Hip and low back pain in the presence of femoral anteversion. A case report
Physiotherapy Department, Connolly Hospital, Blanchardstown, Dublin 15, Ireland
Received: March 20, 2014; Accepted: April 8, 2014; Published Online: April 15, 2014
Physiotherapy Department, Connolly Hospital, Blanchardstown, Dublin 15, Ireland
1. Background
Structural variations of the femur are potential contributing factors to lower limb pain. One such variation can occur in the angle of torsion (AOT) which is the inclination of the axis of the femoral neck with reference to the transcondylar plane at the distal end of the femur (Ruby et al., 1979).
The reported normal hip AOT in adults can vary from 10 to 20° (Bråten et al., 1992, Tönnis and Heinecke, 1999, Hetsroni et al., 2012). An increased angle is considered to be femoral anteversion, whilst femoral retroversion refers to a decreased angle. Increased anteversion effectively increases the range of functional internal rotation while correspondingly reducing the range of external rotation (Bedi et al., 2011). It is widely accepted that females have a 4–5° larger AOT than males (Bråten et al., 1992).
Excessive femoral anteversion has been associated with increased risk of anterior dislocation post total hip arthroplasty (Di Schino et al., 2009, Sariali et al., 2012). The AOT is therefore an important consideration when planning orthopaedic hip surgery. However, evidence of it being considered in the evaluation of hip pain and the planning of rehabilitation is limited.
It is reasonable to assume that the hip AOT has an influence on biomechanical movement patterns of the lower limb because of the consequent reduction in available range of hip internal or external rotation. During functional activities, adjusted movement patterns may need to occur in the kinetic chain to compensate for the restriction in hip movement. This case report describes the evaluation and management of a patient with hip and low back pain (LBP) in the presence of an increased AOT.
2. Case description
2.1. Patient history and subjective examination
The patient was a 23 year old female pharmacy student, referred to a physiotherapy orthopaedic triage clinic for evaluation and treatment of a four year history of right groin pain and LBP. Pain episodes varied from one week to four months. Some pain-free periods of up to three months occurred between exacerbations. The groin pain severity was rated 9/10 on the Numerical Rating Scale (NRS). Over the previous year she had developed some LBP which she rated at 3/10 on the NRS (Fig. 1). Episodes of groin pain triggered by prolonged periods of studying were reported. Standing for periods of 8–10 hours in her pharmacy course resulted in particularly severe groin pain in the evenings. She had previously partaken in ballet and zumba classes, which she felt were also aggravating her pain. The LBP was worse in the mornings, whereas the groin pain worsened as the day went on. She had no significant past medical history. She took ibuprofen on average 3–4 days per week when her pain was severe. Investigations (blood tests and MRI scans) by a Rheumatologist one year previously eliminated any inflammatory condition. Physiotherapy one year previously, which focussed on core strengthening exercises, helped her symptoms at the time but did not prevent recurrence of pain.
Fig. 1
Body chart illustrating area of symptoms on initial assessment.
2.2. Physical examination
In standing both knees were in a valgus position. She had pronated feet and in the feet forward position her right patella faced anteromedially relative to the left side (Fig. 2). This was her usual lower limb stance position.
Fig. 2
Patient's normal lower limb alignment.
Lumbar range of motion was full and pain-free. Neurological examination (myotomes, dermatomes and reflexes) was normal. Straight leg raise and prone knee bend neural provocation tests were negative. On hip examination, there was no restriction in range or pain provoked with flexion or extension. Hip internal rotation measured 60° in both 90° and 0° of hip flexion bilaterally. She had only 15° of hip external rotation bilaterally and deep right groin pain was reproduced at end of range (Fig. 3, Fig. 4).
Fig. 3
Patient's available range of internal and external rotation.
Fig. 4
Patient's available range of internal and external rotation.
Muscle strength of the hip abductors and internal and external rotators was weaker on the right at 4+/5 on manual muscle testing. Tenderness was elicited on central palpation of the L5 spinous process. Tenderness was also reported on palpation of the region of her right iliopsoas muscle.
