Total Elbow Joint Arthroplasty in Patients Rheumatoid Arthritis By Rowland As a result of better patient selection, implant design, and surgical technique, the long-term results of total elbow arthroplasty in patients with rheumatoid arthritis has improved significantly over the past 10 years. The semiconstrained hinge implant is used in the presence of severe bone and ligament destruction. The nonconstrained surface replacement requires intact bone and ligamentous supports. Best results are
H
ISTORICALLY, total elbow replacement arthroplasty, performed as a last operative resort for the unstable symptomatic elbow in rheumatoid arthritis patients, has often been viewed skeptically by both rheumatologists and orthopedic surgeons. This point of view has been based primarily on the discouragingly high complication rate associated with the constrained hinge type of elbow prosthesis, popularized in the early 1970s. Originating in England, these fixed hinged type prostheses allowed for only flexion and extension of the elbow joint. Three- to 5-year follow-ups reported implant loosening rates of upwards of 50%.’ Ultimately, all these fixed hinges required surgical revision. The uniformly unpredictable results of other surgical procedures, such as interposition fascial or skin arthroplasties and elbow arthrodesis, do not leave the orthopedic surgeon with any better alternative than to design better elbow prostheses.‘-’ Over the past decade, with the advent of new prosthetic designs including both surface replacement and semiconstrained hinge designs, improved surgical techniques relative to the insertion of fixation bone cement with pressure syringes, and better patient selection, the long-term results associated with this operative procedure have improved greatly.
From the Department of Orthopaedic Surgery, Victoria Hospital, Miami, FL. Rowland W. Pritchard, MD: Chief of Orthopaedic Surgery, Victoria Hospital, Miami, FL. Address reprint requests to Rowland W. Pritchard, MD, Chief of Orthopaedic Surgery, Mctoria Hospital, 955 NW 3rd St, Suite 851, Miami, FL 33128. Copyright 0 1991 by W. B. Saunders Company 0049-0172/91/2101-0001$5.00/0
24
With
W. Pritchard obtained if surgery is undertaken before severe soft tissue contractures, muscle atrophy, and neurologic disability of the involved extremity develop. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: Rheumatoid arthritis; elbow arthroplasty; elbow prostheses; surgery.
Like other orthopedic specialties, the results of total elbow arthroplasty are better when the procedure is carried out by an experienced surgeon who performs the operation on a frequent basis. Because of the complex nature of rheumatoid arthritis patients, the best results are seen with a team approach, simultaneously using the skills of the rheumatologist, orthopedic surgeon, and occupational therapist. ANATOMIC
AND BIOMECHANICAL
CONSIDERATIONS
The elbow joint is a tripartite joint, consisting of the ulna-humeral, radial-humeral and radialulna articulations. For practical purposes, the elbow can be considered a hinge-type joint with flexion and extension occurring about a fixed axis at the distal end of the humerus. Rotation of the forearm occurs as the radius rotates about the stationary ulna. Normal range of motion is from full extension to 140 degrees of flexion. Normal forearm rotation consists of 85 degrees of supination and 80 degrees of pronation. For practical purposes, nearly all elbow joint functions relating to day-to-day activities can be accomplished within an arc of motion of minus 30 degrees of extension and 135 degrees of flexion. Similarly, pronation and supination of 50 degrees, respectively, are adequate for most living activities.6 The stability of the elbow joint depends on both bony and soft tissue constraints. The main bony stabilizers are represented by the trochlea and capitellum of the distal humerus, the olecranon process of the proximal ulna, and the radial head of the proximal radius. The major soft tissue stabilizers include the medial collateral
SeminarsinArfhriris
andRheumatism,
Vol 21, No 1 (August), 1991: pp 24-29
TOTAL ELBOW JOINT ARTHROPLASTY
25
IN RA
ligament complex, the lateral collateral ligamentannular ligament complex and the triceps mechanism, and the flexor pronator muscle groups. In addition to flexion and extension, the ulna-humeral articulation has been shown experimentally to accommodate a small degree of rotation and side-to-side motion, known as abduction-adduction.6.7 This motion occurs in the ulna relative to the humerus as the elbow passes from extension to flexion and again to extension. When rotational and stress forces generated by forearm activity reach the elbow joint, the degree of laxity provided by these additional motions allows for dissipation of forces onto the supporting soft tissue constraints (ie, muscles, ligaments, and joint capsule). Understanding these elbow joint motion dynamics was primarily responsible for the advent of the semiconstrained hinge elbow prosthesis. This type of prosthesis was designed to transfer stress forces, generally associated with long-term loosening of the prosthetic bone cement interface, away from the prosthetic fixation and onto the supporting soft tissue complexes of the elbow joint. All of the semiconstrained hinge prostheses currently in vogue use this concept of medial-lateral and rotational laxity at the axis of rotation of the humeral and ulna components. In rheumatoid arthritis, chronic synovitis leads to gradual erosion of the bone stabilizers and attenuation of soft tissue supports due to prolonged increased intra-articular pressures. The long-term clinical result of this pathologic process generally is a painful unstable elbow joint. Soft tissue contractures lead to loss of functional range of motion and disuse atrophy of the supporting forearm musculature, compounding the clinical problems associated with elbow instability.
