Arthroscopic Iliopsoas Lengthening Is a Safe and Effective Treatment for Anterior Iliopsoas Impingement After Total Hip Arthroplasty

Purpose

To assess the demographic characteristics, preoperative variables, and postoperative outcomes of patients who underwent arthroscopic iliopsoas lengthening for anterior iliopsoas impingement (AII) after total hip arthroplasty (THA).

Methods

A retrospective, single-surgeon case series was conducted to identify patients with AII after THA who underwent arthroscopic iliopsoas lengthening between 2017 and 2024. A minimum 1-year follow-up after arthroscopic procedures was required for patients to be included in this study. All arthroscopic procedures were completed by a single orthopaedic sports fellowship-trained surgeon. The primary outcomes were the incidence of THA revision, incidence of reoperations and secondary surgical procedures, and changes in pain scores.

Results

Of 15 hips, 12 (80%) were reported to be pain free at most recent follow-up (median follow-up, 3.8 years [range, 1.3-6.8 years]). There were no THA revisions performed after arthroscopy, no reoperations or secondary surgical procedures, and no infections requiring surgical intervention. The median pain score decreased from 8 preoperatively (interquartile range, 6.5-10; range, 3-10) to 0 postoperatively (interquartile range, 0-1; range, 0-5) ( P <.001). For the index THA, a posterior approach was used in 7 patients (47%) whereas an anterior approach was used in 8 (53%).

Conclusions

Arthroscopic iliopsoas lengthening is a safe and effective treatment for AII after THA. The procedure had minimal complications, provided considerable pain relief in 80% of patients, and helped avoid major revision arthroplasty surgery in 100% of cases.

Level of Evidence

Level IV, retrospective therapeutic case series.

A previously under-recognized sequela of total hip arthroplasty (THA) is the development of anterior iliopsoas impingement (AII) and tendinitis. One study suggested that AII may be the cause of persistent pain after THA in 4.3% of cases. A recent retrospective insurance database study using Current Procedural Terminology (CPT) and International Classification of Diseases, Tenth Revision codes, comprising 314 patients, examined iliopsoas pathology among patients undergoing arthroscopy after THA. International Classification of Diseases, Tenth Revision diagnosis codes for iliopsoas tendinitis were found in 105 of 314 patients (33.4%). In addition, a more comprehensive systematic review suggested similar data, with an iliopsoas tendinitis rate of 35.8%. Several sources of impingement have been proposed, including prominent or malpositioned acetabular components, aberrant placement of screws in the acetabular cup, a proud cement mantle, heterotopic ossification, or the use of a cage construct. The most common site of AII is thought to be at the anterior rim of the acetabulum, causing inflammation and tendinopathy of the adjacent iliopsoas tendon. Other causes of irritation of the iliopsoas after THA have been described, such as increased offset or excessive lengthening of the leg.

Conservative management using nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, and recurrent peritendinous injections of corticosteroids has been proposed and should be considered prior to any surgical intervention, although it has not shown consistent prolonged success. Iliopsoas lengthening, revision of the acetabular component, and trimming of metal phalanges are all surgical treatment strategies that have been described with some success. ^,^, Dora et al. showed pain relief after iliopsoas lengthening or acetabular component revision in 81.8% of patients in whom conservative management had previously failed. The acetabular revision group showed similar functional scores at final outcome assessment but had a significantly higher complication rate compared with the iliopsoas lengthening group.

Iliopsoas lengthening has historically been performed through an open approach, with more recent literature describing the safety and efficacy of endoscopic and arthroscopic iliopsoas lengthening. Endoscopic lengthening involves tenotomy at the level of the lesser trochanter, whereas arthroscopic lengthening consists of a trans-capsular release at the level of the psoas notch. A recent systematic review evaluated the outcomes after endoscopic and arthroscopic treatment. Among the 7 studies evaluating endoscopic technique, the average rate of favorable outcomes was 81.3% (range, 62%-97.2%). Among the 7 studies that used a trans-capsular arthroscopic technique, the average favorable outcome rate was 89.4% (range, 81%-100%).

The purpose of this study was to assess the demographic characteristics, preoperative variables, and postoperative outcomes of patients who underwent arthroscopic iliopsoas lengthening for AII after THA. We hypothesized the iliopsoas lengthening would provide a predictable decrease in visual analog scale pain scores in patients with AII.

Methods

All arthroscopic procedures were completed by a single orthopaedic sports fellowship-trained surgeon (B.C.) at a single institution between January 2017 and January 2024. Inclusion criteria were age 18 years or older with a history of THA and diagnosis of iliopsoas impingement. Common procedural codes were used to include patients, consisting of CPT code 27005 (open tenotomy of the hip flexors), CPT code 1005648 (hip arthroscopy), CPT code 29863 (hip arthroscopy with synovectomy), and CPT code 29861 (hip arthroscopy with removal of loose body or foreign body). A minimum 1-year follow-up after arthroscopic surgery was required for patients to be included. Patients younger than 18 years, those without a history of THA, and those with less than 1-year follow-up were excluded.

After institutional review board approval (University of Tennessee College of Medicine Institutional Review Board No. 2223831) was obtained, a retrospective chart review was performed to identify consecutive patients with painful THA who subsequently underwent hip arthroscopy. The indications for surgery used for the case series were symptoms of AII after previous THA. Iliopsoas lengthening was performed arthroscopically at the level of iliopsoas impingement at the anteromedial rim of the acetabulum. The iliopsoas was lengthened from the central compartment through the tendon only, leaving the muscle intact, and any heterotopic bone was shaved down or excised, as shown in Figures 1 and 2 .

Image, AltText currently not available — Fig 1

Patient characteristics, surgery details, follow-up data, and complication rates were collected and are reported in Tables 1 to 3 . The primary outcomes were the incidence of THA revision, incidence of reoperations and required secondary surgical procedures, and changes in the visual analog scale pain measurement (0-10). Statistical analyses were performed with R, version 4.4.1 (The R Foundation). Comparison of preoperative and postoperative pain scores was conducted with the Wilcoxon signed rank test.

Table 1

Demographic Characteristics of Patients Who Underwent Arthroscopic Iliopsoas Lengthening After Total Hip Arthroplasty

	Data
Total patients	15
Total hips	15
Age, mean (SD), yr	58 (11)
Sex, n (%)
Female	7 (47)
Male	8 (53)
Body mass index, mean (SD)	28.7 (5.5)
Cigarette smoker, n (%)	8 (53)
Diabetes, n (%)	2 (13)
Neuropathy, n (%)	4 (27)
Osteopenia, n (%)	0 (0)
Osteoporosis, n (%)	0 (0)
Peripheral vascular disease, n (%)	0 (0)

SD, standard deviation.

Table 2

Preoperative and Postoperative Details of Patients Who Underwent Arthroscopic Iliopsoas Lengthening After THA

	Data
Total patients	15
Total hips	15
Duration of symptoms, median (range), yr	1.5 (0.3-8.5)
Time between THA and arthroscopy, median (range), yr	2.4 (0.5-8.5)
Approach and cementation at index THA, n (%)
Posterior approach	7 (47)
Anterior approach	8 (53)
Cemented	1 (7)
Non-cemented	14 (93)
No postoperative pain	12 (80)
Reoperation, n (%)
Total hip arthroplasty revision	0 (0.0)
Infection	0 (0.0)