Distal Femoral Osteotomy (DFO) in Reading — Knee Realignment Surgery
A Distal Femoral Osteotomy (DFO) is a bone-realignment operation which is often performed to correct valgus (knock-knee) alignment, which places excess stress on the outer (lateral) side of the knee. It can be used in a variety of different deformities however.
Mr Sam Nahas, consultant knee surgeon at Circle Reading Hospital, performs precision-planned DFO surgery using advanced digital imaging software to optimise angles and load distribution, aiming to preserve the native joint and delay or avoid knee replacement.
At a glance
- Who it is for
- People with knock-knee alignment overloading the outer side of the knee, often with arthritis there, who want to delay or avoid a knee replacement.
- Anaesthetic
- Spinal or general anaesthetic.
- Hospital stay
- Usually 1 night.
- Walking
- Weight-bear as tolerated from day 1, with crutches for about 4–6 weeks and full weight-bearing by around 6 weeks.
- Driving
- Around 6 weeks, once you can do an emergency stop safely.
- Sport
- About 6–9 months for higher-impact activity; gentle cycling or swimming earlier.
- Patient rating
- 5.0 out of 5 from 31 verified patient reviews on Doctify.
- Waiting time
- New patients are usually seen within a week.
- Cost
- Self-pay consultation £400, with a fixed price for surgery quoted after your consultation. Insured patients need a GP referral.
What is a DFO?
In a DFO, a carefully planned cut is made in the lower part of the thigh bone (femur) to change its alignment.
By straightening the leg, the procedure shifts weight-bearing forces away from the damaged outer side of the knee and restores balanced load through the joint.
A titanium plate and screws hold the bone securely while it heals in its new position.
DFO is typically performed for:
Lateral (outer) compartment arthritis in valgus knees
Post-traumatic malalignment after previous injury
Combined realignment with cartilage or meniscal surgery
Young or active patients seeking to maintain high function without knee replacement
Pre-operative assessment
As with high tibial osteotomy, precise planning is critical.
Before surgery, Mr Nahas requests full-length, weight-bearing X-rays of the entire leg — from hip to ankle — to evaluate global alignment.
These images must be high-quality and perfectly centred.
He then analyses them using specialised digital software to determine the exact degree of correction required.
This ensures the surgical plan is mathematically accurate and tailored to each individual's anatomy.
The surgery
The procedure is performed under spinal or general anaesthetic at Circle Reading Hospital.
An incision is made above the knee on the outer side of the thigh. The bone is precisely cut, opened or closed by a few millimetres, and held in position with a titanium plate and screws.
Sometimes a bone graft or synthetic bone substitute is used to aid healing.
It is a major operation that involves bone healing — patients must be prepared for a longer recovery than with keyhole procedures.
This is a major procedure, but in the right patient it can provide lasting pain relief, correct deformity, and preserve the native knee joint for many years.
Recovery and rehabilitation
Because bone healing is required, recovery from DFO takes longer than most keyhole surgeries. The pathway is similar to that of an HTO:
Hospital stay: usually 1 night
Weight-bearing: crutches ~4–6 weeks, but weight-bear as tolerated from day 1 and full by around 6 weeks
Bone healing: checked with X-rays at 6 weeks and ~3 months; functional recovery/union commonly falls in the ~3–4 month window
Driving: around 6 weeks, once you can perform an emergency stop safely and are off strong painkillers; this also depends on which leg was operated on and whether you drive a manual (see Driving after knee surgery)
Return to sport: ~6–9 months for higher-impact activity, earlier for gentle cycling/swimming
Physiotherapy starts early to maintain joint motion and rebuild strength as the bone heals. X-rays are repeated during follow-up to confirm progressive healing and correct alignment.
Evidence and outcomes
Ten-year survivorship after distal femoral osteotomy for valgus lateral compartment osteoarthritis is 89% in a single-centre cohort (Shivji et al., Knee Surgery, Sports Traumatology, Arthroscopy, 2021).
Modern plates, locking screws, and digital planning software have made results more predictable, with high patient satisfaction and durable alignment correction.
Risks and complications
As with any operation, there are risks. Most patients have no serious problems, but it is important to know about them.
Infection of the wound or around the plate
Blood clots in the leg (DVT) or lungs (pulmonary embolism)
Bleeding, bruising or problems with wound healing
Numbness around the scar
Risks from the anaesthetic
Stiffness of the knee
The bone may heal slowly or not heal (non-union), which may need further surgery
The correction may be lost before the bone has healed
The plate may cause irritation and may need removing once the bone has healed
Rarely, injury to the nerves or blood vessels behind the knee
A knee replacement may still be needed later
Mr Nahas will go through the risks that apply to you at your consultation.
Why choose Mr Sam Nahas
Consultant knee-only surgeon specialising in alignment and preservation surgery
Performs both high tibial (HTO) and distal femoral (DFO) osteotomies using computer-assisted planning
Fellowship-trained expertise in cartilage, ligament, and joint preservation
Evidence-based practice and personalised pre-operative planning
Self-pay consultations within a week and access to advanced imaging facilities
Self-pay and appointments
Self-pay packages available. No GP referral is required for self-pay patients.
Location
Procedures are performed at Circle Reading Hospital, serving patients from Reading, Berkshire, Wokingham, Henley, Oxford, and surrounding areas.