RECONSTRUCTION 2023, Jan, 26 | 12:00 am

Head-Sparing Procedures for Osteonecrosis of the Femoral Head

 

Head-Sparing Procedures for Osteonecrosis of the Femoral Head

 

INDICATIONS/CONTRAINDICATIONS

Osteonecrosis of the femoral head is a disease process that results in impaired blood flow to the hip, which ultimately results in bone cell death. Although various joints, including the shoulder, knee, and ankle, are often involved, the hip is most commonly affected.

More specifically, the anterolateral portion of the femoral head has been reported to be the region that is most susceptible (1). This disease process has been found to most commonly affect patients who are in their third, fourth, and fifth decades of life (1). Despite the extensive studies reported in the literature, the exact etiology and pathophysiology remain largely unknown. Osteonecrosis of the femoral head can be broadly subdivided into traumatic and atraumatic causes. Traumatic avascular necrosis is usually the result of a hip dislocation (2) or a displaced femoral neck fracture (3). Nontraumatic causes can be divided into idiopathic osteonecrosis and cases associated with known risk factors. Idiopathic osteonecrosis has no identifiable cause, but may likely be associated with unidentified genetic predispositions to microthromboses (4). Well-documented risk factors associated with osteonecrosis include corticosteroid use (5,6), excessive alcohol intake (7), and certain hemoglobinopathies including sickle cell disease and thalassemia (8). Though the amount of corticosteroid (5,6) and alcohol (7) required to cause impaired vascularity to the femoral head is controversial, multiple studies have shown that there is a dose-dependent increase in the risk of developing osteonecrosis. Several other risk factors that have also been associated with this disease are listed in Table 8-1. However, the majority of patients who have known risk factors usually do not go on to develop osteonecrosis.

Because many patients who have this condition are young and desire to return to high activity levels, the goal of treatment is early diagnosis with prevention of femoral head collapse and preservation of a congruent femoral head. Several classification schemes have been developed to stage the disease process and determine prognosis as well as to aid in the decision-making process in choosing which treatment option is most appropriate. Commonly used staging systems include that of the University of Pennsylvania (9), the Japanese Investigation Committee on Osteonecrosis (10), the Association Research Circulation Osseous Classification (ARCO)(11), and the Ficat and Arlet (see Table 8-2) (12,13).

At our institution, we primarily use the Ficat and Arlet staging system, which is based on a standard roentgenographic evaluation. The modification made by Steinberg et al. (9) is also used to quantify the size of the lesion. Ficat and Arlet stages I and II can be grouped into precollapse, or early, lesions. Ficat and Arlet stages III and IV are considered postcollapse lesions. Steinberg et al. (9) subdivided lesion size into mild (less than 15% involvement of the femoral head), moderate

 

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(15% to 30% involvement of the femoral head), and severe (greater than 30% involvement of the femoral head). Though there is no consensus, treatment options and algorithms are largely based on whether the femoral head is in a precollapse or postcollapse stage at the time of presentation. Other factors to consider when deciding whether to perform a head-preserving procedure versus an arthroplasty include patient age and activity level, acetabular involvement, lesion size and location (14), and associated patient risk factors (15). In those with precollapse and early postcollapse lesions, treatment strategies are aimed at preserving a congruent femoral head and delaying and/or avoiding collapse and subsequent arthroplasty. Femoral head-preserving procedures include core decompression, nonvascularized bone grafting, and vascularized bone grafting. On rare occasions, proximal femoral osteotomies may be considered to rotate an uninvolved portion of the femoral head into the weight-bearing portion of the articular surface. This technique will be described in Chapter 9, Periacetabular Osteotomy and Proximal Femoral Osteotomy.

 

 

TABLE 8-1 Direct and Indirect Risk Factors for Osteonecrosis of the Hip

 

 

Direct risk factors Trauma—fracture, dislocation Sickle cell disease

Human immunodeficiency virus infection Chemotherapy

Radiation

Indirect risk factors Corticosteroids Alcohol abuse

 

Tobacco use

Systemic lupus erythematosus Myeloproliferative disorders Gaucher disease

Organ transplant Renal failure

Coagulation abnormalities Pregnancy

Genetic factors

 

 

 

 

TABLE 8-2 Commonly Used Staging Systems for Osteonecrosis of the Hip

 

Association Research Japanese Circulation Osseous Orthopaedic

Ficat and Arlet University of Pennsylvania (ARCO) Association

Stage

Findings

Stage

Findings

Stage

Findings

Stage

Findings

I

Normal x-ray

0

Normal hip

0

Normal hip

1

Demarcation

 

 

 

 

 

 

 

line

II a

Diffuse cystic/sclerotic

I

MRI findings only

1

MRI findings

2

Early

 

lesions

 

 

 

only

 

femoral

 

 

 

 

 

 

 

head

 

 

 

 

 

 

 

flattening

II b

Crescent sign (subchondral

II

Diffuse

2

Focal

3

Cystic

 

fracture)

 

cystic/sclerotic

 

osteoporosis,

 

lesions

 

 

 

lesions

 

cystic lesions,

 

 

 

 

 

 

 

sclerosis

 

 

III

Presence of sequestrum in

III

Subchondral step-

3

Crescent sign

 

 

 

radiograph; femoral head

 

off

 

(subchondral

 

 

 

collapse,

 

 

 

fracture)

 

 

IV

Loss of articular cartilage

IV

Femoral head

4

Acetabular

 

 

 

and osteoarthritis with a

 

flattening

 

involvement

 

 

 

deformed femoral head

 

 

 

 

 

 

 

 

V

Acetabular

 

 

 

 

 

 

 

involvement or

 

 

 

 

 

 

 

joint space

 

 

 

 

 

 

 

narrowing

 

 

 

 

 

 

VI

Advanced joint

 

 

 

 

 

 

 

degeneration

 

 

 

 

 

 

There are several factors that are considered relative contraindications to performing a femoral head-preserving procedure including evidence of more than minimal collapse (greater than 2 mm), the presence of acetabular involvement, and the location and size of the lesion. Patients who have postcollapse (Ficat and Arlet stages III/IV) lesions generally have substantially worse results when compared to those performed in a precollapse state. Lateral-based lesions in the femoral head as well as lesions involving greater than 30% of the femoral head have shown poorer results when

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compared to medial-based lesions and those involving less than 30% of the femoral head. Thus, the low likelihood of success within this subset of large-sized lesion patients may be considered by some to be a contraindication to performing a femoral head-preserving procedure. The quality of the articular cartilage on the acetabulum must also be considered when attempting head-preserving procedures as those with substantial degenerative changes on the acetabular side may be best treated with a total hip arthroplasty. If

marked involvement of the weight-bearing portion of the femoral head is involved, many authors may opt for a total hip arthroplasty. Similarly, femoral head depression of greater than 2 mm has been considered an indication for arthroplasty surgery.

Other relative contraindications include patients who are unable to comply with postoperative precautions and instructions, those who are unable to control their risk factors (i.e., continued excessive corticosteroid intake, alcohol abuse, untreated thalassemias), and those who are medically unable to tolerate multiple anesthetics because many of these patients may require several procedures over the course of treating their lesion.

