n tips & techniquesSection Editor: Steven F. Harwin, MD

Anterior Approach in Total Hip ReplacementMatteo Cadossi, MD, PhD; Andrea Sambri, MD; Giuseppe Tedesco, MD; Antonio Mazzotti, MD; Silvio Terrando, MD; Cesare Faldini, MD

The anterior approach is intermuscular and inter-

nervous and allows surgeons to reach the hip joint capsule with-out muscle detachment through the muscular interval between the sartorius and rectus femo-ris medially (innervated by the femoral nerve) and the tensor fascia lata laterally (superior gluteal nerve) (Figure 1).

The anterior approach is gaining popularity,1,2 most likely because of the percep-tion of a faster recovery, re-duced risk of dislocation, good functional results, and early return to strenuous activities.3

However, several studies have reported a higher complica-tion rate for the anterior ap-proach, compared with other

approaches, as a consequence of the learning curve.4-7 This article reports the most crucial steps in total hip replacement (THR) through the anterior approach and describes the potential pitfalls and solu-tions.

Surgical TechniquePatient selection is crucial

during the learning curve. Al-though the anterior approach can be performed for all pa-tients, the ideal candidate is a tall woman who is not too muscular. The longer lever arm of the femoral shaft enhances femoral exposition. A rather valgus hip or a long femoral neck allows easier femoral os-teotomy, while mild arthritis without pelvic complications facilitates femoral head re-moval. The anterior approach can be performed using a leg positioner, which requires fewer members of the surgical team and allows direct control of leg movements8 (Figure 2) (Video).

The incision (Figure 3) should be approximately 10 cm; longer incisions do not im-

prove visualization. A mini-in-cision or a bikini-like incision is also possible.9 Remaining lateral to the anterior superior iliac spine avoids damage to the lateral femoral cutaneous nerve that runs medially.

The sheath of the ten-sor fascia lata is incised lon-gitudinally at a slight slant downward and outward. The intermuscular interval be-tween the tensor fascia lata and the sartorius can be iden-tified by smooth dissection and widened using a special Beckmann retractor to reveal

The authors are from the Istituto Ortopedico Rizzoli, Bologna, Italy.The authors have no relevant financial relationships to disclose.Correspondence should be addressed to: Andrea Sambri, MD, Istituto

Ortopedico Rizzoli, Via Pupilli 1, 40136 Bologna, Italy (andrea_sambri@libero.it).

Received: March 4, 2016; Accepted: June 14, 2016.doi: 10.3928/01477447-20161202-06

Abstract: In total hip replacement, the anterior approach is intermuscular and internervous and allows the surgeon to reach the capsule without muscle detachment. Advantages include faster recovery and excellent functional outcome as well as reduced postoperative pain and hospital stay. Expe-rienced surgeons currently performing total hip replacement should be aware of all of the difficulties associated with this procedure as well as all of the tricks to overcome the most challenging steps in order to reduce complications during the learning curve. The authors present the most crucial steps in total hip replacement through the anterior approach and de-scribe the potential pitfalls and solutions. [Orthopedics. 2017; 40(3):e553-e556.]

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Figure 1: Axial section of an anatom-ical preparation showing the anterior approach. Abbreviations: R, rectus femoris; S, sartorius; TFL, tensor fascia lata.

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n tips & techniques

the aponeurosis of the rectus femoris. This is incised longi-tudinally and the muscle body is retracted medially. Usually,

the circumflex pedicle can be detected and ligated between the distal and the middle third of the approach (Figure 4).

The anterior capsule of the hip joint can be exposed by re-moving the fat pad.

Capsular preservation is important for stability. There-fore, it is advisable to preserve the capsule and suture it at the end of surgery (Figure 5).

The femoral neck osteoto-my (Figure 6) is not complet-ed with the saw. The posterior cortex is left intact. Some trac-tion is applied, thus allowing the osteotomy to slightly open. The femur is externally rotated at 45° to break the posterior cortex.

