Introduction

Orthopedic trauma of the lower extremity is common in both military and civilian populations. As such, the goal of the surgical and rehabilitative team focuses on the return of a patient to their previous level of function often in the setting of competing short-term goals. For example, aggressive early ambulation, range of motion, and weight bearing may fulfill an expeditious return and mitigate deconditioning but may place fracture fixation or soft tissue repair at risk for failure. Further complicating patient rehabilitation may be poor patient compliance, pain management issues, and immobility. Among the elderly population in particular, immobility can result in serious medical complications such as deconditioning, venous thromboembolic events, catheter-associated infections and pneumonia, and/or decubiti. These poor outcomes have led to some paradigm shifts with some allowances of early weight bearing and range of motion. Furthermore, technical advances in rehabilitative equipment and non-pharmacologic pain modalities have succeeded in promoting more reliable return to function. This article reviews the physiologic rationale for long-standing rehabilitation protocols, introduces novel treatment modalities, and offers our experience with implementing novel rehabilitation approaches to combat casualties with complex lower extremity trauma.

Fracture Healing

Wolff’s Law states that the trabeculae in trabecular bone line up with principle stresses placed on the bone during development, thereby allowing bone to adapt to mechanical forces placed on it [1, 2]. This principle, which has been more broadly applied to include cortical bone, is also relevant to fracture healing. The process of fracture healing is sensitive to strains and requires stability provided by surgical fixation to drive callus formation and neovascularization [3, 4]. However, per Wolff’s Law, stress is also critical to this healing process.

Given these facts, the choice of surgical fixation constructs is heavily dependent on fracture characteristics to include location of fracture along the bone, degree of comminution, and soft tissue damage or periosteal disruption. Operative fracture fixation may include internal (i.e., plate and screw) fixation, intramedullary fixation, or external fixation. These various strategies can be manipulated to determine whether a fracture will undergo primary bone healing via endochondral ossification or secondary bone healing following the calcification of cartilage and callus formation.

In addition, fracture fixation can employ a load-bearing or load-sharing construct. With load-bearing constructs such as internal fixation in which the orthopedic device accepts the forces across the fracture site, the patient is typically prevented from full weight bearing to avoid repetitive loading across the device [5] until sufficient healing has been achieved to permit sharing of this stress. In this setting, compression facilitated by the device induces the process of contact healing by osteoclasts and osteoblasts. Conversely, load-sharing constructs such as intramedullary fixation are used for segmental or comminuted fractures and allow for division of interfragmentary strain among fragments. These constructs are more tolerant of early weight bearing as the forces are shared between bone and device, and strain is shared among fragments [6].

Surgeons have historically been hesitant to allow early load bearing after lower extremity fractures to limit risks of loss of reduction and implant failure [7•]. While orthopedic device constructs and physiologic theory support early weight bearing, many providers remain hesitant to this approach. This section will address these concerns, by providing a review of the principles, which are also listed in Table 1, that have generally been accepted as weight-bearing protocols in the rehabilitation of individuals with lower extremity injuries; further, it will introduce more recent outcomes of early weight-bearing protocols.

Table 1 Weight bearing protocols following lower extremity trauma
Full size table

Internal Fixation

Internal fixation functions to promote primary bone healing through haversian remodeling when bone fragments are intimately fixed and there is absolute stability of the construct. While open reduction, internal fixation (ORIF) provides adequate fixation of most fracture types, interfragmentary instability [5] and excessive axial strain [28] delay fracture healing and may result in malunion, nonunion, or implant failure. Thus, patients are normally non-weight bearing for 6 to 12 weeks following ORIF, particularly for articular fractures.