The aforementioned femoral head-preserving procedures have been performed with mixed results for both precollapse and postcollapse lesions. As such, no consensus currently exists as to which head-preserving procedure is superior. Treatment should be tailored to the individual patient taking into account not only the characteristics of the osteonecrotic lesion but also patient-related factors and surgeon familiarity with the procedure.

Core Decompression

 

Indications

 

Precollapse lesions (Ficat and Arlet stages I and II)

 

 

Small- to medium-sized lesions (30% head involvement or less or Kerboul angle less than 200 degrees) Postcollapse lesions in patients who are unable to tolerate a more extensive femoral head-preserving procedure

 

Contraindications

 

 

Postcollapse lesions (Ficat and Arlet stages III and IV) Femoral head depression greater than 2 mm

 

 

Large-sized lesions involving greater than 30% femoral head Acetabular involvement

 

Patients who are unable to comply with postoperative weight-bearing restrictions

Preoperative Preparation Every patient must be treated on an individual basis with age, activity level, and medical comorbidities and risk factors taken into consideration. Deep groin pain is the most common presenting symptom. Appropriate diagnostic imaging including plain radiographs, magnetic resonance imaging, and on rare occasion CT scans (to assess for collapse) should be available both preoperatively and intraoperatively for accurate location of the lesion. Because osteonecrosis of the femoral head is often first diagnosed by the orthopedic surgeon, the possibility of an occult contralateral femoral head lesion must be evaluated as there is a 50% to 80% chance of involvement (1,16,17). If the patient is also complaining of other arthralgias, namely, at the knee, the surgeon should have a high index of suspicion for further osteonecrotic lesions. This is especially true for those with risk factors for the development of femoral head osteonecrosis (e.g., corticosteroid use, alcohol abuse). If other areas are found to be affected, the possibility of performing preservation procedures (e.g., core decompression) of multiple sites under the same anesthetic setting may be considered and discussed with the patient.

 

Technique The rationale behind the use of core decompression is to reduce excessive intraosseous pressure within the femoral head. Traditional core decompressions use 8- to 10-mm trephines and/or cannulas (Fig. 8-1) and are often combined with nonvascularized cortical strut grafting (Phemister technique) or vascularized grafts with encouraging results. Grafts are either cortical or cancellous bone and can be from an autogenous or allogeneic source. This technique not only relieves the intraosseous pressure from the core decompression but can remove necrotic bone (Fig. 8-2), provide additional structural support to prevent collapse, as well as provide both osteoconductive and osteoinductive media depending on what type of graft is used (Video 8-1). At our institution, we use a variation of a core decompression using a percutaneous technique with a 1/8-inch Steinmann pin with either a single pass or multiple passes depending on the size of the lesion as determined by plain radiographs and/or magnetic resonance imaging. Small-sized lesions are treated with 1 to 2 passes, while large-sized lesions are treated with 2 to 3 passes (Video 8-2). We do not routinely incorporate cortical or cancellous strut grafting during the core compression.

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FIGURE 8-1 Illustration of 8- to 10-mm trephine inserted into the necrotic osteonecrosis lesion of the femoral head.

 

 

 

FIGURE 8-2 Illustration of proximal femur with core decompression biopsy removed.

In the operating room, the patient is placed in a supine position on a radiolucent table or a fracture table. Preoperative prophylactic antibiotics are routinely given. We have found that this procedure can be done under sedation without the need for general anesthesia. Once the patient is adequately sedated, the fluoroscopy unit is brought into the field prior to prepping and draping the extremity to ensure adequate imaging of the involved hip in both the anteroposterior (AP) and frog-leg orthogonal views.

 

Once adequate images free of metal artifact can be obtained, the hip is prepped and draped in the usual aseptic manner. The extremity is slightly internally rotated by an assistant to neutralize the natural anteversion of the femoral neck while performing the procedure. The proper starting point is immediately inferior to the lateral cortical flare at the metaphyseal-diaphyseal junction in the center of the proximal femur. The 1/8-inch Steinman pin is then inserted percutaneously at the predetermined level. Care must be taken not to create a starting point below the level of the lesser trochanter in order to minimize the risk of creating a stress riser and potential future subtrochanteric femur fracture. The pin is then advanced to the level of the proximal femoral neck under fluoroscopic guidance towards the lesion as previously determined from imaging studies. There is a risk of thermal skin necrosis from the Steinman pin, and as such, we prefer to use saline-soaked 4 × 4

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gauze around the skin-pin junction during all drilling maneuvers. The position and trajectory of the pin is now assessed in the AP and frog-leg lateral planes by removing the drill from the pin and having an assistant maneuver the leg into the appropriate position. If the trajectory is acceptable, the leg is brought back into the starting position and the pin advanced through the femoral neck towards the lesion. If unacceptable, the pin is backed out and redirected ensuring that the same starting hole is used to avoid creating another stress riser. The pin is then advanced to the appropriate depth in the subchondral bone taking care not to penetrate through the articular surface into the joint. While drilling through the lesion, it is common for areas of sclerosis to be encountered. The surgeon must avoid the urge to use larger amounts of force when attempting to drill through these lesions as the risk of plunging through the femoral head into the hip joint is increased. Larger-sized lesions may be treated with 2 to 3 passes of the Steinman pin using the same technique and starting hole (Fig. 8-3). Once adequate decompression is obtained, the pin is backed out while holding a saline-soaked 4 × 4 gauze around the pin-skin junction. Direct pressure is held at the skin entry

 

site until adequate

 

hemostasis is achieved. A simple suture using absorbable monofilament may be required although a Band-Aid is usually sufficient.

 

 

 

FIGURE 8-3 Anteroposterior and lateral radiographic demonstration of first and second pass of percutaneous drilling core decompression.

 

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Pearls and Pitfalls

 

Care must be taken to create a starting point above the level of the lesser trochanter in order to avoid creating a stress riser and potential for future subtrochanteric femur fracture.

 

There is a risk of skin-edge necrosis when drilling the Steinman pin in a percutaneous fashion. This risk can be minimized by keeping a saline-soaked 4 × 4 gauze sponge at the skin-pin junction during all drilling maneuvers.

 

When adjusting the trajectory of the pin, the same entry hole should be used as creation of a new pilot hole adjacent to the original hole can create a new stress riser.

 

Exercise caution when drilling through osteonecrotic lesions as areas of hard bone are commonly encountered. The surgeon must resist the urge to push harder and risk plunging through the femoral head into the hip joint.

Postoperative Management Patients are discharged home the same day and placed on 50% partial weight-bearing precautions with crutches for 6 weeks. We do not routinely prescribe deep venous thrombosis (DVT) prophylaxis other than early mobilization. Patients are scheduled to return to the office for a follow-up appointment at 6 weeks, 12 weeks, 6 months, 12 months, and then yearly thereafter. Plain radiographs of the involved hip are obtained at each office visit to ensure no collapse of the femoral head. After 6 weeks, the patient's weight-bearing status is progressed to full weight bearing, and crutches are discontinued. Patients are instructed to perform simple hip strengthening exercises with special focus on the abductors. We instruct patients to avoid high-impact activities for the first year.

Complications

 

Subtrochanteric stress riser leading to proximal femur fracture from multiple entry holes or entry point made at or below the level of the lesser trochanter.

