Hip Sideline Emergencies and Hip Injuries in Elite Athletes

Abstract

Purpose of Review

Hip injuries in elite athletes are an increasingly recognized problem and range from chronic overuse injuries, such as adductor strains and labral tears, to acute traumatic injuries such as hip dislocations. In this article, we review common hip pathology experienced by elite athletes and sideline management of emergent hip injuries.

Recent Findings

Elite athletes are subject to unique physical and mental stresses and therefore must be evaluated and treated in a unique manner. Hip and groin injuries account for approximately 6% of sport injuries overall and 3–15% of all injuries in professional sports. Hip sideline emergencies were rare but can include hip dislocations, subluxations, and avulsion fractures.

Summary

Hip and groin injuries represent an important subset of injuries which can greatly impact an athlete’s ability to perform. Understanding the physiology and types of hip/groin injuries, which athletes are prone to injuries, the impact on recovery time, recurrence risk, and the potential need for surgery aid sports medicine physicians in decision-making.

Introduction

Elite athletes, often defined as those who participate in high level sports at a professional or semi-professional level, are subject to uniquely strenuous physical activities and grueling competitive calendars. In combination with a high level of competitiveness, financial and mental stresses, as well as hectic travel schedules, their risk of injury is often increased severalfold. While the hip is an inherently stable joint allowing for dynamic and explosive movements in a multitude of planes, the demands placed by these athletes often result in injury [47]. Physicians who clinically treat hip injuries and those that provide sideline coverage must be aware of the common hip pathology and emergent hip injuries that are sustained in elite athletes.

Historically, hip/groin injuries are among the most common causes of pain and missed playing time and have been shown to account for approximately 6% of sport injuries [6, 47, 64]. In the National Basketball Association (NBA) for example, hip injuries have been found to represent 14.6% of all injuries sustained, and occur more often (61.2%) during game competition rather than in practice or pre-season play [34]. Further, it has been reported that upwards of 69.6% of athletes are affected by some level of hip/groin injury in the NBA. Intra-articular hip injuries, accounting for 11.0% of NBA hip/groin injuries, have been found to result in longer time to return to play (RTP), significantly more games missed, and a higher risk for operative management [19]. Further, hip/groin injuries have been reported to comprise 3.1% of all injuries in the National Football League (NFL) and 10.6% in the National Hockey League (NHL). In European professional football or soccer hip/groin injuries have been found to account for 8–16% of all injuries per season with more than half resulting in at least a week before return to play [21, 28, 92]. In a prospective European study looking specifically at elite women’s football (soccer) injuries in 596 athletes across 15 teams, 10% (151/1527 total injuries) were noted to have hip/groin injuries [28]. Of these injuries 4%, 29%, 26%, 35%, and 7% of athletes had slight (0 days missed), minimal (1–3 days), mild (4–7 days), moderate (8–28 days), and severe (> 28 days) injuries respectively [28].

Overall, the majority of reported symptomatic hip/core injuries tend to occur in male athletes and in particular have been observed to occur in male athletes participating in sports such as soccer, hockey, football, basketball, skiing, or rugby [32]. In a systematic review evaluating over 30 studies recording incidence of groin and groin region injuries in elite team sports athletes, when playing the same sport, studies have reported men to have a greater injury incidence of groin injury than women (relative risk 2.45, 95% CI 2.06 to 2.92) [61]. Unfortunately, this reported disparity is likely due to the scarcity of research evaluating injuries in women’s professional sports and may not reflect true demographic or anatomical differences. A study on all collegiate hip injuries over a 10-year span utilizing the NCAA Injury Surveillance System found that athletes participating in impingement sports, such as ice hockey, more frequently sustained injuries compared to contact and cutting sports. Only a small number of emergent hip injuries occurred during this time span including hip dislocation (0.15%, 3/1984), hip subluxation (0.4%, 8/1984), and hip avulsion fractures (0.15%, 3/1984) [12].

Hip Injuries in Elite Athletes

Classification and Definitions

Typically, hip injuries are discussed in combination with adjacent groin and core injuries. Classification and diagnosis of hip/core injuries is complicated by the fact that often multiple overlapping pathologies and injuries can occur simultaneously [85]. Holmich originally proposed diagnostic categorization based on 3 clinical entities: adductor-related pain/osteitis pubis, hernia and lower abdominal pain, and iliopsoas-related pain [31]. This classification was recently updated to include two more clinical entities: hip joint pathology and pubic bone stress injury (PBSI). The term PBSI is now often utilized instead of osteitis pubis to better describe the excessive stress on the bone observed in male athletes with intense training regimens; however, the term osteitis pubis is still commonly used. Many other classifications have been developed to help organize this complex set of injuries including the Doha agreement meeting on terminology and definitions in athletic groin pain which agreed upon the major subheadings (Fig. 1) [91]. But even such clearly defined categories may have limitations. An understanding of how the different anatomical features of this complex joint/core complex may help us understand how best to manage their symptoms.

