Abstract
Background
Tears of the abdominal obliques have previously been reported in the vicinity of the lower ribs but they have not been reported in the vicinity of the iliac crest. The purpose of this case report is to describe the mechanism of injury and diagnosis of a distal abdominal oblique tear and subsequent rehabilitation programming.
Case Description
A 21-year-old male Australian football player experienced acute right-sided abdominal pain during a game while performing a commonly executed rotation skill. He was assessed clinically before being further examined with ultrasound and magnetic resonance imaging which revealed a rupture of the abdominal oblique wall at its insertion onto the iliac crest. The player then underwent a structured and graduated rehabilitation program with clear key performance indicators to optimize return to play and prevent recurrence.
Outcomes
The player was able to return to play at 35 days post injury and had no recurrence or complications at 12 month follow up post injury.
Discussion
This is the first time an abdominal oblique wall rupture at its insertion onto the iliac crest has been reported. In players with acute abdominal pain following twisting an insertional oblique tear should be considered as a differential diagnosis. A structured rehabilitation program may also help optimize an athlete's return to play after distal abdominal oblique rupture.
Keywords: Abdominal Oblique, diagnostic ultrasound, Magnetic Resonance Imaging, side strain
INTRODUCTION
Tears of the abdominal obliques, also referred to as “side strains”, have been previously reported as a common injury in baseball pitchers,1 baseball position players1 and cricket bowlers (Appendix A).2,3 These injuries have also been reported in rowing,3 javelin,3 tennis,4 soccer5 and golf,3 (Appendix A) however, these injuries have not been reported in Australian Football players.
Abdominal oblique injuries usually occur during trunk rotation.1-3 This is potentially due to the role that the obliques have in producing trunk side flexion and rotation.6 The non-dominant abdominal obliques are more commonly injured compared to the dominant side.1-3
Internal oblique (IO) and external oblique (EO) injuries have been reported as strains or tears of the musculotendinous attachment in the vicinity of the lower ribs (Appendix A).1-5 No papers have been published reporting tears of the abdominal oblique at its insertion onto the iliac crest. The purpose of this case report is to describe the mechanism of injury and diagnosis of a distal abdominal oblique tear and subsequent rehabilitation programming.
CASE REPORT
A healthy 21-year-old male Australian Football player (Height = 182 cm, Weight = 83 kg, BMI = 25.1) rotated to the left while in a forward flexed posture to handball the football with his right (dominant) hand towards a teammate on his left side. During this commonly executed skill he experienced severe right sided abdominal pain (10 on a 10 Point Numerical Rating Scale of Pain) and had to be assisted from the field by the club doctor and physiotherapist. No other players were in the vicinity at the time of injury to suggest a contact injury.
Initial off field assessment of the player was performed in supine due to his high level of pain. He was unable to perform a left or right active straight leg raise or cough without pain. The player also experienced pain with any lower limb muscle strength testing involving abdominal co-contraction. After a period of 15 minutes the player was able to stand with assistance of the club physiotherapist and doctor. In standing thoracolumbar range of motion was severely restricted in all planes of movement due to pain. On palpation he had severe tenderness over the right iliac crest and through the distal third of the abdominal obliques. No pain was reproduced on thoracic, lumbar, sacroiliac or rib mobilization. No pain was reproduced with a hip flexion adduction internal rotation (FADIR) test, hip flexion abduction external rotation (FABER) test or hip quadrant test. Given the normal assessment findings of the thoracic spine, lumbar spine and hip they were excluded as a sources of symptoms.
The player was immediately treated with basic pain medications (Paracetamol and Ibuprofen), an elastic compression bandage and ice before being transported home to rest. The next day the player had a radiograph and an ultrasound (US) of the right abdomen to assess potential iliac crest avulsion and/or distal abdominal oblique strain. US has been previously reported for assessing tears of the proximal portion of the abdominal obliques5,7 and it was deemed a logical and suitable modality to assist in confirming the clinical diagnosis. The US revealed a tear at the insertion of the right EO (Figure 1). Given the extent of pain and functional limitations MRI was used to further assess the injury and to confirm the size of the tear. MRI has been reported as the gold standard for imaging proximal abdominal oblique injuries1-4 and it was assumed this was likely applicable to the distal oblique. MRI revealed tearing and retraction of the insertion of the internal and external oblique from the iliac crest (Figure 2, 3).