 

 

Pin penetration of femoral head into hip joint with overzealous drilling. Skin-edge thermal necrosis.

 

Iatrogenic weakening of the femoral head and neck may be created if using large-diameter tre-phines/cannulas or by the creation of multiple pin tracts.

Results Though this procedure has been used in the past to treat Ficat and Arlet stage I, II, and III lesions, results of this technique have been shown to be less successful when there is evidence of femoral head collapse (Ficat and Arlet stages III and IV). Similarly, large-sized lesions, defined as areas involving greater than 50%, have also been shown to have lower success rates when compared to small- and medium-sized lesions (less than 50%). In a literature review by Mont et al. (18) involving over 2,000 hips, satisfactory results were seen in 63.5% of hips treated with core decompression compared to 22.7% treated nonoperatively. Femoral head survival rates were found to be higher in those with Ficat and Arlet stage I lesions (84%, 190 of 227) compared with stage II (65%, 155 of 239 hips) and III (47%, 40 of 86 hips) lesions. Similarly, Mont et al. (19) reported that there was a 71% (32 of 45 hips) success rate in patients who had Ficat and Arlet stage I and II femoral head lesions using a multiple drilling technique at a mean follow-up of 2 years (range, 20 to 39 months). In this prospective study, 80% (24 of 30 hips) of patients who had Ficat and Arlet stage I were found to have had a postoperative Harris hip score greater than 80 points compared with only 57% (8 of 15 hips) in those with Ficat and Arlet stage II. The authors concluded that core decompression using a multiple drilling technique can serve as a low-morbidity treatment option in early-stage femoral head osteonecrosis.

Similarly, Lieberman et al. (20) reported the advantages of core decompression in combination with fibula allograft and human bone morphogenetic protein in a study of 17 hips (15 patients) with early-stage osteonecrosis. At a minimum follow-up of 53 months (range; 26 to 94 months), 17% (3 of 17) of the hips undergoing core decompression went on to develop femoral head collapse and subsequent THA.

 

The overall results of core decompression with or without cortical strut grafting have been mixed and vary by technique as well as stage of lesion. We believe that core decompression is a low-morbidity treatment option with a success rate of approximately 70% in precollapse and small- to medium-sized lesions (Ficat and Arlet stages I and II). In addition, core decompression does not preclude the use of other more invasive head-preserving procedures if femoral head collapse subsequently occurs. See Tables 8-3 and 8-4 for more comprehensive list of study outcome on core decompression performed through traditional percutaneous techniques.

 

 

 

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TABLE 8-3 Outcomes of Traditional Core Decompression

 

Hips Survivorship (%)

Mean Follow-

 

Author

Level of

Stage

Stage

Stage

Stage

Age

up

Stage

Stage

Stage

Stage

 

(Year)

Evidence

1

2a

2b

3

(years)

(years)

1

2a

2b

3

 

Al Omran et al. (21)

(2013)

III

13

25

23

—

26

6.1

100

80

52

—

 

Lieberman et al. (22)

(2004)

IV

—

15

1

1

47

4.4

—

93

0

0

 

Aigner et al. (23)

(2002)

IV

30

9

—

6

41

5.7

97

44

—

33

 

Steinberg et al. (24)

(2001)

III

65

45*

—

13

37

48

72

66*

—

77

 

 

Lavernia

IV

15

30*

—

22

40.2

3.4

100

83*

—

44

 

 

 

et al. (25)

(2000)

 

Maniwa et al. (26)

(2000)

IV

10

16*

—

—

46

7.8

100

56.4*

—

—

 

Bozic et al. (27)

(1999)

IV

12

12

2

0

38

10

92

52

20

0

 

Iorio et al.

(28)

IV

7

20

6

-

41

5

71

45

33

-

 

(1998)

 

 

 

 

 

 

 

 

 

 

 

 

Powell et al. (29)

(1997)

IV

18

8*

—

—

35

4

80

37*

—

—

 

Markel et al. (30)

(1996)

IV

10

32

7

4

38

4

45

38

14

25

 

Fairbank et al. (28)

(1995)

IV

25

51

—

52

40

11

88

72

—

26

 

Saito et al. (31)

(1988)

III

17

—

—

—

33

4

100

—

—

—

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Author (Year)

 

Level of Evidence

 

Stage 1

Hips

 

Stage Stage

2a 2b

 

Stage 3

 

Mean age (years)

 

Followup (years)

Survivorship (%)

Stage 1

Stage 2a

Stage 2b

Stage 3

Al

III

6

14

13

—

26

6.1

100

78

53.8

—

Omran

 

 

 

 

 

 

 

 

 

 

 

et al.

 

 

 

 

 

 

 

 

 

 

 

(21)

 

 

 

 

 

 

 

 

 

 

 

(2013)

 

 

 

 

 

 

 

 

 

 

 

Song

IV

39

64

17

43

36.1

7.2

80

77

77

35

et al.

 

 

 

 

 

 

 

 

 

 

 

(28)

 

 

 

 

 

 

 

 

 

 

 

(2007)

 

 

 

 

 

 

 

 

 

 

 

Mont

IV

30

15*

—

—

42

2

80

57*

—

—

et al.

 

 

 

 

 

 

 

 

 

 

 

(19)

 

 

 

 

 

 

 

 

 

 

 

(2004)

 

 

 

 

 

 

 

 

 

 

 

*Stage 2 hips.

 

 

TABLE 8-4 Outcomes of Studies of Core Decompression with Multiple Drilling Technique

 

 

Nonvascularized Bone Grafting: The Trapdoor and Lightbulb Procedure

Indications Nonvascularized bone grafting can be performed in three distinct forms: cortical strut grafting through a tract in the femoral head and neck, bone grafting of the femoral head through an entry site in the articular cartilage (the “trapdoor” procedure), or bone grafting of the femoral head through the femoral head-neck junction (the “lightbulb” procedure). Indications for nonvascularized bone grafting include:

 

 

Precollapse lesions of the femoral head (Ficat and Arlet stages I and II) and early postcollapse lesions (Ficat and Arlet stage III) Young, active patients

 

 

Previously failed core decompression

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Contraindications

 

 

 

Advanced stage osteonecrosis (Ficat and Arlet stage IV) Delaminated cartilage on femoral head determined intraoperatively No viable bone noted intraoperatively below lesion

 

Acetabular involvement

 

Articular depression greater than 2 mm

 

Patients who are unable to comply with postoperative precautions/protocols

 

 

Large-sized lesions as determined by percentage of head involvement and/or Kerboul (32) angle Patients who are unable to tolerate the surgical procedure

 

Patients with nonmodifiable risk factors (i.e., patients who are required to stay on a prolonged course of corticosteroids for medical reasons)

Preoperative Preparation The size and location of the necrotic lesion must be accurately defined preoperatively with plain radiography and/or other advanced imaging modalities (MRI, CT scan). A diagnostic hip arthroscopy may be performed immediately prior to the procedure for definitive evaluation of the articular surfaces of the femoral head and acetabulum. A thorough preoperative discussion should be conducted with the patient and his/her family regarding the possibility of performing a total hip arthroplasty should any contraindications be discovered intraoperatively. Arrangements should be made with all operating room personnel and the implant manufacturer representative to have all the proper equipment and implants.