Fig. 1.

Doha agreement on groin pain classification

One of the more recent approaches to define hip/core pathologies applies a layered approach concept to facilitate diagnosis and treatment of various hip/groin pathologies [17]. Originally discussed by Kelly et al. [17], the layered concept approaches injuries of the hip/groin based on four separate anatomic layers (Table 1). Understanding the interplay between these layers is essential for comprehending the complexity of hip joint function and pathology. Each layer contributes uniquely to the joint’s stability, and disruptions in one layer can have cascading effects on the others, emphasizing the need for multifaceted approach in the assessment and management of hip-related conditions.

Table 1.

The layer concept

Reproduced with permission from: Draovitch P, Edelstein J, Kelly BT. The layer concept: utilization in determining the pain generators, pathology and how structure determines treatment. Curr Rev Musculoskelet Med Springer 2012

Femoroacetabular Impingement

Femoroacetabular impingement (FAI) represents an important, yet complex anatomical pathology which may predispose the athletic patient to degenerative labral injuries, chondral delamination, pain, disability, and ultimately progression of arthrosis [5]. As such, the evaluation and treatment of FAI in the elite athlete is an important consideration for any sports medicine physician. Experts believe the constant, repetitive, and intense level of activity that athletes place on their hip/groin not only predispose the development of FAI as well as increase risk for subsequent injuries around the hip. Accurate diagnosis requires astute clinical examination and history taking in combination with careful evaluation of radiographs (Table 2) [10, 57, 59, 68]. Advanced imaging may also give valuable information of the bony anatomy as well as intra-articular soft tissue pathology to aid in management decision making [57].

Table 2.

Radiographic parameters for femoroacetabular impingement

Radiographic Parameter	X-ray View	Normal Finding	Abnormal Finding
Alpha Angle	Frog Leg Lateral	< 42°	> 55° indicates CAM
Crossover Sign	AP Pelvis	No Crossover	Crossover sign
Lateral Center Edge Angle	AP Pelvis	> 25–39°	< 25° =dysplasia, > 40° = pincer
Anterior Center Edge	False Profile View	20°-45°	< 20°= dysplasia, > 45° = pincer
Acetabular index	AP Pelvis	0°-10°	< 0°= FAI

Abbreviations AP, Anteroposterior. FAI, Femoroacetabular impingement

It has been shown that nearly 90% of patients with labral pathology also have underlying acetabular and/or femoral structural abnormalities [5, 15]. Typically, management in elite athletes depends on several factors including the severity of the symptoms, ability to perform at the same level, and timing of the athletes’ season. In general, nonoperative modalities are attempted first: which may include activity modification, anti-inflammatories, physical therapy (which includes abductor and core strengthening programs as well as hip-motion exercises) [5]. Despite this, the impact of nonoperative management on the natural history and progression of degenerative changes in patients with known FAI is still unclear but has promising results in at least the adolescent population [5, 29, 62].

Both arthroscopic and open techniques are employed in the treatment of FAI. Overall, operative management aims to address the underlying structural issues contributing to hip impingement, providing patients with relief from symptoms and improved hip function. Return to sport for professional athletes following surgery to address FAI is reportedly very high [33]. In a study by Jack et al., professional athletes were noted to be able to return to sport at an average of 7.1 months post-op and played an average of 3.5 years after hip arthroscopy. In this study, no significant difference was found in games played per season, career length or pre- versus post-operative performance in those athletes involved in professional football, baseball and basketball even when comparing to matched control players. However, professional hockey players in particular were noted to play fewer years and fewer games per season (4.4 vs. 3.3 years, p < 0.001 and 4 fewer games, p < 0.001, respectively) after surgery as compared to a control cohort. It should be noted, however, that this study utilized publicly available data and was therefore unable to determine the exact operative procedure performed beyond that it included hip arthroscopy [33]. Further studies and systematic reviews have corroborated these results demonstrating significant improvements in various outcome scores including modified Harris Hip Score (HHS) and Visual Analog scale (VAS) for pain at latest follow-up [4, 52]. In addition, return to sport ranged from 72.7 to 100% while returning to preinjury or greater level of play in 74.2–100% of these athletes [4].

