The framework is developed from the critical appraisal of the available evidence in order to guide clinical practice. Current evidence supports a postoperative period of restricted weight-bearing and mobility restrictions; however, the specific interventions within the postoperative phases are variable with no comparative trials published to date [5]. Understanding the complex relationship among the bony architecture of the acetabulum and femur, the labrum, as well as the proximate soft tissues (i.e., ligaments and muscles) is important to optimize postoperative rehabilitation. Case reports and case series designs (level IV evidence [6]) identify the need to balance the healing properties of tissues, with restoration of hip motion, stabilization of the lumbo-pelvic-hip complex, and reestablishing muscular coordination and balance in the lower extremity and lower kinetic chain. However, existing reports are descriptive in nature; hence the superiority of a particular program cannot be determined. Clinicians require more than “general guidelines” and/or orthopedic surgeon recommendations to augment postoperative clinical outcomes.

Available studies describe successful postoperative outcomes utilizing a four- or five-phase rehabilitation program [4, 5, 7–9, 23, 34]. In order to bridge the gap between clinical practice consensus and evidence, this chapter will outline a five-phase framework for hip arthroscopy rehabilitation based on:

Prehabilitation typically refers to improving the functional capacity of a patient to be able to withstand the stressors of pain and inflammation, functional limitations, and participation restrictions associated with a hip arthroscopic procedure. If a patient maintains a higher level of functional ability before a surgery, they may recover more quickly through the rehabilitation process postoperatively [95]. To optimize postoperative timelines to achieve maximal recovery and functional outcomes, it is important to identify and manage pain and any predisposing factors that may contribute to a patient’s hip pathology [11].

Griffen et al. [12] described the value and importance of preoperative management for patients preparing for hip arthroscopy. Establishing preoperative baseline functional and PRO measures can aid in a patient’s predicted postoperative outcome. The emphasis generally revolves around patient education and pain management. Managing perioperative pain is crucial for the success of hip arthroscopy. There are many pain management strategies, some of the common ones include:

Patient education related to the arthroscopic procedure, postoperative care and expectations, as well as predicted outcomes, is an important element for the surgical pathway of care. Knowledge around expectations for postoperative restrictions and common pitfalls is necessary to promote postoperative compliance. Understanding the potential benefits of assistive devices can also facilitate postoperative recovery. Collaborating with an occupational therapist (OT) to ensure adaptive equipment is available and in place in the patient’s home and/or workplace (i.e., raised toilet seat, grab bars, shower bench, seat cushions, sock aid) can help protect healing tissue and uphold postoperative restrictions.

As the growing body of research on pain science continues to evolve it needs to be acknowledged as an appropriate patient education intervention for those undergoing an arthroscopic procedure. Given the average timeline to diagnosis of FAI has been shown to be up to 3.1 years [96], it would be rational to expect changes in central pain processing and central sensitization. Additionally, psychological and behavioral factors, such as depression, fear-avoidance beliefs, and pain catastrophizing, often require intervention. A patient’s familiarity with pain expectations and strategies to best control postoperative pain and inflammation has the potential to reduce the anxiety and threat of those symptoms. Mitigating the threat of pain may allow damaged tissues to heal to the best extent possible in a few weeks or months without any prolongation or chronicity. Thus, evaluation from a modern pain science perspective and patient education from a therapeutic neuroscience approach may lead to superior rehabilitation outcomes [98]. Another probable fear-provoking postoperative symptom that requires education is nerve dysfunction or neuropraxia. Dippmann (2014) demonstrated that 46 % of patients reported symptoms of nerve dysfunction within the first 6 weeks following hip arthroscopy [99]. It is important for patients to understand the nerve injury may be caused from external compression (related to surgical table setup and perineal post) causing ischemia to the nerve and/or the traction time applied during the arthroscopic procedure. Patients need to be aware that this is often a temporary issue; once nerve conduction is restored, recovery is spontaneous within a period of days up to 3 months [3, 17]. In the Dippmann (2014) study, 18 % of patients reported nerve dysfunction at 1 year postoperatively. There are a small proportion of documented cases that do not fully recover. The nerves most commonly affected are the pudendal and sciatic. Pudendal neuralgia is one of the most commonly reported complications following hip arthroscopy [100]. The diagnosis of pudendal neuralgia tends to get overlooked despite patients presenting with perineal hypesthesia and dysesthesia. Pailhé (2013) demonstrated that the incidence of pudendal neuralgia is two percent, which was previously underestimated in the literature [100].

