Inclusion and Exclusion Criteria
All adult patients with moderate GF or severe GF were considered for inclusion. The exclusion criteria were: (i) patients who were <18 years of age with GF; (ii) patients who were >50 years of age with GF; (iii) patients who belonged to mild GF; (iv) patients with a history of fracture in the affected hip; (v) the affected side of the hip suffering from moderate to severe arthritis, hip dysplasia or femoral head necrosis.
Patients’ Information
The cases reviewed in this retrospective study were recorded between October 2013 and August 2019. A total of 308 patients who underwent arthroscopic tight fibrous band release at the authors’ institution were included eventually. We excluded 170 patients with mild GF or younger than 18 years. With the exclusions, we had 138 patients (276 hips; all were bilateral) (Fig 1). The patients’ characteristics are summarized in Table 1. Specifically, there were 58 men and 80 women with a mean age of 28.6 years (range, 18–42 years). The study protocol was approved by the Institutional Review Board of the authors’ institution. Informed consent was obtained from all participants before carrying out any research work.
Characteristics of the GF degree
(i) Mild GF [13]: The extorsion of lower limb is mild; the abduction contracture is less than 15° with both hips and knee joints in 90° of flexion or the adduction range is less than 20° with no flexion. The Ober's sign and frog squatting sign are weakly positive. The limp gait is not apparent with the lateral inclination of pelvis on the anteroposterior radiograph being less than 10°.
(ii) Moderate GF [13]: The extorsion of lower limb is moderate; the abduction contracture ranges from 15° to 60° with both hips and knee joints in 90° of flexion or the adduction range is less than 10° with no flexion. The Ober's sign and frog squatting sign are positive. The limp gait is apparent with the lateral inclination of pelvis on the anteroposterior radiograph being less than 20°.
(iii) Severe GF [13]: The extorsion of lower limb is severe; the abduction contracture is more than 60° with both hips and knee joints in 90° of flexion or the adduction range is less than 0° with no flexion. The Ober's sign and frog squatting sign are strongly positive. The limp gait is remarkably apparent with the lateral inclination of pelvis on the anteroposterior radiograph being more than 20°.
Among all the included patients, 108 belonged to moderate GF and 30 belonged to severe GF according to the classification standard of gluteal fibrosis [9].
Surgical Technique
Anesthesia and preoperative skin mark
General anesthesia or spinal anesthesia was executed in the operation process with the patient being placed in a lateral position. A physical examination was conducted preliminarily under different flexion angles and adduction degrees of hip joint before operation to determine the extent and severity of contracture. The anterior and posterior borders of the gluteal muscle contracture (GMC), the greater trochanter (GT) and the sciatic nerve (SN) were marked before operation (Fig 2a, b). A two-portal technique, namely the anterior portal (AP) and posterior portal (PP), was used to perform the operation (Fig 2). These two portals (AP and PP) were located in front of and behind the top of the greater trochanter respectively.
Alternatively, the AP could be placed in front of the anterior edge of the GMC and the PP could be placed behind the posterior edge of the GMC. The position of PP was adjusted based on the position of the contractile bands determined before surgery and the expected release area. For instance, if the contractile bands were relatively posterior, the PP would be adjusted posteriorly along the horizontal line of the greater trochanter. The sciatic nerve was at least 2 cm distal to the PP. The distance between the two approaches was about 10 cm. The line connecting the two portals was roughly perpendicular to the femoral shaft.
Approach and exposure
A 30 ml mixture of 0.01% adrenaline, normal saline and ropivacaine was injected between the GMC and the subcutaneous tissue to reduce bleeding, keep the arthroscopic view clear and relieve postoperative pain. The operative portals (AP and PP) were established according to the preoperative mark. The surface of GMC was separated from the subcutaneous fat by a periosteal dissector to form a 2cm × 10cm cavity, which provided a good working space.
During the operation, 3000 ml of normal saline supplemented with 1 ml of 0.1% adrenaline was used for continuous gravity perfusion, which was beneficial to hemostasis and maintenance of a clear operative field. The PP was used as the viewing portal, while the AP was used as the working portal for instruments such as shaver and radiofrequency device. The subcutaneous adipose tissue overlying the fibrous band of the gluteal muscle group that obstructed the operative view was removed by a shaver through the AP, so that the anterior and posterior borders of the gluteal muscle group could be clearly observed.
GMC release
The GMC, which was confirmed by arthroscopy, was different from the normal muscle tissue. Its structure was usually similar to the white scar tissue. The tight fibrous band around the trochanter major was sectioned from anterior to posterior port by a radiofrequency device through the AP (Fig 2b). The radiofrequency device was also used to coagulate any bleeding point to observe the operation site clearly during the entire procedure and to prevent the formation of post-operative hematoma.
The Ober's test was carried out and the sliding of the contraction band was observed under arthroscopy to determine the degree of release and the position of the residual contraction band. If passive adduction was limited in flexion, it was usually necessary to release the GMC behind the great trochanter. If the adduction was limited in the extended position, it was usually necessary to release the GMC in front of the greater trochanter. The degree and depth of GMC release were adjusted according to the Ober's test and arthroscopic observation.
If passive adduction was still limited after the release of the fascia lata and gluteus maximus, the contractile bands of gluteus medius would be explored and then released selectively. Damage of the attachment of gluteus medius in the greater trochanter should be avoided as far as possible to maintain the hip abductor muscle strength and the hip joint function after operation. If the contraction band was relatively posterior, making the operation difficult, the hip joint should be flexed to slide the contraction band anteriorly. The sciatic nerve should always be cautiously taken care of during the operation and efforts should be made to ensure that the release was not too posterior or deep.
The contracture of gluteus minimus and hip joint capsule was found and released in a few serious cases. Then, any residual deformities were evaluated carefully. The complete release of contracture was confirmed by flexion, adduction, internal rotation, palpable click, the Ober’s sign and the cross leg sign.
Postoperative management
Postoperative hemostasis was achieved by using a lateral position or ice bag compression. The patients were allowed to flex their hips and knees and cross their legs at 30-minute intervals as tolerated on postoperative day 1. The legs had to be crossed as much as possible to extend the released GMC and to minimize the possibility of hematoma formation after surgery. A rehabilitation program which included gradual full range of hip movement and stretching of GMC (e.g., walking in a straight line, crouching with the knees close together and sitting with stacked legs) was initiated on postoperative day 2 and would continue for 3 months. These exercises were performed three to five times a day with 10 to 30 repetitions depending on the patients’ endurance.
Postoperative evaluation
Postoperative hematoma, ecchymosis under the skin and early wound complications were observed. The operation time, length of hospital stay and surgery‐related complications, such as neurovascular injury and wound complications, were recorded. The gluteal muscle contracture disability (GD) scale (Tab 2) [14] and the subjective satisfaction of patients were used to assess the outcomes at the last follow‐up.
Statistical analysis
Statistical analyses were performed using SPSS software version 22.0 (SPSS Inc., Chicago, IL, USA). The paired t test was conducted to test for the differences in scores between the preoperative and postoperative measurements. A p value <0.05 was considered as statistically significant.