Adductor Strains

Adductor strains represent a common injury occurring in elite athletes and amongst US NCAA athletes, the most common hip/groin injury [38]. The adductor complex includes adductor magnus, longus and brevis but are often coupled with this complex are the gracilis, obturator externus and pectineus musculature [41]. Typically adductor strains present as an insidious aching groin or medial thigh pain worsened with resisted adduction [47]. Of the adductor complex, the longus is typically the pathologic tendon. Adductor strains were found to encompass 23% of all injuries in male professional soccer, with a nearly 18% reinjury rate in professional soccer (and 24% in professional hockey) [20, 49], [67]. In elite level male soccer players, they also noted a mean absence of 14 ± 24 days, an injury burden of 8 days per 1000 h of exposure, and a 14% season prevalence of acute adductor time-loss injuries [20].

Diagnosis of adductor complex injuries involves careful physical exam and history taking. Medial groin tenderness and tenderness to palpation of the adductor muscle complex are common as well as pain with resisted adduction. In some cases, magnetic resonance imaging (MRI) can aid the diagnosis by better characterizing areas of inflammation or enthesophytes.

Non operative treatment most often involves activity modification and anti-inflammatories in combination with a formal rehabilitation program. Conservative treatments with a well-designed RTS program have demonstrated a median of 15 days, 22 days, and 24 days to reach clinical milestones (clinically pain free, completion of controlled sports training, and first full team training, respectively) [78, 79]. Further, it was demonstrated that tenderness to palpation at adductor longus insertion, palpable defect, and/or an injury at the bone-tendon junction on see on MRI were predictors of increased RTS delay after acute adductor injury [79]. In patients with injuries recalcitrant to such treatments, various injection based treatments have been proposed including platelet-rich plasma (PRP) and corticosteroid injection. Schilders et al. demonstrated relief of groin pain and resolution of MRI findings in elite athletes [73]. However, they did note worse results in patients with evidence of enthesopathy at MRI or with worse adductor disease [73]. In addition, PRP for core muscular/groin injuries have been shown to increase the risk of heterotopic ossification (HO) within the core muscles and/or adjacent soft tissues. Specifically, HO was observed in 40.7% patients treated with PRP for their core/hip injury and only 0.7% patients without previous PRP treatment [65]. As with any treatment, these risks should be carefully weighed with their purported benefit.

Surgical treatment is often reserved for recalcitrant groin pain but has been shown to have favorable outcomes in elite athletes. In cases of acute adductor avulsions there has been growing debate as to the benefit of surgical reattachment and conservative treatment. While many studies have demonstrated favorable outcomes in high level athletes treated surgically [14, 46, 69], success with non-operative management and electromyographic studies (which downplay the importance of the adductor group in many athletic maneuvers such as sprinting and cutting have cast doubt on the importance of surgical reattachment) [58, 74]. Schlegel et al. previously reported on NFL players with adductor longus ruptures and noted that time RTS for players treated conservatively was half that of those treated with surgical reattachment (6.1 weeks vs. 12.0 weeks, respectively) [74].

Further, the relative success of adductor tenotomies in the professional athlete population calls into question the necessity of surgical management of adductor avulsions. Often utilized in partial tears or tendinosis, adductor longus tenotomies have demonstrated high return to sport rates [2]. Several studies demonstrated over 90% return to sport with minimal residual symptoms and high satisfaction level [2, 26].

Pubic Bone Stress Injury (Osteitis Pubis)

Another common cause of chronic groin pain is PBSI (osteitis pubis) occurring in 0.5-8% of all athletes but as much as 18% of male soccer players [21]. Typically PBSI is characterized by tenderness over the pubic symphysis and anterior/medial pelvic/groin pain, commonly affected athletes with repetitive kicking, turning, cutting, or pivoting motions [90]. Diagnosis can be difficult as it is often difficult to distinguish from other hip/groin pathologies. Palpatory exam as well as single adductor, squeeze and bilateral adductor tests can be helpful in diagnosis [88]. Imaging can aid the diagnosis with radiographic findings including widening of the pubic symphysis and sometimes sclerotic changes (Fig. 2) whereas MRI may demonstrate bony edema [47].

Fig. 2.

