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Disassembly of a modular humeral prosthesis
The Journal of Arthroplasty
Disassembly
of a Modular
Humeral
Vol. 8 No. 6 1993
Prosthesis
A Case Report Domenick J. Sisto, MD, Matthew P. France, MD, Martin E. Blazina, MD, and Linda C. Hirsh
Abstract: A modular humeral hemiarthroplasty utilizing a prosthesis with a taperlock design was performed on a 77-year-old woman with a diagnosis of rotator cuff arthropathy. Radiographic examination at 3 moths after surgery revealed disarticulation of the modular head and neck from the humeral prosthetic stem. This is a case report of a disarticulated modular humeral hemiarthroplasty. Key words: prosthesis disassembly, shoulder hemiarthroplasty, modular humerus.
Shoulder hemiarthroplasty technique and results for the treatment of degenerative joint disease have been well described.3,6 A modular humeral component has been designed with a modular, taper-lock humeral head. The disassembly of a modular hip prosthesis has been previously reported in the literature as a rare complication.4,7,8 Since the taper-lock head design of the modular hip has been incorporated into the shoulder prosthesis, similar occurrences could be expected. Cooper and Brems2 reported the first case of a disassembly of a modular humeral prosthesis in a patient with a total shoulder arthroplasty. This is a case report of a disassembly of a modular hemiarthroplasty shoulder prosthesis in a patient with rotator cuff arthropathy.
1) . The preoperative range of motion was 90” active, 160” passive flexion; 30” active, 40” passive extension; and 90” active, 150” passive abduction. Internal rotation, both actively and passively, was to T-10. Active external rotation was 10” and 15” passively. The patient had minimal function. At the time of surgery, the shoulder revealed a massive rotator cuff defect, erosion of the proximal humeral articular surface, extensive glenoid bone loss, spurring of the acromial undersurface, and reactive synovitis. The biceps tendon, although degenerated, was intact. A diagnosis of rotator cuff arthropathy was confirmed. Due to the irreparable rotator cuff defect and risk of glenoid loosening, a humeral hemiarthroplasty was performed as previously described’s5 (Fig. 2). The hole in the humeral component was meticulously dried prior to attaching the reverse morse-taper humeral head. The humeral head was impacted on with a mallet and not merely placed on. Two months after surgery the patient showed progressive gains in shoulder mobility, significant relief of pain, and an increase in function. The postoperative range of motion was 100” active, 170” passive flexion; 40” active, 40’ passive extension; and 120” active, 170“ passive abduction. Internal rotation actively was to T- 10 and passively to T-8. Active external rotation was 15” and 2 5” passively. Three months
Case Report A 77-year-old woman was treated with a hemiarthroplasty (Biomet, Bio-Modular Shoulder, Warsaw, IN) of her nondominant shoulder secondary to pain, limited motion, and decreased function (Fig. From fornia.
the Los Angeles
Orthopaedic
Institute,
Sherman
Oaks,
Cali-
Reprint requests: Domenick J. Sisto, MD, Los Angeles Orthopaedic Institute, 4955 Van Nuys Boulevard, Suite 615, Sherman Oaks, CA 91403.
653
654
The Journal of Arthroplasty
Vol. 8 No. 6 December
1993
Fig. 1. Preoperativeanteroposteriorradiographof shoulder joint with severeosteoarthritis.
Fig. 3. Disarticulated components 3 months after sur-
gery.
Fig, 2, Immediate postoperative radiograph with components in place.
after surgery, the patient presented for routine follow-up examination and radiographs. The patient denied any injury, fall, excessive internal or external rotational stresses, or abduction and adduction motions. Radiographic examination revealed separation of the modular head and neck from the humerai prosthetic stem (Fig. 3). The patient had lost some motion, but had no pain and maintained acceptable function. She declined any revision surgery.
