|Year : 2013 | Volume
| Issue : 1 | Page : 41-43
Treatment of chronic hip osteoarthritic pain with intra-articular phenol
John Monagle1, Joanne Ee2
1 Pain Medicine Unit, Southern Health, Academic Board of Anesthesia and Perioperative Medicine, Monash University, Melbourne, Australia
2 Pain Medicine Unit, Southern Health, Melbourne, Australia
|Date of Web Publication||10-Jul-2013|
Department of Anesthesia and Pain Medicine, Southern Health, Level 3, 246 Clayton Rd, Clayton 3168
Source of Support: None, Conflict of Interest: None
This case report aims to introduce the use of intra-articular phenol in the management of chronic pain due to severe hip osteoarthritis in a patient with multiple comorbidities, in whom operative management was not an option. Phenol has been used in pain medicine since 1936, as a neurolytic agent. It has been used intrathecally, epidurally, in paravertebral somatic blocks, peripheral nerve blocks, and sympathetic blocks. It has been used for joints in the lower spine, but has not yet been described as an intra-articular agent for pain management of major weight-bearing joints.
Keywords: Hip, osteoarthritis, phenol
|How to cite this article:|
Monagle J, Ee J. Treatment of chronic hip osteoarthritic pain with intra-articular phenol. Indian J Pain 2013;27:41-3
| Introduction|| |
Osteoarthritis is a common source of pain. When this occurs in the hips or knees, there is a significant impact on mobility. Even as joint replacement is a remedy for many patients, comorbidities frequently prevent this option. Where pharmacotherapy provides inadequate pain relief or excessive side effects, and surgery is not an option, there are few other options to provide pain relief and maintain mobility. We present a case of hip arthritis with improved analgesia and functional capacity following intra-articular phenol.
| Case Report|| |
This is a case report of a 77-year-old female, admitted to hospital from her high level care accommodation facility for management of pain and mobility issues. Her pain was secondary to severe left hip degenerative disease. She described severe left hip pain at night and when she mobilized. She was previously deemed not for surgery due to end-stage chronic obstructive pulmonary disease (COPD). Her other medical issues included bipolar affective disorder on lithium, ex-alcohol abuse, and multiple falls. Previously seen in the Aged Care Pain Clinic, she was recommended to be non-weight bearing on her left leg and was also advised to mobilize using a wheelchair. However, she was non compliant with these recommendations because she believed that this took away her independence. This admission to hospital was a result of increasing hip pain, which prevented the nursing staff at her nursing home from providing care, due to increasing difficulty in transferring her.
She was admitted under the Rehabiliation Medicine team and was consulted by Pain Medicine and Psychiatry (for her symptoms of behavioral disturbance and confusion). The hip and pelvis x-rays showed advanced degenerative change within the left hip joint, with complete destruction of the articular cartilage and longstanding associated deformity of the femoral head and acetabulum. There was no evidence of avascular necrosis.
The Pain Team was consulted about her pain management strategy. A left-sided obturator nerve block was performed with 10 ml of 0.75% ropivacaine. She was more alert and cooperative and her hip pain appeared somewhat improved in the 24 hours post the obturator nerve block. There was improved range of movement and weight bearing was well tolerated. Her main complaint then was leg cramps and left knee pain.
Pregabalin 25 mg mane and 50 mg nocte and oxycontin 10 mg mane and 20 mg nocte were commenced. She was on a stable lithium dose for bipolar affective disorder. Quetiapine 25 mg nocte was started for nocturnal agitation. Crampeze and Magnesium was also started for complaints of leg cramps.
The pain relief from the nerve block lasted several days. Subsequently, the nursing staff reported that she was still calling out in pain and was requiring an increasing amount of oxycodone. She was also difficult to nurse and refused to mobilize with the allied health staff.
Further discussion with the Rehabilitation Unit, Pain Management Unit, and the patient and her family concluded that a longer lasting solution, with less dependence on drugs, would be worth pursuing. Neurolysis of the obturator nerve was deemed to be problematic due to further decreases in mobility. Intra-articular phenol was considered to be of potential benefit, and consent was obtained.
An intra-articular injection was performed, under an image intensifier, on 19/10/2011, to her left hip. A total of 3 ml of 6% aqueous phenol was used, and demonstrated good spread throughout the hip joint. Two further injections with 0.5 ml of phenol provided periarticular coverage on the anterior surface of the joint.
In the 24 hours following the intra-articular injections, she reported that her hip pain had improved, with some movement demonstrated in the left hip. Her main complaints now were left leg cramps and left knee pain. When assessed on the subsequent days, she was able to move her legs in bed on request without complaining of pain in the hip. She was also able to transfer with a Pick-up frame with one assist, weight bearing through her left leg. Her only complaints were of heel and feet pain and leg cramps. Due to her improvement, oxycodone was no longer required, and she was discharged to her high level care accommodation on pregabalin 75 mg bd and buprenorphine 5 mg / hour.