Radiograph depicting classic findings in pubic bone stress injury (Osteitis Pubis) with widening of the pubic symphysis and sclerotic changes

Management of PBSI is typically conservative with a prolonged healing process (6–12 months). This generally includes a period of activity modification, anti-inflammatories and physical therapy based around core strengthening and pelvic floor stabilization. In addition, corticosteroid injections have been utilized as adjunctive treatments with some studies demonstrating accelerated RTP and pain relief [60]. Failure of conservative management has been shown to be around 7–9% with as much as 25% recurrence rate [45, 50]. In such cases, operative management is typically prescribed. Options include curettage/debridement (both open and endoscopic), arthrodesis, and resection all with reported success in the athletic populations [48, 50]. As the success of nonoperative management is so high, surgical indications are consequently not well defined [47].

Interestingly, more recently the association of FAI and the resultant decreased range of motion to PBSI has been discussed [87, 89]. An NFL study demonstrated a nearly 54% prevalence of radiographic PBSI in athletes with FAI [45]. Saito et al. demonstrated a clinical improvement in PBSI and improvement bone marrow edema on MRI in soccer players treated for FAI with hip arthroscopy, with 92.0% of players able to return to competition at a median of 5.5 months [72]. This highlights the fact many groin/hip pathologies may be inter-related and understanding the layered approach to diagnosis helps determine optimal treatment options (Table 1).

Athletic Pubalgia

Groin pain has been estimated to be present in anywhere from 2 to 20% of elite athletes [96]. In particular, those participating in sports requiring significant lower abdominal and proximal thigh muscular use (soccer, ice hockey, football, etc.), groin pain often results in time loss and may impact the athletes ability to perform at a high level [22, 67]. This type of pain often manifests as athletic pubalgia, colloquially known as a “sports hernia.” Athletic pubalgia represents a complex injury to the core and groin structures. Despite the somewhat misleading terminology, athletic pubalgia does not involve a true hernia but instead represents a weakening or tearing of the core/abdominal musculature and groin structures. Although secondary to overuse as repetitive stresses and strain on the involved muscles and tendons, symptoms can occur rapidly or develop insidiously. Athletes involved in explosive movements, rapid change of direction, and frequent twisting actions are particularly susceptible.

Patients with sports hernia commonly present with pain elicited during specific activities, such as resisted sit-ups, which engage the core muscles. Additionally, mundane actions like sneezing, coughing, and Valsalva maneuvers can provoke pain in the affected area. Groin tenderness is often accompanied by radiating pain towards the perineum and the proximal adductor muscles [47]. Understanding these distinctive clinical features aids in the differential diagnosis of sports hernia from other groin-related pathologies.

Diagnosis of athletic pubalgia is typically made through history and physical exam. However, recalcitrant and severe acute injuries are often examined with advanced imaging to better characterize the extent and location of the injury to help guide management. Ultrasound and MRI are commonly employed to visualize soft tissue structures and assess the extent of injury [55]. These imaging modalities can help in identifying abnormalities in the pelvic region, including tears or inflammation of the muscles and tendons involved as well as associated pathology such as osteitis pubis, pelvic muscle strains, and visceral pathology [40, 55, 94]. In particular, “athletic pubalgia-dedicated protocols” have been developed in order to better improve sensitivity and specificity in diagnosing abdominal wall defects through MRI [40, 56]. This protocol includes axial single-shot fast-spin echo imaging performed with and without the having the patient performing Valsalva maneuver [95].

The management of athletic pubalgia requires a comprehensive approach. Non-surgical interventions may include rest or activity modification, physical therapy, and anti-inflammatory medications to alleviate symptoms and promote healing. Core stabilization and sport-specific exercises are often incorporated to enhance muscular support around the affected area. Typically a minimum 2-month trial of nonoperative modalities with rehabilitation emphasizing strength and stability including postural exercises is recommended [32]. The evidence for success of nonoperative treatment regimens is sparsely reported in the literature, but ranges from 40 to 100% [22, 96]. In cases where conservative measures fail to provide relief, surgical intervention may be considered.

Surgical treatment of athletic pubalgia in the athlete has been well studied with various approaches including open and laparoscopic methods with or without the utilization of mesh [7, 24, 27, 42]. Broadly, surgical procedures are categorized into three groups: open repair, with or without mesh reinforcement; laparoscopic repair with mesh; and comprehensive pelvic floor repair, potentially involving adductor release/repair and neurectomy [47]. In many studies, RTP has been reported at greater than 84% of athletes after operative management [7, 18, 24, 27, 32, 42, 47]. A study looking specifically at NHL players who were diagnosed with athletic pubalgia and underwent a surgery to address sports hernia noted 80% return to play for two or more seasons but did note a decrease in games played [35]. Overall, while there has been a long history of treatment, no current consensus on optimal method of treatment and there is a lack of high level randomized controlled trials or systematic reviews.

