A NOVEL APPROACH TO TREATMENT FOR CHRONIC AVULSION FRACTURE OF THE ISCHIAL TUBEROSITY IN THREE ADOLESCENT ATHLETES: A CASE SERIES

Abstract

Background and Incidence:

Ischial tuberosity fracture and its associated complications are an under recognized diagnosis in the adolescent athlete. Apophyseal injuries of the pelvis in the skeletally immature athlete can occur in multiple locations but are most common at the ischial tuberosity, affecting males more commonly than females.

Description of Injury and Current Management:

The most common cause of ischial tuberosity avulsion fracture is a quick eccentric load to the proximal hamstrings, occurring with kicking as in soccer, football, or dance. Signs and symptoms are similar to a proximal hamstring injury but avulsion injuries often go undiagnosed, as radiographs are not frequently obtained. In acute cases, rest and relative immobilization are the recommended course of care. In chronic cases, including those with delayed diagnosis, or those that remain symptomatic after initial care due to non‐union or associated sciatic nerve adhesions, surgery is often performed in order to restore normal anatomy, alleviate symptoms, and help return the athlete to full activity.

Purpose:

The authors' share a novel treatment approach consisting of ultrasound guided percutaneous needle fenestration for the treatment of three adolescent athletes with symptomatic delayed diagnoses of ischial tuberosity fractures. Needle fenestration was followed by a physical therapy progression which was developed based on tissue healing rates, symptom presentation, and the available literature related to proximal hamstring injuries.

Outcomes:

Two athletes reported elimination of pain, full functional recovery and return to sport without limitations as measured by use of the Numeric Pain Rating Scale, the Global Rating of Change Scale, and the Lower Extremity Functional Scale. One athlete reported elimination of pain and full functional recovery and chose to return to a new sport. Symptoms of possible concurrent hamstring syndrome are discussed as well the management of this condition.

Discussion/Conclusions:

This case series introduced a novel approach for treatment of symptomatic delayed union ischial tuberosity fractures in three adolescents prior to consideration of surgical intervention. Percutanous needle fenestration and the described subsequent rehabilitation provided positive treatment outcomes in the presented cases, including full return to athletic and recreational endeavors.

Level of Evidence:

Level 5

BACKGROUND

Management of proximal hamstring injuries can be challenging for the sports medicine practitioner. In the skeletally immature, chronic traction of the hamstrings origin on the ischium can lead to apophysitis and limited sporting abilities.^1,2 More acutely, the hamstring tendons can be partially or completely avulsed from the ischial tuberosity,¹ occasionally with fracture occurring through the ischial apophysis.² Complete avulsions of the hamstring tendon or bone were once thought of as rare injuries, however the true incidence may be underestimated due to the common misdiagnosis as a “hamstring strain” or “hamstring pull.”^1,3 Complications of apophyseal avulsion injuries include non‐union, chronic posterior thigh pain, weakness, as well as development of scarring along the sciatic nerve,⁴ termed “hamstring syndrome.”^5–7 In patients with hamstring syndrome adhesions and or tethering occurs between the sciatic nerve and the proximal hamstring tendons causing radiating pain down the posterior aspect of the leg.^6,7 (Figure 1) Symptoms are aggravated by compression (such as sitting)^6,7 or any maneuvers that stretch or place traction on the sciatic nerve (such as running or sprinting).⁷ Hamstring syndrome often presents in the athletic population,^6,7 and surgical intervention is often used as a last resort with good outcomes in those patients who failed conservative care.^6,7

Figure 1.

Schematic posterior view of the sciatic nerve and the Hamstring tendons reproduced with permission from Saikku, KS, Entrapment of the proximal sciatic nerve by the hamstring tendons. Acta Orthop Belg. 2010,76,321‐324.

Avulsion fractures of pelvic apophyses occur frequently in adolescents⁸ because cartilaginous secondary centers of ossification are weaker in tension and shear than tendon during this period of development. Secondary centers of ossification are present on the iliac crest, ischial tuberosity, anterior inferior iliac spine, pubic tubercle, angle of the pubis, ischial spine, and lateral wing of the sacrum.⁹ The secondary ossification center of the ischium is first seen in early adolescence and fuses at 19 to 25 years of age.⁹ Avulsion injuries affect the secondary centers of ossification primarily in children and adolescents between the ages of 11‐17 years.⁹

INCIDENCE

Apophyseal injuries of the pelvis in the skeletally immature athlete can occur in multiple locations^2,3,8 but are most common at the ischial tuberosity.² These injuries are more prevalent in males than females with an approximate 2:1 ratio.^2,3 While there are descriptions of ischial avulsion fractures in the skeletally mature, the average age of occurrence of ischial apophyeseal injuries/avulsion fractures ranges from 13.5‐13.8 years^1–3 to 16‐18 years of age.¹⁰ Many other small case series or single case studies of ischial tuberosity avulsions are present in the literature^10–16 almost all of which consist of adolescents who have not reached full skeletal maturity. It is rare for this injury to occur in a skeletally mature adult.² The authors only found two single case reports of this injury occurring in an adult. One was an 80 year old from traumatic hip abduction¹⁷ and the other occurred after a complicated total hip arthroplasty.¹⁸ There are presently no case series that describe an alternative to surgery or cessation of sport in adolescent patients who are still symptomatic after failed conservative care.

In the largest series reported to date, Rossi² found 203 avulsion fractures of the pelvic apophyses in 198 adolescent athletes. The most frequent location was the ischial tuberosity (IT) (109), followed by the anterior inferior iliac spine (AIIS) (45), the anterior superior iliac spine (ASIS) (39), the superior corner of the pubic symphysis (SCPS) (7), and the iliac crest (3).² In a recent systematic review Porr⁸ et al found the the ischial tuberosity to be the most frequent site of avulsion, followed closely by the ASIS, and AIIS, with fewer occurrences at the iliac crest, pubis, and lesser trochanter. They concluded that avulsion fractures of the pelvis represent a prevalent pathology among the adolescent population and apophysitis may be a precursor to these avulsion injuries.^2,8

Kujala⁴ described 14 subjects with ischial apophysitis and 21 subjects with ischial tuberosity avulsion fractures. In the 21 subjects with avulsion fractures all but two of them were identified at the time of initial radiographs. Sundar³ reviewed 80 pelvic fractures in children over a ten year period and reported 17 ischial tuberosity (IT) avulsions in 12 patients. They reported that the avulsed fragment was most clearly visualized utilizing an anterioposterior (AP) radiographic view of the pelvis in almost all patients with acute injuries, but in those with chronic traction injuries the radiological changes were subtle, described as well circumscribed radiolucent areas with periosteal reaction.³ These findings often correlate with clearly defined areas of bony edema on magnetic resonance imaging (MRI).

