Pathology of the hip abductors is common, affecting primarily middle-aged and older adults. Often grouped under the moniker of “greater trochanteric pain syndrome,” abductor pathology presents on a spectrum ranging from tendinitis/trochanteric bursitis to complete ruptures of the gluteus medius and minimus.1 Limited data exist on the epidemiology of abductor tendon pathology, but small prevalence studies suggest that as many as 20% of patients with hip arthritis have concomitant abductor tendon tears, though in many cases these may be clinically silent.2,3 Nonoperative treatment of hip abductor tendinitis/trochanteric bursitis is successful in up to 81% of patients,4 and primary repair of partial and complete hip abductor tendon tears has been shown to be successful in relieving pain and functional deficits.5–7

However, not all tears are repairable, even with extensive soft tissue releases. Further, in cases of complete tendon rupture with muscle atrophy and fatty replacement, the results of surgical repair are disappointing. A recent series has shown that increasing fatty infiltration of the gluteus medius correlated to increased pain and decreased patient-reported outcome scores (PROs) after endoscopic repair of hip abductor tendon tears.8

Several techniques for addressing irreparable tears or tears with extensive fatty atrophy have been described, including advancement of the vastus lateralis,9,10 augmentation with Achilles allograft,11 and transfer of the gluteus maximus.12,13 Many of these techniques are technically challenging, and only a few studies describe the outcomes of these procedures in patients with a native hip joint.

The purpose of this study is to describe our technique for addressing irreparable hip abductor tendon tears or those with advanced fatty atrophy of the gluteus medius muscle belly. Our preferred approach to this challenging clinical problem is a transfer of the upper half of the gluteus maximus tendon to the abductor footprint to stabilize the pelvis during ambulation. We present both the technique and the clinical results of a small series of patients followed for a mean of 3.8 years postoperatively.

METHODS

Since 2010, we have maintained an institutional registry tracking patients undergoing arthroscopic/endoscopic and open hip preservation surgery. All patients agreeing to enrollment in the institutional review board approved registry sign an informed consent form before surgery and complete a baseline questionnaire. The registry tracks selected PROs including the modified Harris Hip Score (mHHS), Hip Outcome Score-Activity of Daily Living Scale (HOS-ADL), Hip Outcome Score-Sports Scale (HOS-S), and the International Hip Outcome Tool (iHOT-33). In addition, clinical examination findings including hip range of motion (ROM) and strength in flexion, abduction, and adduction. Assessments are performed preoperatively and postoperatively at 3 months, 6 months, and annually thereafter. For this study, the registry was queried for all patients undergoing gluteus maximus transfer for hip abductor tendon tears.

Inclusion and Exclusion Criteria

Included patients had (1) symptoms of lateral or posterior hip pain with tenderness over the greater trochanter, (2) magnetic resonance imaging (MRI) scan demonstrating a tear of the hip abductor tendons, (3) surgical treatment involving transfer of the gluteus maximus tendon, and (4) a minimum of 1-year follow-up on PROs. We excluded patients with an ipsilateral total hip arthroplasty or patients with <1-year follow-up. Patients who did not complete the preoperative baseline questionnaire were not excluded, but were not included in the analysis.

Data Collection

We collected demographic, clinical, intraoperative, and outcome data from our registry. We further supplemented this collection with an examination of patient electronic medical records, which was approved by a supplemental filing with our institutional review board.

Demographic data included patient age, sex, race, and affected side. Clinical data included duration of symptoms, acute versus chronic onset, prior ipsilateral hip surgery, prior peritrochanteric corticosteroid injections, preoperative and postoperative ROM, abductor strength on manual muscle testing, and the presence of a Trendelenburg gait. Preoperative MRI scans were reviewed independently by 2 of the authors to assess the Goutallier/Fuchs classification of the gluteus medius muscle belly of each patient.

Intraoperative data included the number of anchors used in the procedure and the performance of any secondary procedures. Outcome data included the preoperative and postoperative PROs and examination findings, postoperative complications, and any reoperations over the follow-up period.