Iliopsoas-Related Pain

Iliopsoas-related pain is a condition involving discomfort or pain associated with the iliopsoas muscle, often impacting elite athletes who require repetitive hip flexion movements in their sport. These injuries include iliopsoas bursitis, tendinitis, iliopsoas snapping/internal snapping hip, and iliopsoas impingement and are reported to account for 12–36% of all groin pain in athletes [3, 30, 66]. Athletes in sports such as soccer, football, and dance may be particularly susceptible due to the repetitive nature of their movements. Diagnosis can be made with clinical examination but imaging studies such as MRI may be used to assess the extent of the injury. Recently a classification based on iliopsoas signal intensity patterns on MRI has suggested dividing these injuries into muscle strain type and the peritendinous type, with significantly decreased RTP time for muscle-strain type [86].

In addition, the iliopsoas can be involved in internal snapping hip syndrome also known as coxa saltans interna which can also contribute to the symptomology in these athletes. Symptomatic snapping has been observed in up to 58% of elite ballet dancers [93]. Interestingly, internal snapping hip syndrome has been associated with a history of trauma in as much as 50% of cases [3, 36]. The diagnostic modality of choice for internal snapping hip syndrome tends to be ultrasound which allows for dynamic evaluation in conjunction with physical examination [93].

Management strategies for iliopsoas-related pain in elite athletes depends on the exact etiology of their pain but early management often include a combination of rest, physical therapy, and targeted exercises to address muscle imbalances and enhance flexibility [3]. In some cases, anti-inflammatory medications may be recommended to alleviate pain and inflammation. Rehabilitation aims to restore proper biomechanics and strength to the hip region, allowing athletes to gradually return to their sport while minimizing the risk of recurrence.

Multiple operative techniques have been described in treatment of iliopsoas related pain. These typically involve various techniques to release or lengthen the iliopsoas tendon often in conjunction with management of associated intra-articular pathology. Both open and arthroscopic/endoscopic procedures have been described with success, however, a systematic review by Kahn et al. did demonstrate a significantly lower rate of complications in patients treated arthroscopically as well as less pain and recurrent snapping (2.3% vs. 23%) [39]. In a study by Domb et al. 95% of patients reported “much improved” physical ability and none reported worse symptoms at an average of 21 months following an arthroscopic tendon lengthening and either labral debridement or repair [16].

Hip Sideline Emergencies in Elite Athletes

Anatomy/Mechanism of Injury

The hip is an intrinsically stable diarthrodial joint comprised of the femoral head and acetabulum. The bony stability is augmented by soft tissue structures including the acetabular labrum and capsuloligamentous complex. The labrum runs circumferentially around the acetabulum providing increased contact area for the femoral head assisting in the maintenance of femoral head congruity during its three planes of motion [80]. Along with physical support, the acetabular labrum acts similar to the glenoid labrum providing a suction seal concavity compression effect. The capsuloligamentous complex is another soft tissue stabilizer of the hip made of three discrete ligaments: Ischiofemoral, pubofemoral and the iliofemoral. The iliofemoral ligament is the strongest of the capsular ligaments with its most distal fibers forming the zona orbicularis which helps control motion of the hip in the sagittal plane [80]. The intra-capsular and extra-capsular structures of the hip allow for the transfer of forces between the spine and lower extremity providing capacity for athletes to perform complex multi-directional movements during play [71]. Supra-physiologic stress of these structures, particularly in a traumatic-contact manner, can result in disruption of the hip stabilizers.

Hip Dislocation, Subluxation, and Concomitant Injuries

Hip dislocation is an uncommon injury; however, it has been reported in a wide variety of athletes participating in non-contact, contact, individual, and team sports. Athletes involved in American football, rugby, soccer, gymnastics, basketball, skiing, snowboarding, biking, and evening jogging have sustained hip dislocations, with American football and rugby the most commonly associated sports reported [76, 80]. 90% of hip dislocations that occur during sporting events are posterior with the hip in a flexed, adducted, and internally rotated position. The knee often acts as the conduit, transferring the contact force from another athlete or object to the hip. This contact force may occur directly from the collision between two structures or indirectly from an impact behind an athlete positioned on all fours causing the distal femur to secondarily be driven in a retrograde fashion towards the hip [9, 76]. Hyperabduction and extension of the hip allow the femoral head to dislocate anteriorly from the acetabulum. This may occur during the deceleration phase of running when the athlete’s hip is in provocative position: hip abducted, hip external rotation, knee flexion [51].