MECHANISMS OF INJURY AND SYMPTOM PRESENTATION

The mechanism of injury for IT avulsion is most often a sudden forceful eccentric contraction of the hamstrings occurring during activities such as a kicking maneuver,^2,3,8,19 a fall into the splits,^3,4 extreme lower extremity range of motion,⁸ sprinting,^2–4,^8,20 or jumping,^2,8,20 where the secondary ossification center is the weakest link in the muscle tendon bone unit.²⁹ Ischial tuberosity avulsion can occur in sports that lead to this eccentric overload such as gymnastics, football, soccer, and sprinting. The type of injury depends on the skeletal maturity of the patient. Often the athlete reports a “pop” followed by severe pain and difficulty walking. He or she presents acutely with tenderness over the ischial tuberosity and loss of muscular function of the hamstrings in adolescents.² The two sports with the highest prevalence of ischial tuberosity fractures are gymnastics and soccer,^2,3 followed by endurance running/sprinting,^2–4,10,14 judo,⁴ ice hockey,^4,16 figure skating,¹⁶ long jump,¹⁰ handball,² fencing,² basketball,¹⁶ tennis,² football,^13,21 high jump,⁴ baseball,^4,16 and rugby.^1,3,10 Apophyseal injuries may initially be diagnosed as a “torn hamstring” or a “groin pull”, muscular or musculotendinous injuries with which they share common symptoms.¹ More chronically, radiographic changes may be mistaken for more grave disease processes such as Ewing's sarcoma^3,16 or pseudo tumor of the ischium.¹²

MANAGEMENT

Because of their unusual occurrence, there are currently no randomized controlled trials determining optimal management for the adolescent athlete who has not reached full skeletal maturity sustains an IT avulsion fracture. Therefore, one must rely on lower levels of research evidence, consisting of primarily case reports and retrospective case series for management guidelines. Currently, the only suggested treatment option is a prolonged period of conservative care or surgery with or without cessation of sport. In reviewing the literature, little to no discussion of specific physical therapy rehabilitation management exits, so the current authors share a therapy progression which was developed based on tissue healing rates, symptom presentation, and literature on proximal hamstring injuries.

Most adolescents, when diagnosed early, appear to heal well with a prolonged period of rest,⁴ but in those patients who presented with delayed diagnosis and/or failure of conservative care surgery is often recommended.^1,4 The amount of displacement of the avulsion fracture is often used to help determine the need for early surgical intervention. While there is no exact consensus, some authors state that in those with fragment displacement of more than 10‐20 millimeters^1,4,10,22 or in those patients with persistent symptoms after more than two months of relative rest,⁴ surgery may be warranted.^{4 10,22} Although surgical technique described in the literature is variable, open reduction‐internal fixation (ORIF) appears to be the treatment of choice for fragments displaced more than 1‐3 centimeters.^1,10,14,22 Gidwani¹ reported on 6 ischial apophysis fractures in the skeletally immature (ages 9‐16), all but one presenting in a delayed fashion. The early‐diagnosed patient exhibited a non‐displaced avulsion that healed with conservative management. The five remaining patients exhibited fracture fragment displacement more than two centimeters and a time range from injury to diagnosis of three months to three years. Four of five patients were managed with surgical intervention, consisting of a ‘Kocher‐Langerbeck’ approach for posterior column acetabular fractures that was adapted more posteriorly; all of whom achieved favorable outcomes as defined by the patients being able to return to their previous levels of sports between six and 12 months post‐surgically. No specific validated outcome measures were used or described. All surgical patients and the non‐displaced/non‐surgical case were able to return to their previous levels of sports between six and 12 months post‐operatively.¹ Of interest with regard to the above mentioned case series is that in the majority of patients who underwent ORIF, the time from initial injury to surgery ranged from 6‐30 months.^1,10

Adolescent patients with IT avulsion fractures have been reported to develop fibrous non‐unions and complain of functional limitations in sporting activities as well as chronic pain, especially with sitting.⁴ In the second largest series of IT avulsions (n=21), most subjects⁴ who exhibited delayed diagnosis or did not rest after injury experienced protracted symptoms ranging from 8‐36 months, consisting of pain referral to the posterior thigh mimicking entrapment of the sciatic nerve (which has also been termed as hamstring syndrome). In comparison, those who were diagnosed early (less one month post injury) and who followed a period of prolonged rest fared better. For patients with persistent symptoms in this series,⁴ surgery consisted an ORIF for a fracture displaced more than three centimeters as well as posterior femoral fasciotomy. Eight other patients had surgery for persistent symptoms, five consisting of debridement of scar tissue around the sciatic nerve and biceps tendon, and two excisions of bone fragments.⁴ Neurolysis of sciatic nerve following chronic symptoms was also described by other authors' as an adjunct procedure.¹ Neurolysis of the sciatic nerve at the area of the proximal hamstrings for symptoms consistent with hamstring syndrome has been more frequently described in the literature^6,7 but not in the adolescent population.

Percutaneous needle tenotomy, or fenestration, has been described both with and without image guidance as an effective treatment for chronic tendinopathy of the common extensor tendon of the lateral epicondyle,^23–25 achilles tendon,^25–27 adductor tendon,^28,29 and patellar tendon.^25,30 Percutaneous tenotomy has been shown to associate with decreased visual analog pain scores in a heterogenous group of tendinopathic tendons; achilles, patellar, common extensor tendon, proximal gluteus medius, proximal rectus femoris, proximal iliotibial tract, and the proximal hamstrings tendon.²⁵

Testa et al²⁷ studied 68 athletes with Achilles tendonopathy who had failed conservative care. After undergoing percutaneous fenestration and rehabilitation 35 had an excellent outcome, 12 good outcome, 9 fair, and 7 poor. Testa et al³⁰ also studied the outcomes after percutaneous fenestration for treatment of patellar tendonopathy in 38 athletes who failed conservative care; 16 patients reported excellent outcomes, 9 good, 8 fair, and 5 poor.³⁰ Similar improvements have been reported for the common extensor tendon of the elbow.²³ Schilders et al²⁹ studied partial percutaneous tenotomy in 43 professional athletes (39 soccer and 4 rugby) with an average follow up of 40 months. In this series 42/43 returned to their pre‐injury level of sport after an average of nine weeks. Their VAS scores were also improved significantly. Maffulli et al²⁸ studied 29 athletes with chronic unilateral adductor longus tendonopathy who underwent bilateral percutaneous adductor fenestration. Mean follow up was 36 months and 69% returned to their pre‐injury level of sport, 7% above pre‐injury level and the others either did not return to pre‐injury levels or ceased participation in sport.

