Exposure of the hip joint via partial anterior release of the vastus lateralis and gluteus medius muscles from the greater trochanter is referred to as the direct lateral approach to the hip. The continuity of the gluteus medius and vastus lateralis through the thick periosteum overlying the greater trochanter is preserved, either by elevating this periosteum off of bone as an anterior sleeve, or by cutting off a slice of the bone underlying this tissue. The direct lateral approach has the advantage of providing increased post-operative stability because the posterior capsule and musculature are repaired anatomically. The popularity of this exposure has increased as the technique has been refined.

           A number of variations of the technique exist. Sources of variation include the skin incision; the percentage of gluteus medius and vastus lateralis released anteriorly; release through soft tissue or bone; the size of the fragment when the bony release is used; handling of the gluteus minimus and hip capsule; and the technique of reattaching the anterior sleeve to bone. Dr. Hugh Chandler was one of the first orthopaedic surgeons at Harvard to begin using the direct lateral approach on a routine basis. His technique is described herein and comments from other surgeons at Harvard the use the direct lateral approach follow.

Background

           In 1954, McFarland and Osborne described a method of preserving the integrity of the gluteus medius muscle when performing a posterior approach exposure of the hip joint.1 The technique was predicated on the recognition of what they described as a direct functional continuity of the gluteus medius and vastus lateralis through the thick, tendinous periosteum covering the greater trochanter. This area was released by separating "bony flakes" with the periosteum in the belief that bone-to-bone healing was more reliable than the healing of periosteum back to bone. They handled the gluteus minimus by releasing its tendon from the greater trochanter and retracting the muscle belly proximally.

           Hardinge modified the technique by splitting the gluteus medius, releasing only half of the muscle anteriorly.(2) He felt that this facilitated subsequent repair since division of the anterior half of the gluteus medius splits the muscle in the thick tendinous region which can be securely sutured. Dall also utilized partial release of the gluteus medius, but preferred an osteotomy of the anterior part of the greater trochanter.3 He created a bony fragment large enough to incorporate the insertion of the minimus tendon.

Operative Technique

           After induction of general endotracheal anesthesia, the patient is positioned in the lateral decubitus position. Dr. Chandler uses a beanbag and kidney rests to reinforce the position. The skin is degreased with ethylene glycol and prepared with iodine followed by careful removal of iodine when dry with an alcohol sponge to prevent skin burns

           Draping is performed using large sheets first to protect the surgeon from the unsterile field, followed by smaller towels. An Aufranc drape is used to isolate the perineum. A large bag is prepared and attached to the side of the table which the patient faces (the anterior side). The bag is used to contain the leg and keep it sterile as it is dropped below the level of the table during anterior dislocation of the hip. Prior incisions are traced with a sterile marking pen prior to placement of an iodine adhesive drape. These are incorporated when possible, but there is little risk in ignoring them.

           Some surgeons prefer to curve the proximal portion of the incision anteriorly in order to facilitate exposure of the acetabulum. Dr. Chandler has emphasized that most exposures of the hip joint can be performed through an incision made directly in line with the femur with the hip flexed 45 degrees. (Figure 2)

          Sharp dissection is emphasized as it is less traumatic to soft tissue than blunt approach. Dr. Chandler stresses careful tissue handling and will only use hand held retractors since he feels that prolonged use of self-retractors can contribute to tissue necrosis. At the level of the deep fascia, the subcutaneous tissue is separated from deep fascia using sharp "plowing" technique, for a width of two centimeters to either side of the planned split in the deep fascia. The deep fascia is split distally over the shaft of the femur and proximally in the interval between gluteus maximus and tensor fascia femoris. Wound towels moistened with antibiotics are then sewn to the depths of the incision to prevent desiccation of the soft tissues.