The femoral head is re-moved with a corkscrew. If this procedure proves com-plex, it may be useful to per-form a double osteotomy of the neck to obtain a wider op-erating space.

A modified Charnley re-tractor is positioned inside the capsular flaps. The labrum is excised to better visualize the acetabular rim (Figure 7). Once the acetabular fossa has been identified, the reaming process can begin with the use of an offset reamer.

The acetabulum is prepared in a standard manner and the final component is impacted,

being careful to avoid implant verticalization or excessive anteversion. If the incision is small, the cup is seated manu-ally inside the joint. Next, the handle is connected and the inclination, version, and rota-tion are adjusted before ham-mering it.

During acetabular ream-ing, the proximal femur lies beneath the posterior wall of the acetabulum. By applying a slight traction with the leg po-sitioner, the knee is externally rotated at 90° (placing the traction boot at 180°) to avoid bone impingement between the femur and the acetabulum. This procedure is facilitated by hooking the femoral canal to pull the femur laterally.

External rotation can be extremely limited in arthritic hips because of the shortening of the posterior capsule. Soft tissue retraction may hinder the femoral exposure; there-fore, capsular release is often necessary (Figure 8).

The hip is hyperextended using the leg positioner; trac-tion is automatically released in order not to stretch the fem-oral nerve. Once the hip has been hyperextended, if femo-

Figure 2: The patient is positioned on a traction table with 10° of hip flexion, thus obtaining anterior muscle relaxation and neutral abduction/adduction with slight foot internal rotation to neutralize femoral neck anteversion. The surgeon should be able to slide his or her hand between the pressure block and the buttock.

Figure 3: Starting 1 inch lateral and inferior to the external edge of the anterior superior iliac spine, the incision (+++) runs obliquely downward and slightly outward toward the fibular head.

Figure 4: Finger dissection in the muscular space between the sarto-rius and the tensor fascia lata.

Figure 5: The capsule is opened along the lateral border. The anterior intertrochanteric line (blue) is fol-lowed just above the superior inser-tion of the vastus lateralis. If neces-sary, the pars reflecta of the rectus femoris muscle can be excised.

Figure 6: Hohmann retractors are placed inside the capsule below and above the femoral neck. The oste-otomy level is identified by palpat-ing the pretrochanteric tubercle. The intertrochanteric line (blue) suggests the direction of the osteotomy, 1 cm proximal to the lesser trochanter.

Figure 7: Optimal acetabular expo-sure with the modified Charnley re-tractor fixed inside the open capsule.

n tips & techniques

ral exposure is not satisfactory, the hip is returned to the neu-tral position and the maneuver is restarted from the begin-ning. The adduction of the leg positioner below the contra-lateral leg facilitates broach insertion. For very muscular patients, excessive adduction increases tensor fascia lata ten-sion, which may finally result in a reduced operating space.

During femoral broach-ing, the position of the trac-tion boot should not be trusted because there is a wide dis-crepancy between the external rotation of the foot and that obtained at the knee. The pa-tella is palpated to confirm 90° of external rotation. A dedicat-ed curve handle designed for the anterior approach must be used for broaching the femur.

To avoid leg-length dis-crepancy, a few tricks must be adopted (Figures 9-10). Leg length can also be assessed by fluoroscopy, which is not pre-vented when using a traction table.

Reduction is performed through a series of steps. First, the adduction is removed and the hip is elevated until slightly flexed. With traction applied, the femur is internally rotated to perform the reduction. Once reduction is achieved, the trac-tion is released. The stability of the THR can be checked via the anti-dislocation test with the foot in 90° of external rotation.

The anterior capsule is su-tured. The anterior approach permits preservation of all muscular insertions. There-fore, only fascia, subcutane-ous tissue, and skin must be closed.