Fig 1:
Mark II Pritchard semiconstrained
prosthesis-cemented
hinge
version.
stability, but allowing a mild amount of mediallateral and rotational motion in addition to unrestricted flexion and extension. The component parts of the surface replacement prosthesis, on the other hand, are not linked together and depend on ligaments and muscle to keep
TYPES OF PROSTHESES
Two types of elbow joint prostheses are currently in use, the semiconstrained hinge prosthesis (Fig 1) and the nonconstrained surface replacement prosthesis (Fig 2). These implants differ from each other based on their degree of internal constraint or stability. In the case of the hinge prosthesis, the ulna and humeral components are linked together by an axle pin, giving maximal amount of internal
Fig 2: ment.
Ewald capitellocondylar
surface replace-
26
ROWLAND W. PRITCHARD
them aligned while functioning. Inadequate ligament balancing or inappropriate positioning of component parts can result in loss of desired alignment and painful joint subluxation or dislocation. The hinge prosthesis is used when destruction of bony and soft tissue elbow supports has occurred to the extent that a prosthesis with internal stability is required. Under conditions of less advanced bone and soft tissue destruction, the surface replacement type of prosthesis generally is used. The advantage of this implant over the hinge is that less intrusion into the medullary canals of the distal humerus and proximal ulna is required for fixation of the implant stems. Should a surface replacement implant fail because of infection, component loosening, or instability associated with dislocation, revision surgery can be undertaken with a semiconstrained hinge implant. However, the converse of this situation generally is not true. SURGICAL CONSIDERATIONS
Rheumatoid arthritis patients who are surgical candidates for total elbow joint arthroplasty often have complicated medical histories in relationship to the use of both antimetabolites and exogenous steroids. Many patients are immunocompromised and have a greater risk of postsurgical complications, particularly infection and wound healing. Since there is little soft tissue coverage on the dorsum of the elbow joint, where the surgical incision typically is located, wound healing in the rheumatoid arthritis patient with paper-thin skin often is difficult to achieve. The presence of rheumatoid nodules or vasculitis of subcutaneous tissues, and in many cases a history of previous surgical procedures relating to radial head excision and synovectomy, creates a greater risk for wound healing and requires utmost surgical skill when handling these tissues. Chronic synovitis of the elbow may be associated with ulnar nerve dysfunction as it passes through the cubital tunnel of the distal humerus. Paresthesias and decreased sensory and motor function of ulna nerve innervated hand structures are commonly seen in rheumatoid arthritis patients. Since dissection and decompression’of the ulnar nerve in the cubital tunnel of the elbow generally is necessary during surgi-
cal implantation of an elbow prosthesis, it is wise to document preexisting ulnar neuropathies by the use of electromyographic (EMG) and nerve conduction studies before surgery.’ In any case, great care need be taken when working with the ulnar nerve during surgery to avoid postsurgical conduction problems. The combination of small medullary canals of the distal humerus and proximal ulna and radius and the presence of osteoporosis, so common in rheumatoid arthritis, places demands on the elbow surgeon that are not necessarily required for hip or knee implant surgery. Because of the fragile nature of rheumatoid bone, pathologic fractures occur easily during the surgical procedure. Undesirable extrusion of methacrylate bone cement into the surrounding soft tissues about the elbow may occur in association with pathologic fractures induced by over-zealous reaming of the medullary canals. Fractures of the epicondyles of the distal humerus are associated with over-zealous reaming of the distal humerus during total elbow joint replacement surgery.’
