Decision Making in Combined Hip Arthroscopy and Femoral Derotational Osteotomy Surgeries

Abstract

Background:

Femoral version abnormalities can contribute to intra-articular hip pathology. Combined hip arthroscopy with femoral derotational osteotomy (FDRO) has been shown to successfully treat those with intra-articular hip pathology with excessive anteversion or retroversion of the femur.

Indications:

We describe the technique for combined hip arthroscopy and FDRO in patients with symptomatic intra-articular hip pathology in the setting of excessive anteversion or retroversion of the femur.

Technique Description:

Hip arthroscopy is performed using standard anterolateral, modified mid-anterior, and distal anterolateral accessory portals. The labrum is repaired using a narrow diameter suture. Femoroplasty is performed with utilization of fluoroscopic imaging to assess resection. Dynamic flexion is performed as a final check of adequacy of resection. Capsular closure is performed in all cases. After hip arthroscopy, the patient is repositioned on a radiolucent table. A piriformis start point is obtained with a guide pin followed by standard opening reaming and ball-tipped guidewire placement. A femoral osteotomy is made just proximal to the isthmus and made through a lateral approach to the femur. Two K-wires are placed distal and proximal to the osteotomy site. A goniometer is then used to measure rotation. A drill is used to perforate the cortex circumferentially at the osteotomy site. After standard reaming, a sagittal saw is then used to start the osteotomy cut followed by an osteotome. An intramedullary nail is inserted over a ball-tipped guidewire while rotational reduction is assessed from the foot of the operating table. Distal interlocking screws are placed, and the nail is backslapped to create compression at the osteotomy site prior to placing proximal interlocking screws.

Results:

Recent studies show improved hip outcome scores in patients who undergo concomitant hip arthroscopy and FDRO for symptomatic abnormal femoral version.

Discussion/Conclusion:

Identifying patients who would benefit from concomitant surgeries requires thorough preoperative evaluation. Correct identification and treatment of these patients leads to improved outcomes.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

The following video will discuss decision making and surgical techniques for performing combined hip arthroscopy and femoral derotational osteotomy (FDRO) surgeries.

Here are our disclosures.

Femoral derotational osteotomies are performed to correct excessive femoral version. Femoral version is measured as the axial plane angle between the femoral neck and posterior femoral condyles.^5,7 This differs from femoral torsion, which measures the rotation of the femoral shaft itself, and is defined as the position of the lesser trochanter in relation to the femoral condyles. ¹

Femoral anteversion indicates abnormal forward rotation of the femoral neck relative to the knee, while retroversion indicates posteriorly directed rotation of the femoral neck.^5,7 Although there is a wide variation within the population, normal version measures roughly 15° of anteversion. ¹⁰ Excessive version of both types can be the etiology of hip pain and precipitate significant hip pathology. Femoral anteversion may lead to hip instability with damage to the articular cartilage and labrum. Similarly, femoral retroversion may cause impingement between the femoral neck and acetabulum leading to labral and chondral damage. ² Addressing abnormal femoral version in combination with intra-articular hip pathology has been shown to provide robust results over time. ⁴ Although previous studies have discussed decision making and indications for FDRO, ² this video aims to address decision making and indications regarding concomitant hip arthroscopy in patients with excessive femoral version.

Patients presenting with hip pain are evaluated with an extensive hip examination. As part of this examination, we routinely assess the patient’s lower extremity rotational profile. This starts with evaluation of the patient’s gait and foot progression angle walking test. ⁹ Hip rotation is assessed in both the supine and prone positions. Additional maneuvers are performed to assess for excessive anteversion, including measuring the thigh-foot angle, ⁶ Craig’s test, ³ and a Prone Apprehension Relocation Test (PART) examination ¹² for hip instability.