This approach is supported by much of the existing literature. The plate fixation of calcaneal [8, 9], tibial plafond [12], high-grade tibial [16], distal femoral, femoral shaft [29], and acetabular fractures all typically benefit from restricted weight bearing or non-weight bearing for up to 12 weeks after fixation. A notable exception is the use of percutaneous cancellous screw fixation for hip fracture, which may permit immediate weight bearing in the elderly [23–25]. As noted above, compression allows for more rapid weight bearing than indirect reduction, likely explaining the capacity for immediate weight bearing after this type of fixation. There may also be an additional component of elderly patients applying decreased axial force and demonstrating poorer compliance in weight restriction [7•].

Intramedullary Fixation

Intramedullary (IM) fixation allows for axial loading across the fracture site which promotes callus formation and secondary bone healing. Since IM fixation is more tolerant of repetitive axial loading than plate fixation, its application typically allows earlier ambulation due to the minimal deformation of the system by these forces. Although permitted, not all patients with IM fixation are able to achieve immediate weight bearing because of other complications [19–21]. IM fixation is currently being used with increasing frequency when managing diaphyseal fractures of long bone, including comminuted fractures, without significant increase in complications associated with early weight bearing [18–20, 22]. The increase in popularity with using IM fixation is likely secondary to improved materials, which are currently more rigid and less likely to fail, as well as the positive benefits of allowing early weight bearing as tolerated.

External Fixation

External fixators can be used to apply compressive, neutral, or distractive forces on bone, allowing treatment of both long bone and periarticular fractures. Due to their low level of tissue disruption and easier removal than internal fixators in the setting of osteomyelitis, their application is particularly useful in the setting of trauma, when treating open fractures, especially with compromised soft tissue envelopes [30]. The protection of the interfragmentary space allows for the development of a callus but limits axial loading optimal for complete healing [31]. At times, limited healing with the use of external fixators and statically locked intramedullary devices must be overcome with dynamization. Dynamization allows for micromotion at the fracture site with weight bearing, further driving callus formation. This may be followed by a period of restricting the construct to minimize micromotion and stabilize the formed callus.

Multiple studies confirm the safety of immediate weight bearing after external fixation in most trauma settings, including calcaneal [10, 11], tibial plafond [12, 13], and tibial diaphysis [14, 15] fractures. However, some studies have demonstrated higher rates of nonunion and infection in AO type C and comminuted tibial diaphysis fractures [12, 17]. Among limb salvage patients undergoing long-term bone and soft tissue stabilization, particularly in the setting of distraction osteogenesis, ringed fixators with rigid constructs can be used to allow full weight bearing.

Ligamentous Healing

Depending on the location and extent of injury, ligamentous injuries can be treated in a multitude of fashions. Pelvic fractures in the trauma setting present particularly unique challenges, depending on the mechanism and severity of injury. Treatment options include limited weight bearing and no surgery, external fixation, ORIF, percutaneous fixation, or a hybrid of these fixation constructs. Critical to the success in treating these injuries is the ability to stabilize the pelvic ring, which predominantly relies on the healing of ligamentous as opposed to osseous structures. Ligamentous healing is characterized by the initial proliferative phase of healing, during which time weak and disorganized collagen is synthesized. The end of the proliferative phase of healing overlaps with remodeling, at which point the ligament is thought to have recovered sufficient strength. The period of non-weight bearing in ligamentous injury, as exemplified by pelvic instability, therefore reflects the 8–12 weeks that ligaments require to recover strength before patients are able to tolerate normal weight bearing. While this remains the standard, some believe that rigid fixation replaces ligamentous support in vertically stable fractures and patients can be allowed to weight bear as tolerated [26, 27].

Amputations

Weight bearing following the closure of traumatic amputations is dependent upon the resolution of soft tissue wounds. Most importantly, a stable soft tissue envelope that will tolerate prosthetic wear requires full healing of all wounds and marked decrease in postoperative edema [32]. In our practice, we have found that this typically occurs within 4–6 weeks. This timeline cannot be dogmatic, however, because it is not uncommon for amputations of the lower extremity to also require additional soft tissue reconstructions, such as myocutaneous or free flap reconstruction with or without skin grafting, which may further delay prosthetic fitting. Traumatic lower extremity amputations are further often coincident with ipsilateral fractures or a destabilized pelvis, which will also prolong weight bearing. However, in the absence of ipsilateral fracture management or soft tissue concerns, weight bearing with a prosthesis can typically be initiated at 6 weeks’ time, at which point both the deep myodeses and superficial incisions are adequately healed to prevent full weight bearing in a prosthetic trial socket, provided frequent skin checks are performed to assess soft tissue healing and integrity.