CLINICAL RESULTS
A review of the current literature relative to 5- and lo-year follow-up periods for total elbow joint replacement in patients with rheumatoid arthritis suggests that both pain relief and improved functional range of motion can be achieved with either type prosthesis. Ninety percent of patients undergoing this surgical procedure are expected to obtain good to excellent results in terms of pain relief and restoration of function.“-18 Postsurgical improvement in range of motion is more predictable when the hinge prosthesis is used. Shortening the distal humerus at the time of surgery overcomes the problems of contracted soft tissues in the anterior aspect of the elbow joint. These contractures prevent the surgeon from obtaining full functional range of extension when the surface replacement prosthesis is used. Shortening of the distal humerus is undertaken only when a hinge prosthesis is used, since shortening sacrifices the function of the supporting medial and lateral collateral ligaments, so necessary to maintain the stability of a surface replacement prosthesis. In general,
TOTAL ELBOW JOINT ARTHROPLASTY
27
IN RA
a postsurgical arc of motion of 120 degrees is achievable when a hinge prosthesis is used.9,16-18 POSTSURGICAL
COMPLICATIONS
Complications from elbow joint replacement are common in rheumatoid arthritis patients. Postsurgical complication rates as high as 40% are reported in the literature.15 Sepsis results from delayed skin healing and generalized susceptability to infection due to a depressed immune system. Long-term infection rates following total elbow joint arthroplasty vary between 1% and 3% for the hinge and surface replacement prostheses.10,11.12’1517 If infection occurs, destruction of bone surrounding the implant and implant loosening develop. To cure the infection, the implant and all the methacrylate cement must be removed and the patient then treated with long-term intravenous antibiotic therapy. After eradication of infection within the joint and medullary canals of the involved bone, revision surgery in the form of another cemented prosthetic implant or an interposition fascial arthroplasty can be performed. Implant loosening without infection occurs more often with the hinge prosthesis (Fig 3). Loosening rates of upwards of 40% with the old constrained hinge-type prosthesis have been greatly reduced with the advent of the semiconstrained hinge. Currently, long-term loosening rates of the modern hinge implant vary from 1%
Fig 3:
Aseptic loosening of both humeral and
ulnar components of a hinge prosthesis. bony destruction of proximal ulna.
Note
When symptomatic loosening occurs, to 8%.q,‘7,‘8 revision surgery with longer-stemmed implants generally can be undertaken. Aseptic loosening of surface replacement implants ranges from 1% to 3%.10-12Since these implants are not linked together, loosening of the independent component parts is unusual, but may be associated with trauma. DISLOCATION
Dislocation of a hinge prosthesis is uncommon and generally occurs as a result of mechanical failure of the hinge mechanism (ie, axle pin disengagement). The prevalence of this mechanical problem, on a long-term follow-up, is between 1% and 5%.9,‘7,18Dislocation or subluxation of a resurfacing prosthesis results from loss of integrity of the ligamentous constraints of the elbow, from improper alignment of the component parts during surgery, or as a direct result of postsurgical trauma. The rate of postsurgical instability of surface replacement prostheses varies between 3% and whether due to symptomatic sublux15%,R.2n-22 ation or complete dislocation of the component parts. Chronic instability of a surface joint implant is painful and disabling and requires further revision. Such surgery generally is performed with a semiconstrained hinge after removal of the resurfacing prosthesis. The advent of intramedullary alignment cutting jigs has helped prevent misalignment problems from surface prostheses. For the most part, available surface replacements do not replace the radial capitellar articulation. In this investigator’s experience, replacement of the radial head at the time of surface replacement arthoplasty greatly reduces the problems associated with postoperative subluxation and dislocation (Fig 4). Ninety percent of day-to-day physical activities associated with elbow function place a valgus or outward stress on the elbow joint. As the main bony stabilizer against valgus stress, the radial head performs an important function in stabilizing the normal elbow joint. In the absence of a radial head, valgus stress is opposed only by the medial collateral ligament complex. Chronic weakening of this important soft tissue constraint can lead to undesirable instability of the humeral-ulna components of a surface replacement prosthesis.
