Slipped Capital Femoral Epiphysis Surgery Treatment & Management

Medical care for slipped capital femoral epiphysis (SCFE) includes treatment of any underlying conditions (eg, renal failure, endocrinopathies).

The following consultations may be useful:

• A consultation with a pediatric endocrinologist may be useful in cases in which an underlying endocrinopathy is suspected.
• A consultation with a pediatric nephrologist is useful for management of renal failure.
• A dietitian may be consulted for a graduated weight-loss program. At least 50% of patients are above the 95th percentile for weight.

The treatment of slipped capital femoral epiphysis (SCFE) is essentially surgical. Principles of treatment are stabilization of the slip to prevent progression, and promotion of closure of the upper femoral physis. The current treatment methods for a patient with an SCFE include the following:

• Hip-spica cast immobilization^[61]
• In situ stabilization with single or multiple pins or screws^{[50, 53, 62, 63]}
• Open epiphysiodesis with autograft or allograft bone^{[64, 65, 66]}
• Open reduction with a corrective osteotomy through the physis and internal fixation with use of multiple pins^{[67, 68]}
• Compensatory basilar neck osteotomy with in situ stabilization with multiple-pin fixation^{[69, 70]}
• Intertrochanteric osteotomy with internal fixation^[71]

The advantages and disadvantages of each method are discussed below.

Hip-spica cast

Duration is usually approximately 12 weeks.

Advantages are as follows:

• It avoids the complications of anesthesia and surgery.
• It also provides prophylactic treatment for the opposite hip. Bilateral slips are seen in 20-40% of cases.^{[16, 35, 36, 37]}

Disadvantages are as follows:

• The hip-spica cast does not stabilize the SCFE, and most investigators have reported progression of the slip in 5-10% of patients, despite immobilization in the cast.^{[61, 72]}
• The frequency of chondrolysis appears to be higher than with surgical treatment.^{[61, 72]}
• It is cumbersome, especially if the patient is obese, and restricts the mobility of the patient. It can also cause cast sores.

For all of these reasons, the authors do not recommend a hip-spica cast for treatment of SCFE. The routine use of a hip-spica cast in the treatment of SCFE is no longer recommended.

In situ stabilization with use of single or multiple pins or screws

The patient lies supine on a fracture table or a radiolucent-top table for this procedure. Excellent intraoperative imaging is absolutely essential. In acute slips, positioning of the patient's affected limb in slight flexion and internal rotation may result in an incidental reduction. An aggressive reduction maneuver should be avoided.

A screw or screws are inserted percutaneously under fluoroscopic guidance as described previously by other authors.^{[65, 73]} Use of 7.3-mm cannulated screws is recommended. Use of a single screw for a stable slip is preferred. Whether to use 1 or 2 screws for unstable slips is controversial. Use of multiple (>2) screws is not recommended because it increases the risk of iatrogenic damage to the vascularity of the femoral head.

The entry point must be at or above the level of the lesser trochanter to avoid subtrochanteric fracture. It also should be anterolateral, as opposed to the lateral entry point used in fixation of fractures around the hip. Screws are directed from anterolateral to posteromedial. Care is taken to remain in the center of the capital epiphysis and perpendicular to the physis on AP and lateral views.^[73] Posterosuperior placement in the epiphysis is to be avoided at all costs to prevent damage to the lateral epiphyseal vessels.^{[38, 74]} At least 2.5 threads should engage the epiphysis for a good hold. See images below.

Screw position must be confirmed. Although temporary penetration of guide pins into the joint has not been shown to be associated with chondrolysis, hardware that remains in the joint must be avoided to decrease the risk of chondrolysis and joint degeneration.

Advantages to pinning are as follows:

• It is a simple, short procedure.
• Blood loss is minimal.
• Success rates are high; rates of slippage and complications are low.^{[14, 73, 75]}

Disadvantages are as follows:

• It may be technically difficult in patients with severe slips.
• It is associated with a risk of pin penetration into the joint, especially if multiple pins are used.

