Definition
Proximal Focal Femoral Deficiency / Congenital femoral deficiency
- congenital malformation
- characterised by failure of normal development of the proximal femur
Hip deformity + leg length discrepancy
Epidemiology
Rare - 1 in 50 000
Bilateral 15% - usually more severe
Association
Fibular hemimelia 50%
- have knee instability
- shortened tibia
- equinovalgus foot + absent lateral rays
Clinical
Child with very short leg
- short bulky upper thigh
- held flexed, abducted and externally rotated
Foot level with contralateral mid tibia
Aitken's Classification
Continuum of deformity with PFFD
- mild with coxa vara / pseuoarthrosis / acetabular dysplasia
- femoral had absence and severely short femur
- absent femur
| Class A | Class B | Class C | Class D |
|---|---|---|---|
| Femoral head present | Femoral head present | Femoral head absent or very small | Femoral head absent |
| Acetabulum normal | Acetabulum mildly dysplastic | Acetabulum severely dysplastic | Acetabulum absent |
| Femoral neck absent early but appears | No connection between femoral head and femur | No articular between femur and acetabulum | No relationship between femur and pelvis |
| Short femur with coxa vara | Short abnormal femur | Very short tapered femur | Severely short femur |
|
May be subtrochanteric pseudoarthrosis |
|
Class A: Femoral head present, normal acetabulum Class B: Femoral head present, abnormal acetabulum
Class C: No femoral head present
Issues
Hip
- pseudoarthrosis
- coxa vara
- instability
Leg length discrepancy
Management Class A & B / femoral heads present
Pseudoarthrosis / coxa vara
Pseudoarthrosis
Cervical
Subtrochanteric
Goddard et al J Pediatr Orthop 1995
- 78 PFFD
- cervical pseudoarthrosis did not spontaneously fuse
- subtrochanteric pseudoarthrosis: 30% spontaneously fuse
- subtrochanteric fusion achieved with bone grafting
- cervical fusion more difficult to achieve
Femoral osteotomy / resection of pseudoarthrosis / correction of varus +/- pelvic osteotomy
Hip instability / acetabular dysplasia
Pelvic osteotomy
Dora et al J Pediatr Orthop B 2004
- 13 patients with mild PFFD
- deficiency posteriorly with retroversion
Leg length discrepancy
Options
Femur lengthening / beware ACL deficiency and knee dislocation
Shorten contralateral femur / epiphysiodesis
Issue
ACL +/- PCL deficiency
Leite et al EFORT Open Rev 2021
- systematic review of knee in PFFD
- 93% ACL insufficiency
- 44% ACL + PCL insufficiency
- 26% of patients developed knee subluxation during lengthening
Technique
- compared femoral lengthening with external fixation v motorized IM nail in 29 patients
- complications: external fixation 100%, IM nail 75%
Management Class C & D / no femoral heads
Hip instability
Pelvic support osteotomy
Osteotomy proximal femur
Leg length discrepancy
Options
Equinus prosthesis
Van Nes Rotational Osteotomy: rotate then fuse knee, ankle acts as knee joint
Syme amputation + AKA prosthesis
- 23 patients with unilateral PFFD
- equinus prosthesis versus rotationplasty versus syme amputation
- equinus prosthesis walked the fastest
- no benefit of rotationplasty despite more surgery
Bilateral
Usually Class C or D
Non operative management
- can usually walk well without prosthesis
- surgical procedures usually detract from mobility
- consider surgery if severe foot deformity that cannot ambulate without prosthesis / Symes