 

Technique

Exposure [Anterolateral Approach] The patient is placed in the lateral decubitus position on the operating room table with the affected side up. We prefer to use padded hip positioners placed anteriorly on the anterior superior iliac spine (ASIS) and posteriorly over the sacrum. The hip positioners are secured so that the patient's pelvis is perpendicular to the floor. Obese patients will require their pannus to be held superiorly out of the way by an assistant so that the anterior positioner can be in contact with the ASIS. Once the hip positioners are in proper position, the operative hip is flexed up to ensure at least 90 degrees of hip flexion can be obtained to facilitate adequate exposure and possible dislocation. All bony prominences of the contralateral leg including the lateral malleolus and fibular head are well padded and placed in slight flexion. We prefer to place a venous compression device on the contralateral leg at the start of the procedure. This device is kept on throughout the duration of the procedure. The leg is then hung on a candy cane leg holder and prepped and draped in the usual sterile fashion.

Anatomic landmarks are marked out prior to the skin incision including the ASIS, greater trochanter, and anterior and posterior borders of the proximal femur. An approximately 10-cm straight lateral skin incision centered over the greater trochanter in line with the femoral diaphysis is made with a No. 10 scalpel. Subcutaneous dissection is taken down to the level of the fascia lata. This is facilitated with the use of a Cobb elevator. The anterior and posterior borders of the greater trochanter are palpated through the fascia lata, and a 1-cm longitudinal incision is made with a fresh No. 10 scalpel. The fascia lata incision is then extended both proximally and distally for the extent of the skin incision with a pair of curved Mayo scissors. Once the anterior and posterior gutters are adequately cleared of bursal tissue, a blunt Hohmann retractor is placed posterior to the greater trochanter. Be careful not to pass this retractor too deep into the wound as the sciatic nerve lies in close proximity and can be injured. A blunt Hohmann retractor is then placed along the medial femoral neck at the junction of the anterior aspect of the gluteus medius and vastus lateralis muscle to define the anterior extent of the abductor complex. A right-angle Meyerding retractor is used to retract the fascia lata anterosuperiorly to help further identify the abductor mass. Using electrocautery, the proximal limb of the abductor sleeve is made by incising the anterior 40% of the gluteus medius muscle in line with its fibers to the level of the greater trochanter. The distal limb of the sleeve is then made through the tendinous portion of the gluteus medius muscle along its tendinous attachment on the greater trochanter. The incision must be made through the tendinous portion to ensure an adequate cuff of tissue for later repair at the end of the procedure. The gluteus medius and

minimus complex is then peeled off the anterior hip capsule to the level of the anterior acetabulum. A right-angle Meyerding retractor can be used by an assistant to aid in “peeling” the abductor sleeve anteriorly. A Hohmann retractor is then placed along the superior and inferior aspects of the femoral neck. A Cobb elevator can be used to peel off the reflected head of the rectus femoris muscle to further expose the anterior hip capsule medially.

 

Once the anterior hip capsule is adequately exposed, an anterior capsulectomy is performed in line with the femoral neck to create superior and inferior flaps. Care must be taken not to compromise the integrity of the labrum. The anterior femoral neck and head-neck junction is now clearly exposed. The majority of the femoral head can now be inspected with gentle longitudinal traction and rotation of the limb from an assistant. The presence of articular surface or subchondral collapse

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is evaluated with direct visualization and gentle palpation. The presence of acetabular cartilage damage as well as femoral head

depression greater than 2 mm or femoral head cartilage flap serve as contraindications to this procedure. In this case, a resurfacing or

total hip arthroplasty can be performed. In rare cases where suspected areas of the femoral head are not able to be adequately evaluated with longitudinal traction and rotation, dislocation may be necessary. This is performed by the assistant on the anterior side of the patient through a combination of gentle traction, adduction, and external rotation.

LIGHTBULB PROCEDURE Once the femoral head is deemed appropriate for this procedure, an approximately 2- × 2-cm cortical window is marked at the femoral head-neck junction with either electrocautery or methylene blue (Fig. 8-4). The cortical window is created using a microsagittal saw. The edges of the window are created in a beveled fashion to aid in later repair. Once the borders of the cortical window are made, a ¼-inch osteotome is used at the corners to complete the osteotomy and prevent propagation of the cut borders. The cortical window is then elevated and placed in a saline-soaked gauze pad for later reattachment.

 

Using a combination of curved curettes and a 6-mm round-tipped burr, the necrotic segment of bone is debrided and excavated from the femoral head (Fig. 8-5). Inadvertent penetration of the

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femoral head with the burr or curette must be avoided. If this occurs, abandonment of this procedure with a conversion to a total hip arthroplasty should be considered. To assess the adequacy of debridement, an arthroscope can be placed through the cortical window and the area directly visualized on a monitor. Once the necrotic segment has been adequately debrided, the defect is filled and packed using autogenic or allogenic cortical bone graft, cancellous bone graft, or a combination with a bone tamp and mallet (Fig. 8-6).

Several commercially available bone graft substitutes can also be used alone or in combination with the aforementioned options. At our institution, we prefer to use a bone morphogenetic protein-enhanced allograft.

 

 

 

FIGURE 8-4 Illustrated image of 2 × 2 cortical window being made in the femoral head-neck junction.

 

 

FIGURE 8-5 Illustrated image of a burr removing the osteonecrotic lesion in the femoral head through the femoral headneck junction entry point.

After the femoral head is filled and packed, the cortical window fragment is removed from the saline-soaked gauze and placed back into the defect and gently impacted back into place with a bone tamp and mallet. The fragment is then secured with two to three 2-mm bioabsorbable pins. The pins are placed in a diverging orientation to maximize fixation strength. The ends of the pins are then welded in place with electrocautery (Video 8-3). The wound is copiously irrigated with normal saline.

TRAPDOOR PROCEDURE The exposure for the trapdoor procedure is identical to the lightbulb procedure described above. In this procedure, the femoral head is dislocated anteriorly by an assistant through gentle longitudinal traction, adduction, and external rotation. The femoral head and acetabulum are thoroughly inspected. Once the joint is deemed appropriate for the procedure and the lesion identified, an approximately 2- × 2-cm (or approximately 10% to 30% of the femoral head) osteochondral window is made over the involved area on the femoral head with the use of a No. 15 scalpel and ¼-inch osteotome. The osteochondral flap is hinged back on its base for later repair (Fig. 8-7). Using a combination of curved curettes and a 6-mm round-tipped burr, the necrotic segment of the bone is debrided until a bleeding bed of viable bone is encountered (Fig. 8-8). If no bleeding bone is encountered after extensive debridement, abandonment of this procedure with conversion to resurfacing versus total hip arthroplasty should be considered. As with the lightbulb procedure, once the necrotic segment has been adequately debrided, the defect is filled and packed using autogenic or allogenic cortical bone graft, cancellous bone graft, or a combination with a bone tamp and mallet (Fig. 8-9). Several commercially available bone graft substitutes can also be used alone or in combination with the aforementioned options. If using cortical strut grafts, it is ideal to place them perpendicular to the articular surface to optimize structural support. Any dead space between the strut grafts should be packed with autogenic or allogeneic cancellous graft. At our institution, we prefer to use a bone morphogenetic protein-enhanced allograft. The wound is then copiously irrigated with normal saline. The hip is relocated, and the excess capsular tissue around the joint is excised to prevent any adhesive capsulitis or capsular hypertrophy.

