Combined bony and soft tissue reconstruction for hip joint stabilisation in proximal focal femoral deficiency (PFFD)

2.1 Indications and current treatments

2.1.1 Proximal focal femoral deficiency is a congenital syndrome typically characterised by poor hip joint development and femoral shortening. The severity of the syndrome is variable. In severe cases, there may be no hip joint and the femur may be very short. In addition, PFFD may be associated with other lower limb abnormalities, such as an abnormal knee joint, lower limb malrotation, inadequacy of the proximal musculature and limb length discrepancy.

2.1.2 Treatment options depend on the extent of the PFFD. In patients with severe forms of PFFD, it may not be possible to produce a leg that is functional and of the correct length, so partial limb amputation and fitting of a prosthesis may be the preferred management. In patients with relatively mild PFFD, an attempt can be made to correct the abnormalities of the hip joint and the upper femur.

2.2 Outline of the procedure

2.2.1 Combined bony and soft tissue reconstruction for hip joint stabilisation in PFFD is carried out with the patient under general anaesthesia. There are several variations on the procedure. Hip stabilisation involves a long incision on the outer side of the thigh. With the soft tissues retracted or released, the upper femur deformity is corrected by bone division and fixation. If needed, the pelvic bone may also be divided and moved to help reconstruct the hip joint. After surgery, the joint may need to be immobilised in a plaster cast. If the hip joint cannot be salvaged, the upper femur may be stabilised against the pelvis using a pelvic support osteotomy, and this may be combined with leg lengthening procedures.

2.2.2 Several additional procedures may be required to achieve reconstruction or to enable prosthetic attachment, either at the same time or afterwards as separate procedures. These may include leg lengthening, epiphysiodesis of the normal (opposite) femur, knee reconstruction, Van Nes rotationplasty, and 'above-the-knee' amputation.

2.3 Efficacy

2.3.1 A case series of 14 patients reported that 64% (9/14) of patients had a good clinical outcome after hip stabilisation, leg lengthening and external fixation (based on a composite measure of gait, range of movement, degree of dislocation and residual shortening), at a mean follow-up of 17 years. At final follow-up, the mean difference in patients' limb length was 11.6 cm (range 1–20 cm) (duration of follow-up not stated). Angular deformity was reported in 21% (3/14) of patients (mean follow-up 17 years).

2.3.2 A case report of 3 patients who had plaster casts for 3 months then valgus osteotomy described successful reorientation and stabilisation of the hip and straightening of the femur. Femoral lengthening was undertaken in 1 patient and planned in 2 others at a follow-up of 2.3–8 years. The case series of 14 patients reported that 43% (6/14) needed more than one lengthening procedure.

2.3.3 The Specialist Advisers considered key efficacy outcomes to be overall limb function and a reduced need for repeat procedures. The Specialist Advisers also stated that for some patients, the result may not be as good as would have been achieved by amputation and fitting of a prosthesis.

2.4 Safety

2.4.1 The case series of 14 patients reported osteitis in 43% (6/14) of patients, fracture (not otherwise described) in 7% (1/14) of patients, and pseudoarthritis in 7% (1/14) of patients (mean follow-up 17 years).

2.4.2 The Specialist Advisers stated that adverse events (reported in the literature or anecdotally) include significant hip and knee stiffness as a result of excessive lengthening, hip dislocation and recurrent deformity. The Specialist Advisers also considered theoretical adverse events to include avascular necrosis, bone non-union, infection, nerve or vascular injury, poor limb function, recurrence of contractures and wound dehiscence.