Restricted Weight Bearing

Given the benefits of early mobilization in returning to functional status, but taking into consideration the requirements for fracture and ligament healing, the use of progressive but restricted weight-bearing protocols would seem a viable compromise. For example, touchdown weight bearing, a common form of restricted weight bearing, is meant to reduce forces on joints during ambulation. One must consider that both non-weight bearing and touchdown weight bearing expend four times the energy for ambulation when compared to the average population [33]. Although patients often perceive touchdown weight bearing as being less tiring, both take an unnecessarily large physiological toll on patients attempting to recover. In addition, increasing evidence has called into question the rationale for these restrictive precautions. For example, multiple studies have shown that pressure on the acetabulum during non-restricted movements such as sit-to-stand far exceed the strains achieved during normal ambulation [34, 35].

In addition to these concerns, the most notable issue with restricted weight bearing is poor patient compliance. Patients consistently exceed the allowed “weight” in partial weight bearing, despite believing they are compliant [33, 36]. Other methods of retraining such as the use of a scale, tactile hand under foot, verbal cues, and auditory biofeedback have also failed to demonstrate efficacy [37, 38]. Furthermore, even the experience of the physical therapist does not seem to increase rates of compliance [39].

Because of the significant lack of compliance and unreliable teaching methods for partial weight bearing, methods have been developed to control forces on the lower extremities. These include body weight supports, hydrotherapy, and lower body positive pressure (LBPP) or “anti-gravity” treadmills. Patil et al. [40], using implanted instrumented knee prostheses, showed the use of the antigravity treadmill significantly decreased axial tibiofemoral forces and shear forces. While hydrotherapy may increase shear at joints at higher walking speeds, LBPP directly decreased anteroposterior shear across all speeds, with no significant changes in gait associated with change in LBPP-determined weight, unlike in other methods. These new modalities offer hope for the more reliable and controlled utilization of limited weight bearing in the rehabilitation of lower extremity trauma and, in our experience, have been very helpful in treating service members with combat-related trauma.

Range of Motion

The rehabilitation of orthopedic trauma in the lower extremity, particularly periarticular fractures of the knee and multi-ligamentous knee injuries (i.e., knee dislocations), is often complicated by joint stiffness. Joint stiffness associated with surgical repair of periarticular fractures may have long-term effects on mobility, gait, and function. Knee stiffness, which is a reduced range of motion (ROM) resulting in functional limitations, can impact normal leg swing and ability to ascend and descend stairs as well as rise from a seated position, particularly when entering or exiting a vehicle. Limited extension may result in a limp, quadriceps strain, functional leg-length shortening, and patellofemoral pain, thus compounding the resulting dysfunction.

Arthrofibrosis is typically a complication of a traumatic event, intra-articular or ligament surgery, arthroplasty, intra-articular fracture, or infection [41]. Arthrofibrosis can be potentiated by diabetes mellitus, lack of physical therapy, and immobilization [42]. Treatment for arthrofibrosis may include physical therapy with active-assisted and passive range of motion exercises, manipulation under anesthesia (MUA), arthroscopic or open lysis of adhesions, and/or quadricepsplasty [43, 44].

