Arthroscopic Focal Subspinal Decompression and Management of Pincer-Type Femoroacetabular Impingement

Subspine femoroacetabular impingement: retrospective study of a series of patients treated by hip arthroscopic resection

BACKGROUND

Femoroacetabular impingement syndrome (FAIS) is a common hip pathology that causes pain and functional limitation in young patients. subspine femoroacetabular impingement (SFAI) is an increasingly diagnosed extra-articular subtype that occurs from mechanical conflict of the anteroinferior iliac spine (AIIS) with the cervico-diaphyseal junction during hip flexion, which is poorly described in the literature.

QUESTIONS/PURPOSES

We aimed to describe the clinical, functional, and radiological results of the arthroscopic treatment of a group of patients with SFAI treated in our Hip Unit.

STUDY DESIGN

Case series.

METHODS

We present a retrospective study of ten patients with SFAI treated between 2013 and 2020 with arthroscopic resection. Clinical results were assessed with scales such as visual analog scale (VAS); modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Radiological results were assessed with radiological measurements, magnetic resonance imaging (MRI), and computed tomography (CT) reconstructions.

RESULTS

Six patients had a Type III AIIS and four of them had Type II. Two patients had previously been surgically treated for FAIS. The range of motion improved in flexion from 107 ± 11 degrees before surgery to 127.5 ± 6 degrees (p = 0.005). MHHS improved from 48.1 (38-75.3) before surgery to 83.1 (57-91) (p = 0.007) and HOOS improved from 65.2 (58-75) to 89 (68.1-100) (p = 0.007). VAS improved from 7.3 (5-9) pre-surgical to 2.5 (0-8) post-surgical (p = 0.005). We did not have significant complications except for an asymptomatic case of heterotopic ossification (Brooker I).

CONCLUSION

Arthroscopic decompression of AIIS in SFAI patients is a safe procedure that provides satisfactory short-term functional results, improving clinical symptoms, function, sports performance, and range of motion in our study.

A comparison between ultrasound-guided AIIS injection and radiography in the diagnosis of subspine impingement in patients with FAI

BACKGROUND

Subspine impingement (SSI) does not have effective diagnostic criteria, especially in patients who also have femoroacetabular impingement (FAI). The classification of anterior inferior iliac spine (AIIS) morphology via three-dimensional CT is controversial.

PURPOSE

To propose a method for ultrasound-guided AIIS injection as a way to diagnose SSI and evaluate the accuracy of radiography methods, including 3-D CT and MRI, as well as intraoperative findings.

METHODS

Patients diagnosed with FAI between September 2020 and December 2021 were evaluated in this prospective study. Those who met the criteria were included in the ultrasound-guided AIIS injection test. Whether the pain was relieved after injection was recorded in the radiology report. Patients who experienced significant relief of the anterior groin pain (more than 50%) after the AIIS injection were considered positive responders. Among these patients, radiography materials, including AIIS morphology as measured by 3-D CT as well as superior capsular oedema on MRI, were compared. The presence of congestion or bruising on the capsule side of the labrum corresponding to the AIIS during hip arthroscopy was recorded.

RESULTS

A total of 73 patients with FAI underwent the ultrasound-guided AIIS injection test. Prevalence rates of 13.70% (10/73), 58.90% (43/73), 23.29% (17/73) and 4.11% (3/73) were recorded for Type I, Type IIA, Type IIB and Type III AIISs, respectively. Thirty-six patients had positive responses to injection, and 37 patients had negative responses to injection. None of the patients with Type I, 23 (53.49%) patients with Type IIA, 11 (64.71%) patients with Type IIB and 2 (66.7%) patients with Type III AIISs had positive responses to the injection. A total of 57.14% of patients with Type II or Type III AIIS had positive responses to the injection. The proportions of patients with superior capsular oedema on MRI in the Type I, Type IIA, Type IIB, and Type III AIIS groups was 0, 30.23, 29.41 and 0%, respectively. Among non-Type I AIIS patients, those who reported positive responses to the injection had a higher incidence of superior capsular oedema (38.89% vs. 14.81%, P = 0.036), but they had no significant differences in the proportion of congestion or bruising of the labrum (47.22% vs. 37.04%, P = 0.419). The results showed that no pairs of methods-ultrasound-guided injection, MRI, and intraoperative findings-achieved good consistency (κ = 0.222, κ = 0.098 and κ = - 0.116).

CONCLUSIONS

Radiographic methods including 3-D CT and MRI as well as the intraoperative findings of the labrum cannot be considered an accurate and reliable basis for the diagnosis and treatment of SSI in FAI patients. It is suggested that ultrasound-guided AIIS injections be combined with radiography to better diagnose SSI.

LEVEL OF EVIDENCE

IV, case series.

An Anatomic Study of the Damage to Capsular Hip Stabilizers During Subspine Decompression Using a Transverse Interportal Capsulotomy in Hip Arthroscopy

PURPOSE

To quantify the damage to the soft tissue stabilizers of the hip after a transverse interportal capsulotomy and subspine trimming in hip arthroscopy.

METHODS

Eight human cadaveric hemipelvises underwent hip arthroscopy through a transverse interportal capsulotomy. Arthroscopic subspine trimming performed on all specimens was classified according to an anatomic index. The width of the proximal capsule was measured before and after subspine trimming. The extent of damage to the iliofemoral ligament (IFL) after dissection was recorded. Potential damage to pericapsular structures was assessed by measuring the distance between the capsulotomy and rectus femoris and iliocapsularis muscle with an electronic caliper.