Surgical Technique

At the time of surgery, patients are positioned in the lateral decubitus with care taken to prevent any pressure on the common peroneal nerve of the down leg. A 15 cm curvilinear incision is made centered over the greater trochanter and the subcutaneous tissue dissected down to the level of the tensor fascia lata (TFL). The TFL is incised at the anterior edge at the junction of the gluteus maximus and carried superiorly through the fascial envelope for ~10 cm. Self-retaining retractors are placed and the bursa excised to reveal the trochanteric insertions of the gluteus medius and gluteus minimus.

In all cases there was a complete rupture of the hip abductor tendons with retraction. Soft tissue releases were performed bluntly and with electrocautery as needed to mobilize the tendon back to the anatomic footprints on the anteromedial and posterosuperior facets of the greater trochanter. The bony footprints are partially decorticated using a burr, and 4.5 or 5.5 mm bone anchors (depending on surgeon assessment of bone quality), and their sutures passed through the torn tendons in modified Mason-Allen manner. The tendons are reduced to the bone and tied. Anchors are typically placed in double-row manner, with the precise number of anchors determined by surgeon assessment and patient size.

Next the gluteus maximus is mobilized medially over the superficial surface using electrocautery, and then the deep surface is bluntly dissected back to the sacrum. The sciatic nerve is identified and neurolysed as needed if there are areas of entrapment. Once mobilization is complete, the proximal third of the muscle is separated along its raphe with electrocautery through the fascia, taking care to leave the underlying muscle fibers intact. The anterior margin of the proximal flap is secured to the greater trochanter using the previously placed suture anchors and tied (Figs. 1–9).

FIGURE 1:

Patient positioned in the lateral decubitus with planning incision marked (12 cm, centered over the greater trochanter).

FIGURE 2:

Exposure of the greater trochanter with severely degenerative and torn hip abductor tendons.

FIGURE 3:

Proximal mobilization of the torn portion of the gluteus medius.

FIGURE 4:

Exposure of the gluteus minimus with identification of a torn portion off the anterolateral facet.

FIGURE 5:

Posterior dissection exposing the superficial surface of the gluteus maximus.

FIGURE 6:

Deep surface dissection of the gluteus maximus with identification of the sciatic nerve (arrow).

FIGURE 7:

Once mobilization of the gluteus medius, gluteus minimus, and gluteus maximus are complete, adequate mobilization is demonstrated by tension free reduction to the greater trochanter.

FIGURE 8:

Following suture anchor placement, sutures are incorporated into the gluteus medius and gluteus minimus, and are tied. Suture ends are then passed through the gluteus maximus tendon and tied again.

FIGURE 9:

Sutures are tied to complete repair.

In patients who are very thin or have relative atrophy of the gluteus maximus, we will sometimes use an acellular dermal allograft secured over the top of the gluteus maximus transfer to promote granulation tissue formation and healing. The TFL is then repaired and secured back to the anterior edge of the gluteus maximus, and the wound closed.

Postoperatively, patients are kept in the hospital overnight for pain control and physiotherapy. They are limited to partial weight-bearing to 20 lbs on the affected extremity using crutches or a rolling walker for 6 weeks. After that, progressive weight-bearing is begun, increasing to full weight-bearing over the following 2 to 3 weeks. A supervised physical therapy program begins 6 weeks after surgery, emphasizing closed-chain functional exercises.

Statistical Analysis

Cohort variables are reported descriptively using counts, means, medians, and ranges. Because of the small number of patients in the study cohort, no statistical analysis was performed on preoperative and postoperative variables.

RESULTS

A total of 73 patients underwent hip abductor surgery over the study period, of which 7 underwent a gluteus maximus transfer. One patient had a concomitant degenerative neurological condition that prevented him from completing postoperative follow-up surveys, and so was excluded. The remaining 6 patients comprise the study cohort, and their demographic details are summarized in Table 1. Mean follow-up for in-person clinical examination was 2.6 years (range, 1 to 6 y), and mean follow-up for PROs was 3.8 years (range, 1 to 6 y).