The results of single-screw fixation in patients with SCFE have been gratifying. Aronson and Carlson reported excellent or good results in 36 (95%) of 38 mild slips, 10 of 11 moderate slips, and 8 of 9 severe slips. AVN developed in only 1 patient (2%) with an unstable SCFE, and chondrolysis developed in no patients.^[50]

Ward et al reported on 42 patients (53 hips) with an SCFE treated with single-screw fixation.^[53] After a mean duration of follow-up of 32 months, 92% of the patients demonstrated physeal fusion and were able to participate in full activities. Neither chondrolysis nor AVN developed in any patient.

Samuelson and Olney, using a similar percutaneous technique, reported excellent results in 7 patients treated with 2 Knowles pins and in 17 patients treated with a single Knowles pin.^[33]

Remodeling or adaptation may occur after pinning, and the loss of internal rotation often improves. Pinning is currently the method of choice for stabilization of all slips.

Controversies include the following:

• Single pins are preferred in stable slips, but the number of pins to use for unstable slips is controversial.
• Data at this time remain controversial regarding whether early reduction and stabilization in unstable slips provides more benefit than delayed surgery.^{[55, 76, 77]}
• Prophylactic pinning of the contralateral hip is recommended in noncompliant patients and when follow-up is not ensured, as well as in patients with endocrinopathy or renal disease in whom the risk of contralateral slip is very high.^{[78, 79]} The indications in other patients are less well defined. The Modified Oxford Bone scoring system may help determine who should be treated prophylactically.^[42]

Open epiphysiodesis with iliac crest or allogeneic bone graft

This procedure was first reported by Ferguson and Howorth in 1931.^[80] The hip is exposed using the iliofemoral approach. A rectangular window of bone is removed from the anterior aspect of the femoral neck. A cylindrical tunnel is created across the physis, and multiple corticocancellous strips of iliac crest bone graft are driven into the tunnel as bone pegs across the proximal femoral physis in an attempt to promote early closure of the physis. A cortical strut allograft, for structural support, also may be used.^[66]

Advantages include the following:

• The risk of damaging the vascularity of the femoral head is reduced because the graft usually is inserted at a proper angle.
• The risk of the graft being inserted too deeply and causing joint penetration is also reduced.
• It avoids the complications of internal fixation, including unrecognized pin penetration and hardware failure.
• It provides rapid, reliable closure of the physis.

Disadvantages include the following:

• The curettage may make the slip even more unstable, and fixation afforded by bone graft is not as solid as that provided by pins. A risk of additional slippage remains.
• The surgery and period the patient is under anesthesia are longer.
• Blood loss is increased.
• The incision is larger.
• A spica cast is needed.

Weiner et al reported on their 30-year experience with this technique, which they used to treat 159 patients (185 hips) who had an SCFE. Additional slipping developed in 4 hips (2%), AVN developed in 1 (1%), and chondrolysis developed in none.^[65]

Rao et al reported on evaluations of 43 patients (64 hips) treated by open bone-peg epiphysiodesis. At the time of healing, 27 hips (42%) had additional slipping. AVN developed in 4 hips (6%), chondrolysis developed in 3 (5%), and additional complications developed in 14 (22%).^[64]

Schmidt et al reported on evaluations of 31 patients (38 hips) with a mean duration of follow-up of 3 years and 6 months, and stated that the Harris hip rating was excellent for 35 hips, good for 1, and fair for 2. Six patients (19%) had a major complication; AVN, chondrolysis, femoral neck fracture, subtrochanteric hip fracture, bilateral coxa vara deformity, and unilateral coxa vara deformity occurred in 1 patient each.^[66] Despite these complications, those authors still recommend this technique, particularly for a patient with a severe SCFE.

Osteotomies

These are recommended most commonly as secondary procedures after clinically significant residual deformity develops. They are aimed at altering the arc of motion and at attempting to retard the onset of osteoarthrosis.

The osteotomies can be performed through the physis, neck, or subtrochanteric regions. As the osteotomies move from proximal to distal, the correction moves further from the point of deformity, but the risk of AVN decreases. See image below.

Open reduction with corrective osteotomy through the physis and internal fixation with use of multiple pins

This procedure is described by Fish and by Dunn and Angel (see image below).^{[81, 82]} The hip is exposed by the anterior Smith-Petersen or anterolateral approach.^{[67, 68]} A wedge of bone is removed from the metaphysis of the femoral neck, allowing the epiphysis to be repositioned anatomically on the metaphysis without creating tension on the epiphyseal vasculature. After the femoral neck is shortened sufficiently, the epiphysis is reduced and internally fixed using 3 pins.