MaTerialS and MeThodSThe authors performed

90 THRs via the anterior ap-proach from April 2009 to February 2013. An anterior minimally invasive surgery leg positioner (AMIS; Medacta International, Castel San Pi-etro, Switzerland) was used in all cases. All of the patients received a short, straight, hydroxyapatite-coated stem (AMIS Stem; Medacta In-ternational), a hemispherical hydroxyapatite-coated cup (Versafitcup CC; Medacta International), and a ceramic-on-ceramic coupling (Biolox delta; CeramTec GmbH, Plo-chingen, Germany). For the purpose of this study, patients were recalled for clinical and radiologic assessment.

reSulTSNo patient was lost to

follow-up. Average Harris Hip Score10 was 90 at latest follow-up, confirming an excellent clinical outcome. One patient had an intraoperative undis-placed fracture of the greater trochanter. Seven patients reported a smooth meralgia paresthetica (burning and/or numbness sensation) that did not interfere with activities of daily living. In 1 patient, signs of implant loosening were observed around the femo-ral stem, which was revised 2 years after implantation. This patient had a 1.5-cm leg-length discrepancy (contralat-eral side longer than the oper-ated on side). A second failure was recorded; the acetabular component was revised a few days after surgery because of hip dislocation.

diScuSSionAdvantages of the ante-

rior approach for THR include minimal soft tissue dissection with no muscle detachment, a low dislocation rate, and reduced consumption of pain medication ultimately result-ing in a shorter hospital stay and faster functional recov-ery.11,12 The authors believe that these advantages are at least partly the result of the minimally invasive nature of this approach, which keeps soft tissue trauma to a mini-mum and leads to faster post-operative mobilization and rehabilitation. In addition, as greater interest in smaller in-cisions has been generated by cosmetic concerns, this ap-proach offers a short incision that can be further cosmetical-ly improved with a bikini-like incision.9

The major concern about the anterior approach relates to the high number of compli-

cations reported, particularly during the surgeon’s learning curve, leading to a higher re-vision rate.13,14 In a series of more than 5000 THRs through the anterior approach, the cu-mulative revision rate at 4 years was 3%. Revision rate is strongly influenced by surgeon experience, with rates of 6% and 2% reported for surgeons who performed fewer than 15 or more than 100 procedures, respectively.15 The main diag-noses leading to revision, in order of frequency, are report-ed to be femoral fracture, loos-ening/lysis, prosthetic disloca-

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Figure 8: Both the ischiofemoral and the pubofemoral ligaments are re-leased close to the acetabular bone to preserve the posterior vessels.

Figure 9: The final broach is left inside the femur. The trial neck is inserted. A ruler is used to check whether the head-neck length match-es preoperative planning.

Figure 10: The trial component is matched with the resected femoral head. The broach is aligned with the neck cut, the center of the trial head is matched with that of the resected head, and the head length is adjusted.

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n tips & techniques

tion, infection, and leg-length discrepancy.15 Nevertheless, a short stem with a smoother shoulder could be useful for avoiding femoral fractures.

A specific drawback of the anterior approach is the pos-sible injury to the lateral femo-ral cutaneous nerve,16 even if this rarely leads to functional limitations. During skin inci-sion, to minimize the odds of nerve damage, the surgeon must remain 1 inch lateral to the anterosuperior iliac spine. In an anatomical study, the lat-eral femoral cutaneous nerve branched before traversing the inguinal ligament in 27.6% of cases.17 If a patient has this anatomical feature, complete nerve preservation is almost impossible.

Another limitation of the anterior approach performed with the aid of a traction table is difficulty with intraoperative leg-length assessment. This may be overcome following the authors’ suggestions.

concluSionIn the authors’ experience,

the anterior approach pro-vides an excellent functional outcome with a low rate of

complications and thus may ultimately result in an over-all reduction in costs. Even among experienced surgeons, a change in surgical approach may lead to a different out-come. To reduce the learning curve, the authors suggest spe-cific training and proper edu-cation in either cadaver labora-tories or reference centers. To overcome the most common difficulties encountered during the anterior approach for THR, reduce complications, and achieve a satisfactory clinical result in a reproducible man-ner, the steps of the surgical technique must be followed.

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