The adductor canal syndrome. Description of a case with quantification of arterial pulsatile blood flow

Chronic Exertional Compartment Syndrome of the Foot

Active individuals can experience exercise-induced pain along the medial, plantar central, and plantarmedial proximal arch. In many cases, these symptoms are consistent with conditions involving the plantar fascia, posterior tibial tendon, or entrapment of branches of the posterior tibial nerve. Unlike these other conditions, chronic exertional compartment syndrome (CECS) of the foot can be aggravated by interventions that impart any pressure or compression to the foot. Practitioners should have a high index of suspicion for CECS when classic treatments tend to aggravate patient's symptoms.

Anatomy of the Hunter's canal and its role in the venous outlet syndrome of the lower limb

BACKGROUND

The "Adductor canal syndrome" has been described as an unusual cause of acute arterial occlusion inside the Hunter's canal in young sportsmen. It may also produce a compressive neuropathy of the saphenous nerve. To our knowledge, femoral vein compression in the canal has never been reported.

OBJECTIVE

To describe the anatomy, to propose a physiology of this canal, and to show that the femoral vein is much more exposed than the artery to compression inside this adductor hiatus, particularly at the outlet.

MATERIAL AND METHODS

The whole adductor canal was exposed in 100 limbs for anatomical study following latex injection. A series of 200 phlebographies and 100 CT venograms were also analyzed.

RESULTS

Anatomically, we found a musculotendinous band called the "vastoadductor membrane," which jointed the adductor tendon to the vastus medialis in all the cases. The femoral vein, located more posteriorly, was frequently narrowed at this level. This band can create a notch with a venous stenosis at the outlet of the Hunter's canal, usually located 12-14 cm above the femoral condyle. Two femoral valves constitute the landmark of the canal on the venograms: the lower is just below the outlet, 9 cm above the condyle. The second valve is 3 cm higher inside the canal.Functionally, the cadaveric simulations showed that the contraction of the adductor longus closes the hiatus, while the adductor magnus opens it. Our hypothesis is that Hunter's canal prevents femoropopliteal axis reflux by synchronizing with calf pump ejection during ambulation.

CONCLUSION

Compression of the femoral vein inside the adductor's canal is an underestimated and misdiagnosed cause of postural stenosis of the femoral vein. Ultrasound investigation of both limbs in patients with chronic venous disease (CVD) should be systematically carried out at this precise level in order to prevent future occlusion and onset of acute deep vein thrombosis.

Saphenous neuritis: a poorly understood cause of medial knee pain

Saphenous neuritis is a painful condition caused by either irritation or compression at the adductor canal or elsewhere along the course of the saphenous nerve. The condition also may be associated with surgical or nonsurgical trauma to the nerve, especially at the medial or anterior aspect of the knee. Saphenous neuritis can imitate other pathology around the knee, particularly a medial meniscal tear or osteoarthritis. Unrecognized saphenous neuritis can confuse the patient's clinical picture, complicate treatment, and compromise results. As an isolated entity, saphenous neuritis may appear in conjunction with other common problems, such as osteoarthritis and patellofemoral pain syndrome, and it can have an indolent and protracted course. Its clinical appearance is characterized by allodynia along the course of the saphenous nerve. The diagnosis is confirmed by relief of symptoms after injection of the affected area with local anesthetic. Initial treatment can include non-surgical symptomatic care, treatment of associated pathology, and diagnostic or therapeutic injections of local anesthetic. In recalcitrant cases, surgical decompression and neurectomy are potential options. The key to treatment is prompt recognition; palpation of the saphenous nerve should be part of every routine examination of the knee.

Saphenous nerve entrapment at the adductor canal

A retrospective study of 30 patients who met the clinical criteria for saphenous nerve entrapment at the adductor canal is described. Patients experienced symptoms, usually anterior knee pain, for an average of 36 +/- 7 months. Each patient received an average of 1.9 +/- 0.4 saphenous nerve blocks at the adductor canal during treatment. Baseline pain level (measured by the visual analog scale) was 6.4 +/- 0.3. Final pain level at followup was significantly decreased (2.8 +/- 0.5, P less than 0.001). Eighty percent of patients had improved after a series of blocks. Age, medications taken, number of blocks performed, and length of followup were unrelated to outcome. Length of symptoms did significantly correlate with final pain level (r = 0.39, P less than 0.05). The diagnosis of this syndrome, description of the saphenous nerve block at the adductor canal, and the possible etiology are presented.