 

The osteochondral trapdoor is reattached with two or three 2-mm bioabsorbable pins placed in a diverging orientation to maximize fixation strength. The ends of the pins can be cut or welded with

 

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the use of electrocautery. Care must be taken to ensure these are flush with or countersunk in the femoral head to avoid damage to the acetabular articular cartilage.

 

 

FIGURE 8-6 Illustrated image of 2 × 2 cortical window with bone grafting in the femoral head.

 

 

 

FIGURE 8-7 Illustrated image of 2 × 2 subchondral flap made in the femoral head.

 

 

 

FIGURE 8-8 Illustrated image of a burr removing the osteonecrotic lesion in the femoral head.

 

 

FIGURE 8-9 Illustrated image of femoral head filled with bone grafting and replacement of the chondral flap.

WOUND CLOSURE The gluteus medius muscle is now separated from the gluteus minimus muscle for repair. Using #5 Ethibond (Ethicon, Somerville, NJ), a running Krackow stitch is placed into the gluteus minimus tendon, which is repaired back to its insertion on the greater trochanter through bony tunnels. A 2.0-mm drill bit may be used to help create drill holes in patients with hard bone. We do not routinely employ the use of a drain. The gluteus medius tendon is then repaired to the cuff of tendon on the greater trochanter using an absorbable barbed suture. The fascia lata is also closed using barbed suture. The subcutaneous tissue is closed in layers using 2-0 Vicryl, and a running barbed subcuticular closure is performed on the skin.

Pearls and Pitfalls

 

Be careful not to violate the acetabular labrum when performing the anterior capsulectomy as instability and pain may result if its integrity is compromised.

 

When performing the lightbulb procedure, use an osteotome to complete the corners of the cortical window as any propagation into the femoral neck creates a stress riser and may lead to fracture.

 

When performing the lightbulb procedure, inadvertent penetration of the femoral head with the burr or curette must be avoided. If this occurs, abandonment of this procedure with conversion to a total hip arthroplasty should be considered.

 

When performing the trapdoor procedure, if no bleeding bone is encountered after extensive debridement, abandonment of this procedure with conversion to resurfacing versus total hip arthroplasty should be considered.

 

The abductor complex must be meticulously repaired at the end of the procedure to optimize hip biomechanics and stability. Failure to perform an adequate repair may result in a Trendelenburg gait.

 

Always be prepared and have the proper equipment available to convert to a total hip arthroplasty if intraoperative inspection reveals a contraindication to nonvascularized bone grafting.

Postoperative Management The patient is admitted to the hospital and placed on mechanical and pharmacologic DVT prophylaxis. At our institution, we prefer to use the venous compression device along with aspirin 325 mg daily unless the patient is at a higher-than-normal risk for developing a DVT. Perioperative antibiotics are discontinued after 24 hours postoperatively. Patients start early mobilization with physical therapy the same day with toe-touch weight-bearing precautions, which are continued for 6 weeks with the use of crutches or a walker. Patients can be full weight bearing by 12 weeks. A prescription for physical therapy for abductor strengthening is also provided. Patients are encouraged to continue performing maintenance hip abductor strengthening exercises after they are discharged from physical therapy. Similar to core decompression, we instruct patients to avoid high-impact loading exercises for 1 year postoperatively. We schedule our patients to return to the office for a follow-up appointment at 6 weeks, 12 weeks, 6 months, 12 months, and then yearly thereafter. Plain radiographs of the involved hip are obtained at each office visit to ensure maintenance of the graft and the absence of collapse of the femoral head.

 

Complications

 

Iatrogenic damage to the acetabular labrum during anterior capsulectomy may result in postoperative pain, instability, and eventual delamination of the articular cartilage on the acetabulum.

 

Inadequate abductor complex repair may lead to a Trendelenburg gait pattern and altered hip biomechanics.

 

A femoral neck stress riser may result from the cortical window created when performing the lightbulb procedure. An osteotome should be used to complete the corners of the cortical window to minimize the risk.

 

Inadvertent penetration of the femoral head with the curettes or burrs (lightbulb technique).

Results: Lightbulb Procedure The success of the lightbulb procedure has been reported to range from 68% to 87% in

 

precollapse and early postcollapse lesions of the femoral head (33). Similar to the results published by Rosenwaser et al. (34), Mont et al. (35) reported an 86% (18 of 21 hips) success rate as defined by a Harris hip score greater than 80 using the lightbulb procedure at a mean follow-up of 48 months (range 36 to 55) in patients who had Ficat and Arlet stage II and

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III osteonecroses. In this study, the authors utilized a bone morphogenetic-enriched allograft and highlighted the relative technical ease of the procedure and avoidance of donor site morbidity by using this allograft that is both osteoinductive and osteoconductive.

The lightbulb procedure has also shown encouraging results for Ficat and Arlet stage III osteonecrosis when combined with proximal femoral osteotomy. Scher and Jakim (36) reported an 87% cumulative survival rate at 5 and 10 years postoperatively in a prospective study involving 45 hips with stage III osteonecrosis treated with the lightbulb procedure and a valgus-flexion intertrochanteric osteotomy. The mean postoperative Harris hip score was 82 points (range, 20 to 100 points) at a mean follow-up of 65 months (range, 36 to 126 months). When the 6 failures (13%) in this cohort were excluded, the mean Harris hip score was 90 points (range, 72 to 100 points). Of the surviving 39 hips at latest follow-up, 20 (51%) hips were rated as excellent and 16 (41%) hips were rated as good as defined by the Harris hip score. At the most recent follow-up, all patients in the survival group could walk for at least 1 hour and none required an assistive device.

Nonvascularized bone grafting has shown to be promising treatment option for precollapse and early postcollapse lesions at short- to midterm follow-up. The success rate is comparable to other head-preserving procedures of the femoral head. See Table 8-5 for more comprehensive section on nonvascularized bone grafting.

Results: Trapdoor Procedure The success rate of the trapdoor procedure has been reported to be from 71% to 89% in the literature (33). In a study involving 30 hips in 23 patients who had Ficat and Arlet stage III or stage IV osteonecrosis of the femoral head, Mont et al. (37) reported good (6 hips) or excellent (16 hips) results as defined by the Harris hip score in 22 of 30 (73%) hips treated with the trapdoor procedure at a minimum follow-up of 2 years. In the patients who had Ficat and Arlet stage III osteonecrosis, 20 of 24 (83%) had good or excellent radiologic results compared with 2 of 6 (33%) of those with stage IV. A higher proportion of patients who had a combined necrotic angle of less than 200 degrees obtained good to excellent results when compared to those with a combined angle of greater than 200 degrees. No complications from the trapdoor procedure were encountered intraoperatively in the seven patients who required conversion to total hip arthroplasty.