Figure 1.
A. Longitudinal and B. Transverse sonographic images. There is an anechoic fluid collection (arrow) filling the defect created by the retracted muscle tear extending proximally from the echogenic iliac crest (star).
Figure 2.
A. Coronal T1w image at the level of the iliac crests. The expected site of insertion of the right oblique abdominal muscles onto the iliac crest is outlined (dotted line) and the oblique abdominal muscle retraction is shown (dashed line). B. Coronal PD fat suppressed MRI at the same position. There is a fluid collection on the right between the proximally retracted oblique abdominal muscles (arrow) and the iliac crest.
Figure 3.
Sagittal FSE T2w image at the level of the right iliac crest. An ovoid fluid collection (arrows) lies between proximally retracted oblique muscle fibres and the iliac crest.
Two days following injury the player began on a graduated rehabilitation program consisting of four phases (Table 1) with clear key performance indicators (KPIs) for progression to the next phase (Table 2) before he returned to full match play at 35 days post injury. During stages one to three of the rehabilitation program the athlete was required to have pain of less than 3/10 on a Numerical Rating Scale. He returned to sport without sustaining a re-injury and remained free of complications at a 12-month follow up. No further imaging was completed due to his uncomplicated rehabilitation.
Table 1.
Rehabilitation Program
| PHASE ONE. Aims: Decrease pain, increase ROM and maintain strength |
|---|
| Thoraco-lumbar Stretching (1 x 45 second hold each): Gentle stretching to the onset of pain into thoraco-lumbar extension, flexion, side flexion and rotation three times daily |
| Upper Limb Strength Training (Endurance Focus 2 sets of 20 reps at his 20RM): Seated and supported resistance training (i.e. seated chest press was one of the exercises performed) 3 x / week |
| Core Training (Sub-Pain Threshold 3 x 45 secs): Isometric rotation and side flexion in neutral 3 x / week |
| Lower Limb Strength Training (Endurance Focus 2 sets of 20 reps at his 20RM): Seated and supported resistance training (i.e. seated leg press was one of the exercises performed) 3 x / week |
| Cardiorespiratory Exercises (2 x 10 mins each): Exercise Cycle and Arm Ergometer daily |
| Running Re-education Program: Hydrotherapy walking and jogging for 20 mins, walking laps on oval for 1km, basic running drilling for 5 mins(i.e. step ups and A drills) 3 x / week |
| Skills: None were included. |
| PHASE TWO. Aims: Increase muscle endurance, return to skills |
|---|
| Thoraco-lumbar Stretching (1 x 45 second hold each): Stretching into full ROM of thoraco-lumbar extension, flexion, side flexion and rotation three times daily |
| Upper Limb Strength Training (Hypertrophy focus 4 sets of 12 reps at his 12RM): Seated and supported resistance training (i.e. seated chest press was one of the exercises performed) 3 x / week |
| Core Training (Endurance focus 2 sets of 20 reps at his 20RM): Isotonic thoraco-lumbar rotation with cables, side flexion with weight plate, flexion in and extension in roman chair 3 x / week |
