Influence of medial parapatellar nail insertion on alignment in proximal tibia fractures--special consideration of the fracture level.
BACKGROUND
Although a lateral starting point for tibial nailing is recommended to avoid valgus misalignment, higher rates of intra-articular damage were described compared with a medial parapatellar approach. The aim of this anatomic study was to evaluate the fracture level allowing for a safe medial nail entry point without misalignment or dislocation of fragments.


METHODS
Thirty-two fresh-frozen cadaver lower extremities were used to create 1-cm osteotomies at four different levels (n = 8) from 2 cm to 8 cm below the tibial tuberosity. Nine-millimeter unreamed solid titanium tibial nails (Connex, I.T.S. Spectromed, Lassnitzhohe, Austria) were inserted from a medial parapatellar incision. Misalignment (degree) and dislocation of the distal fragment were measured in the frontal and sagittal plane.


RESULTS
A medial parapatellar approach for tibial nail insertion mainly caused valgus and anterior bow misalignment and ventral and medial fragment displacement. Mean misalignment and fragment displacement did not exceed 0.5 degree if the osteotomy was performed 8 cm to 9 cm below the tibial tuberosity.


CONCLUSIONS
According to the results of this study, a medial parapatellar approach can be performed without misalignment and fragment dislocation in proximal tibia fractures extending 8 cm or more below the tibial tuberosity.
Weninger
Patrick
P
Lorenz Boehler Trauma Hospital, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Cluster for Tissue, Regeneration, Vienna, Austria. patrick.weninger@gmx.net
Tschabitscher
Manfred
M
Traxler
Hannes
H
Pfafl
Veronika
V
Hertz
Harald
H
D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000503:physiopathology*; D001858:Bone Nails; D002102:Cadaver; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008297:Male; D010027:Osteotomy; D010329:Patella / Q000601:surgery*; D013978:Tibial Fractures / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome