- Email: [email protected]
Total shoulder arthroplasty for patients with cerebral palsy
Total shoulder arthroplasty for patients with cerebral palsy Steven J. Hattrup, MD,a Robert H. Cofield, MD,b Virgilio H. Evidente, MD,c and John W. Sperling, MD,b Scottsdale, AZ, and Rochester, MN
S
houlder replacement can provide patients with excellent pain relief and function. For an optimal outcome, careful soft-tissue balancing with preservation of the rotator cuff attachments is required. Management of soft tissues must continue through the perioperative period to avoid damaging the reconstruction. Any disorder that interferes with the patient’s postoperative rehabilitation can potentially lead to a poor outcome. Patients with cerebral palsy have neuromuscular impairments that could lead to difficulties with rehabilitation. This report describes 3 patients with cerebral palsy who underwent total shoulder arthroplasty. Approval of this study was obtained from the Mayo Foundation Institutional Review Board.
CASE REPORT
Because of the excessive external rotation, the weakness in internal rotation and abduction, and the radiographic appearance of the shoulder, we believed that the repair of the rotator cuff arthrotomy had failed clinically. Nevertheless, the patient had good pain relief and decided to continue with a therapy program; consideration of tendon repair was deferred. At his last follow-up (31 months after surgery), he reported continued pain relief but persistent weakness in the shoulder. Despite the weakness, he was able to achieve 170° elevation, 90° external rotation, and internal rotation to the twelfth thoracic vertebra. Abduction and internal rotation weaknesses were noted. Radiographs confirmed the anterior-superior subluxation of the humeral component. Despite the clinical impression of rotator cuff tearing, the patient was satisfied with his outcome and was considering surgery on the opposite shoulder.
Case 1
Case 2
A 44-year-old man presented for evaluation of shoulder pain that was especially severe on the right side. He had quadriparesis attributable to cerebral palsy. Before his shoulder arthrosis developed, he was able to work as a custodian, hunt, and fish, but his shoulder pain now interfered with his occupation, hobbies, and sleep. Examination showed that he had altered speech and gait patterns, hip and knee flexion contractures, and in-toeing. He had 110° active right shoulder elevation, 35° external rotation, and internal rotation to the fifth lumbar segment. He had normal muscle strength and moderate muscle rigidity. Uncontrolled muscle movements or tremor were minimal. Radiographs showed severe glenohumeral arthrosis (Figure 1, A and B). A standard total shoulder arthroplasty was performed with ingrowth glenoid and humeral components (Figure 1, C and D). No intraoperative complications were noted, and the rotator cuff was normal. Postoperatively, however, slow restoration of active elevation, persistent weakness, and anterior-superior subluxation of the prosthesis were noted. Radiographs showed severe superior subluxation of the humeral head with respect to the glenoid (Figure 1, E).
A 45-year-old man presented with left shoulder pain. He had cerebral palsy, attributable to premature birth, that was characterized by spasticity, dystonia, and athetosis. He used a walker. His previous jobs included working as an agricultural chemist and loan broker. He had a history of traumatic instability of the shoulder with a Putti-Platt repair 20 years earlier that resulted in a stable but stiff joint. For the past several years, he had a gradual onset of increasingly severe pain and further loss of motion. Examination showed an anterior healed incision. Active and passive motion was limited to 70° elevation, 60° abduction, 10° external rotation, and internal rotation to the side of the body. He had diffuse weakness about the shoulder girdle, and electromyography showed evidence of a chronic moderate upper trunk brachial plexopathy that perhaps was related to previous partial neurectomies performed to moderate spasticity. Radiographs showed severe glenohumeral degenerative changes. The patient was encouraged to consider shoulder arthrodesis for pain control, but he strongly preferred joint replacement. A standard total shoulder arthroplasty with a metal-backed glenoid was performed. Because of the previous anterior capsular repair, subscapularis lengthening was necessary. At the 2-year follow-up, the shoulder was only mildly painful, but motion was restricted. He achieved 70° elevation, 60° abduction, 80° external rotation, and internal rotation to the third lumbar vertebra. Radiographs showed substantial anterior subluxation of the prosthesis (Figure 2). Further surgery was not recommended at that time. Fourteen years after arthroplasty, the patient’s pain had again become severe, although the range of motion had not deteriorated further. Exploration of the joint showed
From the Departments of aOrthopedics and cNeurology, Mayo Clinic, Scottsdale, and bDivision of Adult Reconstruction, Mayo Clinic, Rochester. Correspondence to: Steven J. Hattrup, MD, Department of Orthopedics, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259. J Shoulder Elbow Surg 2007;16:e5-e9. Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.08.009
e5
e6
Hattrup et al
J Shoulder Elbow Surg September/October 2007
Figure 1 Case 1. A and B, Preoperative radiographs of shoulder show severe arthrosis. C and D, Early postoperative radiographs show components in satisfactory position. E, Radiograph at 1 year after replacement shows severe superior humeral subluxation.
J Shoulder Elbow Surg Volume 16, Number 5
Hattrup et al
e7
Figure 2 Case 2. Radiographs at 2 years after replacement show marked anterior component subluxation.
erosion through the anterior-superior portion of the polyethylene insert with subsequent metal-induced synovitis. A complementary anterior-superior defect in the rotator cuff was found. The polyethylene insert and humeral component were exchanged and the rotator cuff defect repaired. Two years later, the patient continued to have severe pain, and function was poor, with only 30° active elevation and 60° external rotation.
Case 3 A 68-year-old woman seeking a second opinion presented with pain in her right shoulder. She had a history of cerebral palsy attributed to premature birth. The primary manifestations were severe right upper extremity and neck dystonia, severe dysarthria, and moderate left upper extremity dystonia, but she was a high school graduate and was able to live independently. In the 2 years before presentation, discomfort in the right shoulder had gradually developed. The pain became severe and required narcotic medication. Her function had progressively diminished to the point of jeopardizing her ability to live independently. She had been advised at another institution that the severity of her spasms prohibited her from having surgery on the arthritic shoulder. Examination showed impaired speech due to severe dysarthria. The left shoulder had full active range of motion with good strength, but rapid alternating movements were impaired. The right shoulder was held postured in extension, abduction, and internal rotation. The patient’s active shoulder motion was 30° elevation, 30° abduction, ⫺40° external rotation, and internal rotation to the side of the body. In addition, there was elbow flexion and finger
curling. All muscle groups appeared to contract, although the right upper extremity showed mild diffuse weakness and atrophy. Radiographs of the right shoulder showed profound glenohumeral degenerative changes with marked medial glenoid erosion. The patient wanted to proceed with shoulder replacement surgery to maintain her independent lifestyle. However, she had a high risk of complications because of her inability to control movement in the right shoulder. After neurologic consultation, she received selective botulinum toxin injections to reduce the spasmodic contractions. Because of the abduction and extension posturing of the shoulder and the elbow flexion contracture, the middle and posterior heads of the deltoid and the biceps brachii were targeted. In total, 200 U of botulinum toxin were administered (the toxin was diluted to 100 U/mL). Under electromyographic guidance, 80 U were injected into 2 sites in the middle deltoid, 60 U into 2 sites in the posterior deltoid, and 60 U into 1 biceps site. After follow-up examinations by the patient’s surgeon and neurologist, the decrease in muscle rigidity and spasmodic contractions was believed to be sufficient to allow surgery to proceed. A similar injection sequence was used for the preoperative injections, but the posterior deltoid received 50 U and the biceps received 70 U to fine-tune elbow relaxation. A standard total shoulder arthroplasty was performed. Postoperative pain relief was augmented with an indwelling interscalene catheter and constant infusion of bupivacaine. Because of the patient’s cerebral palsy, she was transferred to a rehabilitation unit after 24 hours. She rapidly regained independence in activities of daily living and was dis-
e8
Hattrup et al
J Shoulder Elbow Surg September/October 2007
Figure 3 Case 3. Radiographs at 1 year after replacement show components in satisfactory position.
charged home to continue a standard outpatient physical therapy program after 1 week. One year after surgery, the patient indicated minimal pain at rest and only mild discomfort with attempts at overhead movements. She felt somewhat frustrated by her limited range of motion. Examination showed 90° forward flexion, 85° abduction, 30° external rotation, and internal rotation to the first lumbar vertebra. The rotator cuff appeared intact with respect to supraspinatus, infraspinatus, and subscapularis strength. Because additional botulinum toxin injections had not been administered, she continued to have relatively uncontrolled right upper extremity movements. Radiographs showed a stable shoulder arthroplasty without apparent complications or component subluxation (Figure 3).
