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Total Ankle Arthroplasty
AUGUST 1988, VOL. 48, NO 2
AORN JOURNAL
Total Ankle Arthroplasty A PROCEDURAL REVIEW Janice M. Spaulding, RN; Richard G. Megesi, RN; Harry E. Figgie, 111, MD; Anthony S. Unger, MD; Allan E. Inglis, MD otal ankle arthroplasty is the artificial replacement of the tibiotalar joint. The procedure has been used successfully both in sedentary or elderly patients with advanced arthritis and in disabled younger patients with systemic arthritis. It has been used for approximately 15 years, but has gained popularity in the past 10 years. There are two general types of total ankle prosthetic devices: unconstrained devices that allow free shifting of the ankle joint and the more constrained ball-and-socket type of joint. Ball-andsocket implants include the Oregon” (Figs 1 and 2), TPR, Mayo, and Buckholz. Recently, a bicondylar implant that more nearly models the ankle joint has been developed and is being evaluated. Figure 3 shows the bones in the ankle joint. Patients with generalized arthritis need to maintain motion of their tibiotalar joint because other leg joints often are painful and have limited
T
motion. Patients with rheumatoid arthritis frequently have arthritic changes in the hindfoot, midfoot, and forefoot. In addition, patients with ankle arthrodesis may have a shifting of gait stresses from hindfoot to forefoot, which exacerbatestheir pain and disability. Thus, patients with extensive arthritis or ankylosis of the ankle and small joints of the foot are candidates for total ankle arthroplasty. Contraindications to total ankle arthroplasty include local or remote sepsis, neuropathic joints, or neuromuscular disease with spasticity. Relative contraindications include a young age, highactivity levels, obesity, isolated tibiotalar posttraumatic arthritis, or osteoarthritis. Patients with a closed growth plate and multiple-joint involvement from rheumatoid arthritis are potential candidates, but a 40-year-old laborer with singlejoint disease is not a candidate. Other contraindications include severe peripheral vascular disease and failed arthrodesis.
Janice M. Spaulding, RN,BSN, is an advanced orthopaedic nurse, University Hospitals of Cleveland She earned her bachelor of science degree in nursing at the University of Akron, Ohio. Richard G. Megesi, RN,is an orthopaedic nurse, University Hospitab of Cleveland He earned his diploma of nursing at the Cleveland Metropolitan Hospital School of Nursing and an associate of science degree in surgical assisting from Cuyahoga Community College, Parma, Ohio. Harry E. Figgie, IIA MD, is an orthopaedic
surgeon, University Hospitals of Cleveland He earned his doctorate of medicine at Case Western Reserve University, Cleveland Anthony S. Unger, MD, is an orthopaedic surgeon, George Washington University Hospital, Washington, DC. He earned h h doctorate of medicine at the State University of New York at Buffalo. Allan E. Inglis, MD, is an orthopaedic surgeon, New York Hospital and the Hospital for Special Surgery, New York City. He earned his doctorate of medicine at the Universitv of Rochester (NY). 201
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7
, s e c t i o n
a
p&\
\
/
0
lateral
anterior-posterior
Fig 1. The Oregon'" total ankle prosthesis. Talar prosthesis (above), tibia1 prosthesis (right).
lateral
anterior-posterior
cement fingers
I anterior-posterior
lateral
Fig 2. Oregon'" total ankle prosthesis in place. (Drawings courtesy of Zimmer USA, Inc, Warsaw,Zd)
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medial malleolus lateral malleolus
calcaneus
Fig 3. Ankle joint bones. Joint has three sets of articular surfaces between the distal tibia and the superior surface of the talus (l), the medial malleolus and the medial side of the talus (2), and the lateral malleolus (of the fibula) and the lateral side of the talus (3). (Drawing courtesy ofZimmer USA, Inc, Warsaw, Id) The quality of the patient’s gait following the total ankle arthroplasty is related to many factors including the physical condition of the patient, muscular strength of the leg, type of implant, implant alignment, and the surgical approach used. The purpose of the procedure is to provide a painfree, stable, and functional ankle joint that allows the patient to perform the normal activities of daily living.
Preoperative Assessmenl
A
preoperative assessment of a candidate for total ankle arthroplasty should include an evaluation of muscle strength and balance, skin integrity, and neurovascular status of the affected leg. When the blood supply of a foot depends on
a single vessel, special care must be taken to preserve that vessel. At University Hospitals of Cleveland, the preliminary vascular evaluation is done with a Doppler ultrasound. Tests of vascular competence such as thermography and fluorescein testing are used elsewhere. An arteriogram is indicated if previous studies reveal deficiencies in the arterial supply of the foot. Any spasticity, flaccidity, or sensory loss in the foot must be identified. Loss of propnoception leads to abnormal load transmission that could cause early failure of the implant. Peripheral neuropathy, stroke, or muscle imbalances are relative contraindications to total ankle arthroplasty. If multiple surgical procedures are indicated, the order of priority for surgical reconstruction is forefoot, hindfoot, and then the tibiotalar joint.