| Lower Limb Strength Training (Hypertrophy Focus 4 sets of 12 reps at his 12RM): Seated and supported resistance training (i.e. seated leg press was one of the exercises performed) 3 x / week |
| Cardiorespiratory Exercises (1 x 10mins each): Exercise cycle, arm ergometer and cross trainer daily |
| Running Program: Deep water running for 10 mins, basic running < 70% maximal speed aiming for distance focus (i.e. repeated 200m and 400m efforts for 2km) 3 x / week |
| Skills: Stationary kicking <20m, stationary hand balling and chest marks 3 x / week |
| PHASE THREE. Aims: Increase muscle strength, commence sports specific drills |
|---|
| Thoraco-lumbar Stretching (1 x 45 second hold each): Stretching into full ROM of thoraco-lumbar extension, flexion, side flexion and rotation twice daily |
| Upper Limb Strength Training (Hypertrophy focus 4 sets of 12 reps at his 12RM): Unsupported weights training (i.e. standing overhead dumbbell press was one of the exercises performed) 3 x / week |
| Core Training (Hypertrophy focus 4 sets of 12 reps at his 12RM): Isotonic thoraco-lumbar rotation with cables, standing side flexion with weight plate, flexion in decline bench, extension in roman chair with weight plate and rotation plus flexion/extension with high to low/ low to high cables 3 x / week |
| Lower Limb Strength Training (Hypertrophy focus 4 sets of 12 reps at his 12RM): Unsupported weights training (i.e. barbell Romanian dead lift/ squats were two of the exercises performed) 3 x / week |
| Cardiorespiratory Exercises (1 x 5 mins each): Exercise cycle, arm ergometer, cross trainer daily |
| Running Program: Sports specific running (i.e. Maximal Aerobic Speed for 3 x 10 x 75m efforts, Fartlek for 3 x 400m efforts and 20acceleration-20hold-20decelleration for 4 x 6 x 60m efforts) < 90% maximal speed 3 x / week |
| Skills: Stationary kicking < 35m, kicking while straight line running <20m, hand balling while straight line running, chest marks, overhead marks and stationary tackling drilling 3 x / week |
| PHASE FOUR. Aims: Increase muscle power, return to full team training |
|---|
| Thoraco-lumbar Stretching (1 x 45 second hold each): Stretching into full ROM thoraco-lumbar extension, flexion, side flexion and rotation once daily |
| Upper Limb Strength Training (Power focus 4 sets of 6 reps at his 6RM): Unsupported weights training (i.e. standing overhead dumbbell press was one of the exercises performed) 3 x / week |
| Core Training (Power focus 4 sets of 6 reps at his 6RM): Isotonic thoraco-lumbar rotation with cables, side flexion with weight plate, flexion in decline bench, extension in roman chair with weight plate and rotation plus flexion/extension with high to low/ low to high cables 3 x / week |
| Lower Limb Strength Training (Power focus 4 sets of 6 reps at his 6RM): Unsupported weights training (i.e. barbell Romanian dead lift/ squats were two of the exercises performed) 3 x / week |
| Cardiorespiratory Exercises (3 x 5 mins each): Exercise cycle, arm ergometer and cross trainer daily |
| Running Program: Return to training, normal training loads and GPS distances to be within 10% of group average for position 3 x / week |
| Skills: Return to full team training without restriction 3 x / week |
Table 2.
