Compartments

A useful way to understand hip arthroscopy is to divide the surgical anatomy into four working spaces: the central compartment, peripheral compartment, lateral (peritrochanteric) compartment, and deep gluteal space. The central and peripheral compartments are intra-articular. The lateral compartment and deep gluteal space are extra-articular. In a routine arthroscopy, the typical sequence is central compartment then peripheral compartment, with the lateral and deep gluteal spaces being accessed only as needed. This order minimized the time under traction.

The four compartments are summarized below:

Compartment	Traction	Key structures	Typical procedures
Central	Required	Articular femoral head and acetabulum, labrum, ligamentum teres, acetabular fossa	Labral repair; acetabuloplasty, chondral treatment, ligamentum teres procedures
Peripheral	Not usually	Femoral head-neck junction, capsule, zona orbicularis, iliopsoas	Femoroplasty, dynamic impingement assessment, capsular procedures
Lateral / peritrochanteric	No	Greater trochanter, trochanteric bursa, IT band, gluteus medius and minimus tendons	Bursectomy, abductor repair, IT band release
Deep gluteal	No	Sciatic nerve, piriformis and short external rotators; ischial tuberosity/ proximal hamstring origin	Sciatic nerve decompression, piriformis release

1. Central compartment

The central compartment is the space between the weight-bearing articular surface of the femoral head and the acetabulum. It is bordered peripherally by the acetabular labrum. Traction is required to create enough space for safe portal entry and instrumentation.

Important considerations: This is the compartment in which iatrogenic labral or femoral-head cartilage injury is most likely during initial access. Adequate distraction should be confirmed before passing the guidewire and cannula. Once central-compartment work is complete, traction should be released as soon as practical.

2. Peripheral compartment

The peripheral compartment is the intracapsular space lateral to the labrum. Traction is released and the hip is commonly flexed approximately 30-45 degrees to relax the anterior capsule and increase the working space.

Important considerations: A T-capsulotomy may improve exposure when a large lesion cannot be adequately visualized through an interportal capsulotomy alone. Care should be taken around the posterolateral femoral neck to preserve blood supply to the femoral head and prevent avascular necrosis.

3. Lateral compartment (peritrochanteric space)

The lateral compartment, also called the peritrochanteric or third compartment, is an extra-articular space around the greater trochanter. It does not require traction. The working space lies deep to the iliotibial band and superficial to the greater trochanter and abductor tendons.

Important considerations: This space is not routinely entered during unless there is lateral-sided pathology to address. Excessively proximal dissection should be avoided to prevent superior gluteal nerve inury.

4. Deep gluteal space

The deep gluteal space is an extra-articular posterior hip space beneath the gluteus maximus. It contains several structures capable of compressing or irritating the sciatic nerve and is entered for selected posterior hip pathology rather than routine hip arthroscopy. It does not require traction.

Important considerations: The deep gluteal space is at high risk for iatrogenic neurovascular injury. Care should be taken to identify and protect the sciatic nerve and inferior gluteal vessels.

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