However, athletes can also sustain less obvious, yet still traumatic injuries to the femoroacetabular joint which include subluxation of the hip [75]. A high degree of suspicion is required to make this diagnosis as it is not uncommon for this injury to be misdiagnosed as a simple hip strain or hip sprain as much less energy is transmitted through the hip [80]. A retrospective analysis of traumatic hip instability events sustained in professional American Football players in the National Football League reported 16 posterior instability injuries in 14 players between 2000 and 2017. Hip subluxation occurred nearly as often as hip dislocation, 43.7% (7/16 injuries) versus 56.5% (9/16 injuries) respectively [1].

The true incidence of concomitant fracture in unclear, but when present may include femoral head, femoral neck, and acetabular fractures. When the femur experiences a longitudinal force, increased hip flexion and hip adduction increased the likelihood of a pure dislocation occurring [51]. Fracture-dislocation, particularly involving the femoral head or the posterior acetabular wall occur when the hip is placed in less internal rotation or less adduction when the same type of longitudinal force is applied to the femur [51]. Abnormal femoral head and acetabulum morphology can also contribute to hip instability, with FAI changes associated with posterior instability [43].

Acetabular fractures in elite athletes devoid of associated traumatic hip instability have also been reported [8, 53, 82, 84]. Fractures of the acetabulum are typically the result of high energy mechanisms that are often secondary to motor vehicle accidents or fall from heights over 10 feet [51]. In the athletic population, acetabulum fractures have been seen in football, lacrosse, and cycling all of which were from ground level height [8, 53, 82, 84]. Cerynik and Stewart case series’ described professional cyclists who sustained acetabular fracture involving the medial wall and the anterior column after falling directly on the hip while cycling [8, 84]. Fractures while performing a dynamic movement of the hip have been described as well. Hip flexion, hip internal rotation, while an athlete applying a longitudinal axial load through the limb during a football game resulted in the player sustained a posterior wall fracture. [82] Similarly, Mozzaz et al. report a posterior wall fracture in a lacrosse player from a longitudinal axial load through the limb while landing [53].

Femoral-pelvic avulsion fractures in the skeletally immature population are a rare occurrence and are the result of supraphysiologic passive stretching or forceful contraction of the inserting muscle. The weaker secondary ossification centers become the site of avulsion as the muscular-tendinous unit of the inserting muscle has a greater capacity to withstand the generated force [13]. Fig. 3 details the common sites of avulsion and associated muscles. Rossi et al. found elite gymnastics sustained a disproportionate number of IT avulsion fractures with 7 members of on an international women’s team presenting with unilateral or bilateral injuries. The authors proposed the ‘floor exercise’ which require sudden and excessive passive hamstring lengthening as a typical setting and mechanism of injury [70]. Femoral pelvic avulsion fractures have also been reported in the skeletally mature elite athlete population. According to the NCAA Injury Surveillance Program ‘hip avulsion factures’ accounted for 0.15% (3/1984) of all hip or groin injuries across all sports from 2009 to 2014 [70].

Fig. 3.

Radiograph demonstrating sites of various pelvic avulsion fractures as well as corresponding muscle attachments

Sideline Evaluation and Immediate Management

Athletes who suffer dislocations, subluxations, or fractures involving the femoroacetabular joint are often found down in severe pain on the playing field. Athletes who sustain avulsion fracture often report a sudden “cracking” sensation and subsequent pain and difficulty bearing weight [76]. Observation of the position of the affected limb can provide clues as to the position of the femoral head in relation to the hip joint, as can obtaining a focused history from the athlete. The limb of a posterior hip dislocation will be shortened with the hip flexed, internally rotated, and adducted [76]. An anterior hip dislocation the limb will be external rotated, flexed and abducted [9]. In the setting of concomitant-fracture involving the proximal femur or acetabulum, the position of the limb may be different [76]. Attempts to actively or passively range the hip as well as load the limb produce pain and are poorly tolerated. A thorough neurovascular exam and a secondary survey should be performed and documented. The athlete should be placed on a backboard with the hip and limb placed in the most comfortable position [81]. An abnormal neurovascular exam should result in the athletes’ immediate transport to the nearest trauma center for further work up [70].

