ORIGINAL ARTICLE G. Maralcan Æ I. Kuru Æ S. Issi Æ A.F. Esmer I. Tekdemir Æ D. Evcik The innervation of patella: anatomical and clinical study Received: 8 January 2004 / Accepted: 31 March 2005 / Published online: 20 September 2005 Ó Springer-Verlag 2005 Abstract As much interest has been focused on afferent innervation of knee than that of patella, there are few articles about patellar innervation. But in clinical prac- tice anterior knee pain due to patellar disorders is a quite frequent problem. Our aim was to review the innerva- tion pattern of patella and to give the topographic anatomy of the nerves. We dissected 30 knees of 15 formaldehyde-fixed cadavers. Two nerves from vastus medialis and lateralis were found to reach patellar edge. Apart from these, we were unable to find any other neural structures around patellae. Mean distances be- tween the tuberosity of the tibia and medial and lateral nerve entry points were 90.1(range 74–102) and 96.3 mm (range 76–109), respectively. The angles between lines which join the entry points of nerves and vertical line to the center point of patella were measured in frontal plane. It was approximately 60° medially and 40° lat- erally. To confirm that these nerves are patellar pain afferents, we performed a local anesthesia test in 32 knees of 20 patients with patellofemoral pain. Clinically, there was a significant difference between the visual analogue scale (VAS) scores before and after local anesthetic injections (p<0.01). Previous studies have emphasized especially the medial innervation. We found that both superomedial and superolateral nerves were important for patellar innervation. We described pre- cisely the entry points of these nerves to patella for se- lective denervation. Keywords Patella Æ Patellar innervation Æ Patellofemoral joint denervation Æ Patellofemoral osteoarthritis Æ Anatomy Introduction Patellar and patellofemoral joint disorders are wide- spread and patients with patellofemoral complaints constitute a considerable proportion of orthopedic clinic applicants. Chondromalacia, degenerative arthritis, maltracking and malposition problems are relatively frequent patellofemoral problems. Along with tibiofemoral joint diseases or alone, patellofe- moral joint problems cause significant disability. The most frequent symptom in patellofemoral disorders is pain behind the patella without function loss. Al- though this is a common clinical problem, pain mechanism and the innervation of the patella have not been fully explained [11]. Reviewing the literature on neural anatomy of the knee, we found that the knowledge about innervation of patella was poor of exact description [6]. Furthermore, in many articles, major nerve trunks and their innervation areas are described without mentioning afferent innervation of patella [7, 8]. There are only a few studies on this subject emphasizing the mainly medial localization of patellar afferents [4, 10, 11]. Moller et al. [11] reported that medial denervation procedure of the patella were not successful, which raises the question of whether patella has multiple innervation patterns. This article reports the results of our anatomical and clinical study on innervation of patella and gives the topographic anatomy of the nerves. G. Maralcan Æ I. Kuru Deptartment of Orthopedics, Kocatepe University Medical School, Afyon, Turkey S. Issi Deptartment of Anatomy, Kırıkkale University Medical School, Kirikkale, Turkey A.F. Esmer Æ I. Tekdemir (&) Deptartment of Anatomy, Ankara University Medical School, 06100 Sihhiye, Ankara, Turkey E-mail: tekdemir@medicine.ankara.edu.tr Tel.: +90-312-3105001 Fax: +90-312-3105001 D. Evcik Deptartment of Physical Medicine and Rehabilitation, Kocatepe University Medical School, Afyon, Turkey Surg Radiol Anat (2005) 27: 331–335 DOI 10.1007/s00276-005-0334-7