TABLE 1 - Demographic and Clinical Summary of Patient Cohort Age (y)  Mean (range) 65 (33-82) Sex [n (%)]  Male 0 (0)  Female 6 (100) Affected side [n (%)]  Right 4 (67)  Left 2 (33) Prior ipsilateral hip surgery [n (%)]  Yes 2 (33)  No 4 (67) Symptom duration [n (%)]  6-12 mo 3 (50)  >1 y 3 (50) Preoperative corticosteroid injections [n (%)]  Yes 5 (83)  No 1 (17) Goutallier/Fuch classification [n (%)]  Grade 2 2 (33)  Grade 3 3 (50)  Grade 4 1 (17)

All patients were female, with a mean age of 65 years (range, 33 to 82 y), and all had pain for at least 6 months before surgery. Two patients had a history of prior ipsilateral hip surgery. One had a history of femur fracture with intramedullary nailing through a trochanteric start point, and subsequent nail removal for persistent lateral hip pain. The other had undergone a prior arthroscopic bursectomy which failed to improve her lateral hip pain. The remaining patients had no history of prior surgery.

All patients had signs of gluteus medius muscle atrophy with fatty infiltration. Two patients (33%) had grade 2 changes, 3 (50%) had grade 3 changes, and 1 (17%) had complete replacement of muscle tissue with fat consistent with grade 4 changes.

All patients had near normal preoperative hip ROM, and there was no significant change in motion after surgery. All patients had a Trendelenburg gait preoperatively, and 3 patients (50%) had resolution of their Trendelenburg gait postoperatively. Mean hip abduction strength preoperatively was 3.8/5; at final follow-up all patients had full abduction strength (5/5). All patients showed improved PROs, as summarized in Table 2.

TABLE 2 - Preoperative and Postoperative Range of Motion, Strength, and Patient-reported Outcome Scores Preoperative Postoperative Mean hip motion (range) (deg.)  Flexion 103 (100-110) 102 (100-110)  External rotation 42 (35-45) 44 (40-45)  Internal rotation 23 (15-30) 21 (10-25) Mean hip abduction strength (range) 3.8 (2-5) 5 (5-5) Trendelenburg gait [n (%)] 6 (100) 3 (50) Mean HOS-ADL (range)* 49.27 (16.18-79.41) 66.18 (48.53-100) Mean HOS Sport (range)* 25.35 (0-47.22) 50.06 (2.78-100) Mean mHHS (range)* 45.38 (30.8-59.40) 63.80 (36.30-100) Mean iHOT-33 (range)* 24.92 (4.61-36.71) 67.66 (21.10-99.03)

*Excludes 2 patients without baseline preoperative scores.

HOS-ADL indicates Hip Outcome Score-Activity of Daily Living Scale; HOS Sport, Hip Outcome Score-Sports Scale; iHOT, International Hip Outcome Tool; mHHS, modified Harris Hip Score.

No patient experienced a postoperative surgical complication, and no patient underwent subsequent hip surgery over the study period.

DISCUSSION

Orthopedic surgeons increasingly recognize the role of hip abductor tendon tears as a causative factor for greater trochanteric pain syndrome. Many cases that were once dismissed as trochanteric bursitis are now being more thoroughly evaluated with a careful physical examination and advanced cross-sectional imaging techniques. Similar to rotator cuff tears of the shoulder, most cases of hip abductor tendon tears likely go through a long period of tendinosis, followed by partial undersurface tearing and degeneration, before eventually rupturing completely.14,15 With time, the gluteus medius and/or minimus tendon will retract, and the muscle belly undergo an irreversible process of fatty infiltration and atrophy. Although not definitively proven in the literature, it seems reasonable to assume that earlier repair, before the irreversible muscle changes, may alter the natural history of these fundamentally degenerative process.

As with the shoulder, however, not all patients will be treated before this point of no return. Pain symptoms vary considerably between patients, as does weakness with abduction. Even a Trendelenburg gait, pathognomonic for abductor insufficiency, is only 73% sensitive and 76% specific for gluteus medius pathology.15 As in this series, patients may be able to compensate for their lack of abductor function, demonstrating 4/5 or even 5/5 strength on manual muscle testing. These factors, coupled with the historical emphasis on “bursitis” as the cause of lateral hip pain, results in many patient presenting months or years after symptom onset. In the present series, all patients had experienced symptoms for at least 6 months before presenting in our clinic, and 3 had symptoms well in excess of 1 year.