DISCUSSION Cerebral palsy, a disorder of movement and posture, results from damage to the immature brain; it can manifest as spasticity, ataxia, dystonia, dyskinesia, or athetosis.13,14 A patient’s functional status can be impaired substantially by these symptoms,7 although the degree of impairment varies among patients. Additional impairment from disorders such as shoulder arthrosis can be poorly tolerated and may be challenging to manage. Because patients with cerebral palsy often desire to maximize their functional capacities, arthroplasty should be considered for those with shoulder arthrosis.
Although no therapy currently can repair the damage to the central nervous system caused by cerebral palsy, a number of interventions may diminish the severity of impairments such as spasticity or dystonia.6 In particular, botulinum toxin has been used to treat spastic and dystonic muscles associated with neurologic disorders such as stroke, hypoxic encephalopathy, trauma, or cerebral palsy.11 Injections of botulinum toxin block acetylcholine release and relax muscles in a dose-dependent manner, and muscle tone and spasticity are reduced. Despite evidence of muscle relaxation lasting for 4 to 6 months, functional improvement usually only lasts for 3 to 4 months.6,15 Because fixed joint contractures and arthrosis are not improved by botulinum toxin injections, physical therapy or surgery frequently is still necessary to improve activities of daily living. A recent meta-analysis failed to show the efficacy of botulinum toxin injections conclusively because only a limited number of randomized controlled studies were conducted; nevertheless, the injections may considerably aid postoperative recuperation for patients with cerebral palsy.15 Weakness and poor coordination may produce limited functional improvement after injection alone, but reduction of muscle tone may provide protected mobilization after surgical releases in arthroplasty.12 Soft-tissue balancing is an integral part of successful shoulder arthroplasty.8 Postoperative rehabilitation that preserves repaired structures such as the subscapularis is essential.1–3,10 Rotator cuff tearing is a frequent complication, even for patients without cerebral palsy. In a meta-analysis
Hattrup et al
J Shoulder Elbow Surg Volume 16, Number 5
of 32 published series (examining ⬎1600 replacements), Wirth and Rockwood16 reported that rotator cuff tears were the third most common complication of shoulder arthroplasty. Similarly, Cofield4 determined that rotator cuff disorders were the second most frequent indication for revision of total shoulder replacement and humeral head replacement. Cofield and Edgerton5 calculated that the overall incidence rate of this complication was 2.2% to 2.7%. The outcome of an arthroplasty may be adversely affected by comorbidities that diminish a patient’s ability to cooperate with postoperative therapy. For example, the spasticity and dystonia of cerebral palsy can make restoration of joint mobility difficult and also may predispose the shoulder to rotator cuff tearing. The patients described in this report were affected by these challenges. Although all of them reported satisfactory pain relief and were pleased with the surgical outcomes, all had postoperative difficulties. The first patient had an excellent range of motion but also had shoulder weakness that clinically was presumed to be a result of tearing of the rotator cuff. The second patient showed more extensive signs of rotator cuff tearing with limited motion, weakness, and anterior-superior subluxation. Rotator cuff tearing likely contributed to the erosion of the polyethylene glenoid component. For these patients, repair of rotator cuff tissues was satisfactory intraoperatively, but over time, uncontrolled movements of the shoulder appeared to gradually stretch tissues and impair function. The third patient had more stiffness than expected in the replaced shoulder, but clinically, the rotator cuff healed with good strength and had a stable radiographic appearance. The patient and her physicians agreed that the botulinum injections caused a substantial reduction in her spasticity and dystonia and thus aided the postoperative therapy. However, stiffness eventually redeveloped as the effects of botulinum toxin wore off, and repeat injections were not performed. Although the number of patients in this report is small, the apparent occurrence of tearing of the subscapularis repair in 2 of 3 patients is a concern. Certain techniques may help minimize the development of this complication, such as the use of nonabsorbable, heavy sutures (No. 2 or larger) through bone and tendon for the repair. Alternatively, use of a lesser tuberosity osteotomy may be even stronger by incorporating bone and tendon tissue on both sides of the repair; however, this was not used in our series. With either technique, the horizontal portion of the arthrotomy should be low to resist anterior-superior instability patterns if the subscapularis fails to heal. Postoperatively, the extremity is maintained in slight flexion and internal rotation during rest for the first 6 weeks, and passive range of motion is allowed only in a limited manner. External rotation is limited to neutral positions, and elevation is allowed only in forward flexion. It is incumbent on the surgeon to communicate realistic goals, the specific vulnerability of the subscapularis, and appropriate range-ofmotion restrictions to the therapist. For the patient treated with botulinum toxin in this series, injections were limited to the deltoid and biceps muscles. These muscles were chosen after assessment of the patient’s dystonic pattern. For example, the deltoid injection was believed to benefit the shoulder during abduction posturing. The efficacy of the injections was reassessed subsequently before the final decision to proceed with surgery was made.
