Avascular Necrosis of Femoral Head

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Avascular necrosis (AVN) is a disease resulting from a temporary or permanent loss of blood supply to the bones. It generally aects people between the ages of 30 and 50 years of age. is disease is also known as osteonecrosis, aseptic necrosis and ischemic bone necro - sis. Avascular necrosis is the death of the bone marrow cells due to ischemia. In some cases, the bone will collapse. It aects the epiphy - sis of the long bones and is most commonly seen in the femur.

SYMPTOMS Avascular necrosis of the femoral head presents with groin pain that radiates down the anteromedial thigh. Some patients may demon - strate a limp and/or limited range of motion in !exion, abduction and internal rotation. Pain is sometimes induced by standing, walk - ing, moving or other mechanical stress. It’s usually relieved by rest.

CAUSES Avascular necrosis has several causes. Trauma is the most common cause of AVN. It can occur within eight hours a"er a traumatic inju - ry. Types of trauma associated or leading to AVN include:

฀ Fracture of the femoral neck ฀ Slipped capital femoral epiphysis ฀ Proximal femoral epiphysisiolysis ฀ Dislocated femoral head ฀ Epiphyseal compression ฀ Vascular trauma ฀ Radiation exposure ฀ Chronic renal failure

NOVEMBER 2006 The Surgical Technologist 11 275 NOVEMBER 2006 1 CE CREDIT

Articular cartilage

Proximal Epiphyseal line epiphysis

Spongy bone (containing red bone marrow)

Medullary cavity

Endosteum

Compact bone

Diaphysis Yellow bone marrow

Nutrient artery

Distal epiphysis SurgicalTechnology for the Surgical Technologist: APositive Care Approach. Reprintedfrom FIGURE !: Structure of long bones.

12 The Surgical Technologist NOVEMBER 2006 e two most common etiologies of atraumatic avascular necrosis are alcohol consumption Secondary Epiphyseal and long-term use of corticosteroids. Excessive ossification line Primary center alcohol consumption may have a toxic eect on ossification osteogenic cells. Alcohol intake increases the center risk of AVN more than 11 times, because alcohol Cartilage causes an increase in the amount of fat within only bones. e extra fat may squeeze the surround- Blood ing blood vessels, which causes reduction of vessel blood !ow to the bones. is eventually leads to the death of the bone. Corticosteroids, such as prednisone, are commonly used to manage diseases that cause in!am- mation, including lupus, rheumatoid arthritis and Marrow cavity irritable bowel disease. Possible side eects of long- Primary term use include osteoporosis and AVN. Supple- ossification ments of calcium and vitamin D may be prescribed Marrow to counteract these side eects. e estimated inci- cavity Blood vessels dence of necrosis among long-term users is 3–4 %. developing Secondary e use of long-term steroids is associated with ossification Epiphyseal 35% of all cases of atraumatic avascular necrosis. formation Corticosteroid-related avascular necrosis is more severe and more likely to affect both hips than Cartilage noncorticosteroid-related AVN. e use of alco- Calcified cartilage hol and corticosteroids can also lead to increased Periosteum levels of fat in the blood, called hyperlipidemia. Marrow cavity AVN is also a side eect of other conditions, Bone including Gaucher’s disease (a lipid storage dis- Blood vessel ease characterized by an accumulation of fatty material in the liver, spleen, kidneys, lungs, brain and bone marrow), pancreatitis, chemotherapy, FIGURE ": hemodialysis, and blood disorders, such as sickle be performed. e tests listed here can be used to Progression of bone cell anemia. determine the amount of bone aected, as well growth. as the progression of the disease. DIAGNOSIS ฀ X-ray (See Figure $.) A complete physical exam by a physician, includ- ฀ Magnetic resonance imaging (MRI) (See ing blood work, family history, history of alcohol Figure &.) and/or long-term steroid use, as well as AP and ฀ Bone scan (also known as scintigraphy) lateral X-rays of the aected bone, is the #rst step ฀ CT scan in identifying AVN. e necessary blood work should include a CBC with differential. This AVN is classi#ed by #ve stages through the use of test would identify any abnormalities, such as normal radiological clinical #ndings. is spe- inflammation, acute or chronic infection, and cific staging system was developed by Marvin autoimmune disease. A cholesterol work-up may Steinberg, *+, and remains the most comprehen- also be necessary to check on the amount of lip- sive and practical classi#cation system for AVN. ids in the blood. If the #lms show the presence of AVN, a series of additional imaging exams may

NOVEMBER 2006 The Surgical Technologist 13 FIGURE #: X-ray shows left hip with avascular necrosis.