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A postsurgical forefoot or hindfoot infection may infect an ankle implant, which would necessitate removing the implant. A painful forefoot or subtalar joint may prevent the patient from placing the foot in a plantigrade posture, and thus compromise rehabilitation. In addition, a muscular balance at the tibiotalar joint may require tendon transfer, and these should be performed only after the foot is in its final reconstructive stage. Surgeons at University Hospitals of Cleveland recommend that all forefoot and hindfoot surgery be performed before a total ankle arthroplasty.
Preoperative Planning
P
reoperative planning is based on a true anterior-posterior and lateral x-ray obtained in the weight-bearing position and/or a computed axial tomography scan if the anatomy is severely distorted. Routine preoperative studies include a chest xray, electrocardiogram, and complete blood testing. After the patient is accepted as a candidate, the orthopedic surgeon explains the surgical procedure. The surgeon also reviews the general postoperativecourse, length of hospitalization,and recovery. The orthopedic nurse completes the preoperative teaching. The nurse instructs the patient on how to wash the affected leg with an antibacterial soap twice a day for three days before surgery; how to perform postoperative isometric leg exercises, such as quadricep and gluteal sets, every hour until able to walk; and how to use the incentive spirometer for deep-breathing exercises. The nurse also describes the postoperative bulky dressing and the neurocirculatory checks that will be performed. How to walk with a crutch and weight-transfer techniques are usually taught by a physical therapist. The orthopedic nurse also explains the longterm postoperative course. Patients are instructed to be kind to their implant. Implants may have fatigue-type failure, and repeated overuse may lead to a breakdown of the interface between the implant and the bone or the polyethylene gliding surface. Activities such as bike riding, swimming, rowing, golfing, or walking are encouraged;
AUGUST 1988, VOL. 48, NO 2
racquet sports and running are discouraged. Controlling infections is a primary concern of all OR personnel during total ankle arthroplasty surgery. Several steps are taken at University Hospitals of Cleveland to avoid infections. These precautions include using a room with a glass enclosure and a vertical laminar airflow system. Both this “glass house” and surrounding outer room are closed to traffic, and inside and an outside circulating nurses are needed. A body exhaust ventilation system “space suit” is used by all OR personnel. When the patient is put on call to the operating room, the floor nurse preps the operative leg with a povidone-iodine paint. In the OR, the ankle is shaved then scrubbed and prepared with alcohol and povidone-iodine. This procedure is repeated before incision. The patient is given 1 g parenteral cephalosporin before the leg tourniquet is inflated. Instrument sets used are those for ankle or subtalar arthrodesis of the ankle. Special instruments, including the trial prostheses for the system, also are needed. Because total ankle arthroplasty is an uncommon procedure, the nurse needs to make a final check to ensure that an adequate number of implant prostheses are available and sterile before the start of the case. Other instruments that may be used, depending on the surgeon’s preference, are Hohmann and Bennett retractors, small and medium lamina spreaders, smooth Steinmann pins, straight and curved osteotomes,a power drill, and an oscillating saw. Methyl methacrylate and a pulsatile lavage irrigation system will be needed if the implants are to be cemented. This article describes the two surgical approaches that can be used to implant a total ankle prosthesis the anterior approach and the posterior approach.
Anterior Approach
T
he anterior approach is similar to that used for ankle arthrodesis. The patient is brought into the OR, put in the supine position on the OR bed, and a pneumatic tourniquet is applied to the operative thigh. The patient is then anesthetized, and the surgeon inflates the
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malleolus
i
i
I
Fig 4. Skin incision from the base of the second metatarsal to the crest of the tibia. tourniquet to approximately 100 mm of mercury higher than the patient’s systolic blood pressure. The surgeon makes a 15 cm incision from the base of the second metatarsal proximally to the crest of the tibia. The distance between the medial and lateral malleolus is the center point of the incision (Fig 4). The surgeon divides the skin and subcutaneous tissue to the deep fascia (Fig 5). Bleeding is controlled with electrocautery.
Fig 5. Incision to the deep fascia. Extensor retinaculum (I), superficial peroneal nerve (2).