e9
Injections were repeated a few days before surgery to maximize their effect during rehabilitation. Patients with different dystonic patterns may benefit from other injection sites. For optimal rehabilitation, each patient requires an individual assessment to decide which muscles should receive an injection. Electromyographic guidance during injections allows specific muscles to be targeted. The results of shoulder arthroplasty in patients with cerebral palsy were similar to those in patients with Parkinson’s disease. Koch et al9 found an increased incidence of component subluxation in patients with Parkinson’s disease, and most had an unsatisfactory functional outcome. These outcomes were attributed to the increased tone of the shoulder girdle musculature. Nevertheless, pain relief typically was achieved. In conclusion, shoulder arthroplasty was beneficial for our patients with severe shoulder arthritis and cerebral palsy. Pain relief was satisfactory, but soft-tissue complications occurred in 2 of 3 patients. Botulinum toxin injections may smooth the postoperative course. Patients need to understand, however, that shoulder arthroplasty is likely to improve pain but not range of motion. Editing, proofreading, and reference verification were provided by the Section of Scientific Publications, Mayo Clinic. REFERENCES
1. Boardman ND III, Cofield RH, Bengtson KA, Little R, Jones MC, Rowland CM. Rehabilitation after total shoulder arthroplasty. J Arthroplasty 2001;16:483-6. 2. Brown DD, Friedman RJ. Postoperative rehabilitation following total shoulder arthroplasty. Orthop Clin North Am 1998;29:535-47. 3. Caniggia M, Fornara P, Franci M, Maniscalo P, Picinotti A. Shoulder arthroplasty. Indications, contraindications and complications. Panminerva Med 1999;41:341-9. 4. Cofield RH. Revision procedures for shoulder arthroplasty. In: Morrey BF, editor. Reconstructive surgery of the joints. Vol 1. 2nd ed. New York: Churchill Livingstone; 1996. p. 789-99. 5. Cofield RH, Edgerton BC. Total shoulder arthroplasty: complications and revision surgery. Instr Course Lect 1990;39:449-62. 6. Goldstein M. The treatment of cerebral palsy: what we know, what we don’t know. J Pediatr 2004;145(Suppl):S42-6. 7. Gorter JW, Rosenbaum PL, Hanna SE, Palisano RJ, Bartlett DJ, Russell DJ, et al. Limb distribution, motor impairment, and functional classification of cerebral palsy. Dev Med Child Neurol 2004;46:461-7. 8. Ibarra C, Craig EV. Soft-tissue balancing in total shoulder arthroplasty. Orthop Clin North Am 1998;29:415-22. 9. Koch LD, Cofield RH, Ahlskog JE. Total shoulder arthroplasty in patients with Parkinson’s disease. J Shoulder Elbow Surg 1997;6:24-8. 10. Maybach A, Schlegel TF. Shoulder rehabilitation for the arthritic glenohumeral joint: preoperative and postoperative considerations. Semin Arthroplasty 1995;6:297-304. 11. Morton RE, Hankinson J, Nicholson J. Botulinum toxin for cerebral palsy: where are we now? Arch Dis Child 2004;89:1133-7. 12. Pidcock FS. The emerging role of therapeutic botulinum toxin in the treatment of cerebral palsy. J Pediatr 2004;145(Suppl):S33-5. 13. Rosenbaum P. Cerebral palsy: what parents and doctors want to know. BMJ 2003;326:970-4. 14. Shapiro BK. Cerebral palsy: a reconceptualization of the spectrum. J Pediatr 2004;145(Suppl):S3-7. 15. Wasiak J, Hoare B, Wallen M. Botulinum toxin A as an adjunct to treatment in the management of the upper limb in children with spastic cerebral palsy. Cochrane Database Syst Rev 2004: CD003469. 16. Wirth MA, Rockwood CA Jr. Complications of shoulder arthroplasty. Clin Orthop Relat Res 1994;307:47-69.