Her AOT was measured in prone using the trochanteric prominence test as described by Ruwe et al. (1992)). With her knee flexed to 90°, passive hip internal rotation angle at the point of maximum greater trochanter prominence was measured using a handheld goniometer (Fig. 5). Her pelvis was stabilised throughout the manoeuvre. Her AOT measured 40° on both the right and left sides. Ruwe et al. (1992)) reported stronger correlations between this method of femoral anteversion measurement and intra-operative measurements than with CT scanning and X-ray.
Fig. 5
Trochanteric prominence test.
2.3. Clinical impression
Based on the patient's history and examination findings, a working diagnosis of biomechanical hip pain due to reduced external rotation range in the presence of a greatly increased AOT was developed. In the patients natural foot forward stance position, the significantly anteverted hip joint assumes a position towards the end range of external rotation. This has implications in terms of increased loading of her hip joint (Heller et al., 2001) and dysfunction of muscle forces in the pelvis and hip region (Nyland et al., 2004). Furthermore a history of participating in ballet, which emphasises a turn out position of her lower limbs, in the presence of a severe restriction of hip external rotation may have predisposed her hips to the development of pain.
LBP has also been associated with changes in hip rotation range of motion (Van Dillen et al., 2008). A reduction in external rotation range in this patient may have contributed to increased forces and compensatory motion of the lumbopelvic area leading to the onset of LBP.
2.4. Physiotherapy intervention
The patient was educated regarding the altered position of her hip and demonstrated that when she assumed a standing position with her feet pointed slightly inwards, there was greater range of movement of her lower limb into the direction of external rotation. She was encouraged to adopt an in-toeing position of her lower limbs (Fig. 6) with prolonged standing, sitting, gait and ascending stairs. It was felt that this would allow her hip to function in a more neutral position.
Fig. 6
Modified lower limb alignment.
A tailored exercise program was designed to improve control and strength of her hip joint in its new position. The program included theraband strengthening exercises into internal rotation in a prone position, standing in internal rotation with arm exercises in order to activate her pelvic stabilising muscles, wall squats and bridges internally rotating against a ball (Fig. 7, Fig. 8, Fig. 9). Manual therapy involved trigger point release of her right iliopsoas muscle.
Visit 2: Two weeks following the initial treatment, adopting the new lower limb position in her daily life and performing the rehabilitation exercises, she reported being pain-free. Exercises were then progressed to include activation of hip external rotators and abductors from an internally rotated position to neutral, avoiding end of range external rotation. Balance board exercises in an internally rotated lower limb position were also performed (Fig. 10, Fig. 11).
Visit 3: Five weeks following initial assessment the patient reported that she continued to be pain-free in terms of hip and back pain but had developed some medial knee pain. It was hypothesised that internal rotation was creating an increased valgus force on her knee joint. Simple anti-pronatory orthotics were prescribed to counteract this.
Visit 4: Nine weeks following initial assessment the patient was pain-free and her knee pain had resolved with the use of the orthotics. She had continued her home exercise program and increased the repetitions of each exercise to improve muscle endurance. Single leg stance and step-up exercises in an internally rotated position were added to her exercise program (Fig. 12, Fig. 13). On examination, there continued to be a large difference between internal and external rotation of her hip, which is consistent with a structural variation of her hip joints. Hip external rotation and palpation of iliopsoas and L5 spinous process were now pain-free. Strength of her right hip muscles had improved to 5/5 on manual testing.
Long Term Follow-Up: On telephone follow-up the patient reported no recurrence of pain in the first year following treatment. On 2 year follow-up she reported that she had two episodes of hip pain in that year. One episode occurred when she walked on average 8–10 hours per day for 5 days when on holidays. The other episodes occurred when she was required to stand for greater than 10 hours in her job. She was satisfied that her episodes of pain were not as severe or frequent as prior to her course of physiotherapy treatment. She continued to adopt an in-toed position of her lower limbs with daily activities. She was aware of minimising activities that require an externally rotated position of her lower limbs e.g. ballet turn-out and swimming breaststroke. She felt that this knowledge was giving her good control over her pain and was responsible for reducing her episodes of pain.