The extensor retinaculum muscle is opened longitudinally. The surgeon identifies the extensor hallucislongus and reflects it medially;the extensor longus digitorum is reflected laterally. Sharp dissection is used to identify the capsule of the ankle joint. The surgeon then makes a periosteal dissection to identify the lateral and medial malleolus. Careful dissection is necessary to avoid injuring the deltoid
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Fig 7. Steinmann pins in place. 210
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and lateral collateral ligaments. After placing Bennett retractors beneath the periosteum of the medial malleolus and lateral malleolus (Fig 6), the surgeon inserts Steinmann pins parallel to the proposed cuts, approximately 2 cm proximal to the joint (Fig 7). X-rays are taken to confirm the position of the pins. Attention is then directed to the lateral malleolus. The surgeon makes a small longitudinal incision over the lateral malleolus at its tip and resects the tip distal to the origin of the fibular collateral ligament. This prevents lateral impingement of the fibula on the calcaneus. After reviewing the x-rays to determine where to make the cuts, the surgeon uses an oscillating saw and makes two parallel cuts in the bone oriented toward the Steinmann pins (Fig 8). Varus and valgus deformities of the hindfoot of greater than 20 degrees should not be corrected at the ankle joint. The surgeon then makes two parallel saw cuts through the dome of the talus. The cuts are made parallel to the longitudinal axis of talus so that the neck of the talus will not be cut (Fig 9). The tibia1 saw cut is usually made 7 mm above the articular surface; care is taken to protect the medial malleolus. After making the two parallel cuts and removing the bone, the surgeon sizes the cut using the appropriate spacing blocks. The largest prosthesis that will fit in the medial lateral plane is selected. There should be balanced, equal tension on the lateral and medial ligament complex, and 2 to 4 mm of overall laxity. After the tibia and the talus are prepared, trial components are put in place and the surgeon tests the ankle through a full range of motion. If the components are placed too far anteriorly, the implant will lack dorsiflexion. If the implant is placed too far posteriorly, there will be a relative lack of plantar flexion. If dorsiflexion or plantar flexion contracture remains, it can be corrected by additional bony cuts. When the range of motion tests are finished, the surgeon removes the trial components and thoroughly cleans the bone with a pulsating lavage. When cement fixation is used, the surgeon places the cement in the bony cavities and inserts the
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malleolus
\
Fig 8. Schematic view of bone cuts. 211
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oscillating saw cut
4
dome of the talus
L - \
\ \ --
body of tke talus
head neck
I
.y
\
Fig 9. Saw cut through the dome of the talus parallel to the longitudinal axis of the talus. tibila component first followed by the talar component. The foot is then brought up to the neutral position, and the cement is allowed to harden. If biologic fixation is used, the tibia1 component is placed first. The surgeon places a drain deep in the upper part of the wound and closes the superficial fascia with interrupted absorbable sutures. The skin and subcutaneous tissue are closed in a standard fashion. The ankle is placed in a neutral position (0 degrees valgus and varus flexion) in a wellpadded, soft dressing with a posterior splint.
Posterior Approach
W
hen compared to the anterior approach, the posterior approach produces less soft-tissue and wound complications, and it offers wider exposure of the implant. In addition, the center of the rotation of the implant arthroplasty can be better assessed from the posterior approach because the anatomy 212
of the posterior cortex of the tibia and calcaneus (0s calcis) is constant. For this surgery, the patient is placed in a prone position and draped. Positioning is especially crucial in patients with rheumatoid arthritis, and extra padding, pillows, or arm boards may be necessary to avoid complications. After the tourniquet is applied, the surgeon makes a medial zigzag incision starting 10 cm proximal to the medial malleolus and parallel to the medial border of the Achilles tendon (Fig 10). Skin and subcutaneous tissue are divided sharply, and bleeding points are controlled using bipolar electrocautery. The surgeon opens the crural fascia longitudinally (Fig 11). The plantaris tendon is identified and released from the insertion of the medial aspect of the calcaneus. Taking care to avoid the medial flexor group and neurovascular bundle, the surgeon dissects underneath this tendon subperiosteally around the medial malleolus. This preserves the medial flexor group (muscles and
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Fig 10. For the posterior approach, the surgeon makes a zigzag incision and two parallel incisions.
Fig IZ. Crural fascia opened longitudinally. Deep fascia (I), deep fascia over Achilles tendon (2).
tendons) and the neurovascular bundle. A Bennett retractor is placed medially around the malleolus. Approximately one eighth of the Achilles tendon can be taken down (making a vertical cut in the tendon and moving it aside) for better exposure. Subperiosteal dissection then is done laterally around the lateral malleolus exposing the entire ankle joint (Fig 12). The surgeon then inserts Steinmann pins parallel to the proposed level of cuts, approximately 2 cm proximal to the distal tibial articular surface (Fig 13). X-rays are taken of the joint. While awaiting the x-ray results, the surgeon makes a longitudinal incision directly over the lateral malleolus and resects the tip of the lateral malleolus distal to the origin of the fibular collateral ligament. To prevent lateral impinge-
ment, the orientation of the Steinmann pins to the long axis of the tibia is used to guide the angle of the tibial cuts. Removing too much talar bone can damage the talar neck, which can cause avascular necrosis or talar neck fractures. Preoperative varus or valgus deformities of the ankle of up to 20 degrees can be corrected by bony resection. After making the cuts, the surgeon sizes the cuts with the appropriate spacing blocks. Trial components are then used to assess the range of motion. If methyl methacrylate is used, the surgeon thoroughly cleans the bony surfaces using a pulsating lavage. Cement is then pressurized into bony surfaces and the components are cemented sequentially (tibial component first). Excess cement is removed.
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incision into fascia
Fig 12. Tibiotalar joint exposed. The foot is then brought up to a neutral position
as the cement is allowed to harden. When biologic fixation is used, the tibia1 component is placed first. The wound is then irrigated thoroughly, a drain is put in place, and the wound is closed in layers. A well-padded dressing is used with a posterior splint. The patient is then transferred to the postanesthesia care unit.