Manipulation has been applied for treatment of knee stiffness. However, MUA has not been well studied for post-traumatic stiffness and arthrofibrosis. Evans et al. [45] compared outcomes after operative treatment versus MUA in 56 patients with posttraumatic arthrofibrosis. Both groups received active-assisted and passive ROM exercises, regional anesthesia catheters, and continuous passive motion (CPM). Immediately and at 2-year follow-up, knees treated with MUA demonstrated significant improvement in the arc of motion with fewer complications over those treated with both open and arthroscopic lysis of adhesions. Unfortunately, and a notable limitation of that study, is that not all knees can be successfully manipulated by closed means without concurrent surgical intervention.

Since the treatments for arthrofibrosis are expensive, painful, and limited in their efficacy [46], prevention is preferred. Efird et al. [47] investigated the use of oral montelukast, intra-articular injections of forskolin, and intra-articular triamcinolone in rats for prophylaxis against post-traumatic arthrofibrosis. Results demonstrated efficacy of all treatments over untreated control in reducing stiffness by both reduced joint capsular contracture and reduced scar formation, with steroid injections being most efficacious. Similar results in humans would offer an additional tool for treating arthrofibrosis and optimizing function after injury. Regardless of novel preventative therapeutics, primary prevention via aggressive early motion is to be advocated as soon as osseous and soft tissue stability permits following injury.

Continuous Passive Motion

Continuous passive motion (CPM) is a form of early postoperative motion commonly used to reduce the development of stiffness after lower extremity injuries. However, the practical application of CPM is controversial due to the high monetary cost, extra work for nurses, and additional time of recumbency [48]. Several studies have investigated CPM’s potential ability to facilitate faster recovery and better outcomes after articular fractures, with inconclusive findings. The use of CPM has been reported after the surgical fixation of articular femur fractures, both distal [49] and Hoffa type [50], and of acetabular fractures [51]. In a well-controlled trial, Boese et al. [52] demonstrated no significant differences in hospital stay, pain, or range of motion in 145 patients treated with CPM for 2 days post total knee arthroplasty (TKA), although CPM increased cost per patient by $2000. It is clear that, while there is some evidence supporting the use of CPM after periarticular fractures, more studies will be needed to determine the ideal protocol for this therapy given the limited efficacy seen with TKA and the costs associated with this modality [53].

Muscle Strengthening

Diminished strength is very common following lower extremity injury. For patients with hip fracture, loss of strength contributes to rapid deterioration in function and an extremely high rate of repeat falls [54]. Multiple randomized controlled trials show that both community and home-based strength-training regimens moderately but significantly improve strength, balance, and functional mobility at 6 to 9 months following hip ORIF [55, 56]. Additionally, strength training provides long-term reduction in patient’s perceived difficulty completing activities of daily living (ADLs) compared to controls [57]. Strength training starting even as late as 6 months post-fixation can provide significant improvement of functional outcomes for an extended period of time even beyond the end of treatment [58].

The benefit achieved by muscle strengthening is not isolated to proximal femur fractures. In patients with acetabular fractures treated with ORIF, muscle strength was shown to be directly correlated with functional outcomes [59]. Strength training after the immobilization period for ankle fractures also results in significant functional improvement [60]. The benefit of strengthening exercises during the immobilization period, however, is less clear; however, a systematic review performed by Lin et al. [61] demonstrated that strength training contributes to significant improvements in activity, pain control, and range of motion, albeit at the risk of increased minor adverse events such as surgical wound irritation and arthrosis.

Physiologic Value of Lower Extremity Rehabilitation

As described above, evidence suggests the potential benefit to fracture healing and patient outcomes when early mobilization and muscle strengthening are employed during the rehabilitation of patients with lower extremity trauma. In addition, improved mobility also confers more general benefits, such as reduced risk of muscular atrophy, joint stiffness, venous thromboembolism (VTE) [40], and pressure ulcers [62]. In elderly patients recovering from hip fractures, the restoration of mobility is a critical goal as it allows improved independence with activities of daily living (ADLs), increases social interaction, and has even been shown to decrease mortality at 1-year follow-up [63]. Mobility also decreases permanent institutionalization in nursing homes, reducing financial burden on patients.