          The muscle fibers of the gluteus medius are separated using two wing tipped elevators at the anterior border of the greater trochanter, approximately four to five centimeters anterior to the posterior edge of the muscle.(Figures 3, 4) This leaves the abductor portion of the medius in continuity with the greater trochanter, and the flexion/internal rotation portion with the anterior soft tissue sleeve. The split in the gluteus medius is limited to less than five centimeters from the tip of the greater trochanter in order to protect the superior gluteal nerve.

          A fat pad is encountered between the gluteus medius and underlying gluteus minimus. (Figure 4) The gluteus minimus is split one centimeter anterior to its posterior border along with the underlying capsule. Distally, the quadriceps are left in continuity with the abductors, and the anterior fascia of the vastus lateralis is split a distance of six centimeters or so distal to the greater trochanter. The transverse branch of the lateral circumflex artery is consistently located just distal to the vastus ridge, and should be ligated. (Figure 4)

           Subperiosteal elevation of the vastus lateralis, intermedius and medius is performed with a 1/2 inch curved osteotome. Sharp dissection and electrocautery are used to separate capsule, minimus and medius from the anterior portion of the greater trochanter. An anterior cuff of soft tissue is developed including the gluteus medius, gluteus minimus, anterior capsule, vastus medialis and vastus intermedius. (Figure 5) The hip is dislocated anteriorly with flexion, adduction and external rotation.

          Dr. Chandler emphasizes respect for and maintenance of the separation of gluteus medius and minimus at the time of wound closure. The gluteus minimus is a pure abductor and inserts on the inferomedial aspect of the greater trochanter, anterior to the vastus tubercle and just superior to the femoral neck. (Figure 6) If the minimus is reattached with the medius to the superior aspect of the greater trochanter, then a significant limp will result. The medius tendon is thick and stout in its anterior portion, and attaches to the lateral and posterior aspect of the greater trochanter. Firm reattachment of the anterior cuff of capsule, gluteus minimus and gluteus medius is critical if abductor weakness is to be avoided. Decortication of the anterior trochanteric bed with an oscillating saw facilitates firm healing of soft tissue to bone. Repair of the anterior capsule and gluteus minimus is performed with #2 braided nonresorbable mattress sutures through drill holes. The anterior tendinous portion of gluteus medius is then repaired primarily using #1 braided resorbable suture. The gluteus medius and vastus medialis fascia are then reapproximated directly, also using a #1 braided resorbable suture.

          A deep drain is placed over the abductors. The deep fascia is repaired with a running #1 braided resorbable suture, beginning at the musculotendinous junction and running one proximally and one distally. A superficial drain is placed over the deep fascia. The subcutaneous tissue is closed with a running 2-0 braided resorbable suture, followed by multiple interrupted 2-0 resorbable sutures near the dermis. The skin is closed with a subcuticular 3-0 braided resorbable suture and adhesive strips. A compression dressing extending from the toes to the waist is used over sterile gauze and ABD pads to minimize fluid collection in the subcutaneous space.

Post-operative Management

           Post-operatively, patients are placed in pillow suspension for the first night after surgery. Protected partial weight bearing (60 to 80 pounds) is begun on the first post-operative day and continues for six weeks to protect the soft tissue healing to the trochanter. Patients begin active side-lying abduction exercises and full weight bearing at six weeks.

Summary

          Dr. Chandler's technique for the direct lateral approach to the hip is a modification of the original technique, with the underlying principle being protection of the abduction mechanism and the continuity between the hip abductors and knee extensors. Dr. Chandler's technique has yielded extremely low rates of infection, which he attributes to sharp dissection technique and meticulous handling of soft tissues. The continuity of the posterior capsule with the greater trochanter, and subsequent primary repair contributes to a remarkably low rate of dislocations. Attention to the position of the split in the medius and the proximal extension on the abductor split has led to no significant Trendelenberg gait in primary arthroplasties that are attributable to exposure. Heterotopic bone formation is apparent radiographically in 30-40% of patients, but it is distal and over the trochanter, resulting in only one patient with motion limited by bone formation.