Recently, platlet rich plasma injections (PRP) have been utilized concurrently with tendon fenestration in order to enhance the healing effect in chronic tendonopathy. Wetzel et al³¹ retrospectively reviewed 15 patients with 17 proximal hamstring tendonopathy. Twelve were treated with PRP injections after failing conservative care of physiotherapy and non‐steroidal anti‐inflammatories. After the PRP injection those patients showed improvement in their visual analog pain scales (VAS) and Nirschl Phase Rating scales. While improvements in both groups were not statistically significant different those patients who failed conservative care (71%) improved with the addition of the PRP injection. The research on PRP and this potential management tool is still in its infancy for intervention in those with proximal hamstring injuries and deserves further examination.

It is hypothesized that percutaneous fenestration or needling disrupts scar tissue and induces bleeding, releasing growth factors to stimulate neovascularization and a healing response.^25,32,33 Platlet rich plasma injections are also thought to facilitate similar healing properties and release of multiple growth factors.^31,34 Currently, there is no published evidence on percutaneous healing response procedures on apophyseal avulsion injuries. Therefore, the purpose of this case series is discuss an alternative to surgery consisting of ultrasound guided percutaneous fenestration with or without the additions of platlet rich plasma injection followed by conservative rehabilitation for treatment of delayed diagnosed ischial tuberosity avulsion fractures in three skeletally immature athletes. All subjects and their parents consented to and signed disclosure paperwork to allow their cases to be presented for publication.

CASE 1

The first patient was a 14‐year‐old multi‐sport athlete (soccer and football) who was referred to the clinic for a right chronic proximal hamstring injury that was sustained eight months prior. At the time of injury he reported he felt a “pop” and felt like he “broke something.” He experienced severe pain in his proximal hamstring area and was unable to walk. He used crutches to assist with ambulation for approximately one week and then reported continuing to limp for “a few weeks” thereafter. Symptoms eased but did not resolve with avoidance of aggravating activities. His aggravating activities included squatting, running, and prolonged sitting. He experienced difficulty and pain with participation in soccer, football, and weight training. Past medical history was unremarkable.

Prior treatment consisted of chiropractic care without radiographs early after his injury diagnosed as a “hamstring strain”. Later, five months post injury, he saw another chiropractor who took anterioposterior (AP) radiograph view of the pelvis which demonstrated an ischial apophyseal avulsion fracture. (Figure 2a) He was referred to physical therapy. After three months of physical therapy by two different physical therapists ,his symptoms were not improved. Consultation was obtained from a pediatric orthopedist who obtained a magnetic resonance image (MRI). (Figure 2b‐d) This demonstrated a non‐healed avulsion fracture of the right ischial apophysis, distracted five millimeters, with edema between the ischium and the ischial apophysis and intact hamstrings tendons. The apophysis was hypertrophied and exhibited a small area of fragmentation medially. Magnetic resonance imaging is recommended for cases that are difficult to diagnose² or those who have failed conservative care and those in which surgical intervention is contemplated. The patient was referred to the primary author (SS) for physical therapy for a trial of instrument assisted soft tissue mobilization, which has been advocated for use in treatment in proximal hamstring tendinopathy with favorable outcomes in a small case series of competitive distance runners,³⁵ but has not been advocated for the treatment of avulsion fractures.

Figure 2.

Images for Subject 1. A. Anteroposterior (AP) radiograph view of pelvis showing the ischial tuberosity avulsion fracture (white arrow). B. Anteroposterior (AP) Magnetic Radiographic T2 Weighted view of the avulsion injury left side of image (white arrow), note also the bony edema C. Sagittal Magnetic Radiographic T2 Weighted view of Ischial Tuberosity Fracture (white arrow). D. Coronal Magnetic Radiographic T2 Weighted view (white arrow).

At initial intake the patient reported his numeric pain rating scale was 0/10 at rest and 3‐5/10 with activity. He described his pain as “sharp” at the ischial tuberosity area. Pain was worsened with squatting, sprinting, stair climbing, and prolonged sitting (> 45 minutes). This patient's Lower Extremity Functional Scale (LEFS) score was 57/80, with a score of 80 translating to no deficits.^36,37 Visual gait assessment was normal with walking but abnormal during treadmill running, exhibiting decreased knee flexion during the swing phase and experienced pain during push off phase in terminal stance. Manual muscle testing of the hip flexors and knee extensors in sitting was 5/5 bilaterally, external rotators and abductors in side lying was 5/5 bilaterally. In prone gluteus maximus was 5/5 bilaterally, and the hamstrings were 4/5 on the right. Hand‐held dynamometry was used to measure specific differences of the hamstrings in prone with the knee in approximately 90° and 30° knee flexion which revealed significant deficits at 30° knee flexion, right being 61% of the left. (Table 1) The performance of hamstring muscle testing with the knee flexed in multiple angles has been recommended by other authors due to changes in the musculotendon length of the hamstrings.^38,39 He was tender to palpation at the right ischial tuberosity. Lumbar AROM was full and pain free. Palpation did not reveal any appreciable pelvic asymmetries. Passive straight leg raise with ankle dorsiflexion reproduced pain at the ischial tuberosity at end range but no referral of symptoms down the leg.

Table 1.

Case 1: Pre‐post intervention data.