While on the field or on the sideline if the diagnosis of a hip dislocation can be confidently made, a closed reduction performed by an experienced physician is reasonable [9]. Ideally the attempt should occur in an environment away from spectators in an awake, stable, and alert athlete without evidence of injuries which may preclude reduction i.e. injury to the spine [9]. There should only be a single reduction attempt performed as further attempts may be futile secondary to lack of muscle relaxation or irreducibility in a closed fashion [81]. If the reduction is deemed to be successful, post-reduction radiographs and CT images should be immediately obtained thereafter to confirm the hip is reduced and to assess for concomitant injuries [9]. In the event that the first reduction attempt is felt to be unsuccessfully, no further attempts should be performed and the athlete should be urgently sent to a nearby hospital equipped to obtain current imaging of the hip and administer anesthesia in order to perform a subsequent reduction [9]. Timeliness of hip reduction is of utmost importance as hips reduced after 6 h of being dislocated have a 60% risk of osteonecrosis compared to a 5% risk in successful reduction within 6 h [81].

Definitive management of the aforementioned emergent hip injuries depend upon the integrity of the involved injured structures and their ability to allow for a stable functional hip. A detailed discussion over treatment protocols and surgical indications is outside the scope of this article, however we provide fundamental information to aid providers who will provide initial management of these injuries. A pure hip dislocation once reduced often remains stable enough to successfully be managed conservatively [80]. Small fragments within the cotyloid fossa does not prohibit non-operative treatment. The stability of the hip and range of motion of the hip should be assessed after reduction making sure the motion is smooth while ranging the hip (Shu et al.). The patient may active and passively range the hip as tolerated however should refrain from hip flexion greater than 90 degrees and internal rotation over 10 degrees for 6 weeks in the setting of a posterior hip dislocation [80]. After an anterior hip dislocation, the patient should refrain from hip extension past neutral and any hip external rotation (Shu et al.). Weightbearing after sustaining a hip dislocation is dependent on provider preference. Concomitant fracture of the femoroacetabular joint during a hip dislocation is not uncommon. Management of the fragment(s) depend upon the anatomic location involved, the size of the fragment(s), and the ability to obtain hip motion without a mechanical block due to the fracture [51]. Insight as to how to treat associated fractures of the acetabulum can be obtained based on if the fracture is within the weightbearing zone of the femoroacetabular joint, fracture displacement, and stability of the hip during a fluoroscopic hip stress exam.

The definitive management of hip subluxation is dependent on associated injuries, which often require additional radiographic views such as Judet views to assess for a “posterior lip fracture” [80]. Additionally, MRI has been found to be helpful in the management of these injuries which can show iliofemoral ligament disruption, hemarthrosis, and posterior acetabular lip fracture considered a characteristic triad after hip subluxation [54]. Shindle et al. recommend a repeat MRI at 6 weeks post-injury to evaluate for osteonecrosis. The authors had a guarded approach to return to contact sports in the presence of osteonecrosis, cautioning the athlete of the risks of continued participation. Athletes devoid of evidence of osteonecrosis after a repeat MRI can safely transition back to sporting activity [54].

There is a paucity of literature on the management of primary acetabular fractures sustained in elite athletes during sport. The information available is based on case reports and case series of this injury occurring in elite cyclists, lacrosse players, and American football players. Cerynik and Swarts both published their case series on pelvic -acetabular fractures sustained in athletes, including professional cyclists [8, 84]. Fractures involving the anterior column, medial acetabular wall, or posterior wall were all the result of falling directly on the hip while cycling. Radiographs, MRI, and/or CT were utilized to identify the extent of the injuries. All of the professional athletes were successfully managed non-operatively being made non-weightbearing for 1–3 weeks prior to progressive weightbearing. Return to full training or competition occurring at 3 to 8 weeks post-injury [8, 84]. Another case reports of a collegiate American football athlete who sustained a primary acetabular fracture and successfully underwent surgical intervention [82]. Definitive management of primary acetabular fractures much like in the concomitant setting of a hip dislocation is predicated upon fracture location, displacement, and hip stability.

Avulsion fractures of the proximal femur and pelvic region have a strong association with sports participation, particularly in the adolescent age group [82]. Literature on the definitive management of these injuries in the aforementioned age group largely captures recreational and amateur athletes with few presenting information on elite athletes likely secondary to the limited involvement of skeletally immature athletes at these levels. In the elite athlete population avulsion fractures involving the ischial tuberosity (IT), ASIS, and AIIS have been reported in those participating in soccer, gymnastics, and tennis [25, 70, 83]. Non-operative treatment is the predominant management of hip and pelvic avulsion fractures consisting of temporary sport cessation, protected weightbearing, and physical therapy [23, 77] When these fractures have an initial displacement of 2 to 3 cm there is an increased risk of non-union and/or decrease in strength resulting in some authors reporting surgical intervention may be more beneficial than non-operative treatment [23].