3. Discussion
This case study looked at the effect of exercise and modification of lower limb alignment on a patient with hip pain and LBP when her individual AOT was taken into account. By increasing the internal rotation alignment of her lower limbs during her activities of daily living and performing lower limb strengthening exercises in the new alignment, this patient with a four year history of episodic pain had a resolution of her symptoms at one year follow-up and a reduced number of episodes in the second year following treatment.
The AOT is an important consideration in the physiotherapy assessment of lumbar and lower limb pain. Measurement of this angle can readily be performed clinically using the trochanteric prominence angle test (Ruwe et al., 1992). This patient's AOT at 40° was significantly outside the normal reported range of 10–20°. This test has been shown by Souza and Powers (2009)) to have high levels of intra- and inter-rater reliability, but only moderate agreement with MRI measurements. Alternatively, a large discrepancy between medial and lateral rotation range of hip motion can highlight an altered AOT. Kozic et al. (1997)) found that a ≥45° difference between internal and external rotation on clinical examination predicted an abnormally high anteversion angle. In this patient's case the difference in range between internal and external rotation was 45°, indicating the presence of hip anteversion.
Although not extensively studied, there is some evidence that an altered AOT is associated with hip and knee pain.Reikeråls et al. (1983)) found that femoral anteversion was increased by 6° in patients with primary hip osteoarthritis compared with controls and the change in femoral angle was not compensated for by a decrease of acetabular anteversion in symptomatic patients. There has also been some suggestion that hip anteversion has a relationship with patellofemoral pain. Eckhoff et al. (1994)) found in 20 patients with anterior knee pain who failed conservative treatment, that the average AOT was 23°(SD = 12) compared to controls 17°(SD = 7). It was hypothesised that the pathological entity may not be the patella but the underlying torsion of the femur, leading to increased patellofemoral contact pressure. The relationship of an altered AOT with hip and knee pain warrants further research.
Following four physiotherapy sessions over nine weeks, the patient experienced a resolution of hip pain and LBP at one year follow-up. It is difficult to ascertain whether the change in her symptoms was primarily related to a positional change in her hip joint with adopting an in-toeing position or whether it was related to an increase in lower limb muscle strength as a consequence of the exercise programme. A reduction in hip joint loading is a likely factor. Heller et al. (2001)) found that hip contact forces during walking and stair climbing were increased by up to 28% in patients with increased hip anteversion. According to Bedi et al. (2011)) increased femoral anteversion can result in pain from chondral overload of the anterosuperior femoral head and acetabular dome as well as the anterior capsule and psoas tendon. By adopting a relatively internally rotated position of her lower limbs on a daily basis these forces on the patient's hip joint structures may have been reduced. Furthermore, this lower limb alignment would reduce movement into end of range hip external rotation, decreasing the likelihood of compensatory movement in her lumbar spine. It is noteworthy that there was an elimination of this patient's LBP with treatment solely directed at hip biomechanics and strength.
An increase in muscle activity and strength is also likely to be relevant to her change in symptoms. Exercises directed at activation and strengthening of the hip rotators, abductors and extensors, as well as the quadriceps muscles, were prescribed for this patient, in a position of greater hip internal rotation than she had previously used. Although strength of hip internal rotators and extensors has not been studied in relation to hip anteversion, activation of the gluteus medius and vastus medialis of the anteverted hip has been found to be diminished by 34% and 27% respectively (Nyland et al., 2004). By activating the surrounding muscle groups it is likely that this patient had improved static and dynamic control of her hip joint.
4. Conclusion
This case highlights the importance of considering variations in the hip AOT in designing exercise programs. This patient had a substantial reduction in hip pain and a resolution of LBP following treatment. This was not in keeping with the pattern over the previous four years of episodic pain. Therefore, the change in symptoms may be attributed to altered biomechanics and the treatment received. Clinical research is necessary to explore the validity of this approach. It would also be relevant to consider whether this strategy of altering lower limb alignment in the presence of increased femoral torsion has any future implications in terms of knee, foot and ankle mechanics.
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