28
ROWLAND W. PRITCHARD
Fig 4:
Three-year
operative
post-
follow-up
x-rays on Pritchard-type elbow resurfacing system (EN)
prosthesis using ra-
dial head replacement.
ULNARNERVENEUROPATHY
Postsurgical paresthesias of the ulnar nerve are relatively common following total elbow joint arthroplasty. They generally develop as a result of traction on the nerve at the time of surgery, and are transatory, lasting from 1 to 4 months. Loss of ulnar nerve motor function is unusual following this type of surgery. Overall, ulnar nerve neuropathy of a transitory nature following elbow joint replacement is between 3% and 18%15 (Pritchard RW, unpublished results). Permanent ulnar neuropathy following total replacement is between 1% and 3% (Pritchard RW, unpublished results). Previously healed anterior ulnar nerve transposition protects against postsurgical neuropathies associated with elbow arthroplasty. OTHER COMPLICATIONS
Uncommon surgical complications, ranging between 1% to 2%, are triceps tendon rupture15,23due to devascularization of the insertion of the triceps tendon onto the olecranon process at the time of surgery, and skin sloughs in the area of the incision, often associated with
previous surgery. Rupture of the triceps tendon causes loss of active elbow extension and requires surgical repair. Skin sloughs must be dealt with aggressively to prevent contamination of the wound with bacteria. Rotational skin flaps commonly are used to manage wound healing problems. CONCLUSION
Current results suggest that total joint arthroplasty can significantly relieve pain and restore function in the severely damaged elbow of rheumatoid arthritis patients. Improved design of implanted prostheses, improved intraoperative instrumentation for achieving more anatomic alignment of the component parts of the implant, more realistic patient selection, and better cement fixation techniques all have been responsible for improved long-term results. Pain relief is predictable when either the semiconstrained hinge or resurfacing prosthesis is employed. Range of motion is more predictably improved with the semiconstrained hinge prosthesis. Risks of delayed wound healing and infection in the immunocompromised rheumatoid arthritis patient are significant, but the benefits often warrant surgical intervention.
REFERENCES 1. Garrett JD, Ewald FC, Thomas WH, et al: Loosening associated with G.S.B. hinge total elbow replacement in patients with rheumatoid arthritis. Clin Orthop 127:170174,1977 2. Dee R: Total replacement of the elbow joint. Orthop Clin North Am 4:415-433.1973
3. Dickson RA, Stein H, Bentley G: Excision arthroplasty of the elbow in rheumatoid disease. J Bone Joint Surg 58-B:227-229,1976 4. Hurri L, Pulkki T, Vainio K: Arthroplasty of the elbow in rheumatoid arthritis. Acta Chir Stand 127:459-465, 1964
TOTAL ELBOW JOINT ARTHROPLASTY
29
IN RA
5. Silva JF: Total elbow replacement. Clin Orthop 117: 283-288,1976 6. Morrey BF, Chao EYS: Passive motion of the elbow joint-A biomechanical analysis. J Bone Joint Surg58-A:501508,1976 7. Walker PS: Human Joints and Their Artificial Replacements. Springfield, IL, Thomas, 1977 8. Ewald FC, Jacobs MA: Total elbow arthroplasty. Clin Orthop 182:137-142, 1984 9. Pritchard RW: Long term follow-up study of semiconstrained elbow prosthesis. Orthopedics 4:151-158, 1981 10. Ewald FC, Hungerford DS: Rheumatoid Arthritis I: Primary care, shoulder/elbow, ankle/foot-Cementless implants. Presented at the Annual Meeting of the American Academy of Orthopedic Surgeons, Atlanta, GA, February 12,1984 1 I. Ewald FC, Scheinberg RD, Poss R, et al: Capitellocondylar total elbow arthroplasty. Two to five year follow-up in rheumatoid arthritis. J Bone Joint Surg 62-A:1259-1263, 1980 12. Kudo H, Iwano K, Watanabe S: Total replacement of the rheumatoid elbow with a hingeless prosthesis. J Bone Joint Surg 62-A:277-285, 1980 13. London JT: Resurfacing total elbow arthroplasty. Presented at the Annual Meeting of The American Academy of Orthopedic Surgeons, Atlanta, GA, February 1980 14. Soutier WA: A New Approach to Elbow Arthroplasty. Eng Med 10:59-64, 1981 15. Dennis DA, Clayton ML, Ferlic DC, et al: Capitello-
condylar total elbow arthroplasty Arthroplasty .5:583-588, 1990
for rheumatoid
arthritis.