Each stage identi#es and explains the pathologi- NONINVASIVE TREATMENT cal progress and the severity of the disease. During the early stages of AVN, a physician ฀ Stage : Cell death; undetectable by plain #lms may begin treatment by having patients limit ฀ Stage !: Cell modulation; characterized by the amount of weight they place on the affect- localized osteoporois ed joint. Limited activity or crutches will likely ฀ Stage ": Development of the margin of dead be recommended to slow the damage caused by bone; appears sclerotic AVN. Range-of-motion exercises may be done by ฀ Stage #: Margin increases; takes on a cres- a physical therapist or by the patients themselves. cent shape is can improve and maintain the joint’s range ฀ Stage $: Total destruction and possible col- of motion. e reduction of weight, together with lapse of the bone prescribed medications, can be an eective way to avoid or delay surgery for some patients.

14 The Surgical Technologist NOVEMBER 2006 FIGURE %: Magnetic resonance imaging shows AVN and collapse of left hip and arthritis in right hip.

When surgery is indicated, one of two pro- cedures is typically performed—either a core decompression or a total hip arthroplasty.

S U R G I C A L O P T I O N 1 $ CORE DECOMPRESSION The first and least invasive is a core decompression. During this procedure, a section of the dis- eased cancellous bone is removed from the fem- Photocourtesy of Synthes, USA. oral head. is relieves pressure from within the bone and increases blood !ow to the bone, possibly allowing new blood vessels to form. Core decompression is most successful during the early stages of the disease and prior to collapse of the joint. Instrumentation and supplies needed for a core decompression include: FIGURE &: ฀ Basic bone instruments Mayo stand set-up should include: Instrumentation. ฀ Orthopedic so" tissue set ฀ 89< blade ฀ Stryker® drill and battery ฀ Hemostat ฀ Synthes® DHS instrumentation (See Figure 6.) ฀ Small elevators (½–¾ in) ฀ Ioban™ drape ฀ One pair of small skin rakes ฀ Major basin (lap sponges, electrosurgical ฀ Curved Mayo scissors pencil, suction tubing, Yankauer suction, ฀ Guide pin (Synthes DHS set) 89< blade, bulb syringe) ฀ Lag drill (Synthes DHS set, drill depth set to <) ฀ Fracture table ฀ Lead gowns ฀ C-arm

NOVEMBER 2006 The Surgical Technologist 15 FIGURE ': ANESTHESIA AND POSITIONING Positioning on e patient is brought into the operating room, fracture table. and general or spinal anesthesia is administered. The patient is then placed on a fracture table with the aected leg placed in an ankle cu. A C- arm is then used to create an X-ray image of the aected hip. e C-arm is then locked in place to hold the proper position for additional X-rays. (See Figures 6, 7, and 8.) e patient is then prepped with either beta - dine scrub and paint or 4% chlorhexidene, depending on whether the patient is allergic to iodine. Once the preparation solution is dry, four sterile towels are used to determine the ster - FIGURE (: ile area. A large Ioban drape is used to drape the Positioning on patient. A time out is then done to verify the fracture table. patient’s name, surgery performed, correct site, and surgeon’s name. e date consent form is also checked to verify that the patient has signed it.