The trapdoor procedure has also been shown to delay subsequent surgery in precollapse osteonecrotic lesions as well as in small- to medium-sized lesions. In a retrospective study involving 39 hips in 33 patients treated with the trapdoor procedure using a combination of cancellous bone chips, bone marrow, and recombinant BMP-7, 18 of 22 (82%) hips with Ficat and Arlet Stage II osteonecrosis avoided any subsequent surgery at a mean follow-up of 36 months (range, 24 to 50 months). Twenty-five of thirty hips (80%) with a small- and medium-sized lesions as defined by Kerboul et al. (32) did not require any further surgery at latest follow-up (33).

 

Nonvascularized bone grafting of the femoral head using the trapdoor procedure is a viable option in the treatment of precollapse and early postcollapse lesions. Small- to medium-sized lesions with a combined necrotic angle of less than 200 degrees provide a positive prognosis in delaying arthroplasty surgery at short- to midterm follow-up. Similar to the lightbulb procedure, further randomized,

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prospective studies are needed to examine the long-term results of this procedure. See Table 8-5 for more comprehensive information on nonvascularized bone grafting.

 

 

TABLE 8-5 Non-vascularized Bone Grafting

 

 

Author (Year)

Level of Evidence

 

Stage

Number of Hips

Mean Age

Mean Followup

 

Survivorship

 

Mont et al. (37)

IV

Ficat 3 and 4

30

26

56

80

(1998)

 

 

 

 

 

 

Mont et al. (35)

IV

Ficat 2 and 3

19

31

4

86

(2003)

 

 

 

 

 

 

Seyler et al. (33)

IV

Ficat 2 and 3

39

35

3

67

(2008)

 

 

 

 

 

 

Wang et al. (38)

IV

ARCO IIA to

138

32.3

2

68

(2010)

 

IIIA

 

 

 

 

 

 

 

Yuhan et al. (39) (2009)

 

IV

 

ARCO IIC to IIIA

 

11

 

37

 

5

 

73

 

 

Wei et al. (40) (2011)

IV

ARCO II to III

223

33.5

2

81

 

 

Zhang et al. (41) (2012)

IV

Steinberg II to IV

85

31.4

2.3

85.4

 

 

 

 

 

 

 

 

 

 

 

 

Free Vascularized Fibular Graft

 

Indications

 

Symptomatic precollapse lesions of the femoral head (Ficat and Arlet stages I and II)

 

Patients who have early postcollapse lesions (Ficat and Arlet stage III) may be candidates for free vascularized fibular grafting. The decision to proceed should be made on a case-by-case basis based on age, activity level, risk factors for osteonecrosis, and rate of progression of the lesion.

 

 

Young, active patients who are age 50 or younger Previously failed core decompression

 

Contraindications

 

Asymptomatic precollapse lesions

 

Advanced stage osteonecrosis (Ficat and Arlet stage IV)

 

 

Patients who have early postcollapse lesions (relative contraindication) Age greater than 50 years

 

Acetabular involvement

 

Femoral head articular depression greater than 2 mm

 

Patients who are unable to comply with postoperative precautions/protocols

 

 

Large-sized lesions as determined by percentage of head involvement and/or Kerboul angle Significant peripheral vascular disease

 

 

Patients who have thalassemias/hemoglobinopathy Active heavy smoking, alcoholism

Preoperative Preparation The size and location of the necrotic lesion must be accurately defined preoperatively with plain radiography and/or other advanced imaging modalities. The assistance of a microvascular surgeon is invaluable when planning for a vascularized fibular graft for graft harvest and pedicle anastomosis. Ideally, two surgical teams should be set up to operate simultaneously: one for the graft harvest and one for the hip exposure and proximal femoral preparation for the vascularized graft. The radiology technician should be asked to be on standby as fluoroscopy will be needed throughout the procedure.

Technique The patient is placed in the lateral decubitus position on the operating room table with the affected side up. We prefer to use padded hip positioners placed anteriorly over the ASIS and posteriorly over the sacrum. The hip positioners are secured so that the patient's pelvis is perpendicular to the floor. Obese patients will require their pannus to be held superiorly out of the way by an assistant so that the anterior positioner can be in contact with the ASIS. All bony prominences on the contralateral leg including the lateral malleolus and fibular head are well padded and placed in slight flexion. We prefer to place a venous compression device on the contralateral leg at the start of the procedure. This device is kept on throughout the hospital course and is continued after discharge home. An axillary roll is routinely placed. The entire operative extremity is prepped and draped from toes to the iliac crest in order for two operating teams to work simultaneously. At our institution, we prepare for the microvascular team to harvest the fibular graft while the orthopedic team adequately exposes and prepares the proximal femur for graft insertion.

VASCULARIZED FIBULAR GRAFT HARVEST The fibular graft is harvested with the assistance of a microvascular surgeon. An aseptic tourniquet is applied above the knee at the start of the procedure and set to 300 mm Hg. Anatomic landmarks including the lateral malleolus and fibular head are marked out with methylene blue prior to skin incision. A 15-cm straight lateral skin incision is made centered over the fibula beginning 10 cm distal the fibular head and ending 10 cm proximal to the lateral

 

malleolus. The subcutaneous tissue is dissected off of the fascia of the lateral compartment, and an incision is then made through the fascia. The peroneal muscles are dissected off the fibula from a posterior to anterior direction, taking care to preserve the periosteum along the entire length of the planned graft. Dissection continues with reflection of the anterior compartment musculature off of the fibula. The anterior neurovascular bundle (deep peroneal nerve and anterior tibial artery) is now bluntly dissected off the interosseous membrane. The interosseous membrane and posterior intermuscular septum are then divided off the fibula in a longitudinal direction immediately adjacent to the fibula to avoid any damage to the adjacent neurovascular structures. The peroneal pedicle can now be identified proximally beneath the soleus muscle and distally beneath the flexor hallucis

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longus muscle. Using broad malleable retractors, the pedicle is protected both proximally and 15 cm distally in preparation for the fibular osteotomy. Using an oscillating saw, the fibular osteotomy is made. During the harvest, care must be taken to protect the superficial peroneal nerve proximally as it lies under the peroneus longus. Once both ends of the osteotomy are made, the fibula is grasped with a sharp bone clamp, and the remainder of the soft tissue attachments from the flexor hallucis longus, tibialis posterior, and soleus are dissected free from the bone and peroneal pedicle proximally and distally. The distal pedicle is now ligated with hemostatic clips and divided. The proximal pedicle is then ligated with hemostatic clips and divided from the posterior tibial artery ensuring at least 4 to 5 cm of pedicle is available. The tourniquet is released and hemostasis is achieved. The wound is copiously irrigated and packed with a saline-soaked lap sponge for later closure in order for the second surgeon to freely manipulate the leg for fluoroscopic views while exposing and preparing the proximal femur. Once the appropriate fluoroscopic views have been obtained, the lower leg wound is closed in the standard fashion over a medium Hemovac drain. The deep fascial layers are not closed to minimize the risk of postoperative compartment syndrome.