Orthopedic trauma has a relatively high incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) [64], with risk increased by injury severity score (ISS) >50, greater than two surgeries, a history of venous thromboembolism (VTE), comorbidities, traumatic brain injury, prolonged hospitalization, and reduced mobility [64–66]. In a cohort study of 18,151 orthopedic and trauma patients, Gudipati et al. [66] found that PE still developed in these patients despite mechanical and chemical thromboprophylaxis, implicating the importance of optimizing other modifiable risk factors. Even restricted weight bearing may be beneficial for VTE prevention, as venous return is not diminished in partial weight bearing when compared to full weight bearing [67].

Pain Management

Intense postoperative pain is a major risk factor for transition to chronic pain [68]. In addition, inadequate pain control is often associated with longer bedrest, delays in ambulation and physical therapy, increased rate of VTE, and poor functional outcomes [68]. Pain, particularly chronic pain, is complex and very challenging to treat. The effective management of complex pain often requires a multimodal approach including a shift away from pharmacologics and opiates, with emphasis toward rehabilitation, cognitive techniques, and managing psychologic aspects of pain. Because of the complexities in managing pain and its significant impact on orthopedic trauma outcome, a further review of some of the advances in pain management is discussed below.

Acute/Postoperative Pain

Orthopedic trauma and surgical pain are often severe and prolonged. Many methods have been used to control this pain, with multimodal approaches showing improved analgesia, better patient satisfaction, and decreased opiate use postoperatively in multiple studies [69]. Peripheral nerve blocks (PNB), particularly after lower extremity surgery [70, 71], are reported to have fewer side effects than IV opioids [72] and epidurals [73]. Aguirre et al. [74] supported the use of continuous peripheral nerve block (cPNB) postoperatively for its adequate pain control without need for large bolus doses as with single-injection blocks, thus reducing the risk of systemic toxicity, positioning injury, and falls [75]. Blumenthal et al. [76] found that cPNB for 48 h after major ankle surgery resulted in decreased pain at 6-month follow-up. This may be due to better mobilization and rehabilitation or directly due to inhibiting pain “chronification.”

Many low-risk non-pharmacologic approaches normally applied for chronic pain control may also be useful for postoperative pain, including acupuncture, thermal therapy, massage, and cognitive techniques such as relaxation, guided imagery, and music therapy [77]. One approach that has been studied with good result is transcutaneous electrical nerve stimulation (TENS), which has been shown to reduce postoperative opioid use in multiple controlled studies [78].

Chronic Pain

Chronic pain is extremely common after limb-threatening lower extremity injury [79]. Many studies have focused on the prevention of chronic pain, with the major focus being multimodal analgesia as defined above [80]. Pharmacologics including opioids, NSAIDs, local and regional anesthetics, anticonvulsants, antidepressants, and NMDA antagonists have shown some degree of benefit in preventing chronic pain. Several non-pharmacologic methods have been studied for control of this pain with proven benefit including cognitive behavioral therapy (CBT) [81] and repetitive transcranial magnetic stimulation (rTMS) [82]. Unfortunately, CBT has been notoriously difficult to study due to non-uniform application and lack of meaningful outcome measures [81]; however, in a recent study, Nash et al. [83] demonstrated increased pain self-efficacy in patients with chronic pain after CBT.

Complex Regional Pain Syndrome

One troublesome complication of chronic post-traumatic pain is the development of complex regional pain syndrome (CRPS). CRPS is a clinical process starting hours to days after initial injury that involves severe, chronic pain with hypersensitivity to normal stimuli. The pain is also typified by autonomic skin changes with cyanosis, altered temperature, and inappropriate sweat response, and increasing joint stiffness accompanied by muscle wasting and bone demineralization [84]. Several studies suggest that vitamin C may help prevent the development of CRPS, particularly after foot/ankle surgery [85]. Treatment is difficult, especially in lower extremities [86], and many modalities lack sufficient evidence to guide therapy.

