Open Gluteus Medius Double-Row Repair With Acellular Allograft Augmentation

Abstract

Background:

Gluteus medius tears are a common pathology affecting the lower extremity, predominantly in older female patients, and most often caused by chronic degenerative changes. Due to the associated morbidity with gluteus medius insufficiency, various surgical repair techniques are utilized, including open and endoscopic approaches, with equivalent biomechanical outcomes.

Indications:

Open gluteus medius double-row repair with acellular allograft augmentation is indicated for patients with massive, full thickness tears, full thickness tears with extensive retraction, degenerative tears, poor tissue quality, revision cases where tendon reduction to the footprint is challenging, and impaired hip abduction strength. The primary benefit of acellular allograft use is the provision of immediate structural strength to the repair construct.

Technique Description:

The patient is placed in the lateral decubitus position, and a direct lateral incision is made over the greater trochanter. The gluteus medius and/or minimus tendons are identified, mobilized, and provisionally reduced to the footprint. The tendon footprint is then debrided, and proximal anchors are placed. The graft is provisionally fixed to the tendon with sutures anteriorly and posteriorly to ensure correct placement. Sutures are passed from the proximal row through the tendon and prepared allograft, where 1 suture limb from each mattress is placed into a double-row anchor in the distal row. Once secured, the repair is checked through a range of dynamic positions.

Results:

Although outcomes studies are limited, case series of patients undergoing open gluteus medius repair with allograft have demonstrated favorable patient-reported outcomes, improved pain, improved hip abduction strength, and improved gait.

Discussion:

Open gluteus medius repair with acellular allograft provides immediate structural strength to the repair construct and should be considered in patients with massive, full thickness tears with extensive retraction, degenerative tears with poor tissue quality, revision cases, and impaired hip abduction strength.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

The following is our technique for open gluteus medius double-row repair with acellular allograft augmentation.

Here are our disclosures.

Gluteus medius tears are more common in older patients, particularly women, and are most typically degenerative in nature. While traumatic etiologies are possible, and may occur in younger patients, these are rare.^5,6,10 Degenerative medius tears typically originate from the central fibers of the insertion, then propagate anteriorly and posteriorly.^5,6,10

Given the morbidity associated with abductor insufficiency or deficiency, it is not surprising that a multitude of repair techniques exist. Each have various indications and are optimal in different clinical situations.^1,3-6,8-10 Considerations for augmentation with acellular allograft are based on the size of the tear, tissue quality, and tendon excursion. While the gluteus Medius is a big muscle, it has a short tendon, so in cases with questionable tendon quality or likely tension on the repair, a patch can provide structural integrity to pass sutures through.

Potential negatives of the graft include increase cost, risk of infection, though this is low, and added time to the procedure.

The gluteus medius origin starts at the anterosuperior iliac spine, then spans the entirety of the iliac crest, ending at the posterosuperior iliac spine. There are 3 components to the medius tendon—the anterior and middle fibers insert onto the lateral facet, while the posterior fibers insert onto the superoposterior facet. The gluteus minimus originates on the iliac wing from the anteroinferior iliac spine to the posteroinferior iliac spine along the middle gluteal line. It inserts on the anterior facet of the greater trochanter.

Both open and endoscopic techniques have been evaluated in biomechanical studies, with most finding similar load to failure between methods. Importantly, the most common mode of failure in biomechanical studies is often the muscle pulling off its origin, not the repair construct, suggesting repairs using either technique can be robust. ⁴ A 2012 cadaver study comparing knotted vs knotless double-row gluteus medius repairs found the knotless technique to be equal or superior to the knotted technique for both cyclic loading and load-to-failure trials. ³

With that background in mind, we present a case of a 69-year-old woman who presented with 1 year of right lateral and buttock pain, which acutely worsened over the 2^1/2 months prior to presentation.

Bursal injections initially provided relief, but their efficacy waned, and her pain limits her ability to perform activities of daily living. On physical examination, the patient had a slight Trendelenburg gait, with weak hip abduction and tenderness over the greater trochanter.

Anteroposterior (AP) and Dunn lateral x-rays of the right hip demonstrate Tonnis grade 0, and no bony abnormalities. Magnetic resonance imaging (MRI) of the left hip without contrast demonstrates a full thickness gluteus medius tear with about 2.5 cm of retraction. This can best be appreciated on the coronal and sagittal planes.

The primary benefit of acellular allografts is they may provide additional time-zero strength to a repair. Accordingly, indications for allograft use are related to tendon quality, where there is concern for ability to achieve a robust repair in the operating room (OR).^2,7 In this case, given the complete tear with large amount of tendon retraction on preoperative MRI, it was decided allograft augmentation would be utilized.