Even when the tendon(s) can be mobilized back to the greater trochanter, primary repair in the presence of advanced fatty atrophy has disappointing results. Bogunovic et al8 described a series of 30 consecutive hip abductor tendon repairs performed endoscopically, and stratified their results on the basis of the Goutallier/Fuchs classification of the abductor muscle belly on preoperative MRI. Among the patients with more advanced fatty infiltration, there was higher postoperative pain, lower patient satisfaction, and lower PROs at mean 35 months follow-up. Although the series has somewhat confounded by an asymmetric distribution of ages in their cohort (older patients tended to have more fatty infiltration) and the performance of joint osteoplasty procedures in at least one third of their grade 1 patients, this is strong evidence that advanced fatty infiltration degrades the short-term and mid-term results of primary repair.

Publications from several high-volume hip preservation centers reference the use of muscle transfers in the setting of advanced fatty infiltration or irreparable tears. However, only a few groups have reported their clinical outcomes. Fehm et al11 described an Achilles bone block allograft reconstruction in 7 patients with abductor deficiency after total hip arthroplasty. Six of the 7 patients had substantial improvement in Harris hip score and pain score at minimum 2 years follow-up, though 5 had some residual Trendelenburg gait noted on examination. Kohl et al10 reported on 11 patients with symptomatic abductor insufficiency after total hip arthroplasty who underwent a vastus lateralis shift. Their technique involves division of the vastus lateralis from the rectus femoris, identification and mobilization of the lateralis neurovascular pedicle, and proximal shift of the lateralis origin to the residual abductor tendons. Although pain and function scores improved at minimum 2 years postoperatively, they also experienced 3 major complications (1 peroneal nerve palsy, 1 avascular necrosis of the patella, and 1 heterotopic ossification requiring excision with revision of the lateralis shift). Their technique also requires exposure of the entire vastus lateralis, as a distal release of the muscle is necessary to allow proximal excursion of the muscle.

Whiteside and colleagues have described transfer of the gluteus maximus for hip abductor deficiency associated with total hip arthroplasty. Their original 2006 technique was focused on management of severe osteolytic destruction of the greater trochanter in revision total hip arthroplasty.16 They raised a proximal muscle flap of the gluteus maximus, transferred it lateral and anterior, suturing the flap into the anterior hip capsule, residual quadratus femoris, and posterior edge of the gluteus medius. When compared with a control group, patients undergoing gluteus maximus transfer had superior function, reduced pain, and less likelihood of a Trendelenburg sign. Whiteside would later modify the procedure for patients who had an adequate greater trochanter, using 2 flaps from the gluteus maximus to recreate the posterior capsule/short external rotators and hip abductors, respectively.12,17

Chandrasekaran et al13 reported on 3 patients using flaps of the anterior one third of the gluteus maximus and posterior one third of the tensor fascial lata reattached to the greater trochanter using suture anchors. Similar to Whiteside and colleagues, they argue that this recreates the force vectors of the gluteus medius and gluteus minimus. Two of the 3 patients they reported on in their series experienced dramatic improvements in pain and function. The third had complete relief of pain, but less evidence of functional improvement and only moderate satisfaction at 2.5 years postoperatively.

Out results compare favorably with those of Chandrasekaran and colleagues. All our patients with available preoperative scores showed objective signs of improvement postoperatively at mid-term follow-up. Strength on manual muscle testing improved in all cases, though half of patients had some persistence of Trendelenburg gait. Anecdotally we have found that this is not uncommon, and even in cases where the Trendelenburg gait “resolves,” it is often replaced by a circumduction gait because of the loss of forceful hip extension with transfer of the gluteus maximus tendon. However, we generally have found that patients tolerate this alteration in gait well, given that this procedure reliably relieves the pain associated with large, chronic gluteus medius, and gluteus minimus tears.

In summary, we present a simplified procedure for gluteus maximus transfer for patients with irreparable hip abductor tendon tears or those with advanced fatty infiltration of the gluteus medius muscle belly. Our patients have shown good relief of symptoms and improvement in function at mid-term follow-up. This procedure has proved useful in this challenging patient population.

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