Key Performance Indicators (KPI's) for Phase of Rehabilitation Progression
| KPI'S TO PHASE TWO (Day 14) |
|---|
| Active Range of Motion: Full range thoraco-lumbar extension, flexion, side flexion and rotation pain free |
| Muscle (Mm) Strength: Isometric thoraco-lumbar rotation 75% contralateral side, pain free on hand held dynamometry testing (Appendix B) |
| Running: Pain free walking |
| KPI'S TO PHASE THREE (Day 21) |
|---|
| Mm Strength: Isometric thoraco-lumbar rotation 100% contralateral side pain free on hand held dynamometry (Appendix B) |
| Running: Pain free running 200m and 400m @ 70% maximum intensity (time based) |
| KPI'S TO PHASE FOUR (Day 28) |
|---|
| Mm Strength: Isotonic core training weights equal bilaterally with <20% difference in self-reported difficulty on a rating of perceived exertion measured with a numerical rating scaled between sides |
| Running: Pain free sprint in 20-20-20 at 90% maximal speed and maximal aerobic speed 90% normal distances |
| Skills: Pain free kicking and hand balling on the run, pain free overhead marking and pain free stationary tackling |
| KPIS TO RETURN TO PLAY (Day 35) |
|---|
| Mm Strength: Isotonic core training weights equal bilaterally with <10% difference in self-reported difficulty on a rating of perceived exertion measured with a numerical rating scaled between sides |
| Training: No limitations with full training |
Weekly load monitoring and player wellbeing data was retrospectively analysed to assess any potential contributing factors to the injury. Acute versus chronic workloads as measured through Global Positioning System (GPS) tracking and self-reported loads in Arbitrary Units (AU) were assessed. Both metrics have been shown to predict soft tissue injury in AF players.8,9 The acute: chronic workload ratio was calculated by dividing the acute workload (1 week total) by the chronic workload (4 week total).10 GPS tracking included total weekly running and sprint (>25km/hour) distance per week.8 Self-scored AU were calculated by multiplying the players rating of perceived exertion for a specific training session by training duration.9 Training load was considered within normal limits and did not show any acute on chronic load spikes in the preceding six weeks. Player wellbeing screening recorded sleep quality (assessed on a visual analogue scale of 0-10), sleep duration (assessed in hours), self-rated fatigue (assessed on a visual analogue scale of 0-10) and stress levels (assessed on a visual analogue scale of 0-10). This data showed that in the two weeks prior to the injury the players sleep duration had decreased from an average duration of 8 hours to an average of 6.5 hours per night while all other data was within normal limits. A decrease in sleep duration has been shown to be a predictor of injury11 and may have contributed to the occurrence of the injury. However other potential injury risk factors such as recovery practices or nutrition were not assessed so it is possible that other contributing factors were involved.
DISCUSSION
This case report describes the presentation of a distal abdominal oblique tendon rupture at the iliac crest in a male Australian Football player. However, rotational trunk injuries are reported in a variety of sports and the results and details contained in this case report may be valuable for anyone dealing with rotational trunk injuries. In athletes with acute, severe lateral abdominal pain following trunk rotation a tear of the distal abdominal oblique should be considered as a differential diagnosis and confirmed using US or MRI if available. Given the better correlation to clinical signs MRI imaging may be superior to US for assessing the extent of these injuries.
Valid and reliable measures of trunk strength are lacking in the literature and while functional isometric dynamometry of trunk flexion and rotation were performed, validity and reliability data for these tests does not exist and is an area for further research. A structured rehabilitation program with clear KPI's provided an excellent progression allowing this athlete to regain full capacity in an optimal timeframe without subsequent re-injury.
The limitations of this case report include the potential lack of generalizability to other sports that more commonly report abdominal oblique injuries such as baseball and cricket. This case report also describes only the diagnosis and response to treatment of a single athlete and larger studies looking at rehabilitation of abdominal oblique injuries using reliable and validated outcome measures are needed. Tissue healing, assessed with US or MRI, was also not followed up in this athlete which may have provided further information on tissue healing.
CONCLUSION
Distal abdominal oblique tendon tearing should be considered as a differential diagnosis for acute lateral abdominal pain following a rotational injury. US and MRI are important adjuncts to confirm the clinical diagnosis and determine the extent of the injury. Structured rehabilitation allowed this athlete to return to play within 35 days without re-injury.
APPENDIX A.