FIBULAR GRAFT PREPARATION The diameter of the harvested fibula is measured so that the hip surgeon can prepare the core tract of the appropriate diameter. The artery and two veins of the peroneal pedicle are divided from each other on the back table using microvascular surgical instruments. The vessels are then injected with a mixture of lactated Ringer solution and heparin to assess for any leaks. If present, the leaks are repaired prior to the anastomosis with 8-0 nylon suture or hemostatic clips. One vein from the peroneal pedicle is selected for anastomosis while the other is ligated. The proximal pedicle is now peeled back in a subperiosteal fashion until a nutrient vessel is seen entering the fibular cortex. The exposed proximal stump of the fibula is then osteotomized with an oscillating saw at the level of the nutrient vessel. The nutrient vessel is adequately protected during the osteotomy. The final length of the graft will be determined from the core tract being prepared by the hip surgeon. Once this is determined, the appropriate length is marked on the distal end of the fibular graft. Another mark is made approximately 1 cm distal to the first mark. This extra 1 cm of periosteum is also peeled back in a subperiosteal fashion to the level of the final length of the fibular graft. The osteotomy is now completed at the distal end of the graft with an oscillating saw. The peeled periosteum and vascular pedicle are then bound to the fibular graft with a 3-0 Vicryl suture to prevent stripping of the pedicle and periosteum during graft insertion.

 

HIP EXPOSURE/PROXIMAL FEMUR PREPARATION Anatomic landmarks are marked out prior to skin incision including the ASIS, greater trochanter, and anterior and posterior borders of the proximal femur. An approximately 10-cm straight lateral skin incision centered over the anterior aspect of the greater trochanter is made with a No. 10 scalpel. Subcutaneous dissection is then taken down to the level of the tensor fascia lata. This is facilitated with the use of a Cobb elevator. A 1-cm incision is made in the fascia lata at the junction of the gluteus medius and tensor fascia lata muscle. The fascia lata incision is then extended both proximally and distally to the extent of the skin incision with a pair of curved Mayo scissors. The interval between the gluteus medius and tensor fascia lata is identified. Under loupe magnification, the ascending lateral femoral circumflex artery and vein and then carefully dissected out and identified as they lie between the vastus intermedius and rectus femoris. A minimum length of 4 cm is required for a tension-free anastomosis. The origins of the vastus intermedius and lateralis muscle are identified, detached, and reflected distal from its origin with electrocautery. A nonabsorbable monofilament traction stitch can be placed to facilitate retraction. The proximal femur is now adequately exposed. The entry site for a 3-mm guide pin is now determined on the lateral proximal femoral cortex approximately 2 cm distal to the vastus ridge under fluoroscopic guidance. Care must be taken to stay above the level of the lesser trochanter to avoid a subtrochanteric stress riser. Once the appropriate entry point and trajectory are established, the guide pin is advanced into the center of the lesion under fluoroscopic guidance in both AP and frog-leg lateral views. Care must be taken to avoid femoral head penetration into the joint. A core tract of 16 to 21 mm is now made with cannulated reamers in a gradual, stepwise manner under fluoroscopic guidance. The core diameter will depend on the measured diameter of the harvested fibular graft. The core tract serves two purposes: to decompress the osteonecrotic lesion and create an adequate diameter tract for the vascularized fibular graft (Fig. 8-10). The final diameter of the core tract must be 1 to 2 mm larger than the diameter of the harvested vascularized fibular graft in order to allow the vascularity of the pedicle in the core tract to flow freely. The core reamers should reach subchondral bone, approximately 3 to 5 mm from the articular surface. A specialized ball-tipped reamer may also be used as the final reamer to further debride any areas left behind by the straight reamers. Healthy bone from the reamers is saved for later bone grafting of the osteonecrotic lesion. Once the necrotic lesion has been debrided, water-soluble contrast media is injected through the core tract and the

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adequacy of debridement is assessed under fluoroscopy. The core tract is then copiously irrigated with normal saline. With the use of curved curettes, cancellous autograft is harvested from the greater trochanter and densely packed into the debrided necrotic segment with a specialized cancellous bone impactor. Under fluoroscopy, water-soluble contrast media is again injected into the core tract to assess the adequacy of the bone grafting. The contrast media is gently irrigated out of the core tract, taking care not to flush out any of the packed cancellous bone graft. The length of the required fibular graft can now be measured and relayed to the microvascular surgeon.

 

 

 

FIGURE 8-10 Illustrated image of reaming of the femoral head and vascularized fibular graft.

GRAFT PREPARATION AND INSERTION The graft is inserted into the core tract within the previously packed cancellous bone graft adjacent to the subchondral bone of the femoral head, ensuring the fibular pedicle is facing anteriorly and superiorly (Fig. 8-10). After adequate seating of the graft, the pedicles of the peroneal and ascending lateral femoral circumflex artery and vein are anastomosed with the assistance of a microvascular surgeon using 8-0 or 9-0 interrupted nylon suture. The vascularity of the graft can be confirmed by back bleeding from the fibular endosteal bone at the base of the graft. The vascularized fibular graft is then stabilized within the core tract with a 0.062-mm Kirschner wire from just above the distal end of the fibular graft (proximal-lateral) to the medial cortex of the lesser trochanter (distal-medial). Be sure to protect the pedicle from the traversing Kirschner wire during drilling. The Kirschner wire is then bent and cut with a wire cutter and buried into the bone or the gluteus medius to minimize the risk of hardware irritation. The wound is copiously irrigated with normal saline.

Wound closure begins with reapproximating the fascia lata using an absorbable barbed suture over a drain. The origins of the vastus intermedius and lateralis muscle are not repaired in order to prevent any compression or tension on the pedicles. The subcutaneous tissue is closed in layers in a standard fashion. The skin is closed with a running subcuticular absorbable suture.

 

Pearls and Pitfalls

 

Avoid establishing the entry point of the reamers at or below the level of the lesser trochanter in order to avoid creating a subtrochanteric stress riser.

 

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The core tract diameter must be made 1 to 2 mm larger than the fibular graft diameter in order to facilitate graft insertion and to avoid

any compression of the vascularity once seated.

 

Care must be taken to harvest a graft of adequate length (approximately 13 cm) while leaving at least 10 cm of fibula both distal to the knee joint and proximal to the ankle joint.

 

Avoid leaving the end of the 0.062-mm Kirschner wire prominent as pain and bursitis from soft tissue irritation may develop.

 

Do not repair the vastus intermedius and lateralis muscle back to their origin as this can lead to compression and compromise of the pedicles.

 

Patients who are scheduled to undergo bilateral vascularized fibular grafting procedures should be staged at least 12 weeks apart in order for one extremity to be allowed partial weight bearing postoperatively.

Postoperative Management A short-leg posterior splint is applied to the operative extremity and discontinued at the first dressing change on postoperative day 2. The patient is admitted to the hospital and placed on mechanical and pharmacologic DVT prophylaxis.