She was referred to the Pain Medicine Unit again, exactly 12 months later, with an increase in her hip pain and reduced mobility. On this occasion she complained of significant pain in both hips. Both hips were injected under fluoroscopic control, each with 3ml of 6% phenol, which provided good coverage across the joint. The patient's spontaneous complaints of pain significantly decreased and she again became less distressed, with improved weight bearing and transferring. She was then able to be discharged back to her high level care accommodation.
| Discussion|| |
Longer duration neural blockade can be achieved by using drugs that cause damage to the nerve axons. Phenol is a chemical composite containing carbolic acid, phenic acid, phenylic acid, phenyl hydroxide, hydroxybenzene, and oxybenzene. It is highly soluble in organic solvents such as alcohol and glycerol. It can be diluted with saline and is compatible when mixed with radiocontrast dye, to allow fluoroscopic guidance during the injection of the agent and to monitor the spread of the solution. Aqueous solution of phenol is more potent than the glycerine solution.
Phenol causes nerve destruction by inducing protein precipitation. There is loss of cellular fatty elements, separation of the myelin sheath from the axon, and axonal edema. It has an immediate local anesthetic effect, due to its immediate selective effect on smaller nerve fibers. This differential blocking ability is believed to be the result of small vessel destruction that initially spares large fibers. Phenol in lower concentrations acts as a local anesthetic and in higher concentrations is neurodestructive. Phenol used in 6 - 10% of the solutions can be used in aqueous solution or with glycerol. It is not painful to inject and has a variable duration of days to months.
The effects of the block cannot be evaluated until after 24 - 48 hours, to allow time for the local anesthetic effect to dissipate. The neurolytic effect may be clinically evident only after three to seven days. If inadequate pain relief is obtained after two weeks, this may indicate incomplete neurolysis and requires repetition of the procedure. The subsequent fibrosis that occurs following phenol injection makes nerve regeneration more difficult. ,
Sensory nerve fiber density in the bone remains intact with advancing age, despite loss of bone mineral and strength.  As with chronic low back pain, the correlation between x-ray changes and pain experience in the osteoarthritis of other joints is poor. The pathogenesis of pain in osteoarthritis is poorly understood.  It has been suggested that painless osteoarthritis is a feature of the fibrosis of nerves as part of the disease process, with loss of axons.  The nerve growth factor is secreted within the osteoarthritic joints, and is associated with increased angiogenesis in the regenerating cartilage. This angiogenesis is accompanied by the development of small, unmyelinated nerve fibers. The presence of the nerve growth factor also sensitizes these nerves to noxious stimuli. 
A retrospective case series by Ward et al, reported the use of fluoroscopy-guided 6% phenol injections for the ablation of sacroiliac joints (SIJs). They reviewed 10 patients with persistent sacroilitis, who had two to four weeks of relief after injections with bupivacaine 0.5% and 80 mg of Depo-Medrol. All patients had repeat fluoroscopy-guided injections of the SIJs with 6% phenol. Phenol 6% with saline 2.5 cc per joint was injected. Twenty percent of the patients had greater than 70% improvement, with an average duration of 24 weeks.
Schulte et al, evaluated 39 patients with the lumbar facet syndrome, who were treated with a standardized protocol, with injection of steroid, lidocaine, and 5% phenol under fluoroscopic control. A combination of phenol and steroid had not been previously recommended, as phenol induced inflammation, whereas, prednisolone suppressed inflammation. However, the results were positive with 62% of patients reporting excellent or good pain relief after one month, with a single block, which extended to 36% of the patients after six months.
Previously, a single abstract had described the use of phenol in a hip joint, with a positive outcome.  This case reports the first use of phenol in a major weight bearing joint. Long lasting analgesia (approximately 12 months) was achieved and the analgesia was repeatable. The analgesia is independent of specific nerve identification and ablation. The joint remains functional. The impact of phenol on the integrity of the joint cartilage and the risks of joint leakage and major nerve trunk impairment need further study.
| Conclusion|| |
We report a case of osteoarthritis of the hip, which has responded twice to intra-articular phenol, with improved pain behavior and increased functional capacity. Phenol is neurolytic and presumably acts on small nerve fibers that develop as part of the osteoarthritic inflammatory process. Intra-articular phenol may be an inexpensive, repeatable procedure for managing joint pain in patients unsuitable for joint surgery and who experience inadequate outcomes from pharmacotherapy.
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