To improve a patient’s functional capacity preoperatively, it is advised that clinicians assess movement patterns to reduce compensatory strategies that lead to joint pain [18]. Interventions to address altered motor control strategies in the lumbo-pelvic-hip region, hip-muscle weakness and inhibition, imbalances in the lower kinetic chain, and postural malalignment must be addressed cautiously [11]. Preoperative teaching of correct gait mechanics using assisted devices (i.e., crutches) within the prescribed postoperative weight-bearing restrictions can help eliminate persistent pain-avoidance strategies. Also, teaching appropriateness and correct execution of postoperative exercises may help improve neuromuscular efficiency to induce compensatory changes in muscle activation patterns and facilitate early functional stability [19]. It is essential that a patient be aware of the timely commencement for postoperative rehabilitation to maximize his/her recovery.

One of the most beneficial components of prehabilitation is the formation of a patient’s support network. In addition to family and friends, establishing a rehabilitation team is of critical importance. In particular, research on the therapeutic alliance acknowledges the importance of a positive interpersonal relationship between a clinician and patient and recognizes this to be an essential component of patient-centered care [13, 14]. Building trust and establishing an emotional bond with a patient are critical dimensions of the therapeutic alliance that lead to therapeutic progress [15]. Recent evidence supports the theory that biopsychosocial factors, especially the therapeutic alliance, may account for up to 60 % of a clinical outcome [14]. The findings of this study suggest that the alliance between patient and clinician positively correlates with clinical outcomes for individuals in physical rehabilitation settings, including treatment adherence and treatment satisfaction [14]. Failing to acknowledge the importance of the therapeutic alliance and the need to understand the patient’s goals can interfere with clinical outcomes.

Phase I overview: the primary rehabilitation goals are (1) to reduce postoperative pain and inflammation, (2) limit the stress to the femoral neck and labrum (if repaired/reconstructed), and (3) protect the integrity of the soft tissues, in particular the capsule. The secondary focus is to commence restoration of uniplanar range of motion (ROM) and normalization of gait with an assistive device.

Systematic review of the literature states hip arthroscopy has an overall complication rate around four percent. There is a very low rate of major complications such as dislocation, fracture, infection, and avascular necrosis [24]. Nevertheless, a hip arthroscopic procedure requires that clinicians take into consideration the excision of the anterior capsule (capsulotomy), osteochondroplasty to remove the bony abnormality, and the location of the labral tear (if present and repaired/reconstructed). Appropriate healing of a labral repair/reconstruction can restore multiple aspects of hip mechanics, including regulation of synovial fluid flow, maintenance of a suction seal and joint stability, proprioception, and force transmission to the articular cartilage [8, 26–29]. The hip fluid seal, in addition to regulating intra-articular fluid pressurization, contributes to hip stability. Evidence supports that labral repair and reconstruction improves distractive stability at small displacements and reduces micro-instability within the hip joint. Additionally, the capsule contributes to the suction effect by providing distractive stability at larger displacement forces [97]. As a clinician, being aware of capsular and/or labral alterations during FAI surgery is imperative to know which interventions to apply versus avoid early into the rehabilitation process to enable the restoration of stability and function. This phase also requires significant patient education to uphold postoperative restrictions in weight bearing, ROM, and muscle activation to avoid the many possible pitfalls.

