Intraoperative Guidance for the Surgical Correction of Cam Deformities Using Hip Arthroscopy Based on Alpha Angle Measurement

Figures

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  Fig 1. (A) Operating room setup for right-sided hip arthroscopy using HipCheck navigation monitor with patient in supine position. The navigation monitor (covered with a sterile sheath) can be positioned opposite the surgeon and lower than the C-arm and arthroscopy monitor during arthroscopy of the central compartment. The monitor is attached to the operating table with the support arm and has the ability to move in all axes. The monitor is moved closer to the surgeon while moving on to the peripheral compartment and starting the cam resection. (B) Position of HipCheck monitor (circle) during surgery.

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  Fig 2. Interportal capsulotomy in right hip. (A) After sufficient traction, the hip joint is entered under fluoroscopic control and the anterolateral portal is created. (B) Interportal capsulotomy is performed between the modified midanterior portal and the anterolateral portal with an arthroscopic blade (Samurai). (C) Suspension suture passing is performed with the aid of a suture passer (Pivot Injector II) through the anterolateral and modified midanterior portals to the proximal side of the capsulotomy for better visualization.

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  Fig 3. Labral repair in right hip through anterolateral, midanterior, and distal anterolateral portals. (A) For labral repair, the anchor is placed from the anterolateral portal at the 12-o’clock position of the acetabulum. In the midanterior portal view, the threads of the anchor are indicated with a red arrow and the suspension sutures through the capsule are indicated with a green arrow. (B, C) The suture is passed through the labrum with a suture passer (NanoPass; Stryker) via the anterolateral portal, viewing from the midanterior portal (B), and the thread from the joint is grabbed with the same tool (C). (D) View of labrum from anterolateral portal after repair with 3 anchors placed in acetabulum.

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  Fig 4. T-capsulotomy during arthroscopy of peripheral compartment in right hip. (A) The red line indicates the previous interportal capsulotomy, and the green arrow indicates the direction of the T-capsulotomy after debridement of the capsule in the peripheral compartment in the midanterior portal view. (B, C) After completion of the T-capsulotomy from the medial to lateral aspect of the femoral neck axis using a radiofrequency probe through the distal anterolateral portal (B), the view is improved by suspension sutures passed through the medial and lateral ends of the capsulotomy using a suture passer (Pivot Injector II) (C). (D) Arthroscopic view of cam deformity at femoral head-neck junction from midanterior portal.

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  Fig 5. Hip positions for HipCheck application in right hip with patient in supine position. The 6 hip positions in which to obtain the fluoroscopic images required for the HipCheck system before and after resection are as follows: 30° of internal rotation with 0° of flexion (FL) (A); 0° of rotation with 0° of FL (B); 30° of external rotation (ER) with 0° of FL (C); 0° of rotation with 50° of FL (D); 40° of ER with 50° of FL (E); and finally, 60° of ER with 50° of FL (F).

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  Fig 6. Osteochondroplasty performed through distal anterolateral portal with arthroscopic burr in right hip: views of superolateral aspect of cam deformity before (A) and after (B) resection with arthroscopic burr from midanterior portal and arthroscopic views of superolateral (C) and anterior (D) aspects of cam deformity after resection.

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  Fig 7. Instant assessment of cam resection performed in right hip. (A) During resection of the cam deformity, the surgeon observes the measurement of the alpha angle on the fluoroscopic image using the HipCheck monitor. (B, C) Simultaneous views of arthroscopic image from midanterior portal (B) and alpha angle measurement on HipCheck monitor (C).

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  Fig 8. Pre- and post-resection measurements in right hip. Measurements made by the HipCheck system on images obtained from repeated fluoroscopies in 6 different hip positions before and after resection are shown. The radiographs obtained at different hip positions, as specified at the beginning of the lines, are shown in each column to juxtapose the pre-resection and post-resection alpha angle values ​​at those positions from left to right. (AA, alpha angle; ER, external rotation; FL, flexion; IR, internal rotation; R, rotation.).

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  Fig 9. Capsule closure in right hip. The part of the T-capsulotomy parallel to the femoral neck is closed first, followed by the interportal part. In the midanterior portal view, passing the suture through the capsule with the aid of a suture passer (Pivot SlingShot) is indicated by the red arrow (A) and tying the sutures passed by both capsulotomy sides is indicated by the green arrow (B).