PROCEDURE A #10 blade is used to make a 3- to 5-inch, lateral incision. Hemostasis is achieved with the use of an electrosurgical pencil. Underlying tissue is incised with a #10 blade, followed by curved FIGURE ): Mayo scissors. A ½-inch periosteal elevator is used to expose the underlying bone. e femur Final position for is then exposed, and proper retraction is used. A core decompression. 2.5-mm guide pin is placed against the cortex of the femur, and the X-ray #lm is checked to deter - mine proper placement. e pin is placed on the drill, and the surgeon drills to the proper depth, according to the X- ray. Once the correct position is confirmed on X-ray, a reamer is used. e reamer is placed on the guide pin and is drilled down to the proper depth until the devascularised bone is reached. e drill is then reversed, and the bone is le" on the drill. e removed bone is submitted to pathology as a specimen. A #nal X-ray is taken as a hard #lm for the patient’s chart. e incision is irrigated, checked for hemostasis and closed. The fascia is closed with 0-Vicryl® suture, and 2-0 Vicryl is used to close the subcutaneous tis - sues. Either 4-0 Vicryl or staples are used to close the wound on the skin surface. The incision is then cleaned, and the dressing is applied.

16 The Surgical Technologist NOVEMBER 2006 FIGURE *: AP of pelvis pre-core decompression.

Drill tunnel Drill tunnel

FIGURE !+: FIGURE !!: After core After core decompression. decompression. Right hip. Left hip.

NOVEMBER 2006 The Surgical Technologist 17 SURGICAL OPTION 2$ at 60 degrees of flexion, and the landmarks are TOTAL HIP ARTHROPLASTY drawn with a sterile marking pen. An Ioban drape e second surgical option is a total hip arthro- is applied. This drape is an iodine-impregnated plasty, typically used in the last stage of AVN drape used to reduce the risk of infection. A time when the joint is destroyed. A total hip arthro - out is then done to verify the patient’s name, surgery plasty is also indicated for patients who are not performed, and correct location. e consent form good candidates for any other treatments. is then checked for the patient’s signature and date. Instruments and supplies needed for a total hip arthroplasty include: PROCEDURE ฀ Total hip pack (lap sponges, electrosurgical A #20 blade is used to make the skin incision. pencil, scratch pad, Ioban drapes, needle box, e surgeon begins the incision proximally at the 89osteotomy guide is used to aected hip, which is being held by the surgeon mark the area of the proposed osteotomy of the fem - with a stockinette. Sterile towels are then placed oral neck. e planned cut is marked with either an to de#ne the intended incision site. electrosurgical pencil or a sterile marking pen. A u-drape is applied over the towels, followed by e oscillating saw is used to cut the head o a large total hip extremity drape. e leg is placed the femur. e femoral head is measured with a

18 The Surgical Technologist NOVEMBER 2006 caliper, and the measurement is relayed to the surgeon. A self-retaining retractor or blunt Hohmann is used to retract tissue from the acetabular opening. e acetabulum is checked to ensure that any bony overgrowth or tissue is removed. A long, heavy hip curette is used to scrape any remaining cartilage from the acetabulum and expose the inner table. The patient’s position is veri#ed prior to reaming to ensure proper placement of the implant. e femur is retracted anteriorly to allow passage of the reamers. Acetabular reamers are used to remove cartilage and bone to the predetermined size. e smallest reamer is used first, followed by pro- gressively larger ones. Save any bone shavings in the event that a bone gra" is needed. Reaming is complete when there’s complete contact between the reamer and the acetabular rim. Bone shavings are used to #ll any voids in the acetabulum; then the last reamer used is reapplied and oper- ated in reverse to help compact the bone gra". An acetabulum trial is inserted and impacted with the proper degree of anteversion, using the patient’s shoulder as the reference. If it is not FIGURE !": a good fit, the next size trial shell will be used. any excess bone around the implant. Head and X-ray of patient’s left Once the #nal cup size has been established and neck components of the anticipated size are hip following total impacted, the larger or smaller acetabular liner is assembled and inserted into the femur. hip arthroplasty. inserted, according to the patient’s size. e hip is reduced and brought into !exion, To expose the proximal end of the femur, the extension, adduction, and internal and external patient’s foot is lowered toward the !oor, inter- rotation. e leg is measured to determine accu- nally rotating the hip. Two Bennett retractors racy of the size of the implants. e hip is then are used to stabilize the femur during prepara- dislocated, and the trial implants are removed. tion of the femoral canal. e wound is irrigated with either antibiotic irri- Any remaining soft tissue is removed from gation or plain saline. the distal femur, and a box osteotome is used to If cement is to be used, a cement restrictor provide a straight entry into the femoral canal. will be placed into the distal femoral canal to e intramedullary canal reamer is inserted to prevent the cement from migrating distally. e expose the opening, followed by the use of addi- necessary implants will be opened, assembled tional flexible reamers, the sizes of which are on the inserters and placed in a safe area until determined by the width of the canal. Reaming the time of insertion. e #nal acetabular cup is should stop once the cortex is reached. inserted into the acetabulum and impacted. Once the canal is opened, the smallest broach e femoral component is impacted into the fem- is inserted into the femur to enlarge the poste- oral canal either with or without the use of cement. rior entry point. Several broach sizes are used to If cement is used, notify the anesthesia provider determine the correct stem #t. Once the proper when the cement is inserted, because the patient stem is inserted, a calcar reamer is placed on the may experience a negative reaction to the cement. proximal end of the trial. is reamer removes Next, the femoral head is impacted onto the