The advantage is that correction is performed at the site of deformity.

The disadvantage is that this procedure is associated with a high risk of AVN.

Fish reported on cuneiform osteotomy in 61 patients (66 hips) and stated that 55 hips (83%) had an excellent result, 6 (9%) had a good result, 2 (3%) had a fair result, and 3 (5%) had a poor result.^[81]

DeRosa et al reported on evaluations of 23 patients (27 hips) with a severe SCFE treated by cuneiform osteotomy.^[67] After a mean duration of follow-up of 8 years and 5 months, no hip had an excellent result, 19 hips (70%) had a good result, 4 (15%) had a fair result, and 4 had a poor result. AVN developed in 4 hips (15%), and chondrolysis developed in 8 hips (30%). In addition, 2 patients (7%) lost fixation and required additional surgery, a skin erosion developed over 1 of the pins and required pin removal, and a buttock pressure sore developed in another patient. Despite the 15% rate of AVN in their study, DeRosa et al stated that they would still recommend the cuneiform osteotomy for patients with a severe SCFE.

Velasco et al reported on evaluations of 65 patients (66 hips) treated with open reduction for SCFE.^[68] In 60 hips, open reduction of the slip was combined with a cuneiform subcapital wedge resection of the femoral neck according to the technique described by Dunn and Angel. At a mean of 16 years, chondrolysis had developed in 8 hips (12%) and AVN in 7 (11%). Of the 48 hips that had been followed for a minimum of 10 years (mean, 20.6 y), 22 (46%) had a good result, 16 (33%) had a moderate result, and 10 (21%) had a poor result. Degenerative arthritis was seen in 19 (40%) of the 48 hips.

Compensatory basilar neck osteotomy with in situ stabilization of the slipped capital femoral epiphysis with use of multiple pin fixation

This technique is described by Barmada et al, Crawford, and Kramer et al. The anterosuperior-based wedge osteotomy is described by Kramer et al, and the extracapsular basilar neck osteotomy is described by Barmada et al.^{[69, 70, 83]}

Advantages are as follows:

• The prevalence of AVN associated with basilar neck osteotomy is less than that associated with cuneiform osteotomy.

Disadvantages are as follows:

• It shortens the femoral neck, which may result in impingement of the greater trochanter against the lateral aspect of the acetabulum during hip abduction.
• If the proximal femoral physis closes prematurely, as is often seen in patients with an SCFE, shortening of the femoral neck may aggravate a limb-length discrepancy.
• Only 35-55° of correction is possible with this technique.

Kramer et al described an anterosuperior-based wedge osteotomy of the femoral neck. They stabilized both the osteotomy site and the SCFE with multiple pins.^[70] They reported on 55 patients (56 hips) who all had a positive preoperative Trendelenburg test result and had walked with a lurching gait. After the osteotomy, 48 patients (87%) had a negative Trendelenburg test result. Nine hips (16%) had a poor result because of pain, a limp, or a decreased range of motion. AVN developed in 2 patients (4%), and chondrolysis developed in 1 (2%).

Intertrochanteric osteotomy with internal fixation

This technique is described by Crawford, Schai et al, and Southwick.^{[71, 74, 84]} It was initially described by Southwick as the primary treatment for severe slips. It is now used primarily if restricted range of motion persists even after remodeling of the slip. This procedure is an intertrochanteric osteotomy at the level of the lesser trochanter with flexion, abduction, and internal rotation of the distal fragment. The osteotomy site is fixed with a compression hip screw, blade plate, or other fixation device.

Advantages are as follows:

• It improves hip motion.
• It is rarely associated with AVN.

Disadvantages are as follows:

• It results in shortening and limb length discrepancy.
• The correction is limited to 45° on the AP radiograph and to 60° on the lateral radiograph, as measured by the Southwick method.^[85]

Schai et al reported on evaluations of 51 patients who had an SCFE of 30-60° that was treated with an intertrochanteric osteotomy and followed for a mean duration of 24 years.^[84] Moderate osteoarthritis developed in 14 patients (27%), and severe osteoarthritis developed in 9 (18%). Thirty-five patients (69%) had a shorter limb on the affected side, and 2 patients (4%) had a limb-length equalization procedure. AVN developed in only 1 patient (2%).