Time	NPRS 0‐10 Rest/Activity	LEFS	Hamstring Strength (prone) HHD (kg) Knee flexion 90°	Hamstring Strength (prone) HHD (kg) Knee flexion 30°
Baseline	0/10 7/10	57/80	R: 17.37 L: 19.18	R: 9.97 L: 16.32
6 weeks	0‐7/10 7/10	34/80	‐ ‐	‐ ‐
13 weeks	0/10 0‐4/10	70/80	R: 24.04 L: 24.49	R: 19.94 L: 24.04
23 weeks	0/10 0‐3/10	76/80	R: 21.31 L: 25.40	R: 19.95 L: 23.58
36 weeks	0/10 0/10	78/80	‐ ‐	‐ ‐
41 weeks	0‐1/10 1‐2× week after workouts	79/80	R: 27.66 kg L: 24.49 kg	R: 18.59 kg L: 18.59 kg
3 years	0/10 0/10	80/80	‐ ‐	‐ ‐

NPRS=Numeric Pain Rating Scale, LEFS=Lower Extremity Functional Scale,

HHD=MicroFet 3 Hand Held Dynamometer

After four additional visits of physical therapy over a period of approximately three weeks including a trial of instrument assisted soft tissue mobilization and eccentric loading exercises with no appreciable improvement in symptoms it was proposed to the patient and family to consider a percutaneous needle fenestration at the fracture site as a means to induce a healing response prior to considering operative fixation of the fracture. The clinical reasoning regarding progression to this intervention included the failure of all prior conservative care, the goal of returning the athlete to full participation in sports in the fall, and the existing literature advocating surgical intervention when symptoms persisted after an extended period of rest or conservative care.¹ The normal healing time frame for avulsion fractures that are acutely diagnosed is approximately sixty days¹⁶ to four months.¹⁹ The risks and potential benefits of this novel treatment approach were discussed in detail with the patient and family and they consented to treatment. The sports medicine physician performed the procedure three days after proposal to the family. Utilizing an 8‐13 MHz linear array transducer ultrasound, the patient's ischial tuberosity was visualized. At the origin of the conjoined tendon and semimembranosus tendon an area of significant cortical irregularity over the ischial tuberosity was visualized with loss of normal convex contour corresponding to the fracture site seen on MRI. In an outpatient facility, under sterile conditions, the skin and soft tissues were anesthetized with 1% lidocaine without epinephrine and 0.25% Marcaine without epinephrine under direct ultrasound visualization. A 21 gauge needle was then used to repeatedly fenestrate the tendon origin into the ischial tuberosity and apophysis, with approximately 40 forceful needle passes circumferentially about and into the fracture site. Following the intervention the patient was placed on crutches and was instructed to remain non‐weight bearing and avoid sitting directly on his right buttock for two weeks.

Rehabilitation after percutaneous fenestration was adapted from the protocol devised Metzamaker and Pappas¹⁶ (Table 2) which was utilized for treatment after acute avulsion fractures. Information regarding specific suggestions for rehabilitation of this condition is scarce. Two other authors only described advocating a period of rest⁴ and delayed stretching²¹ after acute avulsion injuries. Theoretically, percutaneous fenestration consisting of multiple needle penetrations of the periosteum and apophysis produces an environment similar to acute fracture and thus creates an entirely new healing episode. The rehabilitation progression presented herein by the authors was based on proposed healing rates of bone as well as by symptoms. Physical therapy was initiated at nine days post‐intervention and consisted of gentle soft tissue mobilization consisting of light effleurage of the distal to mid portion lateral hamstring muscle belly where he experienced some soreness, reiteration of protected toe touch weight bearing starting at two weeks post intervention, and instruction in gentle isometric exercises consisting of gluteal and quadriceps sets. Neuromobility exercises, consisting of ankle pumps in supine were started to avoid the possible sequelae of sciatic nerve adhesions and hamstring syndrome.^5,7,40 He was instructed to avoid hamstring stretching and activities which produced any increased symptoms at his ischial tuberosity. Visit two; 16 days post‐intervention he reported still experiencing a deep achy pain in the proximal ischial tuberosity area. Toe‐touch weight bearing was reviewed and the subject was educated to avoid any activity or movements which aggravated his symptoms. Home exercises were progressed to include supine abdominal crunches. He was allowed to perform any lightweight upper extremity exercises he could perform in which he felt no additional symptoms in in ischial tuberosity area. Care was taken not to stretch the hamstrings during the first six weeks of treatment to avoid any pulling on the fracture site. The clinical reasoning used for protected weight bearing for a longer duration than that advocated by Metzmaker and Pappas¹⁶ had to do with his symptom presentation (continued pain), and bony healing time frames, as well as factoring in his prior failed conservative care.

Table 2.

Rehabilitation guideline for acute avulsion fractures of the pelvis: Phases of treatment (from Metzmaker JN, Pappas AM, Avulsion fractures of the pelvis. Am J Sports Med, 1985;13(5):355. Reprinted by Permission of SAGE Publications)

Treatment Phase	Days after injury	Subjective Pain	Palpation Subjective‐Pain Objective‐tissue	Range of motion	Muscle Strength	Level of Activity	Radiograph Appearance
I	0‐7	Moderate	Moderate to Severe	Very limited	Poor	None, protected gait	Osseous separation
II	7 to 14‐20	Minimal	Moderate	Improving with guided exercise	Fair	Protected gait Guided ex	Osseous separation
III	14 to 20‐30	Minimal with stress	Moderate	Improving with gentle stretch	Good	Guided exercise, resistance	Early callus formation
IV	30‐60	None	Minimal	Normal	Good to Normal	Limited athletic participation	Maturing callus
V	60‐to RTS*	None	None	Normal	Normal	Normal	Maturing callus

^*Return to Sport

At visit three, approximately six weeks post intervention, he reported that he had been slowly increasing his weight bearing with crutches, as he had ceased to experience any pain with walking. He was instructed to slowly increase his weight bearing as tolerated during walking over the next couple weeks as long as he was symptom free with the goal of weaning off the crutches. Strengthening was progressed to include isometric hip adduction, side lying hip abduction, isometric hamstring sets, standing terminal knee extensions, and standing gastrocnemius stretching. Trunk exercises were progressed and consisted of kneeling with forearms in plank position with ball rollouts and supine trunk rotation with weights in the upper extremities. No exercises caused symptoms in his ischial tuberosity, and this was the guiding factor for progression. At seven weeks post‐intervention he returned to the clinic walking without crutches. He reported that he did experience increased symptoms walking without crutches the first few days. He was still tender to palpation at the ischial tuberosity. At this time gentle resisted knee flexion manual muscle testing was performed which elicited some pain therefore he was only initiated in prone eccentric active range of motion as well as progression of weight bearing exercises of mini‐squats, bridging, planks, side‐planks and standing resisted side stepping and grape vine walking. These exercises have been recommended in the literature for rehabilitation of hamstring muscle injuries to promote improved neuromuscular control, agility, and coordination of the trunk and pelvic musculature.³⁹ Utilization of these exercises has been shown to reduce reinjury rates and slightly hasten time with return to sport in athletes with acute hamstring injuries.⁴¹ At nine weeks eccentric loading exercises were progressed in prone utilizing a three‐pound ankle weight and adding a supine crab walk out exercise. Subjective assessment of pain and function as well as strength was monitored throughout his rehabilitation to help guide clinical decision‐making and progression of exercise and activity levels. (Table 1) At thirteen weeks post intervention when his pain levels had decreased to 0/10 at rest and no more than 4/10 with activity. Hand held dynamometer testing revealed a significant improvement in strength and did not elicit pain therefore hop testing was performed comparing the involved extremity to uninvolved extremity. (Table 3) Hop testing has been reported as a reliable and valid functional measure in athletes following knee injuries⁴² to determine readiness of return to sport and normalization of functional strength. Repeat testing was performed at various intervals, but not until week 23 did his strength begin to equalize with his uninvolved extremity. An outline of therapy progression is presented in Appendix 1.