Postoperative Care
B
ecause the ankle with the arthroplasty should be elevated for three to four days after surgery, nurses need to limit the patient’s activity and keep the ankle higher than the patient’s heart. Suction drainage is continued until drainage ceases, usually in 24 to 48 hours.
After the soft tissue has healed, a short leg walking cast is applied. If the implant has been cemented, the patient may begin weight bearing as tolerated, and the cast is worn an additional three weeks. If biological fixation was used, six weeks of partial weight bearing with cast immobilization is required. Routine postoperative care for any total ankle arthroplasty patient includes deep breathing exercises using the incentive spirometer every hour while awake. The patient’s diet is advanced as tolerated and his or her bowel status is assessed in the early postoperative course to prevent constipation caused by immobility and narcotic analgesics. Isometric leg exercises are done every hour and an elastic support stocking is worn. Postoperative pain is controlled with intramuscular 215
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Bennett retractors
y
7
-!.
dome of talus
distal tibia
Fig 13. Steinmann pins in place.
or intravenous analgesics for several days and then oral analgesics as tolerated. The patient is discharged when the wound is healed and he or she is able to walk independently. Discharge teaching is frequently started preoperatively to identify potential problems with mechanical barriers at home. The nurse reviews written instructions for taking care of the cast with the patient. He or she also explains signs and symptoms of wound infection. The patient is told to alert the physician if he or she experiences a fever, night sweats or chills, or increasing pain in the ankle. For a cemented implant, the patient is seen in the outpatient clinic two to three weeks
postoperatively for cast removal. For a biologicfixed implant, the patient is seen at three weeks postoperatively for a cast change and at six weeks for cast removal. The patient progresses to full weight bearing, as tolerated, at 12 weeks. The patient is seen every three months for the first year, and x-rays are taken at each visit. The patient is then assessed yearly.
Summary
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otal ankle arthroplasty is a demanding surgical procedure, but the advantages of maintaining motion in the tibiotalar joint in the patient with systemic arthritis are known. 217
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Although the technology of ankle implant arthroplasty is still evolving, current results in properly selected patients approach the results of other leg implants. 0 Suggested reading Bolton-Maggs, B G; Sudlow, R A; Freeman, M A. “Total ankle arthroplasty: A long-term review of the London Hospital experience.” Journal of Bone and Joint Surgery 67 (November 1985) 785-790. Samuelson, K M; Freeman, M A; Tuke, M A.
AORN J O U R N A L
“Development and evolution of the ICLH ankle replacement.”Foot and Ankle 3 (July-August 1982) 32-36. Stauffer, R N. “Salvage of painful total ankle arthroplasty.” Clinical Orthopaedics 170 (October 1982) 184-188. Stauffer, R N; Segal, N M. “Total ankle arthroplasty: Four years’ experience.” Clinical Orthopaedics 160 (October 1981) 217-221. Unger, A S; Inglis, A E. “Total ankle arthroplasty,” in Operative Orthopaedics. Philadelphia: J B Lippincott, 1988, 807-813.
Salt Sensitivity Worsens with Age Studies on salt loading and depletion proved that salt sensitivity becomes more severe as people age, according to an article on the American Heart Association meeting in Santa Fe, NM, in the May 9, 1988, issue of Medical World News. Tests were administered to more than 400 normotensive and 250 hypertensive people between the ages of 17 and 72. In the loading phase, the people received 2 L of 0.9% saline solution intravenously during a four-hour period. The depletion phase, which took place the following day, combined a sodium intake limited to 10 mEq and three doses of 40 mg of furosemide. Responses to sodium loading rose gradually with age among the hypertensives. Among the normotensives, an age-related increase appeared only in people older than 50. Hypertensives also had an increased drop in pressure following sodium and volume depletion. Increased sodium sensitivity with age was noted by exaggerated responses in people who were already salt sensitive. Results of the studies emphasize sodium chloride restriction as antihypertension therapy for older patients but do not endorse diuretics as primary therapy, according to the physician who developed and administered the tests. He also noted that diuretics are often an effective solo therapy when used on older hypertension patients, but stressed that diuretics can be dangerous in the elderly. They should be used cautiously, at low doses, and in combination with a
vasodilating antihypertensive drug, according to the article.
OR Product Directory Wins Gold Ink Award Publishing Technology Inc, Philadelphia, presented the 1988 Gold Ink Award to the AORN Journal’s OR Product Directory. The directory was one of more than 600 trade directories entered in the competition and was selected as the winner on the basis of its overall design, cover, typography, manufacturing quality, and printing quality. Jo Ann Sansen, AORN director of publications/business, believes the straightforward approach of the directory was one of the main reasons it won the award. “We wanted to reach O R nurses with a product directory that would relate only to what they needed,” she said. “We did not include a section on how to use the products, we just made it easy for nurses to find what they need.” The directory was distributed in December 1987 to AORN members, perioperative nurses who are not members of AORN, and purchasing agents in hospitals throughout the United States. A new edition of the directory will be mailed October 1, 1988.
