Details

Autor(en) / Beteiligte

• Gobbi, Riccardo G.
• Demange, Marco K.
• de Ávila, Luiz Francisco Rodrigues
• Araújo Filho, José de Arimatéia Batista
• Moreno, Ramon Alfredo
• Gutierrez, Marco Antônio
• de Sá Rebelo, Marina
• Tírico, Luis Eduardo Passarelli
• Pécora, José Ricardo
• Camanho, Gilberto Luis

Titel

Patellar tracking after isolated medial patellofemoral ligament reconstruction: dynamic evaluation using computed tomography

Ist Teil von

• Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 2017-10, Vol.25 (10), p.3197-3205

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• Purpose Medial patellofemoral ligament (MPFL) reconstruction offers good clinical results with a very low rate of instability recurrence. However, its in vivo effect on patellar tracking is not clearly known. The aim of this study is to investigate the effects of MPFL reconstruction on patellar tracking using dynamic 320-detector-row CT. Methods Ten patients with patellofemoral instability referred to isolated MPFL reconstruction surgery were selected and subjected to dynamic CT before and ≥6 months after surgery. Patellar tilt angles and shift distance were analysed using computer software specifically designed for this purpose. Kujala and Tegner scores were applied, and the radiation of the CTs was recorded. Two protocols for imaging acquisition were compared: a tube potential of 80 kV and 50 mA versus a tube potential of 120 kV and 100 mA, both with a slice thickness of 0.5 mm and an acquisition duration of 10 s. Results There were no changes in patellar tracking after MPFL reconstruction. There was no instability relapse. Clinical scores improved from a mean of 51.9 (±15.6)–74.2 (±20.9) on the Kujala scale ( p  = 0.011) and from a median of 2 (range 0–4) to 4 (range 1–6) on the Tegner scale ( p  = 0.017). The imaging protocols produced a dose-length product (DLP) of 254 versus 1617 mGycm and a radiation effective estimated dose of 0.2 versus 1.3 mSv, respectively. Both protocols allowed the analysis of the studied parameters without loss of precision. Conclusions Reconstruction of the MPFL produced no improvement in patellar tilt or shift in the population studied. The low-radiation protocol was equally effective in measuring changes in patellar tracking and is recommended. Although the procedure successfully stabilized the patella, knee surgeons should not expect patellar shift and tilt correction when performing isolated patellofemoral ligament reconstruction in patients with recurrent patellar instability. Level of evidence IV.