J
16. Coonrad RW: Seven year follow-up of Coonrad total elbow replacement, in Inglis AE (ed): Symposium on Total Joint Replacement of the Upper Extremity. St Louis, MO, Mosby, 1982, pp 75-90 17. Figgie HE, Rosenberg G, Ranawat CS, et al: Total elbow replacement-Long term results with a semiconstrained prothesis. Presented at the 4th Open Meeting of the American Shoulder and Elbow Surgeons, Atlanta, GA, February 7,1988 18. Morrey BF, Bryan RS: Infection after total arthroplasty. J Bone Joint Surg 65-A:330-338,1983
elbow
19. Ferlic DC, Morrey BF: The elbow III: Chronic and complex elbow problems. Presented at the Annual Meeting of The American Academy of Orthopedic Surgeons, Atlanta, GA, February 9,1988 20. Davis RF, Weiland A, Hungerford DS, et al: Nonconstrained total elbow replacement-Total elbow arthroplasty of the Ewald type. Clin Orthop 171:156-162, 1982 21. Rosenberg elbow arthroplasty.
GM, Turner Clin Orthop
22. Pritchard RW: plasty-A preliminary 1983
RH: Nonconstrained 187:154-162, 1984
total
Anatomic surface elbow arthroreport. Clin Orthop 179:223-230,
23. Trancik T, Wilde AH, Borden LS: Capitellocondylar total elbow arthroplasty-Two to eight year experience. Clin Orthop 223:175-180, 1987
H
ISTORICALLY, total elbow replacement arthroplasty, performed as a last operative resort for the unstable symptomatic elbow in rheumatoid arthritis patients, has often been viewed skeptically by both rheumatologists and orthopedic surgeons. This point of view has been based primarily on the discouragingly high complication rate associated with the constrained hinge type of elbow prosthesis, popularized in the early 1970s. Originating in England, these fixed hinged type prostheses allowed for only flexion and extension of the elbow joint. Three- to 5-year follow-ups reported implant loosening rates of upwards of 50%.’ Ultimately, all these fixed hinges required surgical revision. The uniformly unpredictable results of other surgical procedures, such as interposition fascial or skin arthroplasties and elbow arthrodesis, do not leave the orthopedic surgeon with any better alternative than to design better elbow prostheses.‘-’ Over the past decade, with the advent of new prosthetic designs including both surface replacement and semiconstrained hinge designs, improved surgical techniques relative to the insertion of fixation bone cement with pressure syringes, and better patient selection, the long-term results associated with this operative procedure have improved greatly.
From the Department of Orthopaedic Surgery, Victoria Hospital, Miami, FL. Rowland W. Pritchard, MD: Chief of Orthopaedic Surgery, Victoria Hospital, Miami, FL. Address reprint requests to Rowland W. Pritchard, MD, Chief of Orthopaedic Surgery, Mctoria Hospital, 955 NW 3rd St, Suite 851, Miami, FL 33128. Copyright 0 1991 by W. B. Saunders Company 0049-0172/91/2101-0001$5.00/0
24
With
W. Pritchard obtained if surgery is undertaken before severe soft tissue contractures, muscle atrophy, and neurologic disability of the involved extremity develop. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: Rheumatoid arthritis; elbow arthroplasty; elbow prostheses; surgery.