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Total Ankle Arthroplasty A PROCEDURAL REVIEW Janice M. Spaulding, RN; Richard G. Megesi, RN; Harry E. Figgie, 111, MD; Anthony S. Unger, MD; Allan E. Inglis, MD otal ankle arthroplasty is the artificial replacement of the tibiotalar joint. The procedure has been used successfully both in sedentary or elderly patients with advanced arthritis and in disabled younger patients with systemic arthritis. It has been used for approximately 15 years, but has gained popularity in the past 10 years. There are two general types of total ankle prosthetic devices: unconstrained devices that allow free shifting of the ankle joint and the more constrained ball-and-socket type of joint. Ball-andsocket implants include the Oregon” (Figs 1 and 2), TPR, Mayo, and Buckholz. Recently, a bicondylar implant that more nearly models the ankle joint has been developed and is being evaluated. Figure 3 shows the bones in the ankle joint. Patients with generalized arthritis need to maintain motion of their tibiotalar joint because other leg joints often are painful and have limited
T
motion. Patients with rheumatoid arthritis frequently have arthritic changes in the hindfoot, midfoot, and forefoot. In addition, patients with ankle arthrodesis may have a shifting of gait stresses from hindfoot to forefoot, which exacerbatestheir pain and disability. Thus, patients with extensive arthritis or ankylosis of the ankle and small joints of the foot are candidates for total ankle arthroplasty. Contraindications to total ankle arthroplasty include local or remote sepsis, neuropathic joints, or neuromuscular disease with spasticity. Relative contraindications include a young age, highactivity levels, obesity, isolated tibiotalar posttraumatic arthritis, or osteoarthritis. Patients with a closed growth plate and multiple-joint involvement from rheumatoid arthritis are potential candidates, but a 40-year-old laborer with singlejoint disease is not a candidate. Other contraindications include severe peripheral vascular disease and failed arthrodesis.
Janice M. Spaulding, RN,BSN, is an advanced orthopaedic nurse, University Hospitals of Cleveland She earned her bachelor of science degree in nursing at the University of Akron, Ohio. Richard G. Megesi, RN,is an orthopaedic nurse, University Hospitab of Cleveland He earned his diploma of nursing at the Cleveland Metropolitan Hospital School of Nursing and an associate of science degree in surgical assisting from Cuyahoga Community College, Parma, Ohio. Harry E. Figgie, IIA MD, is an orthopaedic
surgeon, University Hospitals of Cleveland He earned his doctorate of medicine at Case Western Reserve University, Cleveland Anthony S. Unger, MD, is an orthopaedic surgeon, George Washington University Hospital, Washington, DC. He earned h h doctorate of medicine at the State University of New York at Buffalo. Allan E. Inglis, MD, is an orthopaedic surgeon, New York Hospital and the Hospital for Special Surgery, New York City. He earned his doctorate of medicine at the Universitv of Rochester (NY). 201
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7
, s e c t i o n
a
p&\
\
/
0
lateral
anterior-posterior
Fig 1. The Oregon'" total ankle prosthesis. Talar prosthesis (above), tibia1 prosthesis (right).
lateral
anterior-posterior
cement fingers
I anterior-posterior
lateral
Fig 2. Oregon'" total ankle prosthesis in place. (Drawings courtesy of Zimmer USA, Inc, Warsaw,Zd)
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medial malleolus lateral malleolus
calcaneus
Fig 3. Ankle joint bones. Joint has three sets of articular surfaces between the distal tibia and the superior surface of the talus (l), the medial malleolus and the medial side of the talus (2), and the lateral malleolus (of the fibula) and the lateral side of the talus (3). (Drawing courtesy ofZimmer USA, Inc, Warsaw, Id) The quality of the patient’s gait following the total ankle arthroplasty is related to many factors including the physical condition of the patient, muscular strength of the leg, type of implant, implant alignment, and the surgical approach used. The purpose of the procedure is to provide a painfree, stable, and functional ankle joint that allows the patient to perform the normal activities of daily living.
Preoperative Assessmenl
A
preoperative assessment of a candidate for total ankle arthroplasty should include an evaluation of muscle strength and balance, skin integrity, and neurovascular status of the affected leg. When the blood supply of a foot depends on
a single vessel, special care must be taken to preserve that vessel. At University Hospitals of Cleveland, the preliminary vascular evaluation is done with a Doppler ultrasound. Tests of vascular competence such as thermography and fluorescein testing are used elsewhere. An arteriogram is indicated if previous studies reveal deficiencies in the arterial supply of the foot. Any spasticity, flaccidity, or sensory loss in the foot must be identified. Loss of propnoception leads to abnormal load transmission that could cause early failure of the implant. Peripheral neuropathy, stroke, or muscle imbalances are relative contraindications to total ankle arthroplasty. If multiple surgical procedures are indicated, the order of priority for surgical reconstruction is forefoot, hindfoot, and then the tibiotalar joint.
