Rehabilitation Phases, Precautions, and Mobility Goals Following Total Hip Arthroplasty

Abstract

The prevalence of total hip arthroplasty (THA) for advanced hip osteoarthritis (OA) is both increasing and shifting toward a younger average age. However, THA alone does not typically normalize function in these patients. Postoperative rehabilitation is often recommended to optimize joint motion, strength, and function. To date, there are no peer-reviewed clinical practice guidelines for postoperative rehabilitation following THA. Thus, optimal postoperative rehabilitation requires consideration of the existing literature and clinical expertise. This review article summarizes current recommendations for postoperative management of THA, including phases of rehabilitation, postoperative hip precautions, the effect of rehabilitation setting and mode of delivery on postoperative outcomes, and gait mechanics.

Introduction

The goal of total hip arthroplasty (THA) is to reduce pain and restore function in persons with hip osteoarthritis (OA). Candidates for surgery typically include patients with advanced disease for whom symptoms are not meaningfully improved through less invasive means such as physical therapy, exercise, or medication. Often, however, normalization of function does not come as a natural outcome of surgery alone [3,14]. Instead, postoperative rehabilitation is frequently recommended following THA to optimize joint motion, strength, and function [8].

The prevalence of THA is increasing and shifting toward a younger mean age [21]. In 2009, approximately 440,000 THAs were performed in the United States; the annual number is predicted to reach 650,000 by 2025 and more than 1.4 million by 2040 [42]. It is, therefore, imperative to identify optimal postoperative rehabilitation strategies for the growing number of patients with THA, particularly considering that younger, more active individuals may desire to return to sport or higher intensity physical activities [38].

This review is a summary of the current recommendations for postoperative management of THA, focusing on 4 main areas: goals and phases of postoperative rehabilitation, postoperative hip precautions, the effect of rehabilitation setting and mode of therapeutic delivery on postoperative outcomes, and gait mechanics. We consider both existing literature and our own clinical expertise. It is worth noting that no peer-reviewed clinical practice guidelines currently exist for postoperative THA rehabilitation.

Goals and Phases of Postoperative Rehabilitation

Rehabilitation goals following THA are often 2-fold: to normalize neuromuscular function and to optimize gait. Achievement of these goals is dependent on normalizing muscle activation, restoring functional range of motion, optimizing proprioception and balance, and improving muscular strength and endurance of the lower extremities.

Rehabilitation following THA is often organized into distinct phases, based on postoperative timeline and functional status. The overarching goal is to promote healing, restore joint function, and improve mobility. Because specific protocols may vary, what follows is a general overview of 4 common phases. An example of comprehensive, although not peer-reviewed, postoperative THA practice guidelines from one facility is “Total Hip Arthroplasty Post-op Clinical Practice Guideline” from the Wexner Medical Center at Ohio State University [5] (used with permission).

The earliest of the 4 phases, phase 0, refers to the preoperative period. The purpose of phase 0 is to educate patients and provide recommendations that improve surgical preparedness. The first postoperative phase, phase I, focuses on joint protection and tissue healing in the acute and subacute stages of healing. Phase II emphasizes recovery of joint motion and strength, and phase III targets restoration of function and return to activity. Although each phase provides helpful guidance on goals and the potential focus for interventions, each rehabilitation program should be customized to the patient’s condition, surgical technique, and progress. In fact, progressing through each phase chronologically may prove counterproductive for long-term mobility and pain goals.

Phase 0

Prior to surgery, it is important to discuss with patients the expected short- and long-term postoperative course after THA, including (1) what they will experience right after surgery and (2) what they will be able to do and when. Facts that may seem obvious to health professionals may be unanticipated by patients undergoing their first joint replacement surgery. For example, not all patients expect some level of postoperative pain; rather, they may assume that surgery will resolve all pain, even in the early postoperative period. Similarly, patients may not realize the extent of mobility limitations in the short term following THA, the time required to rehabilitate a postoperative hip, or the time needed to return to or exceed their prior level of function. Discussing these ahead of surgery will likely improve their pain experience and reduce fear that the surgery did not work [19,44].