Table 3.

Case 1: Hop testing post‐intervention, in meters

Hop Testing Time:	Single Leg Hop	Triple Leg Hop	Cross‐over Hop
13 weeks	R: 1.14 m L: 1.32 m	R: 4.03 m L: 4.21 m	R: 3.12 m L: 3.35 m
23 weeks	R: 1.41 m L: 1.70 m	R: 5.15 m L: 5.18 m	R: 4.26 m L: 3.88 m
41 weeks	R: 1.69 m L: 1.57 m	R: 5.10 m L: 5.00 m	R: 4.08 m L: 4.05 m

Follow up questionnaires were completed 18 and 36 months following percutaneous fenestration to determine long term outcome. At the 18 month mark the patient reported a global rating of change score (GROC)^43,44 at +7, no pain 0/10, and LEFS score of 79/80. The global rating of change score is based on an index with subjective reports of improvement in status ranging from ‐7 (a very great deal worse) to 0 (about the same), to +7 (a very great deal better). The GROC is reliable and valid and has been correlated with hop testing.^42,44 The patient had returned to playing football/sports without any limitations at 41 weeks. At the 36‐month post intervention mark the patient continued with a GROC of +7, pain‐free NPRS 0/10, and his LEFS score improved to 80/80.

CASE 2

The second patient was a 14‐year‐old male referred for right chronic posterior thigh pain, which began approximately eight months previously while playing football. He stated that he stepped in a hole and felt his leg jerk, experiencing immediate pain. He was able to continue training and ignored his pain, however his symptoms worsened during football season. Prior treatment reported of chiropractic manipulation and anti‐inflammatories did not help his symptoms. An AP pelvis radiograph taken eight months post injury revealed an abnormal fragmenting in the region of the right ischial apophysis consistent with a chronic avulsion fracture of the ischial tuberosity. (Figure 3) He complained of pain ranging from 0‐8/10, which limited his ability to sprint and eased with rest, and a LEFS score 52/80. He recently had taken up weight training in preparation for a bodybuilding competition and reported difficulty with squatting activities. Past medical history was significant for left tibia‐fibula fracture with complete recovery.

Figure 3.

Subject 2: AP Pelvis radiograph showing abnormal fragmentation in the region of the right ischial apophysis (white arrow), consistent with chronic avulsion.

On visual observation, gait was normal. Palpation produced tenderness over his ischial tuberosity. When performing a deep double leg squat he shifted hips to the left demonstrating unequal weight bearing favoring his uninvolved extremity. Strength testing with a hand held dynamometer revealed weakness in the right hamstrings, especially when tested at 90° knee flexion, 61% right to left ratio. Conservative care was attempted since he stated that his symptoms had improved since avoiding aggravating activities and squatting endeavors over the past two months. Initial treatment consisted of instrument assisted soft tissue mobilization to the proximal hamstrings and active range of motion eccentric hamstring exercises for the first visit. On the second visit, the following week he reported no pain therefore single leg hop testing (an average of three trials) was performed: right 1.12 meters (m), left 1.32 m (84.6%) and was pain‐free therefore he was progressed to jogging. He was able to jog on the treadmill for about five minutes pain‐free. The following visit his LEFS improved to 58/80 and his hamstring strength ratio to 83% at 90° knee flexion. His exercises were advanced to progressive eccentric loading. Approximately two weeks later, he participated in a body building competition and reported no difficulties or pain until the end of the competition where he felt like he re‐injured his buttock during one of his last poses. His pain levels rose up to 7/10. His LEFS score decreased to 44/80 from 52/80 at his initial visit. This re‐injury occurred after three months of relative rest and one month (3 visits) of physical therapy. At this visit, due to re‐aggravation of his injury and his goals of returning to sports and body building endeavors more rapidly, percutaneous fenestration was discussed with the patient and his family by the second author. The patient consented and scheduled the intervention for the following week. Prior to his intervention he was instructed to perform neuromobility exercises, consisting of ankle pumps in supine multiple times per day to avoid the possible sequelae of sciatic nerve adhesions and hamstring syndrome.^5,7,40 The intervention was performed by the sports medicine physician under ultrasound guidance as described for our first case. Following his percutaneous fenestration intervention the patient was placed on crutches and was instructed to remain non‐weight bearing and avoid sitting directly on his right buttock for two weeks.

Two weeks after the procedure he was seen in physical therapy. He reported some soreness for a few days after the procedure but no pain the following week. His NPRS score was 0/10. At this time he was progressed to toe touch weight bearing with crutches and started on pain free isometrics as our first case. Two weeks later, the patient reported to continue to be pain free and his LEFS score was 59/80. It was noted on his LEFS that he reported a “4” or “no difficulty” for both running and hopping activities. However at this time, he was still supposed to be using his crutches. He was questioned specifically about this and reported that he ran across the street once holding onto his crutches. It was decided that due to his report of pain free running for a short distance that the crutches were not longer necessary and they were discontinued at this time. He was also asymptomatic with sitting and walking. Time frames were adjusted based on his clinical presentation. In this case his radiographs showed less irregularity and displacement at the ischial tuberosity, as compared to the presentation of the subject in the first case, which may have contributed to quicker healing rate (based on symptoms). Pain, functional testing⁴⁵ including use of the LEFS, as well as hop testing was performed to help guide rehabilitation and determine readiness for return to weight training activities. (Tables 4‐6) Radiographs were obtained eight weeks after the procedure when the patient was asymptomatic. (Figure 4) He was instructed to resume his weight training activities with a weekly incremental progression of weight over the next two months and to monitor for any symptoms. The same guideline was used for running. At the 6‐month follow‐up, the patient reported absence of pain, NPRS 0/10, LEFS score of 80/80, and a GROC score of +7. He had returned to his full weight‐training activities without any limitations. He had chosen to discontinue football and pursue bodybuilding competitions, as that had become his sport of preference after his initial injury.

Table 4.