S
houlder replacement can provide patients with excellent pain relief and function. For an optimal outcome, careful soft-tissue balancing with preservation of the rotator cuff attachments is required. Management of soft tissues must continue through the perioperative period to avoid damaging the reconstruction. Any disorder that interferes with the patient’s postoperative rehabilitation can potentially lead to a poor outcome. Patients with cerebral palsy have neuromuscular impairments that could lead to difficulties with rehabilitation. This report describes 3 patients with cerebral palsy who underwent total shoulder arthroplasty. Approval of this study was obtained from the Mayo Foundation Institutional Review Board.
CASE REPORT
Because of the excessive external rotation, the weakness in internal rotation and abduction, and the radiographic appearance of the shoulder, we believed that the repair of the rotator cuff arthrotomy had failed clinically. Nevertheless, the patient had good pain relief and decided to continue with a therapy program; consideration of tendon repair was deferred. At his last follow-up (31 months after surgery), he reported continued pain relief but persistent weakness in the shoulder. Despite the weakness, he was able to achieve 170° elevation, 90° external rotation, and internal rotation to the twelfth thoracic vertebra. Abduction and internal rotation weaknesses were noted. Radiographs confirmed the anterior-superior subluxation of the humeral component. Despite the clinical impression of rotator cuff tearing, the patient was satisfied with his outcome and was considering surgery on the opposite shoulder.
Case 1
Case 2
A 44-year-old man presented for evaluation of shoulder pain that was especially severe on the right side. He had quadriparesis attributable to cerebral palsy. Before his shoulder arthrosis developed, he was able to work as a custodian, hunt, and fish, but his shoulder pain now interfered with his occupation, hobbies, and sleep. Examination showed that he had altered speech and gait patterns, hip and knee flexion contractures, and in-toeing. He had 110° active right shoulder elevation, 35° external rotation, and internal rotation to the fifth lumbar segment. He had normal muscle strength and moderate muscle rigidity. Uncontrolled muscle movements or tremor were minimal. Radiographs showed severe glenohumeral arthrosis (Figure 1, A and B). A standard total shoulder arthroplasty was performed with ingrowth glenoid and humeral components (Figure 1, C and D). No intraoperative complications were noted, and the rotator cuff was normal. Postoperatively, however, slow restoration of active elevation, persistent weakness, and anterior-superior subluxation of the prosthesis were noted. Radiographs showed severe superior subluxation of the humeral head with respect to the glenoid (Figure 1, E).
A 45-year-old man presented with left shoulder pain. He had cerebral palsy, attributable to premature birth, that was characterized by spasticity, dystonia, and athetosis. He used a walker. His previous jobs included working as an agricultural chemist and loan broker. He had a history of traumatic instability of the shoulder with a Putti-Platt repair 20 years earlier that resulted in a stable but stiff joint. For the past several years, he had a gradual onset of increasingly severe pain and further loss of motion. Examination showed an anterior healed incision. Active and passive motion was limited to 70° elevation, 60° abduction, 10° external rotation, and internal rotation to the side of the body. He had diffuse weakness about the shoulder girdle, and electromyography showed evidence of a chronic moderate upper trunk brachial plexopathy that perhaps was related to previous partial neurectomies performed to moderate spasticity. Radiographs showed severe glenohumeral degenerative changes. The patient was encouraged to consider shoulder arthrodesis for pain control, but he strongly preferred joint replacement. A standard total shoulder arthroplasty with a metal-backed glenoid was performed. Because of the previous anterior capsular repair, subscapularis lengthening was necessary. At the 2-year follow-up, the shoulder was only mildly painful, but motion was restricted. He achieved 70° elevation, 60° abduction, 80° external rotation, and internal rotation to the third lumbar vertebra. Radiographs showed substantial anterior subluxation of the prosthesis (Figure 2). Further surgery was not recommended at that time. Fourteen years after arthroplasty, the patient’s pain had again become severe, although the range of motion had not deteriorated further. Exploration of the joint showed
From the Departments of aOrthopedics and cNeurology, Mayo Clinic, Scottsdale, and bDivision of Adult Reconstruction, Mayo Clinic, Rochester. Correspondence to: Steven J. Hattrup, MD, Department of Orthopedics, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259. J Shoulder Elbow Surg 2007;16:e5-e9. Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.08.009
e5
e6
Hattrup et al
J Shoulder Elbow Surg September/October 2007
Figure 1 Case 1. A and B, Preoperative radiographs of shoulder show severe arthrosis. C and D, Early postoperative radiographs show components in satisfactory position. E, Radiograph at 1 year after replacement shows severe superior humeral subluxation.