Disassembly
Discussion Before surgery, the patient presented with rotator cuff arthropathy with superior migration of the humeral head. We were concerned about the risk of glenoid component loosening. Patients with chronic rotator cuff insufficiency have upward displacement of the head with respect to the glenoid. Eccentric loading of the glenoid component secondary to upward displacement may cause loosening from a rocking or levering mechanism. A decision was made to perform a hemiarthroplasty in this patient to avoid the risk of glenoid loosening. This is a very unstable situation and may have led to the disarticulation of the prosthesis. There is no compression on the head and no force to maintain the taper-lock fit. The majority of previously reported modular prosthetic disassemblies have occurred in association with hip dislocations or component failure.4,7 It has been demonstrated that a significant distraction force is necessary to pull the head from the taper-lock.8 The absence of a compression force may have allowed the component to disassemble. The eccentric loading on the glenoid in a patient with rotator cuff arthropathy may also have led to the disassembly. Our case report is sufficiently different from one previously described* because our patient had a diagnosis of rotator cuff arthropathy. In the absence of a rotator cuff and a compressive force on the humeral head, the
of a Modular
Humeral
Prosthesis
l
Sisto et al.
655
prosthesis may frequently disassemble. A patient with rotator cuff arthropathy may present a contraindication for the use of a modular prosthesis.
References 1. Arntz C, Matsen F, JacksonS: Surgicalmanagementof complex irreparable rotator cuff deficiency. J Arthroplasty 6:363, 1991 2. CooperR, BremsJ: Recurrentdisassembly of a modular humeralprosthesis:a casereport. J Arthropiasty 6:375, 1991 3. Kay S,Amstutz H: Shoulderhemiarthroplastyat UCLA. Clin Orthop 228:42, 1988 4. Kitzger K, DeLeeJ, Evans J: Disassembly of a modular acetabular component of a total hip replacement arthroplasty: a casereport. J Bone Joint Surg 72A:62 1, 1990 5. Matsen F, Arntz C: Rotator cuff failure. p. 660. In Rock-
wood C, Matsen F (eds): The shoulder. WB Saunders, Philadelphia, 1990 6. Neer C: Replacementarthroplasty for glenohumeralosteoarthritis. J Bone Joint Surg 56A: 1, 1974 7. Pellicci P, HaasS: Disassemblyof a modular femoral componentduring closedreduction of a dislocatedfemoral component:
a case report. J Bone Joint Surg 72A:
619, 1990 8. Woolson S, Pottorf G: Disassembly of a modular femoral prosthesisafter dislocation of the femoral component: a casereport. J Bone Joint Surg 72A:624, 1990
Disassembly
of a Modular
Humeral
Vol. 8 No. 6 1993
Prosthesis
A Case Report Domenick J. Sisto, MD, Matthew P. France, MD, Martin E. Blazina, MD, and Linda C. Hirsh
Abstract: A modular humeral hemiarthroplasty utilizing a prosthesis with a taperlock design was performed on a 77-year-old woman with a diagnosis of rotator cuff arthropathy. Radiographic examination at 3 moths after surgery revealed disarticulation of the modular head and neck from the humeral prosthetic stem. This is a case report of a disarticulated modular humeral hemiarthroplasty. Key words: prosthesis disassembly, shoulder hemiarthroplasty, modular humerus.
Shoulder hemiarthroplasty technique and results for the treatment of degenerative joint disease have been well described.3,6 A modular humeral component has been designed with a modular, taper-lock humeral head. The disassembly of a modular hip prosthesis has been previously reported in the literature as a rare complication.4,7,8 Since the taper-lock head design of the modular hip has been incorporated into the shoulder prosthesis, similar occurrences could be expected. Cooper and Brems2 reported the first case of a disassembly of a modular humeral prosthesis in a patient with a total shoulder arthroplasty. This is a case report of a disassembly of a modular hemiarthroplasty shoulder prosthesis in a patient with rotator cuff arthropathy.
1) . The preoperative range of motion was 90” active, 160” passive flexion; 30” active, 40” passive extension; and 90” active, 150” passive abduction. Internal rotation, both actively and passively, was to T-10. Active external rotation was 10” and 15” passively. The patient had minimal function. At the time of surgery, the shoulder revealed a massive rotator cuff defect, erosion of the proximal humeral articular surface, extensive glenoid bone loss, spurring of the acromial undersurface, and reactive synovitis. The biceps tendon, although degenerated, was intact. A diagnosis of rotator cuff arthropathy was confirmed. Due to the irreparable rotator cuff defect and risk of glenoid loosening, a humeral hemiarthroplasty was performed as previously described’s5 (Fig. 2). The hole in the humeral component was meticulously dried prior to attaching the reverse morse-taper humeral head. The humeral head was impacted on with a mallet and not merely placed on. Two months after surgery the patient showed progressive gains in shoulder mobility, significant relief of pain, and an increase in function. The postoperative range of motion was 100” active, 170” passive flexion; 40” active, 40’ passive extension; and 120” active, 170“ passive abduction. Internal rotation actively was to T- 10 and passively to T-8. Active external rotation was 15” and 2 5” passively. Three months
Case Report A 77-year-old woman was treated with a hemiarthroplasty (Biomet, Bio-Modular Shoulder, Warsaw, IN) of her nondominant shoulder secondary to pain, limited motion, and decreased function (Fig. From fornia.
