Hip Arthroscopy: Femoroacetabular Impingement and Labral Tears

Eilish O’Sullivan, PT, DPT, OCS, SCS

Bryan T. Kelly, MD

Dr. Kelly or an immediate family member serves as a paid consultant to Arthrex; serves as an unpaid consultant to A3 Surgical; and has stock or stock options held in A3 Surgical. Neither Dr. O’Sullivan nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.

Introduction

Femoroacetabular impingement is a relatively new diagnosis in the field of orthopaedic surgery that poses specific challenges to the rehabilitation specialist. The concept consists of abnormal contact between the femur and the acetabulum that restricts hip mobility, creates pain, and leads to degeneration of the hip joint. This may occur on the femoral side (cam impingement) or the acetabular side (pincer impingement), but most often occurs on both sides of the joint (mixed impingement). Cam impingement damages the labrum and cartilage when the deformity enters the joint (inclusion injury). Pincer impingement injures the labrum where the excess rim impacts the femoral head or femoral neck.

The acetabular labrum is a fibrocartilagenous structure that surrounds the acetabulum and increases the depth of the acetabulum. It creates a suction seal effect, resisting distraction of the femur from the acetabulum. It may act as a secondary stabilizer of the hip joint, and with a primary restraint being the iliofemoral ligament, resisting anterior translation of the femoral head and external rotation. The hip capsular ligaments act as static stabilizers of the hip, and are dynamically supported by the surrounding musculature. Crossing the hip joint and aiding in stability are 27 different muscles that work in a coordinated sequence to decrease joint loading with movement.

Pain elicited by impingement may cause weakness with impaired abdominal activation and motor patterning. The hip abductors and external rotators stabilize the hip, holding the femoral head within the acetabulum. The extensors create the most torque across the hip joint, and are paramount in athletic function. The tilt of the pelvis will either create more or less coverage of the femoral head. Challenges in making the diagnosis often lead to delays of up to several years. This delay in diagnosis generates compensatory strategies that must be addressed for recovery. Therefore, examining the entire kinematic chain is imperative throughout the rehabilitative process in order to eradicate dysfunctional patterns that may have developed. The diagnosis is established by clinical examination and diagnostic imaging, including plain radiographs, magnetic resonance imaging (MRI), and three-dimensional computed tomography (CT) scans.

The correct diagnosis allows for appropriate preoperative planning and the required operation. The next step is a structured rehabilitation program, which is an integral part of a successful outcome. Each rehabilitation program is tailored to the patient’s specific needs. As many of these patients are young, active individuals with high-level athletic aspirations, the return-to-sport phase is an important culmination of the rehabilitative process. This phase requires constant vigilance in order to avoid soft-tissue irritation and delayed return.

Hip Arthroscopy for Femoroacetabular Impingement and Labral Tears

Hip arthroscopy is indicated for the treatment of cam lesions, pincer lesions, labral débridement, labral refixation, loose bodies, and ligamentum teres tears. In order to maximize the likelihood of a successful outcome, the patient should demonstrate positive impingement testing, radiographic evidence of impingement, failure of conservative measures (physical therapy, activity modification, nonsteroidal anti-inflammatory drugs [NSAIDs], soft-tissue massage), and a positive result from an intra-articular injection. The most common reasons for failure of an arthroscopic hip surgery are osteoarthritis, residual impingement, and acetabular dysplasia. The success of the surgery is dependent on the amount of cartilage damage and whether or not adequate bony correction of impingement is achieved.

Contraindications

Hip arthroscopy is contraindicated in the setting of advanced arthritis. If there is a question as to the status of the cartilage, appropriate imaging should be completed prior to surgery. Those with developmental dysplasia of the hip that demonstrate a hypertrophic labrum due to static overload are not candidates for a solely arthroscopic surgery, and may require
a concomitant open procedure (periacetabular osteotomy). Complex deformities, such as a previous slipped capital femoral epiphysis or Perthes disease, may require open surgery.

Arthroscopic Femoroacetabular Impingement Surgery

Set-up

The patient is placed in the supine position on a fracture table. Traction distracts the joint, allowing instrumentation to enter the joint without damaging the cartilage. It should be kept to less than 2 hours to minimize the risk of nerve injury. Traction is released to address the peripheral compartment.