RESULTS

In all specimens, ≥50% of the width of the IFL was damaged. The subspine trimming was successfully performed in 7 of 8 specimens (87.5%) according to the proposed index. The sizes of the trimmed bone area measured in the anteroposterior and proximal-distal axis were 21.2 ± 7.5 and 13.1 ± 9 mm, respectively (mean ± standard deviation). The width of the proximal capsule at the anterior and posterior corner of the capsulotomy was 19.8 ± 5.2 and 11.8 ± 1.7 mm, respectively. After subspine trimming, the mean width of the anterior and posterior proximal capsular attachments was 6.4 ± 1.4 and 7.0 ± 1.6 mm, respectively. On average, 13.4 mm of anterior capsule was damaged after anterior inferior iliac spine trimming, versus 4.7 mm of the posterior capsule. The distances from the capsulotomy to the rectus femoris direct and reflected head were 6.8 ± 4.9 and 6.3 ± 7.7 mm, respectively, and to the iliocapsularis muscle, 11.5 ± 7.8 mm.

CONCLUSION

High rates of damage to the IFL were observed with the interportal capsulotomy. Increased tissue damage at the anterior capsule was observed after subspine trimming. The width of the proximal capsular attachment was ≥5 mm in all specimens.

CLINICAL RELEVANCE

Surgeons should be aware of the potential damage to the native capsule and pericapsular structures when using a transverse interportal capsulotomy for the arthroscopic subspine decompression.

LEVEL OF EVIDENCE

IV: cadaveric study, case series.

The clinical outcome of chondrolabral-preserving arthroscopic acetabuloplasty for pincer- or mixed-type femoroacetabular impingement: A systematic review

While preservation and repair of the acetabular labrum are increasingly being recognized as important goals in hip arthroscopy, controversies still exist regarding the clinical outcome of arthroscopic acetabuloplasty with chondrolabral preservation. A systematic review was conducted and implemented by two independent reviewers, who used the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews for their search. These databases were queried with the terms "arthroscopic acetabuloplasty" and "chondrolabral preservation" and "arthroscopic acetabular recession." From the 55 initial studies the reviewers finally chose and assessed five clinical studies which were eligible to their inclusion-exclusion criteria. The reviewed studies included in total 444 patients, mainly young, between 30 and 40 years old. The follow-up evaluation varied between 24 and 41 months, while all studies utilized at least a 24-month final end-point assessment. All five studies illustrated improved outcome with the use of chondrolabral preservation acetabuloplasty without labral detachment. The rate of complications was very low. The different techniques of arthroscopic acetabuloplasty combined with chondrolabral preservation illustrated encouraging results in patients suffering from pincer-type or mixed-type FAI. However, the available clinical evidence was limited and insufficient to establish any superiority of these techniques over the traditional labral detachment and sequential reattachment. In relation to the optimal treatment of FAI without isolated CAM, further research of higher quality is recommended to be conducted in order to lead to definitive conclusions.

MRI Assessment of Subspine Impingement: Features beyond the Anterior Inferior Iliac Spine Morphology

Background The MRI manifestations of subspine impingement (SSI) other than morphologic features of anterior inferior iliac spine (AIIS) have not been extensively explored and validated. Purpose To determine the MRI findings associated with SSI, including AIIS morphologic features, femoral distal cam, and associated soft-tissue injuries. Materials and Methods This is a retrospective study of symptomatic patients who underwent arthroscopic treatment for femoroacetabular impingement between December 2014 and March 2017, with preoperative MRI within 6 months before surgery. The SSI group included patients with clinical and intraoperative findings of SSI; the remaining patients comprised the non-SSI group. Preoperative MRI findings were independently assessed by two radiologists who were blinded to clinical information. Interreader agreement was assessed, and multivariable logistic regression was also used. Results A total of 62 patients (mean age ± standard deviation, 42.1 years ± 11.9; 38 women) were included. SSI was diagnosed in 20 of the 62 patients (32%) (mean age, 43 years ± 12); 42 patients (68%) did not have SSI (mean age, 41 years ± 10). Reader 1 detected distal cam in 16 of the 20 patients with SSI (80%) and eight of the 42 patients without SSI (19%), and reader 2 detected distal cam in 15 of the 20 patients with SSI (75%) and eight of the 42 patients without SSI (19%) (P < .001 for both). Reader 1 detected signs of impingement on the distal femoral neck (IDFN) in 18 of the 20 patients with SSI (90%) and seven of the 42 patients without SSI (16%), and reader 2 detected signs of IDFN in 13 of the 20 patients with SSI (65%) and nine of the 42 patients without SSI (21%) (P < .001 and P = .001, respectively). Reader 1 detected superior capsular edema in 15 of 20 patients with SSI (75%) and three of 42 patients without SSI (7%), and reader 2 detected superior capsular edema in 17 of 20 patients with SSI (85%) and 22 of 42 patients without SSI (52%) (P < .001 and P = .02, respectively). Distal cam was a predictor of SSI after adjustment for IDFN. Interreader agreement was substantial for distal cam (κ = 0.80) and moderate for IDFN (κ = 0.50). Conclusion Soft-tissue injuries and osseous findings other than morphologic features of the anterior inferior iliac spine were associated with subspine impingement. © RSNA, 2019 See also the editorial by Guermazi in this issue.