Like other orthopedic specialties, the results of total elbow arthroplasty are better when the procedure is carried out by an experienced surgeon who performs the operation on a frequent basis. Because of the complex nature of rheumatoid arthritis patients, the best results are seen with a team approach, simultaneously using the skills of the rheumatologist, orthopedic surgeon, and occupational therapist. ANATOMIC
AND BIOMECHANICAL
CONSIDERATIONS
The elbow joint is a tripartite joint, consisting of the ulna-humeral, radial-humeral and radialulna articulations. For practical purposes, the elbow can be considered a hinge-type joint with flexion and extension occurring about a fixed axis at the distal end of the humerus. Rotation of the forearm occurs as the radius rotates about the stationary ulna. Normal range of motion is from full extension to 140 degrees of flexion. Normal forearm rotation consists of 85 degrees of supination and 80 degrees of pronation. For practical purposes, nearly all elbow joint functions relating to day-to-day activities can be accomplished within an arc of motion of minus 30 degrees of extension and 135 degrees of flexion. Similarly, pronation and supination of 50 degrees, respectively, are adequate for most living activities.6 The stability of the elbow joint depends on both bony and soft tissue constraints. The main bony stabilizers are represented by the trochlea and capitellum of the distal humerus, the olecranon process of the proximal ulna, and the radial head of the proximal radius. The major soft tissue stabilizers include the medial collateral
SeminarsinArfhriris
andRheumatism,
Vol 21, No 1 (August), 1991: pp 24-29
TOTAL ELBOW JOINT ARTHROPLASTY
25
IN RA
ligament complex, the lateral collateral ligamentannular ligament complex and the triceps mechanism, and the flexor pronator muscle groups. In addition to flexion and extension, the ulna-humeral articulation has been shown experimentally to accommodate a small degree of rotation and side-to-side motion, known as abduction-adduction.6.7 This motion occurs in the ulna relative to the humerus as the elbow passes from extension to flexion and again to extension. When rotational and stress forces generated by forearm activity reach the elbow joint, the degree of laxity provided by these additional motions allows for dissipation of forces onto the supporting soft tissue constraints (ie, muscles, ligaments, and joint capsule). Understanding these elbow joint motion dynamics was primarily responsible for the advent of the semiconstrained hinge elbow prosthesis. This type of prosthesis was designed to transfer stress forces, generally associated with long-term loosening of the prosthetic bone cement interface, away from the prosthetic fixation and onto the supporting soft tissue complexes of the elbow joint. All of the semiconstrained hinge prostheses currently in vogue use this concept of medial-lateral and rotational laxity at the axis of rotation of the humeral and ulna components. In rheumatoid arthritis, chronic synovitis leads to gradual erosion of the bone stabilizers and attenuation of soft tissue supports due to prolonged increased intra-articular pressures. The long-term clinical result of this pathologic process generally is a painful unstable elbow joint. Soft tissue contractures lead to loss of functional range of motion and disuse atrophy of the supporting forearm musculature, compounding the clinical problems associated with elbow instability.
Fig 1:
Mark II Pritchard semiconstrained
prosthesis-cemented
hinge
version.
stability, but allowing a mild amount of mediallateral and rotational motion in addition to unrestricted flexion and extension. The component parts of the surface replacement prosthesis, on the other hand, are not linked together and depend on ligaments and muscle to keep
TYPES OF PROSTHESES
Two types of elbow joint prostheses are currently in use, the semiconstrained hinge prosthesis (Fig 1) and the nonconstrained surface replacement prosthesis (Fig 2). These implants differ from each other based on their degree of internal constraint or stability. In the case of the hinge prosthesis, the ulna and humeral components are linked together by an axle pin, giving maximal amount of internal
Fig 2: ment.
