Infrapatellar Nerve Research Articles

The Localization of the Infrapatellar Nerves in the Anterior Knee Region With Special Emphasis on Central Third Patellar Tendon Harvest: A Dissection Study on Cadaver and Amputated Specimens

Summary: The aim of this dissection study on cadaver and amputated specimens was to determine the position of the infrapatellar nerves in the anterior knee region, and to investigate whether it would be possible to harvest the patellar tendon through two small vertical incisions, leaving the infrapatellar nerves undamaged and the major part of the paratenon intact. The infrapatellar nerve did not pass through the area between the apex of the patella and the tibial tubercle in 1 of 60 specimens. The nerve passed through this area as one branch in 15 of 60 specimens, as two branches in 37 of 60, as three in 6 of 60, and as four in 1 of 60 specimens. The distance from the apex of the patella to the infrapatellar nerve or the uppermost branch of the nerve was 30 mm (± 27 mm [2 SD]). The distance from the tibial tubercle to the infrapatellar nerve or the lowermost branch of the nerve was 27 mm (± 27 mm [2 SD]). In one specimen, the infrapatellar nerve passed 10 mm distal to the tibial tubercle. In 4 of 60 specimens, a branch of the infrapatellar nerve passed just above the tibial tubercle, and in 2 of 60 a branch passed just above the apex of the patella. In 19 of 20 specimens in which the harvesting procedure was performed, the infrapatellar nerve or the nerve branches were undamaged. The length of the undamaged paratenon was 27 mm (± 23 mm [2 SD]). This study showed that it was possible to harvest consistent bone–patellar tendon–bone autografts through two vertical 25-mm incisions, leaving the infrapatellar nerve undamaged and the paratenon partially intact in the majority of the cadaver and amputated specimens.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 6 (July), 1999: pp 577–586

Serial magnetic resonance imaging of the donor site after harvesting the central third of the patellar tendon. A prospective study of 37 patients after arthroscopic anterior cruciate ligament reconstruction.

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14-50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23-29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4-18) mm at 6 weeks, 5 (range 2-14) mm at 6 months and 2 (range 0-5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.

Injury to Infrapatellar Branch of Saphenous Nerve in Arthroscopic Knee Surgery

Injury to the infrapatellar branch of the saphenous nerve has been reported as a complication of arthroscopic examination and surgery of the knee. The authors studied the anatomic distribution of this branch in cadavers, and investigated the incidence of this complication in 68 patients. The results of anatomic study showed that blind puncture is safe within an approximate 30-mm area from the medial margin of the patella at the level of midpatella, and within an approximate 10-mm area from the medial margin of the patellar ligament at the level of the distal pole of the patella. In 30% of examined cadavers, the infrapatellar branch of the saphenous nerve transverses and runs laterally before it crosses the proximal edge of the tibia. Anatomic findings indicated that blind puncture to the knee in a 90 degrees flexion position should be done horizontally and parallel to the articular surface to reduce the incidence of nerve injury. The results of this study of patients who had arthroscopy from 1990 to 1991 revealed a 22.2% incidence rate of sensory disturbances in the area where the infrapatellar branch is distributed. The incidence can be minimized by clarifying the distribution of the infrapatellar nerve branch in relation to palpable landmarks.

Study of the infrapatellar nerve: By Art Arthornthurasook and Kasem Gaew-Im. Am J Sports Med 1988;16:57-9

Study of the infrapatellar nerve: By Art Arthornthurasook and Kasem Gaew-Im. Am J Sports Med 1988;16:57-9

Study of the infrapatellar nerve.

During operations on the knee, such as open meniscectomy and pes anserinus transplant for chronic anteromedial rotatory instability of the knee, the infrapatellar nerve may easily be damaged or severed. Knowledge of the normal anatomical variations of this nerve is thus of importance to the surgeon, so that he can avoid postoperative distress caused by unintentional injury to the infrapatellar nerve. Anatomical variations of this nerve have been studied in 20 cadavers, with particular reference to its relationship to the sartorius and the nerve's distance from the medial femoral epicondyle. In 52.9% of the cadavers studied, the anatomy of the infrapatellar nerve was identical on both sides. Four types of nerve were found and classified according to their relationship to the sartorius: posterior, penetrating, parallel, and anterior. The commonest type was the posterior (62.2%), where the nerve emerged at the posterior border of the sartorius before passing superficial to it to supply the skin and fascia over the front and medial aspect of the knee and the proximal part of the leg. Situated furthest from the medial femoral epicondyle was the parallel type (average, 105.7 mm), which runs parallel to the posterior border of the sartorius before crossing it at infrapatellar level.

The saphenous nerve: its course and importance in medial arthrotomy.

Both lower extremities of 10 cadavers (20 specimens) were dissected to delineate the course of the saphenous nerve and its two major divisions (sartorial and infrapatellar branches). The course of the saphenous nerve followed the standard text description, except at the point in the sartorius muscle where the infrapatellar branch exited to become a subcutaneous structure. The location of this branch varied slightly in each cadaver but was the same for both lower extremities in the same cadaver. The location of the sartorial nerve and its relationship to the tendons of the pes anserinus was consistant in all 20 specimens. Since 69% of a group of 75 patients found altered sensation significant after routine sectioning of the infrapatellar nerve following medial meniscectomy, a group of surgeons at the University of Michigan is now protecting the infrapatellar branch of the saphenous nerve at operation. Early results on a small number of patients indicate that no alteration in sensation occurs if the nerve is carefully retracted.