Table 1 Fibers sparing of medius gluteus muscle, between the posterior two-thirds and one-third on front

“Longitudinal” skin incision

Good exposure: it can be extended proximally and distally as required

Less scarring might be obtained with an “oblique” incision

Incision of the subcutaneous tissue and fascia without separation

Less bleeding (especially with the timely use of a Charnley retractor)

The fascia is less visible when incising and suturing, as it is not exposed by separation

Exposure and splitting of the gluteus medius between the anterior and middle thirds

Extensive preservation of the split gluteus medius, whose anterior third is retracted anteriorly together with the anterior half of the gluteus minimus and the anterior half of the vastus lateralis

The presence of the anterior branch of the superior gluteal nerve about 4–5 cm from the apex of the greater trochanter makes it difficult to extend the deep field proximally

Exposure of the aponeurosis of the gluteus minimus and its longitudinal incision in half to the apex of the greater trochanter. Elevation of the anterior flap and application of reference stitches to evaluate limb length before and after implantation

This allows its anterior half to be moved to form the anterior flap together with the anterior third of the gluteus medius. Greater respect for the anterior third of the gluteus medius, and better exposure of the capsule. The posterior half, separated from the capsule and transected, is used to monitor limb length with two reference stitches (one on the gluteus minimus tendon, another on the vastus lateralis)

The difficulty involved in detaching the conjoint tendon, with the possibility that the anterior flap will be divided into two parts. The need to coagulate the vascular network near the vastus

Capsular phase. Separation with exposure of the anterolateral wall. Capsulectomy. Osteophytectomy

Facilitates broad and precise anterolateral capsulectomy. View of the femoral neck and axis, with the possibility of either two-stage neck osteotomy or dislocation (the usual practice). The removal of anterolateral osteophyes and limbus (even if calcified)

It does not expose the medial wall of the capsule, which is only resected subsequently

Dislocation of the head. Osteotomy of the neck. Osteophyte removal

Optimal freeing to the base of the neck. Possibility of removing the osteophytes of the head and neck, which is necessary for correct identification of the isthmus (1.5 cm from the greater trochanter)

The passage of the head may damage the posterior part of the gluteus medius. Limited detachment of its trochanteric insertion or two-stage osteotomy (in the case of particularly large and even sub-ankylosed heads) may be preferable

Exposure of the acetabulum and medial capsulotomy

The medial capsule is clearly visible. Separation and sectioning or removal are possible, even when adherent. Optimal visualization of the acetabulum and a greater range of motion, which is particularly useful for postoperative recovery of abduction. The psoas tendon and its relationship with the prosthesis (cup or collar of the stem) are visible

Medial capsulectomy removes a protective barrier (the capsular wall normally shields the psoas) and favors impingement on the psoas, which can lead to persistent medial inguinal pain

Preparation of the acetabulum

Complete removal of osteophytes, even if medial or at the bottom. Removal of the pulvinar (even if covered by an ossified roof). Exact depth of rasping to the point of eliminating the pulvinar from the fossa. Exposure of the transverse ligament, which is respected as part of the biodynamics of the acetabulum and as a guide for the correct anteversion of the cup

Risk of lateralizing the center of rotation because of insufficient cup depth

Implantation of the cup

The access also facilitates orientation. In the case of a T.O.P. cup, the insert can be rotated posteriorly to form an antiluxation long posterior wall because of its two equators

Preserving the neck of the femur is more difficult. The neck needs to be displaced backwards, and this is partially obstructed by the psoas (this does not occur with the posterior route because the neck is displaced forward and holds the psoas)

Implantation of the stem

Greatly facilitated without sacrificing the gluteus medius or other structures

Need to reveal the greater trochanter in the case of straight stems

Reduction and evaluation of the length of the limb before and after implantation

The reference stitches on the gluteus minimus and vastus lateralis are useful. The distance between the two stitches is measured with the limb in repose (neutral)

The lateral body position complicates this

Closure in layers

(a) Attention when reinserting the conjoint tendon together with the anterior flap

(b) Suture gluteus medius

Some difficulty in identifying the conjoint tendon, especially if it is accidentally broken or labile