J Shoulder Elbow Surg Volume 16, Number 5
Hattrup et al
e7
Figure 2 Case 2. Radiographs at 2 years after replacement show marked anterior component subluxation.
erosion through the anterior-superior portion of the polyethylene insert with subsequent metal-induced synovitis. A complementary anterior-superior defect in the rotator cuff was found. The polyethylene insert and humeral component were exchanged and the rotator cuff defect repaired. Two years later, the patient continued to have severe pain, and function was poor, with only 30° active elevation and 60° external rotation.
Case 3 A 68-year-old woman seeking a second opinion presented with pain in her right shoulder. She had a history of cerebral palsy attributed to premature birth. The primary manifestations were severe right upper extremity and neck dystonia, severe dysarthria, and moderate left upper extremity dystonia, but she was a high school graduate and was able to live independently. In the 2 years before presentation, discomfort in the right shoulder had gradually developed. The pain became severe and required narcotic medication. Her function had progressively diminished to the point of jeopardizing her ability to live independently. She had been advised at another institution that the severity of her spasms prohibited her from having surgery on the arthritic shoulder. Examination showed impaired speech due to severe dysarthria. The left shoulder had full active range of motion with good strength, but rapid alternating movements were impaired. The right shoulder was held postured in extension, abduction, and internal rotation. The patient’s active shoulder motion was 30° elevation, 30° abduction, ⫺40° external rotation, and internal rotation to the side of the body. In addition, there was elbow flexion and finger
curling. All muscle groups appeared to contract, although the right upper extremity showed mild diffuse weakness and atrophy. Radiographs of the right shoulder showed profound glenohumeral degenerative changes with marked medial glenoid erosion. The patient wanted to proceed with shoulder replacement surgery to maintain her independent lifestyle. However, she had a high risk of complications because of her inability to control movement in the right shoulder. After neurologic consultation, she received selective botulinum toxin injections to reduce the spasmodic contractions. Because of the abduction and extension posturing of the shoulder and the elbow flexion contracture, the middle and posterior heads of the deltoid and the biceps brachii were targeted. In total, 200 U of botulinum toxin were administered (the toxin was diluted to 100 U/mL). Under electromyographic guidance, 80 U were injected into 2 sites in the middle deltoid, 60 U into 2 sites in the posterior deltoid, and 60 U into 1 biceps site. After follow-up examinations by the patient’s surgeon and neurologist, the decrease in muscle rigidity and spasmodic contractions was believed to be sufficient to allow surgery to proceed. A similar injection sequence was used for the preoperative injections, but the posterior deltoid received 50 U and the biceps received 70 U to fine-tune elbow relaxation. A standard total shoulder arthroplasty was performed. Postoperative pain relief was augmented with an indwelling interscalene catheter and constant infusion of bupivacaine. Because of the patient’s cerebral palsy, she was transferred to a rehabilitation unit after 24 hours. She rapidly regained independence in activities of daily living and was dis-
e8
Hattrup et al
J Shoulder Elbow Surg September/October 2007
Figure 3 Case 3. Radiographs at 1 year after replacement show components in satisfactory position.
charged home to continue a standard outpatient physical therapy program after 1 week. One year after surgery, the patient indicated minimal pain at rest and only mild discomfort with attempts at overhead movements. She felt somewhat frustrated by her limited range of motion. Examination showed 90° forward flexion, 85° abduction, 30° external rotation, and internal rotation to the first lumbar vertebra. The rotator cuff appeared intact with respect to supraspinatus, infraspinatus, and subscapularis strength. Because additional botulinum toxin injections had not been administered, she continued to have relatively uncontrolled right upper extremity movements. Radiographs showed a stable shoulder arthroplasty without apparent complications or component subluxation (Figure 3).
