Open Reduction and Internal Fixation with Plate for Hoffa Fracture

I. Principles

General Considerations
Hoffa fractures involve critical weight-bearing areas of the knee joint and require anatomical reduction and absolute stability of fixation. Generally, a buttress plate combined with lag screws is recommended. However, if the fracture fragment is small, lag screws alone may be the only feasible fixation method. Anterior indirect lag screw techniques are not recommended, as excessively long threads fail to provide adequate stability or effective compression of the fragments. If both condyles are fractured, the same principles apply.

Screw Types
All implants must not protrude above the articular surface. This can be achieved by using countersunk lag screws (A) or headless compression screws (B). To prevent fragment rotation, at least two screws should be used. In this procedure, 3.5‑mm cannulated headless compression screws or standard 3.5‑mm lag screws may be selected. However, other screw sizes may be used depending on the fragment dimensions.

II. Patient Positioning and Surgical Approach

Patient Positioning
The patient is placed in the supine position with the knee flexed 20°–30°.

Surgical Approach
- For lateral Hoffa fractures, the Swashbuckler approach or Gerdy’s tubercle osteotomy approach can be used.
- For medial Hoffa fractures, the medial inter‑nervous approach is employed.

III. Reduction

Use a small ball‑tip reduction forceps or a bone spike to reduce the fracture, and temporarily fix it with K‑wires. Ensure that the K‑wire positions do not conflict with the planned plate placement and screw trajectories.

IV. Fixation

Principles
To enhance stability and avoid axial loading at the fracture site (especially in osteoporotic bone), a buttress plate is used to prevent proximal displacement of the fragment. The plate is positioned according to the location of the unstable fragment; occasionally, such fragments are located laterally. Various plate types are available; for example, this text uses a low‑profile 3.5‑mm narrow plate as an illustration.

Plate Application
The plate is applied to the posterior aspect of the distal femur. It should be placed as distal as possible while avoiding the articular surface. To allow a low‑profile plate to closely conform to the femur, insert a standard cortical screw in neutral mode proximal to the fracture line.

Screw Insertion in Neutral Mode
Fix the plate proximally with one or more bicortical screws placed proximal to the first screw. If screws can be placed in non‑articular areas, additional screws may be inserted distally in the plate. All screws are inserted in neutral mode.

Intraoperative Image
The intraoperative image shows a reduced posterior Hoffa fracture temporarily fixed with K‑wires and reinforced with a posterior buttress plate.

Postoperative Radiograph
Postoperative imaging confirms proper placement of the posterior buttress plate.

Guide Wire Placement
Insert two guide wires perpendicular to the fracture plane, ensuring they do not penetrate the far cortex.

Check Guide Wire Position
Verify the position of the guide wires under image intensifier control in both lateral and oblique views.

Insertion of Headless Compression Screws
Use a cannulated screwdriver to insert the headless compression screws, and check the appropriate screw length under image‑intensified lateral view.

Cancellous Lag Screw Insertion
Alternative: Use of Standard Screws – Insert the lag screws following the standard technique for cancellous lag screws under image intensifier control. Countersink the screw heads to avoid prominence.

V. Case Example

As shown in the figure, if the plate is placed laterally or medially rather than posteriorly, fixation failure is highly likely. The image demonstrates articular surface incongruity, which would require revision surgery.

VI. Postoperative Rehabilitation

After distal femoral fractures, the main obstacles to full knee function recovery include fibrosis and adhesions of the soft tissues around the metaphyseal fracture zone, capsular scarring, intra‑articular adhesions, and muscle weakness. Early range‑of‑motion exercises help restore joint motion in the early postoperative phase. Provided that fracture fixation is stable, the surgeon and physical therapist will design a progressive rehabilitation plan tailored to each patient. The recommendations given here are for reference only and are not mandatory.

Functional Therapy
Unless other injuries or complications exist, knee mobilization can begin immediately after surgery. Active and passive movements of the knee and hip can be initiated on the first postoperative day. The focus of therapy should be on progressive strengthening of the quadriceps and straight‑leg raises. Unloaded stationary cycling, as well as firm but passive knee range‑of‑motion exercises, help the patient achieve optimal joint mobility.

Weight‑Bearing
Touch‑down weight‑bearing (10–15 kg) with crutches or a walker can be started immediately after surgery. This is continued for 6–10 weeks, primarily to protect the injured joint area rather than the diaphyseal region. From 6 to 10 weeks postoperatively, touch‑down weight‑bearing is gradually transitioned to full weight‑bearing over a period of 2–3 weeks. Ideally, the patient should achieve full weight‑bearing without assistive devices (e.g., crutches) by 12 weeks postoperatively.

VII. Follow‑up

Wound Assessment
Wound healing should be evaluated at 2–3 weeks postoperatively. Subsequently, follow‑up visits are usually scheduled at 6 weeks, 12 weeks, 6 months, and 12 months. Serial radiographs allow the surgeon to assess fracture healing progress.

Implant Removal
Implant removal is not mandatory, but if implant‑related symptoms develop after fracture union, removal should be discussed with the patient.

Thromboembolic Prophylaxis
Thromboprophylaxis should follow local institutional guidelines.