Case 1: Pre‐Post Intervention Data

Time	NPRS 0‐10 Rest/Activity	LEFS	Hamstring Strength (prone) HHD (kg) Knee flexion 90°	Hamstring Strength (prone) HHD (kg) Knee flexion 30°
0 days	0/10 8/10	52/80	R: 12.25 L: 19.95	R: 19.05 L: 20.86
8 days	0‐7/10 7/10	58/80	R: 19.95 L: 24.04	R: 22.22 L: 27.21
22 days	0/10 0‐4/10	44/80	R: 20.86 L: 23.58	R: 19.94 L: 24.04

NPRS= Numeric Pain Rating Scale, LEFS=Lower Extremity Functional Scale,

HHD+MicroFet 3 Hand Held Dynamometer

Table 6.

Case 2: Post‐intervention hop testing

Hop Testing: Time	Single Leg Hop	Triple Leg Hop	Crossover Hop
9 weeks	R: 1.60 m L: 1.60 m	R: 4.62 m L: 4.59 m	R: 3.75 m L: 3.81 m

Figure 4.

Subject 2: AP Pelvic Radiograph eight weeks post percutaneous tenotomy, black arrow. Note some increase in sclerosis and callus formation.

Table 5.

Case 2: Post‐intervention data

Time	NPRS (0‐10) Rest Activity	LEFS	HS Strength: HHD, Knee flexed 90°	HS Strength: HHD, Knee flexed 30°
2 weeks	0/10 2/10	‐	‐	‐
4 weeks	0/10 0/10	32/80	‐	‐
6 weeks	0/10 7/10	59/80	R: 20.86 kg L: 21.77 kg	R: 18.59 kg L: 24.49 kg
9 weeks	0/10 0/10	62/80	R: 24.49 kg L: 25.85 kg	R: 23.58 kg L: 23.13 kg
6 months	0/10 0/10	80/80	‐	‐

NPRS=Numeric Pain Rating Scale, LEFS=Lower Extremity Functional Scale,

HHD=MicroFet 3 Hand Held Dynamometer

CASE 3

The third patient was a 16‐year‐old female school dance team member who reported onset of symptoms after performing a high kick with the right leg in practice. Initially she thought that she had “pulled her hamstring” but her symptoms continued to worsen with time, therefore she sought an orthopedic consult approximately five weeks post injury. At that time she complained of a sharp pain in her right proximal buttock that became worse with stretching or kicking activities. Past medical history was unremarkable other than a prior T7 compression fracture sustained snowboarding at age 10 that healed uneventfully. Radiographs were taken which revealed asymmetry in the apophyseal origin consistent with an avulsion fracture. (Figure 5a) She was instructed from the orthopedic surgeon to take six weeks off dancing activities then referred to physical therapy. Physical therapy consisted of ten visits over a two month period utilzing instrument assisted soft tissue mobilization, exercise (hamstring stretching, isometrics, concentric and eccentric exercises) and interferential stimulation. She experienced a decrease in her pain but when she attempted to return to sport she still reported pain with running and kicking activities in dance. She then returned to the orthopedic surgeon who obtained follow up radiographs, approximately three months following her initial radiographs. (Figure 4b) There was no appreciable healing demonstrated. An MRI was obtained that showed widening of the apophysis without any significant displacement of her ischial tuberosity. She was then referred for percutaneous fenestration to the second author by the orthopedic surgeon; it was also suggested to the patient that she may benefit from addition of a platelet rich plasma injection, which may have benefit in treating chronic tendonopathy conditions^46,47 including those involving the proximal hamstrings.³¹ Benefits and risks were discussed with the patient and her family. The patient consented and scheduled the intervention six weeks later. The intervention was performed under ultrasound guidance as described for the previous cases, with the addition of platelet rich plasma injection.³¹

Figure 5.

Subject 3: Close up of AP Pelvis view of the right ischial tuberosity A. Close up AP Pelvic view of her right ischial tuberosity taken 5 weeks post injury. B. Repeat film taken 4 months post‐injury after the first round of physical therapy, note no appreciable healing, with possible increase in bony displacement C. Repeat films taken 10 months following percutaneous fenestration/PRP procedure showing almost complete healing (black arrow).

She was referred to physical therapy with the primary author three weeks status post percutaneous fenestration. At the initial examination she reported her pain levels ranging from 0/10 at best (laying down) up to 7/10 with sitting and her LEFS score was 58/80. She also complained of intermittent sharp shooting pain originating at the proximal hamstring radiating pain down the posterior aspect of her thigh which she rated 7/10. She reported her radiating pain occurred two‐three times per day for duration of two to three minutes. Sitting aggravated her proximal buttock (ischial tuberosity) symptoms, especially when sitting on hard surfaces such as classroom chairs. Additionally, unlike the prior two subjects, she exhibited a positive slump test and straight leg raise (SLR) test for reproduction of her radiating leg pain. Examination of her lumbar spine exhibited only mild radiating pain at end range flexion with the addition of neck flexion, she did not have any reproduction of symptoms or pain with passive accessory testing to the lumbar spine. Her neurological examination was normal. She was tender to palpation at her ishial tuberosity. These symptoms and presentation are consistent with possible concurrent hamstring syndrome, in which the sciatic nerve is irritated and or tethered to the hamstring tendons origin.^5,6 Treatment was similar to the first two subjects, with the additional of progressive of neurodynamic exercises to address her radiating symptoms.^40,48 Turl et al⁴⁰ reported adverse neural tension as assessed using a positive slump tests in 51% of male rugby players with a history of repetitive hamstring strains verses 0% in a control group. In a case report, Aggen and Reuteman⁴⁸ described the utilization of sciatic nerve glides as a component of rehabilitation in a patient with sciatic nerve injury following a hamstring tear. There are currently no reports in the literature of conservative management of hamstring syndrome concurrent with an ischial tuberosity avulsion injury. Neurodynamic exercises consisted of seated and supine active knee flexion/extension with concurrent ankle dorsiflexion with the addition of ankle eversion. This author prefers the supine position secondary to the aggravating position of sitting as it applies less compressive forces to the sciatic nerve at the ischial tuberosity since it is in a non‐weightbearing position. Her strengthening program was initiated and progressed weekly similar to our first two cases. Her crutches were discontinued at four weeks based on no symptoms with walking. At her sixth visit she reported a GROC of +6 (she had not yet returned to dance activities) and an LEFS score of 78/80. She was pain free with sitting and exhibited negative Slump/SLR tests. She was able to perform running activities of short sprinting, side shuffle, and cutting activities without symptoms. Handheld dynamometer testing revealed no side‐to‐side deficits. (Table 7) She did not plan on returning to her previous activity, dance. She was discharged from physical therapy.