Sigurd Berven, MD is a Resident in the Harvard Combined Orthopaedic Residency Program

Hugh Chandler, MD is an Attending in the Department of Orthopaedic Surgery; Massachusetts General Hospital; and Assistant Professor of Orthopaedics at Harvard Medical School

Address correspondence to:
Harry E. Rubash, MD; Department of Orthopaedic Surgery; GRB- 606; Massachusetts General Hospital; Boston, MA 02114

Variations of the Direct Lateral Approach at Harvard:

Stephen B. Murphy; Beth Israel Deaconess Medical Center
          Dr. Murphy emphasizes that no single approach is adequate for all hip problems, and that combined approaches are often required for complex problems. He uses the direct lateral approach for most primary total hip replacements except those with a severe high-riding dysplastic acetabulum due to risk of injury to the superior gluteal nerve. Like Dr. Chandler, he uses the direct lateral approach for simple socket revisions. For many femoral revisions, he uses a vastus slide exposure, which is a direct lateral exposure connected to a lateral approach to the femur. He feels that more extensive revisions require a trochanteric slide exposure.

          Dr. Murphy's technique of direct lateral exposure is similar to Dr. Chandler's, as he trained as Dr. Chandler's fellow. He splits the gluteus medius more anteriorly than Dr. Chandler does, identifying a Òsoft spotÓ at the anterior-superior portion of the greater trochanter, underwhich lies the bursa deep to the medius and superficial to the minimus tendon. The incision is made just posterior to that spot. The medius is then split in line with its fibers from there. He doesn't quantify the percentage of medius split, but the superior portion of the medius remains intact and the anterior portion of the medius becomes part of the anterior flap. Rather than splitting the gluteus minimus as is typically done, he identifies the posterior border of the minimus, just under the piriformis tendon, and mobilizes the minimus anteriorly off of the capsule until the midcoronal line of the capsule is exposed. A thin wafer of the anterior portion of the greater trochanter is then taken. It is about 10 millimeters thick proximal-laterally and thins out as the cut goes anterior and distal. The insertion of the gluteus minimus is attached to the wafer of bone. It is important to make the bone wafer much thinner in elderly osteoporotic patients as such patients are at greater risk of postoperative greater trochanteric fracture at the vastus tubercle. The labrum and osteophytes are excised leaving the capsule intact. The trochanteric osteotomy is repaired using #5 braided nonresorbable suture through drill holes in both the femur and trochanteric wafer.

Dennis Burke, MD; Massachusetts General Hospital
          Dr. Burke uses the direct lateral approach for most primary total hip replacements. Absolute indications are patients with dementia or spasticity, and patients whose cultural behaviors require kneeling or squatting for prayer or toiletry. Exceptions are cases with complex deformity to the proximal femur or acetabulum because he gains a more extensive exposure from the posterior approach, and cases with a high-riding acetabulum due to the risk of injury to the superior gluteal nerve and denervation of the anterior abductors. Dr. Burke also avoids the direct lateral approach in patients with severe osteoporosis due to the risk of fracture to the proximal femur after osteotomy.

           Dr. Burke uses a straight incision through skin and the fascia. He splits the medius with 60% posterior, 40% anterior to maximize the integrity of the retained continuity between abductors and extensors. He uses a single-plane ÒguillotineÓ split to divide medius, minimus and capsule at the same position, facilitating anatomic closure. When the posterior fibers of gluteus medius are hindering preparation of the femoral canal, he uses a Òreverse five for fiftyÓ maneuver. This technique involves releasing the anterior five millimeters of medius from the posterior edge of the greater trochanter in order to protect the abductors that remain with the trochanter from damage during preparation of the femoral canal. Dr. Burke uses an osteotomy of the greater trochanter measuring about eight millimeters in thickness. In osteoporotic patients he uses a thinner wafer to avoid the risk of fracture to the proximal femur. An important feature of his osteotomy is to crack the anterior edge to create a contour that allows for anatomic reapproximation of the osteotomy. He emphasizes the importance of bony reattachment for healing of the abductors to the trochanter and for retention of abductor strength, noting that soft tissue releases of the abductor mechanism may be associated with higher rates of Trendelenberg gait. He reapproximates the capsule only when he feels that the capsular repair is needed to contribute to stability. He uses three or four 18 gauge stainless steel wires to reattach the trochanteric wafer, tensioning the wires with an air drill and the ÒmattababyÓ wire tightener.