Ahead of surgery, patients often benefit from assistive device training and from education on optimizing safety in their home: removing trip hazards (eg, throw rugs, dog toys), clearing walkways (eg, ensuring there are no obstacles in hallways or bathrooms), identifying strategies when spaces are not large enough to accommodate an assistive device (eg, narrow hallways, small bathrooms), and obtaining durable medical equipment (eg, bed rail, shower chair, raised toilet seat). Each of these improves patient readiness and may reduce the risk of adverse events following surgery.

Phase I

Tissue protection and healing are the top priorities of the first postoperative phase. If not appropriately addressed, the motion and function goals of phase I will not be achievable. Similarly, pain management is crucial to optimizing motion and function. The criteria for progression to phase II are (1) minimal pain and swelling with activities of daily living and postoperative exercises, (2) the ability to walk household distances without an assistive device, and (3) the ability to maintain single-leg stance without pelvic drop. Phase I is expected to take approximately 6 weeks.

Additional priorities of phase I include restoring joint range of motion; establishing independence in gait, mobility, and activities of daily living; and improving neuromuscular function. The goal for joint motion is to achieve and maintain pain-free range of motion within the limits set by the surgeon. Early mobility should be emphasized, with considerations given to postoperative weight-bearing precautions. Patients should work toward independence in functional mobility and ambulation during this phase.

Early in phase I, normalization of isolated muscle activation should be emphasized, after which strengthening exercises can be progressed. Cardiovascular fitness should also be addressed, with options such as aquatic therapy (assuming sufficient resolution of the superficial wound) and stationary bikes being appropriate at this stage of healing. Even as exercises are advanced and movements made more complex, there should be a continued focus on appropriate muscle activation. This includes progressing from isolated activation to monitoring muscle activity during a variety of interventions—whether strengthening, range of motion, or functional mobility tasks—ensuring that counterproductive or atypical muscle firing and movement patterns are not emerging.

Phase II

Phase II aims to further improve range of motion, strength, and mobility. Optimally, phase II focuses on normalizing gait and increasing walking endurance, engaging in activities specific to the individual’s functional goals, and providing guidance on safe joint loading and proper joint alignment. Criteria for progression to phase III include (1) achieving full, pain-free range of motion; (2) demonstrating sufficient lower extremity strength for performing functional tasks with good quality of movement; and (3) ambulating community distances. Phase II typically occurs from weeks 6 through 12 postoperatively.

By the end of phase II, joint motion should optimally be restored to functional ranges for both passive and active range of motion. Patient-specific factors and joint motion precautions must be considered when progressing toward greater degrees of motion. Strength goals include regaining hip and lower extremity strength, improving core muscle strength and control, and integrating strength and neuromuscular activation into functional movements. In addition to ambulation distance, improving gait quality includes optimizing gait patterns, increasing gait speed, and adjusting functional range of motion, stride length, and cadence.

Phase III

The final phase of postoperative THA rehabilitation is targeted to patients seeking to return to higher levels of physical activity such as sport participation and running. The duration depends on the patient’s goals, often lasting from 12 to 24 weeks following surgery. Before initiating higher level interventions, however, it is important to consult with the surgeon. Some or all of these activities may be contraindicated for some patients.

In phase III, joint range of motion must not be sacrificed in exchange for progress in other areas. Increasing aerobic fitness is a priority of phase III, as is improving muscular strength and endurance. Balance and stability interventions should be made progressively more challenging throughout this phase, optimally replicating the stability demands of the patient’s targeted sport or level of physical activity. Exercises should include multidirectional movements that mimic the demands of their sport, with emphasis on normalizing movement patterns. Sport-specific movement patterns can be reintroduced in phase III, including plyometric activities.