Opiates, by definition in cases of CRPS, provide insubstantial pain relief or return to function and increase dependence. Anticonvulsants have shown some efficacy in pain reduction in these patients [87], whereas NSAIDs result in very short-term benefit of about 15 days [88]. In a review of 76 RCTs, Albazaz et al. [89] showed sympathetic blockade to be viable diagnostically and therapeutically short term for a subset of patients whose pain is likely sympathetically mediated; however, evidence does not support long-term efficacy [90]. In a review of 16 RCTs, Wertil et al. [91] determined that bisphosphonates are effective at long-term pain control in early CRPS and therefore may offer an alternative approach to treatment.

The use of non-pharmacologics is also widely studied for the treatment of CRPS. Grabow et al. [92] found that spinal cord stimulation (SCS) may be successful in 60–91 % of patients with CRPS. In a long-term follow-up study, Kemler et al. [93] showed that SCS with physical therapy resulted in significantly decreased pain but with no change in functional status, at 6 and 24 months. Pulsed radiofrequency (PRF) of the DRG has also increased for chronic pain syndromes, though there is insufficient evidence to indicate its utility in CRPS.

Civilian and Military Outcomes Following Lower Extremity Trauma

Rehabilitation after lower extremity trauma is extremely difficult and has been studied largely comparing lower extremity amputation and limb salvage. The Lower Extremity Assessment Project (LEAP), a multicenter study of lower extremity trauma in US civilians, assessed 2- and 7-year outcomes of patients treated with limb salvage or amputation. In these patients, critical factors in the decision to amputate were severe muscle injury, absence of plantar sensation, open foot fracture, vascular injury, bone loss, and tibial fracture pattern [94]. The LEAP study found high levels of disability in half of patients, with no difference in functional outcomes between amputation and limb salvage [95–97]. Only patients with through-knee-amputations (TKAs) had worse outcomes [98] in LEAP, although this finding has recently been countered by Penn-Barnwell et al. [99] whose systematic review showed improved function of TKAs compared to transfemoral amputations, despite increased pain with prosthetic wear.

Perhaps paramount in the LEAP study were the findings that socioeconomic factors, rather than surgeon-controlled variables or injury factors, were most related to functional outcomes and quality of life [100]. The early predictors of chronic pain included lower education level, low self-efficacy, and high baseline alcohol consumption, while 3-month post-discharge predictors included high pain intensity, sleep dysfunction, and increased depression and anxiety [79]. Financially, long-term outcomes of prosthesis bear a higher cost over a lifetime, projected as $509,275 compared to $163,282 in limb salvage patients [101].

The outcomes of the LEAP study provide a powerful tool in understanding factors involved in recovery from lower extremity trauma; however, these findings may not be generalizable to all populations. Compared to civilian populations, military trauma patients are typically younger, in better physical condition, and have access to aggressive rehabilitation and prosthesis services. The Military Extremity Traumatic Amputation/Limb Salvage (METALS) study [102••] evaluated 239 patients after unilateral or bilateral lower extremity trauma treated with limb salvage or amputation. Overall, patients reported moderate-to-high levels of physical and psychosocial disability. Older age was also associated with increased pain interference and reduced functional status. Meanwhile, strong social support resulted in better physical and psychosocial functioning.

The results of the METALS study indicated that at 37.5-month follow-up, patients with single limb amputations reported significantly better functional outcomes compared to limb salvage, with no significant effect of amputation level. Interestingly, there was also no significant trend toward better outcomes in bilateral amputations compared to single limb salvage. Individuals with amputation were 2.6 times as likely to engage in vigorous activity, although no differences were seen in depression rates or pain interference. The improved outcomes in military service members with amputation has been attributed to their higher rates of early, focused rehabilitation as compared to those in the military limb salvage group or civilian cohorts [102••]. Furthermore, as described, military service members with lower limb amputation were able to transition more rapidly to weight bearing, whereas full weight bearing generally occurs after more than 3 months in most patients undergoing limb salvage.

