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Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review



This systematic review aimed to evaluate the variability of patellofemoral (PF) alignment and trochlear morphology in osteoarthritic knees.


PF alignment of the knee was defined by the following parameters: the sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle–trochlear groove distance (TT–TG). The electronic databases MEDLINE and EMBASE were searched from database inception to the search date (February 19, 2019) and were screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of osteoarthritic knees in patients over 40 years old were included. Data were extracted and methodological quality was assessed using a 14-item checklist.


A total of 8 studies met the inclusion criteria. The studies reported mean values ± SD between 120° and 141.1° ± 7.7 for the SA; 5.8 mm ± 1.4 for the FTD; between − 0.1° ± 3.3 and 10.3° ± 5.7 for the PTA; between 5.8° ± 5.4 and 17° for the LPFA; between 23.2° ± 5.0 and 27.1° ± 4.4 for the LFTI; and 5.8 mm ± 5.4 for the TT-TG.


PF alignment in the osteoarthritic knee is more variable than expected. This finding should encourage surgeons to consider the individual preoperative PF alignment more precisely with the aim of reducing anterior knee pain (AKP) after TKA. 3D-CT imaging might be of great value to analyse the PF alignment in an appropriate way.

Level of evidence

Level III.

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Fig. 1
Fig. 2



Anterior knee pain


Femoral trochlear depth


Lateral femoral trochlear inclination


Lateral patellofemoral angle


Not available




Patellar tilt angle


Sulcus angle


Standard deviation


Total knee arthroplasty


Tibial tubercle–trochlear groove distance


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Correspondence to Henrik Behrend.

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Hochreiter, B., Moser, L.B., Hess, S. et al. Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review. Knee Surg Sports Traumatol Arthrosc 29, 483–490 (2021).

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  • Patellofemoral
  • Alignment
  • Knee
  • Sulcus angle
  • Trochlear depth
  • Patellar tilt angle
  • Lateral patellofemoral angle
  • Lateral femoral trochlear inclination
  • Tibial tubercle trochlear groove