NOVEMBER 2006 The Surgical Technologist 19 femoral stem. e hip is reduced slowly to pre- Avascular necrosis is a serious disease, but most vent fracture of the greater trochanter. Range- people with AVN can lead normal productive of-motion and stability are tested. e wound is lives with proper treatment and patient educa - irrigated, and hemostasis is veri#ed. e hip is tion. If caught during the early stages, treatment closed and dressed, and a hip adduction splint is may be as minimal as medication or as invasive as placed between the patient’s legs. Compression a total joint replacement. With today’s advanced stockings will be placed on the operative leg to diagnostic testing, patients are diagnosed earlier reduce the risk of deep vein thrombosis. and are taking steps to manage their health and lifestyle to minimize the eects of AVN. POST,OP OF A TOTAL HIP PROCEDURE RECOVERY ABOUT THE AUTHOR e patient is placed in his or her bed and trans- Robert Doheny, CST , has been a surgical technolo- ported to the postanesthesia care unit, where gist for seven years. He was trained on the job at vital signs will be monitored for approximately St Joseph Hospital, Clinton Township, Michigan, one and a half hours. Pain management tech - and graduated from Macomb County Community niques will be implemented. College in Clinton Township, Michigan, in 2002 Once the patient is released to the orthopedic with an Associate degree in surgical technology ward, rehabilitation will begin within two days. and general studies. He was certiﬁed in 2002 and e dressing is changed as needed, and the drain was the primary contributor to the orthopedic is removed on the #rst or second postoperative chapter in the fourth edition of Surgical Technol- day. e average hospital stay for this procedure ogy: Principles and Practice (Elsevier Saunders, is three to #ve days. 2005). He has been employed at William Beau- After being discharged, the patient may be mont Hospital in Troy, Michigan, since 2002. transferred to a rehabilitation facility for addi - tional physical therapy. Once the patient is Acknowledgments mobile, he or she may be sent home. Regular out - I would like to thank my family for their patience and support patient physical therapy visits will continue until during writing and furthering my education. Also a special thank you to Donald Knapke, *+, Laurence Ulrey, *+, Marty full range of motion and strength are achieved. Gross, *+, for the X-rays in this article. Additional thanks to the following orthopedic surgeons at William Beaumont Hos - POSSIBLE COMPLICATIONS pital, Troy, Michigan, for their knowledge, great teaching skills As with any surgical intervention, complications and advanced use of technology in surgery: Charles Stroud, may occur. e following is a list of potential com - *+, Melissa Mozdzen, \]-^, John Schmpike *+, Russel Miller, plications associated with total hip arthroplasty: *+, Christopher Nicholas, *+., and Matthew Kopera, *+. ฀ Deep vein thrombosis ฀ Infection References 1. Bently G, Duthie RB. Mercer’s Orthopaedic Surgery, 9th ฀ Death ed. Oxford, England: Oxford University Press; 1996. ฀ Dislocation of the prosthesis 2. Epps Jr CH. Complications in Orthopaedic Surgery. ฀ Loosening of the prosthesis Philadelphia, Pa: Lippincott Williams & Wilkins;1994. ฀ Femur fracture 3. Fuller JK. Surgical Technology: Principles and Practice, ฀ Change in leg length 4th ed. Philadelphia, Pa: Elsevier Saunders; 2005. 4. Hoppenfeld S, deBoer P. Surgical Exposures in Ortho- ฀ Bleeding paedics, !e Anatomical Approach, 3rd ed. Philadel- ฀ Nerve injury phia, Pa: Lippencott, Williams & Wilkins; 2003. ฀ Pain and stiness 5. Canale ST. Campbell’s Operative Orthopaedics. Vol 1–4, ฀ Anesthesia complications 10th ed. Philadelphia, Pa: Mosby; 2003. ฀ Allergy to metal implants, medications, tape Synthes® is a registered tradmark of Synthes, Inc. Stryker® ฀ Skin rashes is a registered trademark of Stryker Corp. Ioban™ and ฀ Reactions to blood transfusions Coban™ are trademarks of 3M Corp.