Relevance to Rehabilitation

Patients should be assessed at the postoperative visit for neuropraxia. Those with lumbar and sacroiliac pathology may experience discomfort following surgery because of traction. There may be foot and ankle discomfort as a result of traction as well. The nerves commonly affected include the lateral femoral cutaneous nerve (due to portal placement), pudendal nerve (from compression against the perineal post), and common peroneal nerve (due to traction).

Access

A safe zone for portal placement to minimize the risk of injury to the surrounding neurovascular structures is limited by the sciatic nerve posteriorly, the femoral nerve anteriorly, and proximally by the superior gluteal nerve. The two structures that remain vulnerable within this area are the lateral femoral cutaneous nerve (LFCN) and the lateral circumflex femoral artery (LCFA). The most commonly used portals are the lateral, mid-anterior, and distal anterolateral accessory portal. The anterolateral portal is in close proximity to the LFCN. This portal passes through the junction between the iliotibial and gluteal fascia. It then passes through the interval between the gluteus minimus and rectus femoris into the joint capsule. The mid-anterior portal passes through the tensor fascia lata and the interval between the gluteus minimus and the rectus femoris close to the LCFA. The distal anterolateral accessory portal passes through the fascia anterior to the iliotibial band. The anterior portal passes through the tensor fascia lata muscle and the gluteus minimus–rectus femoris interval. This portal poses the greatest risk to the LFCN. Once the portals have been established, an initial survey is conducted of the joint.

Relevance to Rehabilitation

LFCN paresthesias may occur; therefore, assessment should be conducted and symptoms should be monitored. These usually resolve. Scar tissue may form around portal sites and fascial restrictions often occur; therefore, these should be mobilized after adequate soft-tissue healing has occurred.

Capsule Cut/Intra-articular Assessment

An intraportal capsulotomy connects the mid-anterior portal to the anterolateral portal in order to be able to fully visualize the pathology. The joint is examined to determine the injury pattern on the femoral and acetabular sides. Frayed labral tissue may be débrided.

Rim Preparation/Resection

The acetabular rim is prepared with a burr down to bleeding bone. If needed, a resection of the rim may be completed at this point to restore the relationship between the anterior and posterior walls of the acetabulum.

Labral Refixation

If the labral tissue is amenable to repair, suture anchors are placed along the acetabular rim in an attempt to restore normal labral mechanics.

Relevance to Rehabilitation

To avoid stressing the labral repair, weight bearing is restricted for the initial 2 weeks, and forced end range motion is avoided. Impact activities and cutting are not initiated prior to 12 weeks, when the labrum has healed. If the labrum is débrided instead, the patient may move more quickly through the phases, but the same functional milestones must be achieved prior to advancing.

Cam Decompression

Traction is released, and the peripheral compartment is entered. A T-cut in the capsule is created through the plane between the gluteus minimus and iliocapsularis. With a large capsulotomy, there is full exposure of the deformity as well as the ability to visualize the retinacular vessels.

Relevance to Rehabilitation

Weight bearing is restricted initially due to bony decompression, as risk of femoral neck fracture is associated with decompression of the femoral neck greater than 30%. Weight bearing may be restricted for 4 to 6 weeks following surgery.

Capsular Repair

The T-capsulotomy is repaired with sutures to restore native anatomy and stability. In the setting of instability, a capsular plication may be done in order to increase static stability of the hip.

Relevance to Rehabilitation

The anterior capsule should be protected in the initial phase in order to allow healing of the repair, namely, in extension and external rotation (for 6 weeks). Following this phase, range of motion (ROM) is gradually increased as per patient tolerance. Soft-tissue restrictions (fascial and muscular) should be cleared prior to the initiation of joint mobilization techniques.

Complications

Rates of complications from hip arthroscopy surgery vary significantly. Most recently, overall complication rates have been reported at 6.9%, which is greater than reported previously. LFCN irritation is the most likely issue encountered by patients postoperatively, and most often resolves. Other complications may include iatrogenic chondral or labral injury, superficial
portal infections, superficial peroneal neuropraxia, deep vein thrombosis (DVT), pudendal neuropraxia, and heterotopic ossification.

The patient should be assessed for sensory disturbances and monitored for changes if there are deficits. Wounds should be monitored for erythema or drainage, notifying the physician if present. The incidence of heterotopic ossification has decreased dramatically with the use of prophylactic measures consisting of NSAID use for 4 weeks.