Routine radiographs are obtained, including a standing anteroposterior (AP) pelvis, false profile, and 45° Dunn lateral views. Magnetic resonance imaging (MRI) is obtained to assess for labral and articular cartilage pathologies. If surgery is indicated and the patient elects to proceed with this treatment, a preoperative low-dose 3D computed tomography (CT) scan is obtained to assess bony impingement sites and rotational profiles of the bilateral acetabula and femurs.

Regarding the FDRO, either retrograde or antegrade nail or plate fixation can be performed per surgeon preference. In this case, we used a transverse osteotomy and antegrade nail fixation. This avoids violating an otherwise uninvolved knee joint. With antegrade nail insertion, we routinely use a piriformis entry nail.

There are no firm indications for correction of excessive femoral anteversion. ⁸ Our current indications for concomitant hip arthroscopy and FDRO surgery for anteversion generally include greater than 35° of femoral anteversion as measured on preoperative CT, along with anterior hip pain, symptomatic gait abnormalities (typically an in-toeing foot progression angle), and symptomatic femoral acetabular impingement syndrome (FAIS) refractory to conservative management with supporting radiographic imaging and MRI.

In short, the patient should have clinical and radiographic confirmation of FAIS, labral tear, and excessive version abnormality.

If a patient has excessive anteversion but no intra-articular pathology and a lack of FAIS symptoms/examination findings, they may be indicated for FDRO alone. Indications for concomitant correction of femoral retroversion would include more than 10° of retroversion on CT, externally rotated foot progression angle, obligatory external hip rotation upon flexion, hip pain, and symptomatic FAIS along with confirmatory radiographic and MRI studies.

Here, we present the case of a 19-year-old woman who presented with approximately 8 months of anterior hip pain. She reported increased pain with running, deep squats, and weightbearing on the right side. The patient also noted significant in-toeing while running which caused her to trip over her own feet. She tried over-the-counter analgesics and physical therapy, with no improvement in her symptoms.

A focused hip examination was performed, which revealed a positive FADIR (flexion, adduction, internal rotation) and subspine impingement. With the hip at 90° of flexion, internal rotation measured 80° and external rotation measured 30°, consistent with excessive femoral anteversion.

Routine radiographs were obtained, and a standing AP pelvis view showed a lateral center edge angle of 25°. The 45° Dunn lateral view demonstrated an alpha angle of 63°.

On CT, torsional measurements were performed using the axial cut of the femoral neck to assess version. Followed by an axial cut of the knee, the posterior condyles are used to measure the rotation at the knee. The neck measurement is corrected relative to the knee at 0° of rotation, and thus, the patient’s femoral version measured +46° of anteversion.

Sagittal and coronal views of MRI demonstrated an anterolateral acetabular labral tear, with good preservation of the joint chondral surfaces.

Once the patient was sedated in the operating room, we performed a range of motion examination under anesthesia, and rotation was confirmed with a goniometer. The physical examination revealed markedly increased internal rotation on the right side.

The patient was positioned on a postless traction table and standard draping was used for the hip arthroscopy. A standard 3 portal hip arthroscopy was performed, with an anterolateral, modified mid-anterior, and distal anterolateral accessory portal. A small interportal capsulotomy was created and arthroscopic examination demonstrated a labral tear between 11:30 and 2:30, a chondrolabral wave sign in the transition zone representing delamination, with significant fraying of the labrum at the chondrolabral junction, all consistent with a cam pattern of impingement in the setting of femoral anteversion.

Using a shaver and ablation device, the capsule was dissected off the acetabular rim. A bur was then used to minimally debride the rim to prepare for anchor placement. Attention was then turned to the labral repair. A distal anterolateral accessory portal was created at this time, to facilitate anchor placement. The labral repair was performed using suture anchors.

In this case, we used a labral base mattress suture configuration. After completion of the repair, the hip was then taken out of traction, and the knee and hip were brought into slight flexion. The peripheral compartment was then entered and a small T-capsulotomy was made. Under direct visualization with the assistance of dynamic fluoroscopic imaging guidance as well as hip flexion, a femoroplasty was performed. Complete capsule closure was performed with 7 sutures.