Psychological injury is also of considerable concern for individuals with lower extremity trauma. Within the METALS study, 38.3 % of patients reported symptoms of depression, with 13 % meeting criteria for major depression, and 17.9 % with PTSD. These results are commensurate with those reported in the LEAP study, reflecting the high rates of psychologic disease seen in these patient populations. A recent study by Vranceanu et al. [103] showed that catastrophic thinking/pain catastrophizing was the most significant predictor of pain and disability at 5–8 months follow-up after musculoskeletal trauma. This study supports the use of cognitive behavioral therapy (CBT) as an adjunct for patients with greater pain or disability than expected, as addressing PTSD and pain catastrophization early may improve outcomes, along with reducing medical costs.

Advances in Lower Extremity Trauma Rehabilitation: Lessons From Current Conflict

As an adjunct to the early and focused amputee rehabilitation at military treatment facilities (MTFs), the US Department of Defense created multiple Amputee Centers of Excellence to conduct research to improve rehabilitation of wounded soldiers and provide a multidisciplinary approach to care and rehabilitation [104•], including the formation of a DoD and Department of Veterans Affairs Center of Excellence for Extremity Trauma and Amputee Center of Excellence (EACE). In addition, several research consortiums have been formed through coordinated efforts by multiple federal and non-federal agencies. Research from these centers has resulted in the formation of improved clinical practice guidelines, enhanced methods for assessing and optimizing gait and mobility, advanced lower limb orthotics and prosthetics, as well as more aggressive rehabilitation protocols to help return individuals with lower extremity limb loss and dysfunction to their highest level of function [104•].

These technology advances have enhanced functional outcomes immensely in service members with amputation, but until recently, there were few similar advances in patients undergoing limb salvage. Patzkowski et al. [105] attributes the high functional loss in limb salvage patients to muscle loss, nerve injury, and pain, and indicated the need for development of better orthoses given the high rate of delayed elective amputations. In a study of these patients using the Intrepid Dynamic Exoskeletal Orthosis (IDEO) brace (shown in Fig. 1), a relatively new energy-storing carbon fiber orthosis, they demonstrated significant improvements in functional performance compared to all other brace types in virtually all parameters. Hsu et al. [106] showed a similar improvement with IDEO brace in nearly all physical performance measures, thereby leading patients originally desiring amputation to settle on limb salvage.

Fig. 1
figure 1

(top left) A clinical photograph of a US Marine who sustained severe bilateral open tib/fib and bilateral comminuted calcaneal fractures in 2011 (radiographs of left and right shown at bottom). On the right are follow-up radiographs of this patient, who now ambulates with bilateral Intrepid Dynamic Exoskeletal Orthosis (IDEO) (shown at top right) and is now in the Return to Run program

Full size image

The IDEO brace has subsequently become an integral component of the Return to Run program, which is combined with high-intensity physical therapy to restore function in limb salvage patients, and has demonstrated success in assisting patients to regain high-level functioning [107]. In a recent study of 84 limb salvage patients enrolled in the Return to Run program for 8 weeks, Bedigrew et al. [108] demonstrated significant improvement in physical performance measures and an 82 % reduction in ire for delayed amputation.

Conclusion

The process of rehabilitation after lower extremity and pelvic fractures involves a complex interplay of goals that ideally result in a stable, functional, and pain-free bone, joint, and lower extremity. Extensive research from past years has provided a framework of understanding how these goals may be achieved, although many limitations in our knowledge still exist. Future research will ideally focus on the further refinement of surgical fixators and their application to optimize early loading without complication, improved prevention and treatment of contracture formation and stiffness after periarticular insult, post-traumatic pain extinction, and continued development of orthoses and prostheses with near-biologic functionality. In the meantime, controlled but appropriately aggressive early mobilization and range of motion with progressive weight bearing, combined with multimodal pain control and psychosocial support, is indicated for all patients with limb-threatening lower extremity trauma and/or amputation.