Sagittal patellar tilt and concomitant quadriceps hypotrophy after tibial nailing

The aim of the study was to analyse the patellofemoral alignment in the sagittal plane following tibial fracture surgery with intramedullary nailing and its relationship to parapatellar muscle status.

The patellofemoral MRI results of 27 patients (15 males and 12 females) treated with locked intramedullary nailing following tibia shaft fracture were reviewed. The mean age of the patients was 41.8 (±15) years. The patella-patellar tendon angle (P-PT) and the distance between the inferior patellar pole and the tibial tubercle (DP-TT) were evaluated for both the operated extremity and the contralateral normal side. MRI assessment of the infrapatellar fat pad, quadriceps, sartorius, gracilis, semi-membranosus muscles and biceps muscles was also carried out. The correlation between the changes in skeletal muscle mass, the volume of the infrapatellar fat pad and the alterations in the DP-TT distances and P-PT angles were analysed.

The quadriceps muscle cross-sectional diameter had a mean of 157.2 mm(2) (115.6/319.5) in the operated extremity, and it was 193 mm(2) (77.6/282.2) in the non-operated normal side (p = 0.001). For the Gracilis muscle, the mean was 84.4 mm(2) (19.7/171) at the operated extremity and 75.7 mm(2) (26.9/238.2) on the normal side (p = 0.05). The cross-sectional areas of the semi-membranosus, sartorius and biceps muscles in the operated and non-operated extremity were not noticeably different (n.s). The P-PT angle was 153° (129.7/156.4) in the operated extremity and 145.7° (137.6/163.4) in the non-operated normal extremity (p < 0.05). While DP-TT distance was 11.4 mm (9.4/20.4) in the operated extremity, it was 14.1 mm (7.3/17.1) in the non-operated extremity (p = 0.001). The correlation analyses revealed that the quadriceps hypotrophy negatively correlated (r = -0.4, p = 0.02) with the P-PT angle but positively correlated with the increase in gracilis muscle volume (r = 0.4, p = 0.03).

This study revealed that patellofemoral joint kinematics in the operated extremity was diminished in the sagittal plane correlating with the quadriceps muscle volume loss and gracilis muscle hypertrophy. The modalities focused on both preventing and treating the hypotrophy of the quadriceps muscle following the surgical treatment of tibial fracture, which may help to overcome this quite common pathology.