Prophylactic anticoagulation is given in the form of intravenous low molecular weight dextran for 3 days. Once this is discontinued, the patient is placed on aspirin 325 mg daily. Perioperative antibiotics are discontinued after 24 hours postoperatively. Patients are mobilized with physical therapy the same day with non-weight-bearing precautions for 6 weeks with the use of crutches or a walker. We also instruct patients on simple toe and ankle range-of-motion exercises as scarring of the flexor hallucis longus tendon can result in great toe clawing if not recognized early. A digital subtraction angiogram is obtained on postoperative day 5 to assess the patency of the anastomosis. Patients are instructed to avoid potential vasoconstrictors such as smoking, caffeine, and chocolate. We schedule our patients to return to the office for a follow-up appointment at 6 weeks, 12 weeks, 6 months, 12 months, and then yearly thereafter. Plain radiographs of the involved hip are obtained at each office visit to ensure maintenance of the graft and assess for any evidence of collapse of the femoral head. At the 6-week office visit, the patient's weight-bearing status is advanced to toe-touch weight bearing. At 12 weeks, 50% partial weight bearing is permitted and at the 6-month follow-up, full weight bearing is allowed depending on the presence of graft incorporation and the initial size of the lesion. It is not uncommon for patients to be restricted from full weight bearing for 1 year postoperatively. Formal physical therapy is started once full weight bearing commences. We instruct patients to avoid highimpact loading exercises for 1 year postoperatively.

 

Complications

 

 

Motor weakness and/or sensory disturbance in the peroneal nerve distribution from fibular graft harvest. Persistent pain at donor site.

 

Great toe flexion contracture/clawing.

 

Postoperative proximal femur fracture from creation of an iatrogenic stress riser.

 

Subsequent total hip arthroplasty may be made more difficult secondary to the altered bone stock in the proximal femur from the bone graft.

 

 

Trochanteric bursitis from prominent hardware. Pin migration.

Results The survivorship of free vascularized fibular grafting has been reported to be between 61% and 96% (42,43,44). However, the heterogeneity in stage of disease and follow-up period makes direct comparison between studies difficult. In a prospective study involving 103 hips with both precollapse and postcollapse lesions treated by vascularized fibular grafting, Urbaniak et al. (45) reported 31 hips converted to total hip arthroplasty at a minimum of 5-year follow-up (median follow-up 7 years, range, 4.5 to 12.2 years). In those with precollapse or early postcollapse lesions as defined by the criteria by Marcus et al. (46), 2 of 19 (10.5%) stage II hips and 5 of 22 (23%) stage III hips required conversion to total hip arthroplasty. Survivorship analysis revealed a significant difference in probability of conversion to total hip arthroplasty of 11% and 29%, for stage II and IV osteonecroses, respectively ( p = 0.03). Significant increases in mean Harris hip scores were also seen from preoperative assessment to the most recent follow-up across all stages of osteonecrosis ( p < 0.001). Radiographic progression of osteonecrosis as seen by progression of femoral head flattening, loss of joint space, or acetabular change was seen in only 7 of 19 (37%) stage II hips compared to 21 of 22 (95%) stage III hips, 31 of 40 (77.5%) stage IV hips, and 16 of 22 (73%) stage V hips.

 

In a long-term retrospective evaluation of 124 hips with a minimum follow-up of 10 years (mean, 13.9 years; range, 10 to 23.7 years), Yoo et al. (43) reported a survivorship of 93% at 10 years and 83% at 20 years in patients who had Ficat and Arlet stage II and III osteonecroses. The stage of

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disease did not influence survivorship in this study ( p = 0.574). Harris hip scores were above 80 in 48 of 59 (81%) stage II hips and in 50 of 65 (77%) stage III hips. At latest follow-up, 13 of 124 hips (10.5%) underwent conversion to total hip arthroplasty. Of the 13 undergoing total hip arthroplasty, 7 hips were Ficat and Arlet stage II and 6 hips were stage III. The authors failed to identify a significant difference in the conversion rate to total hip arthroplasty between the stage II and stage III hips. The authors concluded that vascularized fibular grafting is able to provide favorable longterm results and that lesions located laterally in the femoral head as well as older age (greater than 36 years of age) were negative prognostic factors.

 

 

TABLE 8-6 Vascularized Bone Grafting

 

 

Level of

 

Number

Mean Age

Mean

 

 

Author (Year)

Evidence

Stage

of Hips

(Years)

Follow-up

Survivorship

Babhulkar et al.

IV

ARCO IIB and IIIC

31

32

8

96.7

(47) (2009)

 

 

 

 

 

 

Bakshi et al. (48)

IV

Ficat stage 1 to 3

187

35.5

16.5

71

(2009)

 

 

 

 

 

 

 

Eward et al. (42) (2012)

IV

Ficat 1 and 2

65

32.1

14.4

75

Hasegawa et al.

(50) (1997)

IV

Inoue and Ono I and II

31

38.3

8

70

Kawate et al. (51) (2007)

IV

Steinberg IB to V

71

39

7

83

Marciniak et al.

(52) (2005)

IV

Marcus-Enneking Stage 2 to 4

101

37

8

42

Sun et al. (53) (2009)

IV

Steinberg II to V

80

31

4.3

100

Yin et al. (54)

(2011)

IV

Steinberg II to IV

14

34

3.3

100

 

Chen et al. (49)

(2009)

IV

ARCO IIIA and IIIB

33

37

6.2

24

 

 

 

 

 

 

 

In a more recent study by Eward et al. (42), 39 of 65 (60%) Ficat and Arlet stage I and II hips had a surviving free vascularized fibular graft at a mean follow-up of 14.4 years (range, 10.5 to 26 years). At 10 years, 49 of 65 hips (75%) had surviving vascularized fibular grafts. The mean graft survival was 14.9 years (range, 10.5 to 26.1 years). The remaining 26 of 65 (40%) hips that eventually required conversion to total hip arthroplasty survived with the vascularized fibular graft for an average of 8.3 years (range, 7 months to 17 years). This finding was similar to the results of Yoo et al. (8.4 years, range, 1.3 to 18.8 years) (43). In those who had surviving vascularized fibular grafts, 64% engaged in impact sports versus only 38.4% in those who required conversion to total hip arthroplasty ( p = 0.04). No association was seen between stage of osteonecrosis and rate of conversion to total hip arthroplasty ( p = 0.84). See Table 8-6 for more comprehensive information on vascularized bone grafting.

 

Summary

Osteonecrosis of the femoral head can be a debilitating disease resulting in considerable morbidity and disability in young, active patients. Early diagnosis of this disease is paramount to the success of head-preserving procedures as the stage and size of the lesion have been shown to affect outcomes. Once identified, treatment algorithms have been developed, which depend largely on the stage of disease. Though several classification systems have been developed to aid in treatment planning, lesions can generally be divided into precollapse and postcollapse lesions. Precollapse lesions and early postcollapse lesions are generally amenable to the femoral head-preserving procedures discussed above. In addition to the stage of disease, patient-related factors must be considered when choosing the most “appropriate” treatment option including age, activity level, and associated risk factors. Location and size of the lesion should also be considered as worse outcomes have been demonstrated with larger and lateral-based lesions. Head-preserving procedures are aimed at decompressing the increased intraosseous pressure from the osteonecrotic lesion and/or debriding the necrotic segment and providing structural support and media for bone regeneration.

Outcomes for each technique have been mixed without one procedure demonstrating superior results than the other. Variations in surgical technique as well as the heterogeneity in patient population and lesion characteristics across studies make direct comparison between study cohorts difficult. As such, treatment should be made on an individualized basis based on specific patient factors and surgeon familiarity with the planned procedure.

 

REFERENCES

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