Preoperative Rehabilitation

Patients should be assessed preoperatively to initiate a strengthening program prior to surgery. The preoperative assessment may highlight the other compensatory movement patterns that have developed and will require reeducation. Lower abdominal and gluteal exercises are emphasized in the pain-free range. Education on appropriate exercises, such as avoiding deep squats and lunges, should occur. Patients are also educated on the immediate postoperative rehabilitation exercises.

Postoperative Rehabilitation

Rate of progression will be based on a number of factors. The greater the duration of symptoms, the longer there has likely been dysfunction and muscle inhibition due to pain. Chondral defects will extend the period of decreased weight bearing. The exact surgical procedures will also impact the rate of progression, such as with a capsular shift. Those with pelvic floor muscle dysfunction/pelvic pain will also progress at a more cautious rate due to the risk of causing a flare of these symptoms. The rehabilitation specialist should be mindful of active external rotation and careful with the stationary bicycle, as both these interventions may cause a pelvic pain flare. Lower back pain and dysfunction is another common disorder in these patients, which will likely have to be addressed during the postoperative course.

General Rehabilitation Principles

First and foremost, one must be cognizant of tissue healing time frames. Overloading tissue structures prematurely may lead to disruption of the surgical repair. The therapist should have an open line of communication with the surgeon’s team to understand the exact procedure carried out. If multiple procedures are done, as often occurs, the most conservative guidelines will prevail. With surgery for femoroacetabular impingement, new motion will be gained with a bony decompression. This new motion must be reeducated or it will not be utilized during functional activities.

Multiple compensatory patterns frequently arise during the often lengthy diagnostic and treatment process. Through the rehabilitation phases, these patterns must be identified and reeducated. This may involve treating the patient’s thoracic spine or foot and ankle complex to maximize the patient’s function. Impaired motor patterning often results from pain in the lower back or groin. Proper sequencing of muscle activation during exercises must be emphasized to ensure optimal stability. An example of this sequence is the following: while bridging, the patient should consciously contract the lower abdominals, followed by gluteals, and then extend the hips. Soft-tissue dysfunction is a frequent issue for these patients, which should be assessed and appropriately addressed as well.

Monitoring a patient’s progress throughout the postoperative course is important to determine appropriate interventions. This should be done with a systematic approach, utilizing certain functional tasks (such as normalized gait or a step down) to determine whether the patient is ready to progress to the next phase of rehabilitation. Patients’ achievement of functional milestones is monitored in preparation for their return to activity—whether activities of daily living (ADLs) or high level sporting activity. Patients often need to be counseled to limit their ADLs at the inception of their postoperative hip rehabilitation course, as these activities will frequently be the cause of increased pain. Many of these patients are young athletes looking to return to sport, some at an elite level. Patients should be educated from early on (preferably preoperatively) about what is entailed in the postoperative rehabilitative course and approximate time frames for recovery.

All phases indicated are approximate and advances are based on a functional criterion-based progression and soft-tissue healing. Those with compensatory disorders will be on the longer end of the spectrum; those who had little compensation will progress more quickly. As the hip is a weight-bearing joint, it is important to see how the patient responds to loading following intervention.

Phase 1: Protection Phase (4–8 Weeks)

The primary goal of the incipient phase of rehabilitation is to protect the surgical rehabilitation in order to ensure appropriate healing. The rehabilitation specialist should aim to reduce pain and inflammation through manual therapy and modalities, as needed. By the completion of this phase, the patient should demonstrate normal gait and should be able to complete basic ADLs. This phase will generally last from 4 to 8 weeks.

Patients are usually evaluated on postoperative day one to assess the patient’s basic functional mobility (transfers and gait) as well as to begin passive range of motion (PROM) and isometric strengthening. Patients ambulate 20% weight-bearing with the foot flat for 2 weeks, then transition to weight bearing as tolerated. It is important to emphasize the placement of the operative foot on the ground to avoid hip flexor irritation. For the initial period following surgery (2 weeks), hip extension during gait should be limited in order to protect the capsular repair. A hip brace is utilized when patients are outside of their home for the first 2 weeks following surgery in order to increase stability. A cryotherapy unit with pneumatic compression is utilized to decrease inflammation and decrease pain for the first 3 weeks following surgery. A Continuous passive motion (CPM) machine is also utilized for 3 to 4 weeks following the surgery in order to reduce adhesion formation and increase nutrition to the joint. If tolerated, the patient may substitute use of a stationary bicycle for the CPM machine. Pivoting while standing or walking should be avoided as well in the
initial stages. Comorbidities, such as soft-tissue laxity, should be taken into consideration when progressing these patients.

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