Review of Previous Cases of Abdominal Oblique Muscle Injury
| Author | Sport | Onset | Side | Recovery (days) | Imaging | Imaging Findings |
|---|---|---|---|---|---|---|
| Conte et al (2012) | Baseball Pitchers n = 173 | Not Reported | Mean Ipsilateral = 21.9% Mean Contralateral = 78.1% |
Mean Ipsilat = 44.5 Mean Contralat = 32.8 |
Not reported | I/O or E/O strain in vicinity of lower ribs or intercostal or rib muscle strains = 92% of cases |
| Conte et al (2012) | Baseball Position Players n = 220 | Not Reported | Mean Ipsilateral = 29.7% Mean Contralateral = 70.3% |
Mean Ipsilat = 21.2 Mean Contralat = 28.9 |
Not reported | I/O or E/O strain in vicinity of lower ribs or intercostal or rib muscle strains = 92% of cases |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 35 | MRI | Tear E/O at rib 10 |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 70 | MRI | Tear E/O at rib 10 |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute on Chronic | Non Bowling Arm | 1 | MRI | No abnormality |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 34 | MRI | No abnormality |
| Humphries and Jamison (2004) | Cricket n = 1 | Gradual | Non Bowling Arm | 4 | MRI | No abnormality |
| Humphries and Jamison (2004) | Cricket n = 1 | Gradual | Non Bowling Arm | 35 | MRI | Transversalis Strain |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 28 | MRI | Tear E/O ribs 9, 10, 11 |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 15 | MRI | Partial Tear I/O at rib 11 |
| Humphries and Jamison (2004) | Cricket n = 1 | Acute | Non Bowling Arm | 55 | MRI | Tear I/O at rib 11 |
| Humphries and Jamison (2004) | Cricket n = 1 | Gradual | Non Bowling Arm | 20 | MRI | Strain I/O at rib 12 |
| Dauty, Manu and Dubois (2014) | Soccer n = 1 | Acute | Not Reported | 21 | US | Strain E/O at rib 11 |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 10mm Partial Tear I/O at 10th costal cartilage |
| Connell, Jhamb and James (2003) | Golfer n = 1 | Acute | Not Reported | Not Reported | MRI | 20mm Complete Tear I/O at 10th rib |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 20mm Complete Tear I/O at 11th rib |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 30mm Complete Tear I/O at 11th rib |
| Connell, Jhamb and James (2003) | Javelin n = 1 | Acute | Not Reported | Not Reported | MRI | 10mm Partial Tear I/O at ribs 10, 11 |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 8mm Partial Tear I/O at ribs 10 |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 32mm Complete Tear I/O at ribs 11 |
| Connell, Jhamb and James (2003) | Cricket Bowler n = 1 | Acute | Not Reported | Not Reported | MRI | 35mm Complete Tear I/O at ribs 10 |
| Connell, Jhamb and James (2003) | Cricket Fielding (Throwing) n = 1 | Acute | Not Reported | Not Reported | MRI | 15mm Complete Tear I/O at ribs 11 |
| Connell, Jhamb and James (2003) | Rower n = 1 | Acute | Not Reported | Not Reported | MRI | 6mm Partial Tear I/O at rib 10 |
| Maquirriain and Ghisi (2006) | Tennis n = 1 | Acute | Non Dominant Arm | MRI | Strain I/O |
Imaging Findings Glossary: I/O, Internal Oblique; E/O, External Oblique; Ipstlat, Ipsitlateral; Contral, Contralateral; Strain, muscle oedema without fibre disruption; Tear, muscle fibre or musculotendinous disruption.
APPENDIX B
Hand held dynamometry (HHD) was used to assess isometric trunk rotation (Figure 1) and side flexion (Figure 2). HHD has been used previously to assess trunk muscle strength with good reliability1,2 however given the assumed high strength in this population the previously reported techniques were modified to ensure that the therapist's strength (ie ability to resist the athletes force) did not influence results.
Figure 1.
Isometric HHD of Trunk Rotation. The athlete adopts a lunge position and performs trunk rotation while holding onto a non-extensible belt. The HHD is positioned between the belt and a fixed immobile pole to ensure that practitioner related bias in HHD is removed (Arrow).
Figure 2.
Isometric HHD of Trunk Side Flexion. The athlete adopts a stance position with feet shoulder width apart and performs trunk side flexion while holding onto a non-extensible belt. The HHD is positioned between the belt and a fixed immobile pole to ensure that practitioner related bias in HHD is removed (Arrow).
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