The Analysis of Risk Factors in No Thumb Test in Total Knee Arthroplasty

Abstract

BackgroundWe would like to analyze the risk factors of no thumb test among knee alignment tests during total knee arthroplasty surgery.MethodsThe 156 cases of total knee arthroplasty by an operator from October 2009 to April 2010 were analyzed according to preoperative indicators including body weight, height, degree of varus deformity, and patella subluxation and surgical indicators such as pre-osteotomy patella thickness, degree of patella degeneration, no thumb test which was evaluated after medial prepatella incision and before bone resection (1st test), no thumb test which was evaluated with corrective valgus stress (2nd test, J test), and the kind of prosthesis. We comparatively analyzed indicators affecting no thumb test (3rd test).ResultsThere was no relation between age, sex, and body weight and no thumb test (3rd test). Patellar sulcus angle (p = 0.795), patellar congruence angle (p = 0.276) and preoperative mechanical axis showed no relationship. The 1st no thumb test (p = 0.007) and 2nd test (p = 0.002) showed significant relation with the 3rd no thumb test. Among surgical indicators, pre-osteotomy patella thickness (p = 0.275) and degeneration of patella (p = 0.320) were not relevant but post-osteotomy patellar thickness (p = 0.002) was relevant to no thumb test (3rd test). According to prosthesis, there was no significance with Nexgen (p = 0.575). However, there was significant correlation between Scorpio (p = 0.011), Vanguard (p = 0.049) and no thumb test (3rd test). Especially, Scorpio had a tendency to dislocate the patella, but Vanguard to stabilize the patella.ConclusionsNo thumb test (3rd test) is correlated positively with 1st test, 2nd test, and post-osteotomy patella thickness. Therefore, the more patella osteotomy and the prosthesis with high affinity to patellofemoral alignment would be required for correct patella alignment.

Comparison of patellofemoral outcomes after TKA using two prostheses with different patellofemoral design features

“…It is characterized by increased contact surface conformity of the femoral and patellar components. Major design features of the femoral component include a rounded sagittal profile and a deep, long, and wide trochlear groove [20, 21, 25]. This component design places the site of transition to intercondylar notch more posteriorly than previous designs, thus avoiding soft tissue impingement in deep knee flexion [34].…”

Risk Factors for Patellar Clunk or Crepitation after Primary Total Knee Arthroplasty: A Systematic Review and Meta-analysis

“…Nearly all surgeons in the included studies declared that they use the no-thumb test as an indication for the necessity of lateral retinacular release 58 ; however, this may not be the Risk Factors for Patellar Clunk or Crepitation after Primary TKA Duan et al 1101 most appropriate method. 59 Furthermore, there are more options for the attainment of proper patellar tracking, including using a patella friendly femoral prosthesis 59 and performing appropriate patelloplasty. 39 Lateral retinacular release may stimulate scar tissue formation up to the synovial lining overlying the top of the femoral component and the peripatellar soft tissue.…”

Total knee arthroplasty using trochlear groove as guide for position of femoral component in severe knee osteoarthritis

“…Firstly, patients aged over 70 years old, who underwent arthroscopy but not had knee osteoarthritis, were rare, so there was a big difference in mean age of knee osteoarthritis and control groups in this study, which would affect the results. Secondly, patellar tracking after the placement of prosthesis model was only assessed using no-thumb test, and the patellar maltracking might be overestimated [ 39 ]. Third, prostheses were finally fixed with the trochlear groove as reference, and comparison of patellar tracking after the placement of prosthesis by using transepicondylar line and trochlear groove as references was not performed.…”