Outcomes

It is fortunate that emergent injuries to the femoroacetabular joint are uncommon as the prognosis after sustaining these injuries can be unfavorable and less predictable. Athletes who sustain a hip dislocation are unable to return to the play the same day of injury and usually are unable to return during the same season [76, 81]. Reports of return to play are mixed in the literature, with studies ranging from favorable return to career ending in some athletes [63, 76, 81]. Philippon et al. reported on 14 professional athletes who sustained hip dislocations that were experiencing persistent pain and were unable to participate in their sport underwent hip arthroscopy at a mean of 125 days post dislocation. All 14 patients were able to return to full competitive sport professional sport after their respective pathologies were addressed intra-operatively [63]. A recent epidemiology study on traumatic hip instability defined as either gross dislocations or subluxations experienced by NFL players found 16 posterior hip instability injuries in 14 players over 18 seasons. Using the NFL’s electronic health record system, time to return to full participation was only available for 68% of the reported injuries with players who underwent surgery missing approximately 27 more games prior to full participation compared to those treated non-operatively [1].

The two most common sequela of a hip dislocation are post-traumatic arthritis and avascular necrosis (AVN) [63]. Prolonged time to reduction increases chondrocyte apoptosis and correlates to the development of AVN. A successful hip reduction within 6 h has produced AVN rates as low as 0 to 10%, however reduction times over 12 h has been shown have a 5.6x increased risk of AVN [51]. In contrast to AVN secondary to medications, systemic illness, or idiopathically, post-traumatic AVN can be highly focal in nature [51]. The presence of radiological findings indicative of avascular necrosis typical presents within 2 to 5 years post injury [51].

Post-traumatic arthritis is common in hip dislocations and subluxations. Arthritic changes are seen more often in posterior hip dislocations than anterior dislocations with increasing likelihood of the degenerative changes in the setting of fracture-dislocation [51]. Hip subluxation can similarly result in post-traumatic arthritic changes. Several case reports and series report mixed return to play results in collegiate and professional football players, showing full return to play in some, but also decreased time in league and progression to hip arthroplasty in others [11, 54].

Similarly, the outcomes after isolated acetabular fracture in elite athletes are reported in case reports and small case series. Several have described results in professional cyclists who had good return to sports after conservative management [8, 84]. Successful cases of non-operative and operative treatment has also been seen in elite athletes who participate in weightbearing sports that require dynamic movements of the hip [53, 82].

Hip and pelvic avulsion fractures have a strong predilection to skeletally immature athletes. There are numerous retrospective studies presenting the treatment types and outcomes of all-comers with these injuries with a predominance of conservative management. Unfortunately, few studies make explicit distinction between an elite-athlete cohort and amateur-athlete group. Sundar et al. reported increased frequency of morbidity in the chronic ischial tuberosity avulsion cohort compared to the acute cohort, resulting in at least 3 athletes ceasing participation at the national level [83]. Over the past few decades surgical indications have evolved expanding outside of fracture displacement, failure of non-operative treatment, and non-unions to include elite athletes in hopes of earlier recovery [44, 77]. Kautzner et al. presented their single institution series of 23 patients with ASIS avulsions which included 7 professional athletes. Five of the professional athletes were treated operatively and all were able to return to their pre-operative level of sport [37].

Conclusion

The hip joint involves a complex confluence of structures which come together to allow athletes to perform a wide range of movements in multiple positions. In the elite athlete, abnormal stresses coupled with varying structural abnormalities subject them to a significant risk of injury and sometimes sidelines emergencies. A strong understanding of the anatomy and pathology of these conditions may be critical in making emergent or urgent decisions. Further, a careful approach to accurate diagnosis is paramount to providing the appropriate treatment options. Often, non-operative modalities can be utilized in the treatment of these conditions even in cases of sideline emergencies. In the case of sideline emergencies, emergency action plans should be reviewed in order to best coordinate early and appropriate care.

Author Contributions

KC and EO contributed to literature search and writing, PS contributed in editing, BG was senior author who reviewed and edited all phases of manuscript submission.

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Competing Interests

The authors declare no competing interests.