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A postsurgical forefoot or hindfoot infection may infect an ankle implant, which would necessitate removing the implant. A painful forefoot or subtalar joint may prevent the patient from placing the foot in a plantigrade posture, and thus compromise rehabilitation. In addition, a muscular balance at the tibiotalar joint may require tendon transfer, and these should be performed only after the foot is in its final reconstructive stage. Surgeons at University Hospitals of Cleveland recommend that all forefoot and hindfoot surgery be performed before a total ankle arthroplasty.
Preoperative Planning
P
reoperative planning is based on a true anterior-posterior and lateral x-ray obtained in the weight-bearing position and/or a computed axial tomography scan if the anatomy is severely distorted. Routine preoperative studies include a chest xray, electrocardiogram, and complete blood testing. After the patient is accepted as a candidate, the orthopedic surgeon explains the surgical procedure. The surgeon also reviews the general postoperativecourse, length of hospitalization,and recovery. The orthopedic nurse completes the preoperative teaching. The nurse instructs the patient on how to wash the affected leg with an antibacterial soap twice a day for three days before surgery; how to perform postoperative isometric leg exercises, such as quadricep and gluteal sets, every hour until able to walk; and how to use the incentive spirometer for deep-breathing exercises. The nurse also describes the postoperative bulky dressing and the neurocirculatory checks that will be performed. How to walk with a crutch and weight-transfer techniques are usually taught by a physical therapist. The orthopedic nurse also explains the longterm postoperative course. Patients are instructed to be kind to their implant. Implants may have fatigue-type failure, and repeated overuse may lead to a breakdown of the interface between the implant and the bone or the polyethylene gliding surface. Activities such as bike riding, swimming, rowing, golfing, or walking are encouraged;
AUGUST 1988, VOL. 48, NO 2
racquet sports and running are discouraged. Controlling infections is a primary concern of all OR personnel during total ankle arthroplasty surgery. Several steps are taken at University Hospitals of Cleveland to avoid infections. These precautions include using a room with a glass enclosure and a vertical laminar airflow system. Both this “glass house” and surrounding outer room are closed to traffic, and inside and an outside circulating nurses are needed. A body exhaust ventilation system “space suit” is used by all OR personnel. When the patient is put on call to the operating room, the floor nurse preps the operative leg with a povidone-iodine paint. In the OR, the ankle is shaved then scrubbed and prepared with alcohol and povidone-iodine. This procedure is repeated before incision. The patient is given 1 g parenteral cephalosporin before the leg tourniquet is inflated. Instrument sets used are those for ankle or subtalar arthrodesis of the ankle. Special instruments, including the trial prostheses for the system, also are needed. Because total ankle arthroplasty is an uncommon procedure, the nurse needs to make a final check to ensure that an adequate number of implant prostheses are available and sterile before the start of the case. Other instruments that may be used, depending on the surgeon’s preference, are Hohmann and Bennett retractors, small and medium lamina spreaders, smooth Steinmann pins, straight and curved osteotomes,a power drill, and an oscillating saw. Methyl methacrylate and a pulsatile lavage irrigation system will be needed if the implants are to be cemented. This article describes the two surgical approaches that can be used to implant a total ankle prosthesis the anterior approach and the posterior approach.
Anterior Approach
T
he anterior approach is similar to that used for ankle arthrodesis. The patient is brought into the OR, put in the supine position on the OR bed, and a pneumatic tourniquet is applied to the operative thigh. The patient is then anesthetized, and the surgeon inflates the
AUGUST 1988, VOL. 48, NO 2
AORN JOURNAL
lateral
malleolus
i
i
I
Fig 4. Skin incision from the base of the second metatarsal to the crest of the tibia. tourniquet to approximately 100 mm of mercury higher than the patient’s systolic blood pressure. The surgeon makes a 15 cm incision from the base of the second metatarsal proximally to the crest of the tibia. The distance between the medial and lateral malleolus is the center point of the incision (Fig 4). The surgeon divides the skin and subcutaneous tissue to the deep fascia (Fig 5). Bleeding is controlled with electrocautery.
Fig 5. Incision to the deep fascia. Extensor retinaculum (I), superficial peroneal nerve (2).