           Dr. Burke identifies stability as the major advantage of the direct lateral approach, with rates of dislocation in the literature consistently less than one percent. He has patients limit weight bearing for six weeks post-operatively, and thereafter has no restrictions on activity, sitting, bending, or leg position.

Thomas Minas, MD; Brigham and Women's Hospital.
          Dr. Minas uses the direct lateral approach for all primary total joint replacements. For revisions, he feels that knowledge of several approaches is necessary, and an approach that optimizes exposure for the defect in revision surgery is best. Dr. Minas does not see the high hip center as a contraindication to the direct lateral approach, noting that the superior gluteal nerve can be identified and protected, and that the approach permits an easy dislocation of the dysplastic hip anteriorly.

           Dr. Minas uses a straight skin incision along the femoral shaft, curving the incision anteriorly roximally to protect the abductor/vastus sleeve. He curves the split in the tensor fascia lata posteriorly to assist with proximal femoral exposure. His split of the abductors is identified by palpation of the junction between the muscular and tendinous portion of the medius, leaving the posterior tendinous portion of medius on the greater trochanter, and elevating the anterior two thirds of medius off the trochanter in a soft tissue sleeve. Dr. Minas uses blunt dissection to develop a split in the gluteus medius and gluteus minimus, and then protects the underlying capsule by packing the interval between abductor and capsule with a sponge. He emphasizes that he rarely needs to split the abductors more than two centimeters proximal to the trochanter, and therefore the superior gluteal nerve is well protected. He then uses electrocautery to elevate a soft tissue sleeve of abductors and vastus lateralis off the greater trochanter anteriorly. He continues to protect the underlying capsule with a sponge in the interval between abductors and capsule, and most medially between psoas and capsule. He releases the indirect head of the rectus femoris from the capsule, and then retracts the soft tissue sleeve using a Bunnell stitch capturing the minimus and medius, a sharp Homan in the ilium, and two cobra retractors, one under psoas, and one over the proximal shaft of the femur. Retraction of the soft tissue sleeve anteriorly exposes the entire anterior and inferior capsule, which he then excises. Dr. Minas feels that he is able to gain excellent exposure of the acetabulum through this approach, even for complex acetabular reconstructions. In closing, he decorticates the anterior portion of the greater trochanter with a saw, and sutures the abductor sleeve back on through three drill holes in the trochanter, using number five nonresorbable braided suture.

           Dr. Minas identifies stability and ease of dislocation with the dysplastic hip as the major advantages of the direct lateral approach.. Post-operatively he uses precautions of partial weight bearing and no active abduction for four weeks. He initiates active abduction exercises at six weeks after surgery. He reports that limps consistently disappear with exercise.

Harry Rubash, MD; Massachusetts General Hospital
          Dr. Rubash uses the direct lateral approach for all primary and revision total hip replacement surgeries. He agrees with Dr. Minas that a high hip center or dysplastic acetabulum is not a contraindication to the direct lateral approach because the superior gluteal nerve is easily identifiable, and the abductors may be split beneath it.

           Dr. Rubash curves his skin incision slightly anteriorly at the level of the greater trochanter to facilitate exposure of the acetabulum, and then may use a transverse split of the posterior portion of the fascia lata to improve exposure to the proximal femur. He splits the medius and minimus tendons in line with the femoral neck, extending the split to the level of the capsule. He then uses periosteal elevation to create an anterior sleeve of abductors and capsule, permitting anterior dislocation of the femur. Dr. Rubash repairs the anterior sleeve to bone with transosseous sutures. He identifies stability and excellent exposure of the acetabulum and femur as the major advantages of the direct lateral exposure.