Patellofemoral Joint

Original Editor - Elvira Muhic

Lead Editors - Elvira Muhic, Lilian Ashraf, Kim Jackson, Ahmed Essam, WikiSysop, Jess Bell, Robin Tacchetti, 127.0.0.1, Admin, Rachael Lowe, Evan Thomas, Michelle Lee, Vidya Acharya and Rucha Gadgil

Anatomy

Articulating Surfaces

The patellofemoral joint is composed of the articulation of the patella with the femoral condyles of the femur. The patella has a configuration of a triangle with its apex directed inferiorly. Superiorly, it articulates with the trochlea, the distal articulating surface of the femur.

Muscles

Medial movement of the patella is controlled by the vastus medialis oblique (VMO) muscle. Lateral tracking is guided by both the vastus lateralis and the iliotibial band. Patellar motion is further constrained by the patellofemoral ligament, the patellotibial ligament, and the retinaculum.

Function

Compression at the patellofemoral joint:

Activity	Force	%Body Weight	Pounds of Force
Walking	850 N	1/2 x BW	100 Ibs
Bike	850 N	1/2 x BW	100 Ibs
Stair Ascend	1500 N	3.3 x BW	660 Ibs
Stair Descend	4000 N	5 x BW	1000 Ibs
Jogging	5000 N	7 x BW	1400 Ibs
Squatting	5000 N	7 x BW	1400 Ibs
Deep Squatting	15000	20 x BW	4000 Ibs

Pathology/Injury

Patellofemoral joint complaints are one of the most common musculoskeletal complaints in all age groups. Complaints vary from anterior knee pain to peripatellar knee pain to retropatellar knee pain. The etiology of patellofemoral joint syndrome is multifactorial and results from a combination of intrinsic and extrinsic factors. Treatment is often conservative in nature. Because of the variable nature of the complaints and an often lack of objective identifiable pathologic cause of patellofemoral joint complaints, this condition can be difficult to evaluate, diagnose, and treat, which may cause great frustration for the physician and patient alike. Patellofemoral joint syndrome may affect as many as 25% of all athletes.

References

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