Table 7.

Case 3: Post‐intervention data

Time (wks)	NPRS (0‐10) Rest /Sitting	LEFS	Slump NPRS	SLR (°) NPRS	Hamstring Strength HHD at 90°	Hamstring Strength HHD at 30°
3	0/10 7/10 >30 min	58/80	+ Right 7/10	+ Right 80° 7/10	‐	‐
4	0/10 7/10 > 30 min	‐	+ Right 4/10	+ Right 95° 7/10	‐	‐
5	0/10 3/10 >30 min	58/80	+ Right 2/10	+ Right 95° 3/10	‐	‐
6	0/10 3/10 > 60 min	‐	+ Right 2/10	+ Right 100° 5/10	‐
7	0/10 1/10 > 90 min	‐	‐ Right 0/10	‐Right 100° 0/10	‐	‐
8	0/10 4/10 > 120 min	78/80	Negative	Negative	‐	‐
10	0/10 0/10 unlimited sitting	‐	Negative	Negative	R: 14.65 kg L: 14.78 kg	R: 13.74 kg L: 13.60 kg
24	1/10 8/10 >30 min	‐	‐	+ Right 110° 7/10
56	0/10 3/10 > 2 hours	77/80	Negative	Negative	R: 16.32 kg L: 15.24 kg	R: 21.51 kg L: 19.95 kg

NPRS=Numeric Pain Rating Scale, LEFS=Lower Extremity Functional Scale, HHD=MicroFet 3 Hand Held Dynamometer

She remained asymptomatic for approximately three months then she started experiencing proximal hamstring pain after taking a new job, which required her to sit for prolonged periods. She had also stopped exercising at the gym. After a few months of continued symptoms she returned to the physician for follow up. Radiographs were taken which showed healing of her ischial tuberosity avulsion fracture, (Figure 4c) and the subject was referred back to physical therapy with pain and symptoms consistent with proximal hamstring tendonopathy/syndrome and concurrent low back pain. She did not exhibit any radicular symptoms but had pain in the proximal hamstring insertion area with Slump testing and SLR at end ranges. Recent tests advocated to aid in diagnosis of proximal hamstring tendinopathy include the modified bent knee stretch test⁴⁹ and the Puranen‐Oravao test⁴⁹ which are similar in position to both the passive SLR test and Slump tests. These tests have been found to be reliable and valid for proximal hamstring tendonopathy as compared to MRI findings in a population of 92 athletes.⁴⁹ These particular two tests were not performed in the first two cases, as the primary author only recently became aware of them. She did exhibit a positive bent hamstring test for reproduction of proximal hamstring pain. Hip examination revealed pain free range of motion including combined motions with overpressures however she did exhibit some mild hip abductor weakness with mild pain, which could be inter‐related to her lumbar spine and distal (buttock) symptoms.

Lumbar examination revealed pain free lumbar AROM with overpressures, but passive accessory movement testing revealed hypermobility at spinous process of lumbar vertebra L5 with local pain in her lumbar spine. Running on the treadmill did not aggravate her symptoms. Sitting was her primary aggravating activity. Her neurological examination was normal. She was treated for an additional eight visits in physical therapy over a three‐month period and during the last month she resumed running and gym activities on a regular basis. Specific details of treatment are beyond the focus of this paper but consisted of limiting her sitting periods, a corticosteroid injection to the proximal hamstring area, lumbar stabilization exercises as she fit the criteria for stabilization according to Hicks⁵⁰ and Rabin,⁵¹ neuromobility, and progressive eccentric loading exercises.⁵² Additionally, core or spinal stabilization exercises have been shown to have a positive effect on athletes who have sustained hamstring injuries,^39,52 therefore a multi‐factorial treatment approach was utilized. She returned to exercising regularly at the gym where she was able to run on the treadmill pain‐free. Three months later she reported a GROC score of +7 and an LEFS score of 77/80. Her low back pain was absent. She did still report mild buttock pain up to 3/10 with sitting for more than 2 hours that eased immediately upon rising from sitting and lasted only 10 minutes in duration. At this time hop testing was performed. She was able to run and do all weight training exercise endeavors without pain. (Table 8) She was discharged from physical therapy. Two months later she joined the track team where she participated in the long jump. She reported initially she had some discomfort in in her proximal hamstring but then it dissipated as the season progressed. Eighteen month follow up after percutaneous fenestration she reported a GROC score of +6 and an LEFS score of 77/80.

Table 8.

Case 3: Post‐intervention hop testing

Hop Testing: Time	Single Leg (m)	Triple Hop (m)	Cross Hop (m)
8 weeks	R: 1.14 m L: 1.19 m	R: 3.48 m L: 3.43 m	R: 3.25 m L: 3.15 m
56 weeks	R: 1.21 m L: 1.20 m	R: 4.12 m L: 3.87 m	R: 3.77 m L: 3.50 m

DISCUSSION

Details of conservative rehabilitation or post surgical rehabilitation of ischial tuberosity avulsion fracture are minimally described in the literature.^1,4,16,20,22 To the authors' knowledge there are no case reports or literature published on the use of percutaneous needle fenestration to induce a healing response in delayed diagnosis ischial tuberosity avulsion fractures in adolescents. Most case reports or case series for the acutely diagnosed injury consist of a period of prolonged immobilization with limited weight bearing and slow return to recreational activities.^1,4,16,20,22 Metzamker and Pappas¹⁶ presented a rehabilitation protocol for conservative care for treatment of all types of acute avulsion fractures of the pelvis. Their series consisted of six IT fractures along with other apophyseal fractures of the pelvis including the lesser trochanter. The protocol was broken into five phases and has been presented earlier in this paper. The criteria for progression was based on time from injury, pain, palpation, range of motion, muscle strength, activity level and radiographic appearance. Recently, after this case series was completed, Biedert²⁰ published a more detailed post‐surgical rehabilitation progression of a case series of three adolescent patients with proximal IT apophyseal fractures. They initially limited sitting to the uninvolved buttock and non‐weight bearing on the involved extremity for six weeks followed by a slow progression to full weight bearing at 12 weeks post‐surgery. Physical therapy consisting of active range of motion and supervised strengthening was started at six weeks post surgery. After four months, dynamic stretching and jogging allowed. At six months the three athletes were released to full sporting activities.²⁰ A recent case report by Ceretti¹⁹ was published outlining a criterion progression for rehabilitation of an acutely diagnosed avulsion fracture in a 15 year old football player, which clearly demonstrates the benefits of early diagnosis with subsequent rest and limited weight bearing in the early stages to facilitate healing. Once bony healing and symptoms diminished, progression included agility and trunk stabilization exercises at low intensity for the following five weeks. At eight weeks therapy was progressed with higher‐level stabilization exercises and agility exercises. Progression to static stretching and isometric strengthening started at sixteen weeks and was then progressed to include dynamic stretching and concentric and eccentric hamstring strengthening. Full return to sport occurred at four months.