The utilization of weight-bearing restrictions is critical to reduce the risk of fracture [3, 25] and to optimize healing of the labral repair/reconstruction (if applicable) [20]. Osteochondroplasty (resection of the bone) of the femoral head-neck junction for a cam impingement and/or acetabular rim for pincer FAI warrants protection to prevent a femoral neck fracture or stress fracture. Commonly, a labral repair accompanies FAI surgery and also requires load protection [4]. The most common documented area of labral tears occurs in the anterior-superior region, which bears the most loads and experiences the greatest shear forces [8]. Without appropriate load restrictions, inflammation will linger and delay tissue healing, which may negatively impact later phases of the rehabilitation process. The majority of patients are prescribed protected weight bearing with underarm crutches postoperatively [4, 5, 7–9, 21–23, 34]. The percentage of protected weight bearing is variable throughout the literature. Weight-bearing status tends to be dependent on the surgeon’s orders and, if additional considerations occur at the time of surgery, related to the extent of the procedure and the healing timelines for the involved tissues (i.e., bone, cartilage, labrum). Patients and clinicians need to adhere to the suggested weight-bearing guidelines and be instructed to progress gradually, in collaboration with the treating surgeon. Typically, patients will be instructed to apply 10 kg (approximately 22 lb) of load onto the surgical extremity during phase I [9, 22, 34]. Additionally, throughout gait retraining it is important that the patient initiates flat-foot contact with the surgical limb. Avoiding toe-touch weight bearing may decrease iliopsoas irritation by reducing sustained hip flexion [8]. Clinicians must ensure gait training with the appropriate assistive device on level surfaces, as well as stairs are addressed with the patient.

The capsulotomy is used to improve visualization and instrument maneuverability [3] during hip arthroscopy by many surgeons, and its integrity should be protected throughout early postoperative rehabilitation. Pushing a patient through painful ROM and/or end-range stretching can result in capsular laxity and hypermobility [5]. Focal laxity most commonly occurs as anterior capsular laxity secondary to repetitive movements involving hip external rotation and/or extension, possibly resulting in iliofemoral ligament insufficiency [30]. Thus, ROM restrictions have been implemented to allow the capsule appropriate healing. Additionally, adhering to these ROM restrictions reduces stresses (i.e., compressive and shear) to the labrum, which can reduce the likelihood of failure of the labral repair and/or reconstruction [31, 101]. Hip ROM is addressed in all three planes of motion within the following limitations: anecdotally extension within 0–10°, external rotation under 10° [4], abduction under 25° [31], and flexion less than 90°. Clinicians must avoid combined movements at this stage, especially extension-abduction-external rotation due to the associated risk of dislocation. With regard to flexion, Sink et al. (2010) demonstrated that the anterior-superior cartilage damage coincided with the area of FAI when the hip was positioned into flexion and internal rotation [32], hence another reason to avoid combined movements of the hip during this phase. Upholding these ROM restrictions will help reestablish the passive structures [33] and avoid hypermobility/instability later on in the recovery process. Panjabi (1992) presented the conceptual basis of a stabilizing system in the spine through three subsystems: (1) passive, (2) active, and (3) neural. The passive subsystem he affirmed can be extrapolated to the bones, capsules, and ligaments of the hip joint. Restoration of passive stability is important, as there are documented cases of over-resection of the bone from the acetabular rim for pincer FAI that may also predispose the hip to structural instability [25].

Other factors that may influence the protection phase of the rehabilitation protocol include whether a capsular repair occurred, microfracture procedure was performed, psoas tendon was released, or biological solutions [3] were introduced into the joint. Some surgeons advocate for the utilization of a rigid, postoperative hip brace that is combined with crutches for ambulation. When prescribed, it is often used for additional protection of the repair and to preserve ROM restrictions [23]. Communication with the surgeon and the rehabilitation team becomes of utmost importance to ensure that the appropriate restrictions are applied in each individual case [4]. Poor verbal or nonverbal communication between the primary clinician and the surgeon is a major link to postoperative pitfalls and likely suboptimal patient clinical outcomes.

Phase II overview: the primary rehabilitation goals are to (1) restore uniplanar ROM, (2) restore lumbo-pelvic core stability, (3) reestablish neuromuscular control, and (4) normalize gait with an assistive device. The clinician should continue to focus on (1) limiting the stress to the femoral neck, (2) reducing postoperative pain and inflammation, and (3) protecting the integrity of the soft tissues, in particular, the capsule and labrum (if repaired).

Phase II is centered on restoring mobility of the hip joint with a moderate focus on protection given that the majority of restrictions are supported throughout this phase. With the understanding that each phase in the rehabilitation process builds upon the previous, clinicians must continue to respect the ROM restrictions associated with the capsulotomy and labral repair (if applicable). The aim is to progressively regain 80 % of full ROM by the end of this phase [34]. Gaining mobility too slowly may result in residual stiffness and intra-articular adhesions, which can result in unnecessary load and shear forces applied within the joint and delay recovery. Conversely, pushing a patient through painful ROM and/or aggressive end-range stretching of the hip capsule (especially anterior) may result in hypermobility or micro-instability [5]. Simultaneously, the need to reduce muscle inhibition through isolated muscle activation in order to regain correct neuromuscular control is a fundamental element [23]. Normalization of gait with the appropriate assistive device, while respecting the healing process, is critical at this phase to restore movement patterns and load transfer. Lastly, patient compliance with restrictions and activity modifications remains important throughout this phase.