20 The Surgical Technologist NOVEMBER 2006 1. Which supplements are used to coun- 6. Which of the following is not true CE ExamExam teract the e!ects of corticosteroids on about core decompressions? 275 NOVEMBER 2006 1 CE CREDIT the bones? a. Increase blood "ow to the bone a. Iron b. Decrease pressure in the bone to stimu - b. Potassium late bone growth c. Vitamin D c. Performed in the early stages of the disease d. Chondroitin d. Increase and improve range of motion

2. AVN is best diagnosed by... 7. Avascular necrosis a!ects what percent- a. MRI age of long-term corticosteroid users? Avascular b. Complete blood cell count a. 20 c. 35 c. Physical exam b. 25 d. 50 necrosis d. Ultrasound 8. Which of the following is not associ - Earn CE credits at home 3. Steinberg’s Stages identify ... ated with AVN of the femoral head? You will be awarded continuing education (CE) credit(s) for a. Osteoblasts formation a. Overexposure of radiation recerti!cation after reading the designated article and com - b. Arthritis b. Dislocation of the femoral head pleting the exam with a score of 70% or better. c. Proper treatment c. Femoral neck fracture If you are a current AST member and are certi!ed, credit d. Pathological progress d. Distal femoral epiphysisiolysis earned through completion of the CE exam will automatically be recorded in your !le—you do not have to submit a CE report - 4. Total hip arthroplasty is indicated in 9. When should physical therapy start ing form. A printout of all the CE credits you have earned, includ - which stage of AVN? after a total hip arthroplasty? ing Journal CE credits, will be mailed to you in the !rst quarter a . 2 a. 48 hrs after surgery following the end of the calendar year. You may check the status b. 5 b. When patient goes home of your CE record with AST at any time. c. 4 c. When patient is transferred to rehabilita - If you are not an AST member or are not certi!ed, you will be d. 3 tion center noti!ed by mail when Journal credits are submitted, but your d. 24 hrs after surgery credits will not be recorded in AST’s !les. 5. Alcohol in the blood causes lipids Detach or photocopy the answer block, include your check or within the bones to ... 10. Which of the following is true about money order made payable to AST, and send it to the Accounting a. Increase avascular necrosis? Department, AST, 6 West Dry Creek Circle, Suite 200, Littleton, CO b. Decrease a. Limits a patient’s physical activity 80120-8031. c. Neutralize b. A#ects people 30-50 years old d. Stabilize c. Causes ischemia in the cancellous bone Members: $6 per CE, nonmembers: $10 per CE d. All of the above

275 NOVEMBER 2006 1 CE CREDIT

Avascular necrosis a b c d a b c d

Certi!ed Member Certi!ed Nonmember 1 6

Certi!cation No. ______2 7

Name ______3 8

Address ______4 9

City ______State ______ZIP______5 10

Telephone ______Mark one box next to each number. Only one correct or best answer can be selected for each question. NOVEMBER 2006 The Surgical Technologist 21