Ewald capitellocondylar
surface replace-
26
ROWLAND W. PRITCHARD
them aligned while functioning. Inadequate ligament balancing or inappropriate positioning of component parts can result in loss of desired alignment and painful joint subluxation or dislocation. The hinge prosthesis is used when destruction of bony and soft tissue elbow supports has occurred to the extent that a prosthesis with internal stability is required. Under conditions of less advanced bone and soft tissue destruction, the surface replacement type of prosthesis generally is used. The advantage of this implant over the hinge is that less intrusion into the medullary canals of the distal humerus and proximal ulna is required for fixation of the implant stems. Should a surface replacement implant fail because of infection, component loosening, or instability associated with dislocation, revision surgery can be undertaken with a semiconstrained hinge implant. However, the converse of this situation generally is not true. SURGICAL CONSIDERATIONS
Rheumatoid arthritis patients who are surgical candidates for total elbow joint arthroplasty often have complicated medical histories in relationship to the use of both antimetabolites and exogenous steroids. Many patients are immunocompromised and have a greater risk of postsurgical complications, particularly infection and wound healing. Since there is little soft tissue coverage on the dorsum of the elbow joint, where the surgical incision typically is located, wound healing in the rheumatoid arthritis patient with paper-thin skin often is difficult to achieve. The presence of rheumatoid nodules or vasculitis of subcutaneous tissues, and in many cases a history of previous surgical procedures relating to radial head excision and synovectomy, creates a greater risk for wound healing and requires utmost surgical skill when handling these tissues. Chronic synovitis of the elbow may be associated with ulnar nerve dysfunction as it passes through the cubital tunnel of the distal humerus. Paresthesias and decreased sensory and motor function of ulna nerve innervated hand structures are commonly seen in rheumatoid arthritis patients. Since dissection and decompression’of the ulnar nerve in the cubital tunnel of the elbow generally is necessary during surgi-
cal implantation of an elbow prosthesis, it is wise to document preexisting ulnar neuropathies by the use of electromyographic (EMG) and nerve conduction studies before surgery.’ In any case, great care need be taken when working with the ulnar nerve during surgery to avoid postsurgical conduction problems. The combination of small medullary canals of the distal humerus and proximal ulna and radius and the presence of osteoporosis, so common in rheumatoid arthritis, places demands on the elbow surgeon that are not necessarily required for hip or knee implant surgery. Because of the fragile nature of rheumatoid bone, pathologic fractures occur easily during the surgical procedure. Undesirable extrusion of methacrylate bone cement into the surrounding soft tissues about the elbow may occur in association with pathologic fractures induced by over-zealous reaming of the medullary canals. Fractures of the epicondyles of the distal humerus are associated with over-zealous reaming of the distal humerus during total elbow joint replacement surgery.’
CLINICAL RESULTS
A review of the current literature relative to 5- and lo-year follow-up periods for total elbow joint replacement in patients with rheumatoid arthritis suggests that both pain relief and improved functional range of motion can be achieved with either type prosthesis. Ninety percent of patients undergoing this surgical procedure are expected to obtain good to excellent results in terms of pain relief and restoration of function.“-18 Postsurgical improvement in range of motion is more predictable when the hinge prosthesis is used. Shortening the distal humerus at the time of surgery overcomes the problems of contracted soft tissues in the anterior aspect of the elbow joint. These contractures prevent the surgeon from obtaining full functional range of extension when the surface replacement prosthesis is used. Shortening of the distal humerus is undertaken only when a hinge prosthesis is used, since shortening sacrifices the function of the supporting medial and lateral collateral ligaments, so necessary to maintain the stability of a surface replacement prosthesis. In general,
TOTAL ELBOW JOINT ARTHROPLASTY
27
IN RA
a postsurgical arc of motion of 120 degrees is achievable when a hinge prosthesis is used.9,16-18 POSTSURGICAL
COMPLICATIONS
Complications from elbow joint replacement are common in rheumatoid arthritis patients. Postsurgical complication rates as high as 40% are reported in the literature.15 Sepsis results from delayed skin healing and generalized susceptability to infection due to a depressed immune system. Long-term infection rates following total elbow joint arthroplasty vary between 1% and 3% for the hinge and surface replacement prostheses.10,11.12’1517 If infection occurs, destruction of bone surrounding the implant and implant loosening develop. To cure the infection, the implant and all the methacrylate cement must be removed and the patient then treated with long-term intravenous antibiotic therapy. After eradication of infection within the joint and medullary canals of the involved bone, revision surgery in the form of another cemented prosthetic implant or an interposition fascial arthroplasty can be performed. Implant loosening without infection occurs more often with the hinge prosthesis (Fig 3). Loosening rates of upwards of 40% with the old constrained hinge-type prosthesis have been greatly reduced with the advent of the semiconstrained hinge. Currently, long-term loosening rates of the modern hinge implant vary from 1%
Fig 3:
Aseptic loosening of both humeral and
ulnar components of a hinge prosthesis. bony destruction of proximal ulna.