All too often these adolescent athletes who sustain ischial tuberosity avulsion apophysitis or avulsion fractures are misdiagnosed with a hamstring strain and will often continue weight‐bearing and stretching/strengthening activities which results in a prolonged period of convalescence and lack of full resolution of symptoms. Contrary to the adult population where isometrics followed by eccentric loading progression are indicated for hamstring injuries,⁵² these activities should be significantly delayed in the adolescent with an apophyseal injury.^1,19

These protocols may work well in the acutely diagnosed patient with ischial tuberosity fractures or a post‐operative patient but may not work as well for the delayed diagnosis patient with minimal to moderate displacement that remains symptomatic. This variability in recovery time is evident in the three subjects presented in this case series. The first subjects' fracture appeared more fragmented and was more displaced that those seen in the other two subjects therefore his progression was slower. Each subject's presentation of signs and symptoms were concurrently considered along with bony tissue healing time frame in order to determine their clinical progression. Hop testing was performed at 9 and 8 weeks in subjects two and three respectively, whereas pain levels prohibited this from being performed until 13 weeks in subject number one. Reasons for this may include a decreased size of the avulsion fracture, less fragment displacement, and earlier diagnosis with limited sports participation immediately post injury for the latter two subjects. The first subject had continued to run and participate in football for an entire season despite his pain and dysfunction. The second subject had taken a couple weeks off after injury but then once he returned to activity, noted a progression of his symptoms. The third subject also limited her activity levels immediately after injury but her symptoms did not improve. This may or may not have been related to rehabilitation prescribed which included static stretching and concentric eccentric exercises despite continued pain presentation. Finally, the third subject also differed due to presentation of concurrent signs (positive straight leg raise and slump) and symptoms (pain radiating down the leg) suggestive of hamstring syndrome. Therefore, in addition to a standard progression, neurodynamic exercises were integrated into her post‐intervention rehabilitation. Interestingly, although she became completely asymptomatic, similar symptoms returned three months after discontinuing therapy, after a period of increased prolonged sitting with a concurrent decrease in activity levels. She presented with possible symptoms of hamstring syndrome (pain with sitting) and low back pain, which have may indicated a more multi‐factorial component to her new presentation. Her follow up radiographs taken six months after her percutaneous fenestration did show significant healing, which might confirm that the percutaneous fenestration technique had induced a healing response. While beyond the scope of this paper, proximal hamstring tendonopathy and/or hamstring syndrome as discussed in the third subject may be a common differential diagnosis or co‐morbidity present in the adolescent, especially in those cases where radiographs are normal.

The three presented cases demonstrated that the use of percutaneous fenestration combined with a conservative rehabilitation may have a significant therapeutic effect for those adolescents whose diagnosis is missed acutely. The authors presented a rehabilitative framework for intervention post percutaneous fenestration, which was also used with a subject with concurrent symptoms hamstring syndrome. Percutaneous fenestration can be performed by any physician who is trained in sports medicine and the used of ultrasound guided techniques. The procedure can be performed in the physicians office. A team approach between the physical therapist and physician is ideal for optimal outcomes.

CONCLUSION

Ischial tuberosity avulsion fracture is an often‐overlooked diagnosis in the adolescent athlete. Initial conservative management of these patients can be delivered appropriately if they are diagnosed early utilizing an AP radiographic view of the pelvis. If an IT avulsion is present, conservative rehabilitation should include a period of non‐weight bearing and limited stretching/strengthening exercises in the affected limb. In those cases where diagnosis is delayed or the patient has continued symptoms, percutaneous fenestration may be an alternative to surgery for symptomatic non‐union ischial tuberosity avulsion fractures. Following needle fenestration with conservative rehabilitation may allow return to full and pain‐free functional and recreational endeavors. Further research is needed to clarify the role of percutaneous needle fenestration on apophyseal fracture delayed union and non‐union IT avulusions in the adolescent athlete. Likewise, the possible presence of concurrent diagnoses such as hamstring syndrome pathology and lumbar involvement needs to be highlighted.

Appendix 1: Specific Rehabilitation Progression Utilized

Phase/Time	Gait	Sitting	Manual Therapy/Exercise
Protection Weeks: 0-2	Crutches: NWB	Protected (decrease weight on involved side)	Supine ankle dorsiflexion/plantarflexion for neuromobilization exercise to prevent possible symptoms of hamstring syndrome. Gait with crutches NWB* hip and knee flexed. Sitting emphasis weight-bearing on uninvolved ischial tuberosity.
Weeks: 2-4	TTWB-50% Symptom dependent	Protected (decreased weight on involved side)	Same as above. Gentle soft tissue mobilization as needed to hamstring muscle belly not ischial tuberosity. Supine partial knee flexion/extension (straight leg raise with dorsiflexion) neuromobility exercise as needed for hamstring syndrome symptoms), Isometric exercises painfree: gluteal sets, quad sets, ankle pumps. Core exercises (crunches).
Weeks: 4-6	75%-WBAT	To pain tolerance	Same as above: progress home exercises (painfree exercise only) add hip abduction, gastroc-soleus stretching, bridging, progress core ex with ball, planks/ side planks with knees flexed to decrease load proximally.
Strengthening, eccentric loading at 6+ weeks	WBAT no crutches	To pain tolerance	Continue above as pain tolerance allows progression.
Weeks: 8-12	FWB	Unlimited	Continued core exercises. Mini-squats, lateral step up/downs, Eccentric loading: prone leg only eccentric lowering, crab walkouts, supine active knee flexion/extension with concurrent hamstring stretching, hip abduction walk. Progressed gym exercise, running, functional activities, eccentric loading exercises May progress slower based on symptoms, size of fracture etc.
Weeks: 12-16+	FWB Jogging- Running	Unlimited	Return to sport criteria: no pain. Functional hop tests: 90% in bilateral comparison. Symptoms guide speed of progression.

NWB=Non weight bearing, TTWB=toe touch weight bearing, WBAT=weight bearing as tolerated, FWB= full weight bearing