Once the hip arthroscopy was complete, the patient was kept under general anesthesia and transitioned onto the radiolucent table in the supine position. A small bump was placed under the operative hip. The right lower extremity was then prepared and draped in sterile fashion.

The piriformis entry nail start point was confirmed on AP and lateral imaging using a percutaneously placed guide pin. We then used the opening reamer to enter the proximal aspect of the femur. Next, a long ball-tipped guidewire was placed and advanced into the distal femur.

A location just proximal to the isthmus of the right femur was marked out for the intended site of the transverse femoral osteotomy. A small incision was made over the lateral femur, the iliotibial band was incised, and a Cobb elevator was used to gently dissect the lateral quadriceps muscle off the femur, taking care to visualize and avoid perforators and cauterizing where necessary. Periosteum was preserved as much as possible while the dissection proceeded anteriorly and posteriorly around the femur. Radiolucent Hohmann retractors were placed around the femur to protect the soft tissues during the osteotomy.

We then placed a 2.4-mm K-wire anterior to the eventual nail path at the proximal femur, and a second rotational K-wire was placed in the distal femur. Using a goniometer, these 2 K-wires were placed at an angle in the axial plane corresponding to the desired degree of rotational correction. In this case, we opted for a 22° correction.

With Hohmann retractors in place, and using a soft tissue protection sleeve, a fresh 2.5-mm drill was used to perforate the femoral cortex at the osteotomy site under fluoroscopic guidance. A guidewire was again placed, nail length was measured, and sequential reaming was undertaken until moderate fill of the femoral canal was reached.

A sagittal saw with irrigation was used to start the osteotomy laterally. An osteotome was used to finish the osteotomy through the perforated medial cortex in an effort to minimize periosteal damage. The ball-tipped guidewire was again passed into the distal femur segment. The femoral nail was then inserted. Rotational reduction was assessed from the foot of the operating table to ensure that preoperative plan was executed, and the direction of the rotational K-wires now paralleled one another.

Distal interlocking screws were placed, and the nail was backslapped to create compression at the osteotomy site. Interlocking screws were placed proximally using the femoral guide.

It should be noted that in patients with excessive femoral anteversion, such as in this case, the hip arthroscopy is usually performed first. However, in cases with femoral retroversion, it is our preference to perform the rotational correction first. This allows for easier hip arthroscopy and also allows for the assessment of cam deformity in the newly positioned femoral neck.

For postoperative recovery, the patient was made 20% weightbearing with crutches for 2 to 3 weeks per standard hip arthroscopy protocol. The patient took 75 mg of indomethacin daily for 4 days for heterotopic ossification prophylaxis. Patients typically begin physical therapy within the first 1 to 3 days after surgery and slowly wean from crutches when gait is normalized and pain free. Range of motion is only limited in hyperextension and external rotation past 30° for the first 6 weeks to protect the capsule and labral repair.

Patients should be given a short course of indomethacin to reduce their risk of heterotopic ossification. Care should be taken during the osteotomy to perform a clean cut and avoid a bone spike at the osteotomy site that would lead to gapping and/or nonunion. An intramedullary saw can be used to create this osteotomy as well. Patients may report pain at the intramedullary nail site, and plate fixation remains an alternative fixation method. Over or under rotational correction is another potential complication. K-wires should be used both proximally and distally, with frequent rotation checks after femoral reduction and before and after fixation screws are placed.

Postoperative radiographs demonstrated healing across the rotational osteotomy site and hardware intact with the patient reporting improvements in preoperative symptoms.

Previous studies have demonstrated improved outcomes after derotational osteotomy. Both Buly et al ² and Shapira et al ¹¹ found improved postoperative patient-reported outcomes in FDRO alone and combined hip arthroscopy and FDRO.

In conclusion, our approach to combined hip arthroscopy with FDRO focuses on the presence or absence of intra-articular pathology and the order of combined procedures depends on whether the patient has excessive anteversion or retroversion.