DISCUSSION Cerebral palsy, a disorder of movement and posture, results from damage to the immature brain; it can manifest as spasticity, ataxia, dystonia, dyskinesia, or athetosis.13,14 A patient’s functional status can be impaired substantially by these symptoms,7 although the degree of impairment varies among patients. Additional impairment from disorders such as shoulder arthrosis can be poorly tolerated and may be challenging to manage. Because patients with cerebral palsy often desire to maximize their functional capacities, arthroplasty should be considered for those with shoulder arthrosis.
Although no therapy currently can repair the damage to the central nervous system caused by cerebral palsy, a number of interventions may diminish the severity of impairments such as spasticity or dystonia.6 In particular, botulinum toxin has been used to treat spastic and dystonic muscles associated with neurologic disorders such as stroke, hypoxic encephalopathy, trauma, or cerebral palsy.11 Injections of botulinum toxin block acetylcholine release and relax muscles in a dose-dependent manner, and muscle tone and spasticity are reduced. Despite evidence of muscle relaxation lasting for 4 to 6 months, functional improvement usually only lasts for 3 to 4 months.6,15 Because fixed joint contractures and arthrosis are not improved by botulinum toxin injections, physical therapy or surgery frequently is still necessary to improve activities of daily living. A recent meta-analysis failed to show the efficacy of botulinum toxin injections conclusively because only a limited number of randomized controlled studies were conducted; nevertheless, the injections may considerably aid postoperative recuperation for patients with cerebral palsy.15 Weakness and poor coordination may produce limited functional improvement after injection alone, but reduction of muscle tone may provide protected mobilization after surgical releases in arthroplasty.12 Soft-tissue balancing is an integral part of successful shoulder arthroplasty.8 Postoperative rehabilitation that preserves repaired structures such as the subscapularis is essential.1–3,10 Rotator cuff tearing is a frequent complication, even for patients without cerebral palsy. In a meta-analysis
Hattrup et al
J Shoulder Elbow Surg Volume 16, Number 5
of 32 published series (examining ⬎1600 replacements), Wirth and Rockwood16 reported that rotator cuff tears were the third most common complication of shoulder arthroplasty. Similarly, Cofield4 determined that rotator cuff disorders were the second most frequent indication for revision of total shoulder replacement and humeral head replacement. Cofield and Edgerton5 calculated that the overall incidence rate of this complication was 2.2% to 2.7%. The outcome of an arthroplasty may be adversely affected by comorbidities that diminish a patient’s ability to cooperate with postoperative therapy. For example, the spasticity and dystonia of cerebral palsy can make restoration of joint mobility difficult and also may predispose the shoulder to rotator cuff tearing. The patients described in this report were affected by these challenges. Although all of them reported satisfactory pain relief and were pleased with the surgical outcomes, all had postoperative difficulties. The first patient had an excellent range of motion but also had shoulder weakness that clinically was presumed to be a result of tearing of the rotator cuff. The second patient showed more extensive signs of rotator cuff tearing with limited motion, weakness, and anterior-superior subluxation. Rotator cuff tearing likely contributed to the erosion of the polyethylene glenoid component. For these patients, repair of rotator cuff tissues was satisfactory intraoperatively, but over time, uncontrolled movements of the shoulder appeared to gradually stretch tissues and impair function. The third patient had more stiffness than expected in the replaced shoulder, but clinically, the rotator cuff healed with good strength and had a stable radiographic appearance. The patient and her physicians agreed that the botulinum injections caused a substantial reduction in her spasticity and dystonia and thus aided the postoperative therapy. However, stiffness eventually redeveloped as the effects of botulinum toxin wore off, and repeat injections were not performed. Although the number of patients in this report is small, the apparent occurrence of tearing of the subscapularis repair in 2 of 3 patients is a concern. Certain techniques may help minimize the development of this complication, such as the use of nonabsorbable, heavy sutures (No. 2 or larger) through bone and tendon for the repair. Alternatively, use of a lesser tuberosity osteotomy may be even stronger by incorporating bone and tendon tissue on both sides of the repair; however, this was not used in our series. With either technique, the horizontal portion of the arthrotomy should be low to resist anterior-superior instability patterns if the subscapularis fails to heal. Postoperatively, the extremity is maintained in slight flexion and internal rotation during rest for the first 6 weeks, and passive range of motion is allowed only in a limited manner. External rotation is limited to neutral positions, and elevation is allowed only in forward flexion. It is incumbent on the surgeon to communicate realistic goals, the specific vulnerability of the subscapularis, and appropriate range-ofmotion restrictions to the therapist. For the patient treated with botulinum toxin in this series, injections were limited to the deltoid and biceps muscles. These muscles were chosen after assessment of the patient’s dystonic pattern. For example, the deltoid injection was believed to benefit the shoulder during abduction posturing. The efficacy of the injections was reassessed subsequently before the final decision to proceed with surgery was made.