Following a hip arthroscopic procedure, simply restoring mechanical restraints is not enough for a functional recovery of the hip. Neuromuscular training enhances unconscious motor responses by stimulating both afferent signals and central mechanisms responsible for static and dynamic joint stability [46]. A lag in the neuromuscular reaction time can result in dynamic joint instability with recurrent episodes of joint deterioration and possible subluxation. Information about the position and movement of the hip comes from the mechanoreceptors located in and around the articular tissues. Disruption to the mechanoreceptors creates an inhibitory effect on the normal neuromuscular system. The objectives of neuromuscular retraining following FAI surgery are to improve the central nervous system’s (CNS) ability to generate and relearn optimal muscle-firing patterns, diminish movement coordination impairments, and achieve a state of readiness in the muscles to manage joint forces that results in enhanced motor control and dynamic joint stability [46, 47, 50, 55]. Another goal is to obtain equilibrium of loaded segments in static and dynamic situations and acquire postural control in situations resembling conditions of daily life and more strenuous activities [19]. It is important to appreciate the focus in this phase on neuromuscular training versus strength training, which focuses on increasing motor output. Neuromuscular training aims principally at improving quality and efficiency of movements [19]. Meaningful repetition of the retraining movements over time is necessary to cause lasting change [48]. Hence, neuromuscular control will prime the system for strengthening in phase III. Placing emphasis on strengthening before restoration of mobility and neuromuscular control often leads to compensatory movement patterns that precipitate soft tissue irritation (i.e., tendinopathy, bursitis).

Phase III overview: the primary rehabilitation goals are to (1) restore full hip ROM, (2) reestablish muscle balance through neuromuscular control and muscle strengthening, (3) optimize proprioception, (4) demonstrate dynamic lumbo-pelvic stability during low-demand exercises, and (5) normalize gait without an assistive device. The clinician should continue to monitor (1) pain and inflammation; (2) the integrity of soft tissues, in particular, the hip flexors, capsule, and labrum (if repaired/reconstructed); and (3) patient adherence to activity modification guidelines.

This phase is based on minimal protection of the surgical procedure. In the majority of cases, patients have their restrictions removed by the beginning of phase III following their postoperative appointment with the surgeon. Endorsement to restore full return of ROM hrough the inclusion of combined hip movements, plus the appropriate weaning of assistive devices to restore loading forces and normalize gait. Thus, it is important in this phase to monitor the pain score of the patient during ADLs. Patients should regain function and independence in ADLs without discomfort by the completion of this phase [34].

Following a hip arthroscopic procedure, restoring muscle balance requires three components: (1) adequate muscle length-tension relationships, (2) appropriate muscle recruitment via subconscious neuromotor pathways, and (3) optimal muscle power and endurance. Adequate stability and motor control of the lumbo-pelvic girdle in low-demand weight-bearing activities are important to restore surgical limb loading and normalize gait cycle early within this phase. Additionally, clinical expertise suggests that Manual Muscle Test (MMT) grading of greater than or equal to 4/5 should be achieved for all hip girdle musculature by the end of this phase. Strength impairments of the trunk, hip, and lower extremity identified through clinical reasoning should be addressed by the commencement of this phase. It is recommended that any asymmetrical muscle weakness be addressed with a strengthening program for the specific weakened individual muscle and/or muscle group. Strength and endurance exercises should build upon the activation improvements of the deep glutei and hip rotators from phase II. However, clinicians must ensure that the patient can actively perform the correct movement pattern within an adequate arc of motion, as well as demonstrate correct firing patterns and timing prior to adding resistance exercises. Following an osteochondroplasty, patients likely have an increase in physiological internal/external arc of motion (particularly in flexion), as well as an increase in abduction range. Clinically, these increases in range of motion seem to be dependent on patient age. Thus, it is important to enhance the activation and strength of the deep hip rotators to control the greater ROM.