The extensor retinaculum muscle is opened longitudinally. The surgeon identifies the extensor hallucislongus and reflects it medially;the extensor longus digitorum is reflected laterally. Sharp dissection is used to identify the capsule of the ankle joint. The surgeon then makes a periosteal dissection to identify the lateral and medial malleolus. Careful dissection is necessary to avoid injuring the deltoid
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Fig 7. Steinmann pins in place. 210
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and lateral collateral ligaments. After placing Bennett retractors beneath the periosteum of the medial malleolus and lateral malleolus (Fig 6), the surgeon inserts Steinmann pins parallel to the proposed cuts, approximately 2 cm proximal to the joint (Fig 7). X-rays are taken to confirm the position of the pins. Attention is then directed to the lateral malleolus. The surgeon makes a small longitudinal incision over the lateral malleolus at its tip and resects the tip distal to the origin of the fibular collateral ligament. This prevents lateral impingement of the fibula on the calcaneus. After reviewing the x-rays to determine where to make the cuts, the surgeon uses an oscillating saw and makes two parallel cuts in the bone oriented toward the Steinmann pins (Fig 8). Varus and valgus deformities of the hindfoot of greater than 20 degrees should not be corrected at the ankle joint. The surgeon then makes two parallel saw cuts through the dome of the talus. The cuts are made parallel to the longitudinal axis of talus so that the neck of the talus will not be cut (Fig 9). The tibia1 saw cut is usually made 7 mm above the articular surface; care is taken to protect the medial malleolus. After making the two parallel cuts and removing the bone, the surgeon sizes the cut using the appropriate spacing blocks. The largest prosthesis that will fit in the medial lateral plane is selected. There should be balanced, equal tension on the lateral and medial ligament complex, and 2 to 4 mm of overall laxity. After the tibia and the talus are prepared, trial components are put in place and the surgeon tests the ankle through a full range of motion. If the components are placed too far anteriorly, the implant will lack dorsiflexion. If the implant is placed too far posteriorly, there will be a relative lack of plantar flexion. If dorsiflexion or plantar flexion contracture remains, it can be corrected by additional bony cuts. When the range of motion tests are finished, the surgeon removes the trial components and thoroughly cleans the bone with a pulsating lavage. When cement fixation is used, the surgeon places the cement in the bony cavities and inserts the
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i medial
malleolus
\
Fig 8. Schematic view of bone cuts. 211
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oscillating saw cut
4
dome of the talus
L - \
\ \ --
body of tke talus
head neck
I
.y
\
Fig 9. Saw cut through the dome of the talus parallel to the longitudinal axis of the talus. tibila component first followed by the talar component. The foot is then brought up to the neutral position, and the cement is allowed to harden. If biologic fixation is used, the tibia1 component is placed first. The surgeon places a drain deep in the upper part of the wound and closes the superficial fascia with interrupted absorbable sutures. The skin and subcutaneous tissue are closed in a standard fashion. The ankle is placed in a neutral position (0 degrees valgus and varus flexion) in a wellpadded, soft dressing with a posterior splint.
Posterior Approach
W
hen compared to the anterior approach, the posterior approach produces less soft-tissue and wound complications, and it offers wider exposure of the implant. In addition, the center of the rotation of the implant arthroplasty can be better assessed from the posterior approach because the anatomy 212
of the posterior cortex of the tibia and calcaneus (0s calcis) is constant. For this surgery, the patient is placed in a prone position and draped. Positioning is especially crucial in patients with rheumatoid arthritis, and extra padding, pillows, or arm boards may be necessary to avoid complications. After the tourniquet is applied, the surgeon makes a medial zigzag incision starting 10 cm proximal to the medial malleolus and parallel to the medial border of the Achilles tendon (Fig 10). Skin and subcutaneous tissue are divided sharply, and bleeding points are controlled using bipolar electrocautery. The surgeon opens the crural fascia longitudinally (Fig 11). The plantaris tendon is identified and released from the insertion of the medial aspect of the calcaneus. Taking care to avoid the medial flexor group and neurovascular bundle, the surgeon dissects underneath this tendon subperiosteally around the medial malleolus. This preserves the medial flexor group (muscles and
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Fig 10. For the posterior approach, the surgeon makes a zigzag incision and two parallel incisions.
Fig IZ. Crural fascia opened longitudinally. Deep fascia (I), deep fascia over Achilles tendon (2).
tendons) and the neurovascular bundle. A Bennett retractor is placed medially around the malleolus. Approximately one eighth of the Achilles tendon can be taken down (making a vertical cut in the tendon and moving it aside) for better exposure. Subperiosteal dissection then is done laterally around the lateral malleolus exposing the entire ankle joint (Fig 12). The surgeon then inserts Steinmann pins parallel to the proposed level of cuts, approximately 2 cm proximal to the distal tibial articular surface (Fig 13). X-rays are taken of the joint. While awaiting the x-ray results, the surgeon makes a longitudinal incision directly over the lateral malleolus and resects the tip of the lateral malleolus distal to the origin of the fibular collateral ligament. To prevent lateral impinge-
ment, the orientation of the Steinmann pins to the long axis of the tibia is used to guide the angle of the tibial cuts. Removing too much talar bone can damage the talar neck, which can cause avascular necrosis or talar neck fractures. Preoperative varus or valgus deformities of the ankle of up to 20 degrees can be corrected by bony resection. After making the cuts, the surgeon sizes the cuts with the appropriate spacing blocks. Trial components are then used to assess the range of motion. If methyl methacrylate is used, the surgeon thoroughly cleans the bony surfaces using a pulsating lavage. Cement is then pressurized into bony surfaces and the components are cemented sequentially (tibial component first). Excess cement is removed.
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incision into fascia
Fig 12. Tibiotalar joint exposed. The foot is then brought up to a neutral position
as the cement is allowed to harden. When biologic fixation is used, the tibia1 component is placed first. The wound is then irrigated thoroughly, a drain is put in place, and the wound is closed in layers. A well-padded dressing is used with a posterior splint. The patient is then transferred to the postanesthesia care unit.