Note
When symptomatic loosening occurs, to 8%.q,‘7,‘8 revision surgery with longer-stemmed implants generally can be undertaken. Aseptic loosening of surface replacement implants ranges from 1% to 3%.10-12Since these implants are not linked together, loosening of the independent component parts is unusual, but may be associated with trauma. DISLOCATION
Dislocation of a hinge prosthesis is uncommon and generally occurs as a result of mechanical failure of the hinge mechanism (ie, axle pin disengagement). The prevalence of this mechanical problem, on a long-term follow-up, is between 1% and 5%.9,‘7,18Dislocation or subluxation of a resurfacing prosthesis results from loss of integrity of the ligamentous constraints of the elbow, from improper alignment of the component parts during surgery, or as a direct result of postsurgical trauma. The rate of postsurgical instability of surface replacement prostheses varies between 3% and whether due to symptomatic sublux15%,R.2n-22 ation or complete dislocation of the component parts. Chronic instability of a surface joint implant is painful and disabling and requires further revision. Such surgery generally is performed with a semiconstrained hinge after removal of the resurfacing prosthesis. The advent of intramedullary alignment cutting jigs has helped prevent misalignment problems from surface prostheses. For the most part, available surface replacements do not replace the radial capitellar articulation. In this investigator’s experience, replacement of the radial head at the time of surface replacement arthoplasty greatly reduces the problems associated with postoperative subluxation and dislocation (Fig 4). Ninety percent of day-to-day physical activities associated with elbow function place a valgus or outward stress on the elbow joint. As the main bony stabilizer against valgus stress, the radial head performs an important function in stabilizing the normal elbow joint. In the absence of a radial head, valgus stress is opposed only by the medial collateral ligament complex. Chronic weakening of this important soft tissue constraint can lead to undesirable instability of the humeral-ulna components of a surface replacement prosthesis.
28
ROWLAND W. PRITCHARD
Fig 4:
Three-year
operative
post-
follow-up
x-rays on Pritchard-type elbow resurfacing system (EN)
prosthesis using ra-
dial head replacement.
ULNARNERVENEUROPATHY
Postsurgical paresthesias of the ulnar nerve are relatively common following total elbow joint arthroplasty. They generally develop as a result of traction on the nerve at the time of surgery, and are transatory, lasting from 1 to 4 months. Loss of ulnar nerve motor function is unusual following this type of surgery. Overall, ulnar nerve neuropathy of a transitory nature following elbow joint replacement is between 3% and 18%15 (Pritchard RW, unpublished results). Permanent ulnar neuropathy following total replacement is between 1% and 3% (Pritchard RW, unpublished results). Previously healed anterior ulnar nerve transposition protects against postsurgical neuropathies associated with elbow arthroplasty. OTHER COMPLICATIONS
Uncommon surgical complications, ranging between 1% to 2%, are triceps tendon rupture15,23due to devascularization of the insertion of the triceps tendon onto the olecranon process at the time of surgery, and skin sloughs in the area of the incision, often associated with
previous surgery. Rupture of the triceps tendon causes loss of active elbow extension and requires surgical repair. Skin sloughs must be dealt with aggressively to prevent contamination of the wound with bacteria. Rotational skin flaps commonly are used to manage wound healing problems. CONCLUSION
Current results suggest that total joint arthroplasty can significantly relieve pain and restore function in the severely damaged elbow of rheumatoid arthritis patients. Improved design of implanted prostheses, improved intraoperative instrumentation for achieving more anatomic alignment of the component parts of the implant, more realistic patient selection, and better cement fixation techniques all have been responsible for improved long-term results. Pain relief is predictable when either the semiconstrained hinge or resurfacing prosthesis is employed. Range of motion is more predictably improved with the semiconstrained hinge prosthesis. Risks of delayed wound healing and infection in the immunocompromised rheumatoid arthritis patient are significant, but the benefits often warrant surgical intervention.
REFERENCES 1. Garrett JD, Ewald FC, Thomas WH, et al: Loosening associated with G.S.B. hinge total elbow replacement in patients with rheumatoid arthritis. Clin Orthop 127:170174,1977 2. Dee R: Total replacement of the elbow joint. Orthop Clin North Am 4:415-433.1973
3. Dickson RA, Stein H, Bentley G: Excision arthroplasty of the elbow in rheumatoid disease. J Bone Joint Surg 58-B:227-229,1976 4. Hurri L, Pulkki T, Vainio K: Arthroplasty of the elbow in rheumatoid arthritis. Acta Chir Stand 127:459-465, 1964
TOTAL ELBOW JOINT ARTHROPLASTY
29
IN RA
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