FAI is a known risk factor for secondary hip arthritis.¹ The three main types of FAI are based on abnormal bony morphology and include the cam, pincer, and mixed types. In cam-type FAI, the deformity is typically located at the anterolateral femoral head-neck junction. Pincer-type FAI is characterized by overcoverage of the acetabular rim causing impingement.² Patients frequently have both cam and pincer deformities, which is called mixed or combined FAI.² These abnormalities lead to abnormal contact between the acetabulum and the proximal femur, resulting in labral tears, chondral damage, and eventually degenerative arthritis of the hip. In symptomatic patients, hip preservation procedures can alleviate symptoms and delay or prevent the progression of arthritis.³ Hip joint-preserving surgery can be performed arthroscopically, with open technique, or with a combination of arthroscopic and open techniques.

Ganz et al⁴ originally described open surgical hip dislocation (SHD) and femoroacetabular osteoplasty for the management of FAI. This allows for circumferential exposure of the acetabulum and femoral head-neck junction; however, there may be complications related to the trochanteric osteotomy. Recently, arthroscopy has emerged as the primary treatment modality for FAI.⁵ Compared with arthroscopy, SHD is a slightly higher morbidity procedure, frequently requiring an overnight hospital stay with increased potential complications such as infection, blood loss, and heterotopic bone (HO) formation.⁶ However, arthroscopy may be insufficient in addressing more severe deformity, and inadequate bony resection is a frequent cause of revision surgery.⁷ A limited or mini-open DAA has been described to address these femoral lesions that cannot be managed arthroscopically⁸ and is also an option for open surgeons transitioning to arthroscopy or who prefer the mini-open approach. This approach is primarily used to address cam lesions, whereas pincer lesions are managed arthroscopically. However, the mini-open DAA also allows for direct visualization of the anterior labrum and capsule. Compared with SHD, the mini-open DAA does not require a trochanteric osteotomy and may allow for faster rehabilitation.

The DAA alone is insufficient in exposing circumferential abnormalities and does not readily allow for the assessment or treatment of central compartment disease (labral and articular cartilage lesions). Thus, the limited or mini-open DAA may be combined with arthroscopic labral repair and rim trimming for pincer impingement when present. Multiple studies have found this combined approach to be safe and effective in providing symptom relief and improved hip function.^9,10,11,12 In severe deformity, SHD may be indicated, and when abnormal femoral rotation is causing impingement, proximal femoral osteotomy may be performed. In patients with nonfocal head-neck deformity or circumferential pincer impingement, alternate approaches may also provide better exposure.

A 21-year-old man had left hip pain that had been progressively worsening for approximately 1 year. He was a collegiate soccer player, and his symptoms were limiting his ability to play. He had participated in extensive physical therapy over the course of the year without improvement. The pain was in his groin and was worse with activity or prolonged sitting. Radiographs demonstrated a preserved joint space, an alpha angle of 63°, and decreased head-neck offset (cam lesion) on the frog lateral view¹³ (Figure 39.1).

On clinical examination, he had 100° of flexion and 10° of internal rotation with pain at the end point. He had a positive impingement test with FADIR (flexion, adduction, internal rotation) as well as a positive FABER (flexion, abduction, external rotation) test.

The patient underwent hip arthroscopy with limited open osteochondroplasty of the head-neck junction. Surgery was performed with the patient under general endotracheal anesthesia. Full muscle relaxation was requested in order to distract the joint. With the patient asleep, an examination of the hip was performed and precorrection range of motion was documented to compare with range of motion after osteochondroplasty. Both feet were then padded and wrapped in Webril and placed in fracture boots. Gross traction was applied to the contralateral hip. Eight to 10 mm of joint distraction was then applied to the affected hip using the fracture table, which was observed using fluoroscopy. The hip was prepped and draped using a hip drape.

The anterior, anterolateral, and posterolateral portals were established using fluoroscopy and direct visualization (Figure 39.2). The hip joint was systematically inspected, revealing a large full-thickness degenerative labral tear with corresponding delamination of the anterior and anterolateral acetabular rim (Figure 39.3). The labrum and chondral lesions were debrided. A conservative acetabular rim trimming was performed using the arthroscopic burr. The labrum was then reattached using three suture anchors (Figure 39.4). The final inspection revealed no further chondral lesions and a stable labrum. Instruments were removed, traction was released, and portals were provisionally closed with staples.