e9
Injections were repeated a few days before surgery to maximize their effect during rehabilitation. Patients with different dystonic patterns may benefit from other injection sites. For optimal rehabilitation, each patient requires an individual assessment to decide which muscles should receive an injection. Electromyographic guidance during injections allows specific muscles to be targeted. The results of shoulder arthroplasty in patients with cerebral palsy were similar to those in patients with Parkinson’s disease. Koch et al9 found an increased incidence of component subluxation in patients with Parkinson’s disease, and most had an unsatisfactory functional outcome. These outcomes were attributed to the increased tone of the shoulder girdle musculature. Nevertheless, pain relief typically was achieved. In conclusion, shoulder arthroplasty was beneficial for our patients with severe shoulder arthritis and cerebral palsy. Pain relief was satisfactory, but soft-tissue complications occurred in 2 of 3 patients. Botulinum toxin injections may smooth the postoperative course. Patients need to understand, however, that shoulder arthroplasty is likely to improve pain but not range of motion. Editing, proofreading, and reference verification were provided by the Section of Scientific Publications, Mayo Clinic. REFERENCES
1. Boardman ND III, Cofield RH, Bengtson KA, Little R, Jones MC, Rowland CM. Rehabilitation after total shoulder arthroplasty. J Arthroplasty 2001;16:483-6. 2. Brown DD, Friedman RJ. Postoperative rehabilitation following total shoulder arthroplasty. Orthop Clin North Am 1998;29:535-47. 3. Caniggia M, Fornara P, Franci M, Maniscalo P, Picinotti A. Shoulder arthroplasty. Indications, contraindications and complications. Panminerva Med 1999;41:341-9. 4. Cofield RH. Revision procedures for shoulder arthroplasty. In: Morrey BF, editor. Reconstructive surgery of the joints. Vol 1. 2nd ed. New York: Churchill Livingstone; 1996. p. 789-99. 5. Cofield RH, Edgerton BC. Total shoulder arthroplasty: complications and revision surgery. Instr Course Lect 1990;39:449-62. 6. Goldstein M. The treatment of cerebral palsy: what we know, what we don’t know. J Pediatr 2004;145(Suppl):S42-6. 7. Gorter JW, Rosenbaum PL, Hanna SE, Palisano RJ, Bartlett DJ, Russell DJ, et al. Limb distribution, motor impairment, and functional classification of cerebral palsy. Dev Med Child Neurol 2004;46:461-7. 8. Ibarra C, Craig EV. Soft-tissue balancing in total shoulder arthroplasty. Orthop Clin North Am 1998;29:415-22. 9. Koch LD, Cofield RH, Ahlskog JE. Total shoulder arthroplasty in patients with Parkinson’s disease. J Shoulder Elbow Surg 1997;6:24-8. 10. Maybach A, Schlegel TF. Shoulder rehabilitation for the arthritic glenohumeral joint: preoperative and postoperative considerations. Semin Arthroplasty 1995;6:297-304. 11. Morton RE, Hankinson J, Nicholson J. Botulinum toxin for cerebral palsy: where are we now? Arch Dis Child 2004;89:1133-7. 12. Pidcock FS. The emerging role of therapeutic botulinum toxin in the treatment of cerebral palsy. J Pediatr 2004;145(Suppl):S33-5. 13. Rosenbaum P. Cerebral palsy: what parents and doctors want to know. BMJ 2003;326:970-4. 14. Shapiro BK. Cerebral palsy: a reconceptualization of the spectrum. J Pediatr 2004;145(Suppl):S3-7. 15. Wasiak J, Hoare B, Wallen M. Botulinum toxin A as an adjunct to treatment in the management of the upper limb in children with spastic cerebral palsy. Cochrane Database Syst Rev 2004: CD003469. 16. Wirth MA, Rockwood CA Jr. Complications of shoulder arthroplasty. Clin Orthop Relat Res 1994;307:47-69.