Medial Approach to the Hip
The medial approach, attributed to Ludloff,19 was originally designed for surgery on flexed, abducted, and externally rotated hips, the kinds of deformities caused by certain types of congenital dislocation of the hip. The uses of the medial approach include the following:
1. Open reduction of congenital dislocation of the hip. The approach givesan excellent exposure of the psoas tendon, which can block reduction of the hip.20
2. Biopsy and treatment of tumors of the inferior portion of the femoralneck and medial aspect of proximal shaft
3. Psoas release
4. Obturator neurectomy
The upper part of the approach can be used for an obturator neurectomy. If a neurectomy is combined with an adductor release, the approach can be performed through a short transverse incision or a short longitudinal incision in the groin that permits division of the adductors close to their pelvic origin, an area where there is less bleeding.
Position of the Patient
Place the patient supine on the operating table with the affected hip flexed, abducted, and externally rotated. This may not be possible in cases with fixed deformity, when the position is often determined for you. The sole of the foot on the affected side should lie along the medial side of the contralateral knee (Fig. 8-64).
Landmarks and Incision
Landmarks
Palpate the adductor longus from the medial side of the thigh and follow it up to its origin at the pubis, in the angle between the pubic crest and the symphysis. The adductor longus is the only muscle of the adductor group that is easy to palpate.
With your finger anchored on the greater trochanter, move your thumb along the inguinal creases medially and obliquely downward until you can feel the pubic tubercle. They are at the same level as the top of the greater trochanter.
Incision
Make a longitudinal incision on the medial side of the thigh, starting at a point 3 cm below the pubic tubercle. The incision runs down over the adductor longus. Its length is determined by the amount of femur that must be exposed (Fig. 8-65).
Internervous Plane
The superficial dissection does not exploit an internervous plane, since both the adductor longus and the gracilis are innervated by the anterior division of the obturator nerve. The plane is nevertheless safe for dissection; both muscles receive their nerve supplies proximal to the dissection (Fig. 8-66).
Figure 8-64 Position of the patient on the operating table for the medial approach to the hip.
Figure 8-65 Incision for the medial approach to the hip.
More deeply, the plane of dissection lies between the adductor brevis and the adductor magnus. The adductor brevis is supplied by the anterior division of the obturator nerve. The adductor magnus has two nerve supplies: Its adductor portion is supplied by the posterior division of the obturator nerve, and its ischial portion is supplied by the tibial part of the sciatic nerve. The two muscles, therefore, form the boundaries of an internervous plane (see Fig. 8-69).
Superficial Surgical Dissection
Begin the superficial dissection by developing a plane between the gracilis and the adductor longus. Like other intermuscular planes in the adductor group, this plane can be developed with your gloved finger (Fig. 8-67A).
Deep Surgical Dissection
Continue the dissection in the interval between the adductor brevis and the adductor magnus until you feel the lesser trochanter on the floor of the wound. Try to protect the posterior division of the obturator nerve, the innervation to the muscle’s adductor portion, to preserve the hip extensor function of the adductor magnus (see Dangers below). Place a narrow retractor (such as a bone spike) above and below the lesser trochanter to isolate the psoas tendon.
Dangers
Nerves
The anterior division of the obturator nerve lies on top of the obturator externus and runs down the medial side of the thigh between the adductor longus and the adductor brevis, to which it is bound by a thin tissue. It supplies the adductor longus, the adductor brevis, and the gracilis in the thigh (Fig. 8-67B).
The posterior division of the obturator nerve lies in the substance of the obturator externus, which it supplies before it leaves the pelvis. The nerve then runs down the thigh on the adductor magnus and under the adductor brevis; it supplies the adductor portion of the adductor magnus (Fig. 8-67C).
Figure 8-66 The intermuscular interval between the adductor longus and the gracilis is not an internervous plane because both muscles are innervated by the anterior division of the obturator nerve. The plane is safe, however, because the muscles receive their nerve supplies proximal to the dissection.
Figure 8-67 A: Develop the plane between the gracilis and the adductor longus. B: Retract the adductor longus and the gracilis to reveal the adductor brevis with the overlying anterior division of the obturator nerve. C: Retract the adductor brevis from the muscle belly of the adductor magnus to uncover the posterior division of the obturator nerve. Note the lesser trochanter in the depths of the wound.
Most of the time, the approach is designed specifically to cut these nerves to relieve muscular spasticity. If you are not using it for that purpose, avoid transecting them.
Vessels
The medial femoral circumflex artery (see Applied Surgical Anatomy of the Thigh in Chapter 9) passes around the medial side of the distal part of the psoas tendon. It is in danger, especially in children, if you try to detach the psoas without isolating the tendon and cutting it under direct vision (Fig. 8-69).
How to Enlarge the Approach
Local Measures
After reaching the femur and detaching the insertions of the psoas and iliacus, you can expose some 5 cm of femoral shaft distal to the lesser trochanter by blunt dissection.
Extensile Measures
This exposure is almost never enlarged by extensile measures.
Figure 8-68 Anatomy of the medial approach to the hip. The thigh is abducted, slightly flexed, and externally rotated. The plane of the superficial dissection runs between the adductor longus and the gracilis.
Figure 8-69 The deep muscular layer of the medial approach to the hip. The dissection lies between the adductor brevis and the adductor magnus. The gracilis, adductor longus, and sartorius have been resected to reveal the deeper structures of the medial aspect of the thigh. Note the relationships of the anterior and posterior divisions of the obturator nerve to the adductor longus and adductor brevis. Note the proximity of the medial femoral circumflex artery to the insertion of the psoas tendon.
Psoas Major. Origin. Anterior surface of transverse processes and bodies of the lumbar vertebrae and corresponding intervertebral disks. Insertion. Lesser trochanter of femur. Action. Flexor of hip and flexor of lumbar spine when leg is fixed. Nerve supply. Segmental nerves from second and third lumbar roots.
Iliacus. Origin. Upper two-thirds of iliac fossa, inner lip of iliac crest, anterior aspect of sacroiliac joint, and from the anterior sacroiliac and iliolumbar ligaments. Insertion. Lesser trochanter of femur by common tendon with psoas. Action. Flexor of hip. Tilts pelvis forward when leg is fixed. Nerve supply. Femoral nerve (L2-L4).