Use of Modalities During Postoperative Rehabilitation

During the postoperative period for THA, several passive modalities may be used to promote recovery, reduce pain, and prevent complications: continuous passive motion, cryotherapy, transcutaneous electrical nerve stimulation (TENS), or manual therapy (such as massage, lymphatic drainage, and scar mobilization) [32,49].

Continuous passive motion devices are often used to move the hip joint gently through a controlled range of motion, ideally to help prevent joint stiffness and promote circulation and healing. Cryotherapy, such as ice packs or cold compression devices, can help reduce postoperative pain, swelling, and inflammation. Compression stockings can aid in preventing deep vein thrombosis and improving blood circulation in the lower extremities. Massage, manual lymphatic drainage, and scar mobilization aim to improve tissue mobility and reduce pain and swelling. Transcutaneous electrical nerve stimulation units deliver low-level electric currents to the skin, which may help alleviate postoperative pain.

Limited evidence exists to support the use of modalities following THA, and much of the existing evidence is of low quality [49], although interventions such as TENS and manual therapy have substantial support for use in populations with chronic pain [12,47]. Considering that many patients experience persistent pain prior to THA, it is reasonable to consider interventions that address chronic pain and thus enable improved participation in functional activities and exercise. This is an example of clinical expertise being foundational in rehabilitation for a population for whom there is insufficient empirical evidence. Recommendations vary based on individual patient factors and the preferences of the patient and the health care team.

Rehabilitation Setting

There is high-quality evidence that postoperative exercise improves physical function following THA and that rehabilitation is beneficial for restoring mobility and returning patients to their prior level of function [8,49]. The precise interventions, timing and dosage of intervention, rehabilitation setting, and level of supervision should be tailored to each patient.

Whether supervised or unsupervised, patients should be encouraged to perform rehabilitation activities following THA, as they improve pain, function, and health-related quality of life [16]. Whether or not supervision is required, however, is patient-specific. For example, patients at elevated risk of delayed postoperative recovery would likely benefit from more frequent, supervised therapy intervention [13]. For patients at lesser risk of poor postoperative healing, supervised rehabilitation can be reserved for later phases of recovery; specifically, the frequency of supervised rehabilitation in the early postoperative period can be decreased, allowing for an increased number of visits in later phases. In some patients, this exchange has been shown to result in better biomechanical outcomes and enhanced function following THA [26]. In some cases, unsupervised rehabilitation may be sufficient for improving joint motion, function, and physical activity following THA [7,13]. Each patient’s unique situation, ranging from postoperative status to health care costs and scheduling logistics, is considered in determining the level and timing of supervision.

Favorable outcomes have been reported when rehabilitation after THA is provided in a home setting or an outpatient rehabilitation setting, including home-based care provided via telerehabilitation or a more traditional format [30,31,33]. Favorable outcomes have also been reported for patients participating in both one-on-one and group-based rehabilitation [9]. For many of the comparisons between distinct treatment environments, there are no differences in rehabilitation outcome [34].

Techniques used with patients after THA include motor imagery, aquatic therapy, body weight–supported treadmill training, and progressive, high-level activity retraining [17,26,28]. Outcomes seem to be similar for these different rehabilitation approaches [20]. Thus, rehabilitation can be tailored based on patient goals, needs, and preferences and in a way that facilitates the therapeutic alliance.

Postoperative Hip Precautions

Postoperative hip precautions, frequently used to reduce the risk of prosthesis dislocation, are supported by modeling studies [29]. The specific set of precautions is dependent on the surgical approach and the surgeon [37] but in general includes recommendations to avoid hip internal rotation, hip adduction, and hip flexion over 90°. Anterior and anterolateral hip precautions often include recommendations to avoid hip extension and external rotation. Global hip precautions incorporate all postoperative movement precautions, regardless of the surgical approach. Most surgeons recommend maintaining hip precautions for the first 6 weeks following THA, while about 10% of surgeons recommend them for 12 weeks [37]. Increasingly, however, health care practitioners are moving away from the strict application of movement precautions following THA.

