in fewer postoperative fracture complications resulting from deficiencies of bone owing to excessive resection.