The following is our surgical technique.

The patient is placed in the lateral decubitus position, with the operative limb free. Landmarks for the lateral approach to the hip include the greater trochanter and the proximal femoral shaft. An incision is made directly over the greater trochanter, between 4 and 6 cm in length with 2/3 proximal, and 1/3 distal to the center of the trochanter. After subcutaneous dissection, the fascia is divided, centered over the greater trochanter, with care not to injure the underlying abductor tendons. The trochanteric bursa is then excised.

Abductor tear identification can be challenging, and care must be taken not to iatrogenically injure the tendon while trying to expose it. This superficial layer retracted with the cobb may be excised, but the senior author prefers to incorporate it into the repair, as it can have a muscular component. The tendon is found deep to this layer, and provisionally reduced to its footprint.

A traction suture is placed through the tendon to aid with mobilization and tendon reduction. This is placed in a figure of 8 fashion to prevent suture pull through. A second traction suture through the gluteus medius is placed to provide a stronger, more uniformly distributed force vector. Finally, a third traction suture is placed anteriorly through the gluteus minimus, which was also torn in this case.

The gluteus medius has 2 insertions. First, the superoposterior facet can be seen here, and then the lateral facet insertion. The footprint is decorticated with a burr to augment the tendon-to-bone healing response. Changing limb position may help with footprint exposure. External rotation can improve visualization of the anterior trochanter, while internal rotation helps with posterior visualization. The first anchor is placed at the superoposterior aspect of the footprint, and the second anchor is placed at the anterior to this one. Each is a triple-loaded anchor (Stryker).

The graft will sit on top of the tendon and is incorporated into the repair construct. The graft should be rectangular in shape, and should be large enough to span the tendon, proximal to the proximal row, and distal to the distal row. A ruler is used to ensure appropriate length and width are obtained. These measurements are drawn on the graft itself, and it is cut to the desired specifications.

The graft is provisionally fixed to the tendon with Vicryl sutures anteriorly and posteriorly to ensure correct placement in the desired location.

Sutures from the superior posterior anchor are passed through the tendon, then through the allograft in mattress fashion. This is done a total of 6 times, which will allow for 3 mattress knots. Next, 4 suture limbs from the superior anterior anchor are placed through the tendon and allograft, which will allow for 2 mattress knots.

With 10 limbs through the medius to form the proximal row, attention is turned toward the minimus. The remaining 2 suture limbs from the anterosuperior anchor are passed through the minimus.

The leg is internally rotated while the proximal row mattress sutures are tied to take tension off the repair. Mattress knots are tied sequentially from posterior to anterior. Each suture limb here is through both the medius tendon and the dermal allograft.

With the proximal row secured, attention is turned toward the distal row. The distal row will consist of 2 knotless anchors, 1 anterior and 1 posterior. Each anchor will receive 5 suture limbs, 1 from each mattress knot securing the medius tendon from the proximal row.

The suture limbs previously passed through the minimus are now passed through the allograft. In this case, this was done after securing the distal row, so that the final graft position would be known, and this mattress suture would assist in securing the edge.

The hip is taken through a range of motion to confirm adequacy of repair. The muscle-tendon-bone complex can be seen moving as a unit throughout range of motion, with the graft secured in place.

To summarize the surgical sequence: (1) A direct lateral approach is used, centered over the greater trochanter; (2) next, the glut medius and minimus tendons are identified, then mobilized to increase excursion and then provisionally reduced to the footprint; (3) the tendon footprint is debrided and proximal row anchors are placed; (4) sutures are passed from the proximal row through the tendon and prepared allograft; (5) one suture limb from each mattress is placed into a double-row anchor in the distal row; (6) the repair is then checked.

Postoperatively, patients are kept partial weight-bearing for 2 weeks with a hip brace preventing extremes of motion. Starting at 6 weeks, patients progress to full weight-bearing, and then transition out of the brace. At 12 weeks, patients should be ambulating without assistance. ²

Outcome studies are currently limited, but a 2021 study of 8 patients who underwent abductor reconstruction with a dermal allograft found no re-tears at 1-year follow-up, with 75% of patients above Patient Acceptable Symptomatic State based on the modified Harris Hip score (mHHS). ²

Another recent study using a mini-open double-row technique found patients had significantly improved abductor strength, decreased Trendelenburg sign, and improved mHHS scores, providing clinical evidence of technique efficacy. ¹

Thank you for your attention.