Ultrasound-guided release of post-arthroscopy extra-articular hip adhesions in femoroacetabular impingement: a novel technique

Adhesions After Hip Arthroscopy Are Associated With Revision But Show Poorly Defined Criteria for Diagnosis and Operative Management: A Systematic Review

PURPOSE

To evaluate the current body of evidence surrounding the diagnosis, management, and clinical outcomes of adhesions that developed after hip arthroscopy (HA).

METHODS

A systematic search of the MEDLINE, Embase, Web of Science, and CENTRAL (Cochrane Central Register of Controlled Trials) databases was designed and conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Eligible studies included patients with confirmed adhesions after HA that reported one or more of the following: (1) diagnostic procedures and criteria used; (2) indications for and details surrounding surgical management; and (3) clinical outcomes after the operative management of adhesions (e.g., patient-reported outcome measures).

RESULTS

Nineteen studies involving a total of 4,145 patients (4,211 hips; 38% female sex) were included in this review. The quality of evidence was found to be fair for both comparative studies (mean, 17; range, 13-21) and noncomparative studies (mean, 10; range, 5-12) according to the Methodological Index for Non-randomized Studies (MINORS) instrument, with the level of evidence ranging from IIB to IV. Adhesions were often diagnosed intraoperatively at the time of revision surgery (10 of 19 studies, 53%), with only 3 studies specifying the criteria used to adjudicate adhesions. The most common indication for operative management (i.e., release or lysis of adhesions) was persistent pain (9 of 19, 47%), but this was often grossly stated for revision HA rather than being specific to adhesions. Patient-reported outcome measures were the most reported postoperative outcomes (9 of 19, 47%) and generally showed significant improvement from preoperative assessment across the short-term follow-up period (range, 24.5-38.1 months). There was a paucity of objective measures of clinical improvement (3 of 19, 16%) and of mid- and long-term follow-up (i.e., 5-7 years and ≥10 years, respectively).

CONCLUSIONS

Despite the growing body of evidence suggesting that adhesions are highly contributory to revision HA, there is ambiguity in the diagnostic approach and indications for operative management of adhesions. Additionally, although the operative management of adhesions after HA has shown satisfactory clinical outcomes in the short term, there is a paucity of research elucidating the mid- to long-term outcomes, as well as minimal use of objective assessment of clinical improvement (e.g., biomechanics).

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

In vivo interrelationships between the gluteus minimus and hip joint capsule in the hip internal rotation position with flexion

BACKGROUND

The flexion adduction internal rotation (FADIR) test is performed by the combined motions of hip flexion (with knee flexion), adduction, and internal rotation, and can often reproduce anterior hip pain consistent with an individual's presenting pain. Since it has high sensitivity for intraarticular pathology diagnosis but low specificity, understanding the extraarticular pathology that can induce anterior hip pain in the FADIR test may also be essential. This study hypothesized that the interrelationships between the joint capsule and gluteus minimus differ in individuals with and without FADIR-positive pain and aimed to elucidate the in vivo interrelationships at hip internal rotation in 90°-flexion, which is also often restricted in individuals with FADIR-positive pain.

METHODS

Ten hips were included in the FADIR-positive group, and ten hips without hip pain in the FADIR test were included in a control group. Based on the ultrasound images at the four hip rotation conditions (20° and 10° external rotations, 0° external/internal rotation, and 10° internal rotation), orientation measurements of the gluteus minimus (muscle belly portion) and joint capsule were performed and quantitatively compared between the FADIR-positive and control groups. Additionally, 3 hips of 3 participants were randomly selected from each of the control and FADIR-positive groups for magnetic resonance imaging analysis.

RESULTS

At 0°-external/internal and 10°-internal rotation, on ultrasound images, fibers of the gluteus minimus and joint capsule in the FADIR-positive group were significantly more oriented in the same direction than those in the control group. Magnetic resonance imaging showed that the loose connective tissue between the gluteus minimus and joint capsule was prominent at 10°-internal rotation in the control group, although this was not apparent in the FADIR-positive group.

CONCLUSIONS

At hip internal rotation in 90° flexion, the muscular belly portion of the gluteus minimus and joint capsule were oriented in the same direction to a greater extent in the FADIR-positive group than in the control group owing to a morphological change in the loose connective tissue between them. The pathological changes in the loose connective tissue may inhibit smooth movement of the gluteus minimus relative to the joint capsule in individuals with FADIR-positive pain.

Adhesions in the setting of hip arthroscopy

With the growing number of primary arthroscopies performed, patients requiring revision hip arthroscopies for various issues is high including postoperative adhesion formation, a source of pain, mechanical symptoms, range of motion limitation, stiffness, and microinstability. Adhesions are a consequence of biological pathways that have been stimulated by injury or surgical interventions leading to an increased healing response. Preventative efforts have included surgical adjuncts during/after primary hip arthroscopy, biologic augmentation, and postoperative rehabilitation. Treatment options for adhesion formation includes surgical lysis of adhesions with or without placement of biologic membranes aimed at inhibiting adhesion reformation as well as systemic medications to further reduce the risk. Postoperative rehabilitation exercises have also been demonstrated to prevent adhesions as a result of hip arthroscopy. Ongoing clinical trials are further investigating pathways and prevention of adhesion formation.

Spatial distribution of loose connective tissues on the anterior hip joint capsule: a combination of cadaveric and in-vivo study

Recently, pathological changes in the fat pad on the anterior inferior iliac spine (AIIS), between the proximal rectus femoris and joint capsule, have been highlighted as a cause of anterior hip pain. However, precise fat pad features, such as the spatial distribution distal to the AIIS, histological features, and in vivo tissue elasticity, remain unclear. This study aimed to investigate the morphological characteristics of the fat pad on the AIIS. Four hips from four cadaveric donors were both macroscopically and histologically investigated, and eight hips from four volunteers were assessed using ultrasonography. The fat pad on the AIIS was also surrounded by the iliopsoas and gluteus minimus, extending distally to the superficial portion of the vastus lateralis, and the anterior portion of the gluteus maximus tendon. Histological analysis revealed that the fat pad was composed of loose connective tissue. Based on the ultrasonography, the shear wave velocity in the fat pad was significantly lower than that in the joint capsule. Conclusively, the pathological adhesion between the joint capsule and pericapsular muscles, if caused by fat pad fibrosis, may occur following the abovementioned fat pad spatial distribution.