Postoperative Care
B
ecause the ankle with the arthroplasty should be elevated for three to four days after surgery, nurses need to limit the patient’s activity and keep the ankle higher than the patient’s heart. Suction drainage is continued until drainage ceases, usually in 24 to 48 hours.
After the soft tissue has healed, a short leg walking cast is applied. If the implant has been cemented, the patient may begin weight bearing as tolerated, and the cast is worn an additional three weeks. If biological fixation was used, six weeks of partial weight bearing with cast immobilization is required. Routine postoperative care for any total ankle arthroplasty patient includes deep breathing exercises using the incentive spirometer every hour while awake. The patient’s diet is advanced as tolerated and his or her bowel status is assessed in the early postoperative course to prevent constipation caused by immobility and narcotic analgesics. Isometric leg exercises are done every hour and an elastic support stocking is worn. Postoperative pain is controlled with intramuscular 215
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Bennett retractors
y
7
-!.
dome of talus
distal tibia
Fig 13. Steinmann pins in place.
or intravenous analgesics for several days and then oral analgesics as tolerated. The patient is discharged when the wound is healed and he or she is able to walk independently. Discharge teaching is frequently started preoperatively to identify potential problems with mechanical barriers at home. The nurse reviews written instructions for taking care of the cast with the patient. He or she also explains signs and symptoms of wound infection. The patient is told to alert the physician if he or she experiences a fever, night sweats or chills, or increasing pain in the ankle. For a cemented implant, the patient is seen in the outpatient clinic two to three weeks
postoperatively for cast removal. For a biologicfixed implant, the patient is seen at three weeks postoperatively for a cast change and at six weeks for cast removal. The patient progresses to full weight bearing, as tolerated, at 12 weeks. The patient is seen every three months for the first year, and x-rays are taken at each visit. The patient is then assessed yearly.
Summary
T
otal ankle arthroplasty is a demanding surgical procedure, but the advantages of maintaining motion in the tibiotalar joint in the patient with systemic arthritis are known. 217
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Although the technology of ankle implant arthroplasty is still evolving, current results in properly selected patients approach the results of other leg implants. 0 Suggested reading Bolton-Maggs, B G; Sudlow, R A; Freeman, M A. “Total ankle arthroplasty: A long-term review of the London Hospital experience.” Journal of Bone and Joint Surgery 67 (November 1985) 785-790. Samuelson, K M; Freeman, M A; Tuke, M A.
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“Development and evolution of the ICLH ankle replacement.”Foot and Ankle 3 (July-August 1982) 32-36. Stauffer, R N. “Salvage of painful total ankle arthroplasty.” Clinical Orthopaedics 170 (October 1982) 184-188. Stauffer, R N; Segal, N M. “Total ankle arthroplasty: Four years’ experience.” Clinical Orthopaedics 160 (October 1981) 217-221. Unger, A S; Inglis, A E. “Total ankle arthroplasty,” in Operative Orthopaedics. Philadelphia: J B Lippincott, 1988, 807-813.
Salt Sensitivity Worsens with Age Studies on salt loading and depletion proved that salt sensitivity becomes more severe as people age, according to an article on the American Heart Association meeting in Santa Fe, NM, in the May 9, 1988, issue of Medical World News. Tests were administered to more than 400 normotensive and 250 hypertensive people between the ages of 17 and 72. In the loading phase, the people received 2 L of 0.9% saline solution intravenously during a four-hour period. The depletion phase, which took place the following day, combined a sodium intake limited to 10 mEq and three doses of 40 mg of furosemide. Responses to sodium loading rose gradually with age among the hypertensives. Among the normotensives, an age-related increase appeared only in people older than 50. Hypertensives also had an increased drop in pressure following sodium and volume depletion. Increased sodium sensitivity with age was noted by exaggerated responses in people who were already salt sensitive. Results of the studies emphasize sodium chloride restriction as antihypertension therapy for older patients but do not endorse diuretics as primary therapy, according to the physician who developed and administered the tests. He also noted that diuretics are often an effective solo therapy when used on older hypertension patients, but stressed that diuretics can be dangerous in the elderly. They should be used cautiously, at low doses, and in combination with a
vasodilating antihypertensive drug, according to the article.
OR Product Directory Wins Gold Ink Award Publishing Technology Inc, Philadelphia, presented the 1988 Gold Ink Award to the AORN Journal’s OR Product Directory. The directory was one of more than 600 trade directories entered in the competition and was selected as the winner on the basis of its overall design, cover, typography, manufacturing quality, and printing quality. Jo Ann Sansen, AORN director of publications/business, believes the straightforward approach of the directory was one of the main reasons it won the award. “We wanted to reach O R nurses with a product directory that would relate only to what they needed,” she said. “We did not include a section on how to use the products, we just made it easy for nurses to find what they need.” The directory was distributed in December 1987 to AORN members, perioperative nurses who are not members of AORN, and purchasing agents in hospitals throughout the United States. A new edition of the directory will be mailed October 1, 1988.
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