In stable slips, partial weight bearing with axillary crutches can be started as soon as the patient is comfortable after pinning, with progression to full weight bearing as tolerated. In unstable slips, toe-touch weight bearing with axillary crutch protection is used for 6 weeks after pinning. Discharge the patient on the day after pinning and after 3-5 days for uncomplicated osteotomies.

In patients with unilateral slips, the patient must return for an evaluation if any pain develops on the contralateral side.

The most common complications associated with slipped capital femoral epiphysis (SCFE) are AVN, chondrolysis, and pin penetration into the joint.

Avascular necrosis

AVN is the most devastating complication of SCFE.^[86] The factors responsible for the development of AVN are as follows^{[1, 38, 67, 74, 81, 87, 13]} :

• An acute, unstable SCFE
• Overreduction of an acute SCFE
• Attempts at reduction of the chronic component of an acute-on-chronic SCFE
• Placement of pins in the superolateral quadrant of the femoral head
• Femoral neck osteotomy, especially if performed prior to physeal closure

Clinical features include pain in the groin or knee. On physical examination, loss of motion of the hip, particularly internal rotation, is evident, and the hip is irritable upon passive internal and external rotation.

Plain radiographs are unremarkable early in the course of the disorder, but changes diagnostic of AVN (collapse of the femoral head with cyst formation and sclerosis) develop after a few months. All cases of AVN after SCFE are radiographically apparent within 1 year. Early bone scanning or MRI often reveals asymmetry between the femoral heads, predicting the eventual development of AVN.^[88]

Symptomatic treatment includes nonweightbearing walking with crutches, range-of-motion exercises, traction, and anti-inflammatory medication. The radiographic evaluation should reassess the position of the hardware, which can protrude into the hip joint with femoral head collapse. Clearly, this should be backed out of the joint or removed if the physis is closed. In severe cases, a hip arthrodesis or joint arthroplasty may be needed.

Chondrolysis

The factors responsible for chondrolysis are unknown. The possible role of an autoimmune phenomenon or some factor interfering with cartilage nutrition is yet to be defined. Risk factors for developing chondrolysis include the following:

• Immobilization in a cast
• Unrecognized permanent pin penetration
• Severe SCFE

The prevalence of chondrolysis is not increased in the black population, as has previously been reported.^{[16, 43, 47, 62]} Prevalence is 5-7%.^[16] Clinical features include pain in the groin or knee and a loss of hip motion, particularly internal rotation.

Radiographs demonstrate a decrease in the width of the joint space of greater than 50% compared with the uninvolved side or, in patients who have bilateral involvement, a joint space of less than 3 mm. Hips that demonstrate increased uptake with premature closure of the greater trochanter on an early bone scan have been associated with an increased risk for the development of chondrolysis.^[88]

Symptomatic treatment is similar to that of AVN. Early and aggressive physical therapy may help regain range of motion. Some authors have recommended surgical interventions such as extensive releases or distraction with external fixation.

Device penetration into the joint

The frequency of problems related to internal fixation devices (slip progression, pin breakage, and joint penetration by the pins) is decreasing with the use of fluoroscopic guidance and cannulated single-screw fixation. The risk of fracture through an unused pinhole can be avoided with the use of fluoroscopy to position the guide-pin, and by entering the bone proximal to the lesser trochanter.

Long-term outcome, if the slipped capital femoral epiphysis (SCFE) is mild or moderate in severity, is good if it is maintained between the femoral head and the acetabulum, and AVN and chondrolysis do not develop. Hips with a severe SCFE and those with AVN or chondrolysis undergo more rapid deterioration with degenerative changes, and ultimately require reconstructive procedures.

The treatment of unstable slipped capital femoral epiphysis (SCFE) is controversial. Whether to use 1 or 2 pins for stabilization is debated, and some authors are now advocating open reduction maneuvers. Prophylactic pinning of the contralateral hip, which has long been the practice in some countries, is now being considered more frequently in North America.