Unintended consequences of movement precautions in patients following THA include engendering fear of movement, generating abnormal movement strategies, restricting sleep [36], and delaying rehabilitation progress. Often, movement restrictions also place a higher burden of care on caregivers. Combined with data that movement precautions may not reduce rates of dislocation [43], it is becoming increasingly important to evaluate the tradeoff between dislocation risk and rehabilitation progress when determining whether to implement movement restrictions following THA. In fact, recent data suggest patients given precautions may be as likely to experience a hip dislocation as those without precautions, whether for anterolateral approaches [2], posterolateral approaches [15,36], or posterior approaches [46] or those in heterogeneous cohorts that include posterior, anterior, and anterolateral approaches [25,39]. Patients who are “unrestricted” following THA often report decreased pain early in their recovery process, demonstrate enhanced functional recovery, have a more expedient return to activities of daily living, and report greater patient satisfaction [2,25,35,48,51].

Increasingly, it seems that postoperative hip precautions may not be necessary and may even be counterproductive following THA, particularly in routine, uncomplicated cases [13]. Decisions about hip precautions ultimately fall on the surgical team. Moving away from hip precautions represents a large shift in postoperative protocol; open dialogue should be encouraged among members of the rehabilitation team, the patient, and the caregivers to ensure that a beneficial consensus is reached.

Walking Mechanics Following THA

Lower limb biomechanics do not simply normalize as an outcome of surgery [1]. This can be attributed, in part, to compensatory movement patterns adopted by patients with hip OA. While a variety of gait deviations have been reported, the most consistent findings among patients with hip OA are spatiotemporal deviations, including reduced gait speed, decreased step length, and decreased stance duration on the painful side [6]. Also common are reduced peak hip extension and increased anterior pelvic tilt [23,45]. Other kinematic and kinetic findings tend to be more variable but can include increased hip abduction and external rotation range of motion, increased asymmetry of gait, and reduced hip joint excursion and muscle moments across all planes of motion [11,18,23,45].

Many of the gait deviations observed preoperatively persist postoperatively; patients often demonstrate reduced walking speed, decreased stride length, and decreased single-limb support time [1]. Frequently, these patients also walk with reduced step length, decreased hip abduction muscle moments, reduced peak hip flexion and extension, and persistent balance impairments [3,4,14,22]. These findings highlight the importance of selecting appropriate pre-gait interventions, including those addressing range of motion, strengthening, neuromuscular activation, and balance training. Equally important is ensuring translation of pre-gait motion and strength gains into functional mobility tasks and gait. This includes using functional movement patterns, appropriate cueing (including use of real-time biofeedback), and gradually reducing feedback to optimize long-term retention [10,40,41,50].

Translating motion and strength gains into normalized gait patterns is not expected to be a quick or easy task. Often, gait alterations exist early in the disease continuum, potentially before OA is present [24]. Altered kinematics persist even when controlling for pain, walking speed, and limitations in available joint motion. In patients with long-standing gait abnormalities, increased time and supervision may be required during gait retraining to optimize kinetics and kinematics of walking and facilitate motor relearning at the central (cortical) level [27].

In summary, postoperative THA rehabilitation prioritizes safety, symmetry, and stability during functional mobility tasks and walking. Success depends on gains in strength and joint motion, normalization of muscle activation patterns, and pain reduction in the early postoperative period followed by patient-based progression through the phases of rehabilitation. Based on current evidence, there are several paths to achieving these goals.

Rehabilitation can be delivered in the home or at an outpatient facility, via telerehabilitation or on-site supervision, or through one-on-one or group-based therapy. Visit frequency can vary and should be tailored to patient needs. The inclusion of hip precautions may also vary, and the health care team must evaluate the associated risks and benefits before making this decision. There can also be variability among interventions. Exercise has the strongest evidence for improving postoperative outcomes following THA and should be incorporated, but specific types and dosages can vary for each patient. Passive modalities, despite limited high-quality evidence, may be appropriate to address pain and motion restrictions. In the absence of empirical data, rehabilitation decisions should draw on clinical expertise and patient preference.