METHODS: The present study consisted of 50 lower limbs from formalin-fixed male adult cadavers aged about 70 years (45-85) belonging to the South Indian population. Total length of the quadriceps tendon, patellar height, patellar ligament height, proximal width, distal width and thickness of the patellar ligament were measured meticulously. Mean, standard deviation, median scores of each parameter were computed for groups using SPSS 16.0. Level of significance was considered as p patella and patellar ligament between the right and left lower limbs. Patellar ligament length showed positive correlation with ligament thickness (r = 0.36; p = 0.078 for right limb and r = 0.33; p = 0.104 for left limb). Proximal width of ligament showed significant positive correlation with distal width (r = 0.41; p = 0.041 for right limb and r = 0.54; p = 0.006 for left limb).
CONCLUSION: This morphometric data and analysis might be fundamental in understanding various knee conditions in situ and necessary to orthopedic surgeons for successful planning and execution for ACL reconstruction using patellar ligament graft and other patellofemoral joint disorders.
LEVEL OF EVIDENCE: I.
METHODS: The quadriceps of eight fresh-frozen knees were loaded on a custom-made jig. Kinematic data were recorded using an optical tracking device for the native knee, following total knee arthroplasty (TKA), then with patellar thicknesses from -2 to +4 mm, during knee extension motion. Staged lateral retinacular releases were performed to examine the restoration of normal patellar kinematics.
RESULTS: Compared to the native knee, TKA led to significant changes in patellofemoral kinematics, with significant increases in lateral shift, tilt and rotation. When patellar composite thickness was increased, the patella tilted further laterally. Lateral release partly corrected this lateral tilt but caused abnormal tibial external rotation. With complete release of the lateral retinaculum and capsule, the patella with an increased thickness of 4 mm remained more laterally tilted compared to the TKA with normal patellar thickness between 45° and 55° knee flexion and from 75° onwards. This was on average by 2.4° ± 2.9° (p patella was tilted laterally by 4.7° ± 3.2° and 5.4° ± 2.7° more than in the TKA with matched patellar thickness.
CONCLUSION: Patellar thickness affects patellofemoral kinematics after TKA. Although lateral tilt was partly corrected by lateral retinacular release, this affected the tibiofemoral kinematics.
LEVEL OF EVIDENCE: IV.