the Los Angeles
Orthopaedic
Institute,
Sherman
Oaks,
Cali-
Reprint requests: Domenick J. Sisto, MD, Los Angeles Orthopaedic Institute, 4955 Van Nuys Boulevard, Suite 615, Sherman Oaks, CA 91403.
653
654
The Journal of Arthroplasty
Vol. 8 No. 6 December
1993
Fig. 1. Preoperativeanteroposteriorradiographof shoulder joint with severeosteoarthritis.
Fig. 3. Disarticulated components 3 months after sur-
gery.
Fig, 2, Immediate postoperative radiograph with components in place.
after surgery, the patient presented for routine follow-up examination and radiographs. The patient denied any injury, fall, excessive internal or external rotational stresses, or abduction and adduction motions. Radiographic examination revealed separation of the modular head and neck from the humerai prosthetic stem (Fig. 3). The patient had lost some motion, but had no pain and maintained acceptable function. She declined any revision surgery.
Disassembly
Discussion Before surgery, the patient presented with rotator cuff arthropathy with superior migration of the humeral head. We were concerned about the risk of glenoid component loosening. Patients with chronic rotator cuff insufficiency have upward displacement of the head with respect to the glenoid. Eccentric loading of the glenoid component secondary to upward displacement may cause loosening from a rocking or levering mechanism. A decision was made to perform a hemiarthroplasty in this patient to avoid the risk of glenoid loosening. This is a very unstable situation and may have led to the disarticulation of the prosthesis. There is no compression on the head and no force to maintain the taper-lock fit. The majority of previously reported modular prosthetic disassemblies have occurred in association with hip dislocations or component failure.4,7 It has been demonstrated that a significant distraction force is necessary to pull the head from the taper-lock.8 The absence of a compression force may have allowed the component to disassemble. The eccentric loading on the glenoid in a patient with rotator cuff arthropathy may also have led to the disassembly. Our case report is sufficiently different from one previously described* because our patient had a diagnosis of rotator cuff arthropathy. In the absence of a rotator cuff and a compressive force on the humeral head, the
of a Modular
Humeral
Prosthesis
l
Sisto et al.
655
prosthesis may frequently disassemble. A patient with rotator cuff arthropathy may present a contraindication for the use of a modular prosthesis.
References 1. Arntz C, Matsen F, JacksonS: Surgicalmanagementof complex irreparable rotator cuff deficiency. J Arthroplasty 6:363, 1991 2. CooperR, BremsJ: Recurrentdisassembly of a modular humeralprosthesis:a casereport. J Arthropiasty 6:375, 1991 3. Kay S,Amstutz H: Shoulderhemiarthroplastyat UCLA. Clin Orthop 228:42, 1988 4. Kitzger K, DeLeeJ, Evans J: Disassembly of a modular acetabular component of a total hip replacement arthroplasty: a casereport. J Bone Joint Surg 72A:62 1, 1990 5. Matsen F, Arntz C: Rotator cuff failure. p. 660. In Rock-
wood C, Matsen F (eds): The shoulder. WB Saunders, Philadelphia, 1990 6. Neer C: Replacementarthroplasty for glenohumeralosteoarthritis. J Bone Joint Surg 56A: 1, 1974 7. Pellicci P, HaasS: Disassemblyof a modular femoral componentduring closedreduction of a dislocatedfemoral component:
a case report. J Bone Joint Surg 72A:
619, 1990 8. Woolson S, Pottorf G: Disassembly of a modular femoral prosthesisafter dislocation of the femoral component: a casereport. J Bone Joint Surg 72A:624, 1990