Combination-type periprosthetic tibial fracture: Felix type (II+IV)A

Abstract

Tibial periprosthetic fractures are rare but present a complicated problem for orthopaedic surgeons. Literature in relation to combination-type periprosthetic fractures is extremely scarce, and there is limited guidance available on its treatment. We report the case of a woman in her 60s, whose radiographs revealed a periprosthetic fracture of the tibia, which was a Felix type (II+IV)A fracture. The tibial tuberosity fragment was fixed with a cannulated cancellous screw. The fracture adjacent to the stem was managed conservatively as the prosthesis was stable. Follow-up radiographs revealed both fractures to have healed completely by 12 weeks. The patient returned to preinjury functional levels by 4 months. Our demonstrated treatment of a Felix type II+IV periprosthetic fracture could be a viable treatment option for such fractures.

Background

Periprosthetic fractures after total knee arthroplasty (TKA) poses a complicated problem for orthopaedic surgeons. They rarely involve the tibia.¹ As a result, literature in relation to tibial periprosthetic fracture is scarce and there is limited guidance available on the ideal treatment for such fractures.² However with the increasing number of TKAs, the incidence of periprosthetic fractures of the tibia is rising.³ The classification proposed by Felix, Stuart and Hansen in 1997 remains the most widely used classification system.⁴ Type I fractures involve the tibial plateau, type II includes fractures adjacent to the stem, type III fractures lie distal to the stem and type IV are those fractures involving the tibial tubercle. They can be further subclassified as type A if the prosthesis is well fixed, type B if the prosthesis is loose and type C if the fracture occurs intraoperatively. Type I fractures have been reported to be the most common type, followed by type II and III, with type IV being extremely rare.⁵

Management of periprosthetic tibial fractures has been shown to involve a relatively high risk of complications and non-union.⁶ The general principle of treatment dictates that fractures with a stable tibial component and well-aligned mechanical tibial axis be managed with closed reduction and cast immobilisation, while major fracture displacement, tibial component malalignment and tibial component instability are indications for surgery.³ Internal fixation with locking plates or intramedullary nails and implant revision are the predominant surgical interventions practised.⁷

Case presentation

A woman in her 60s had a fall and sustained an injury to her right knee. She had previously undergone TKA on same side 6 years earlier. On examination, diffuse swelling and tenderness were present over her right knee.

Investigations

Radiographs of the knee revealed a periprosthetic fracture of the tibia (figure 1A, B). The fracture appeared to involve the tibial tuberosity alone. The tibial prosthesis having a polyethylene stem appeared to be well fixed. As per the Felix classification of tibial periprosthetic fractures, it was classified as type IVA, that is, a fracture involving the tibial tuberosity with a well-fixed implant. Intraoperatively, under radiographic imaging, it was noticed that there was an additional undisplaced fracture adjacent to the stem. This meant it was a Felix type (II+IV) A fracture.

Figure 1.

Radiographs of right knee. (A) Anteroposterior and (B) lateral radiographs showing the periprosthetic tibial fracture. Fracture is seen involving the tibial tuberosity, with the fragment displaced anteriorly. The prosthesis appears stable and well aligned.

Treatment

The tibial tuberosity fragment was fixed with a 4-mm cannulated cancellous screw (figure 2A, B). It was decided to manage the fracture adjacent to the stem conservatively as the prosthesis was stable. An above-knee slab was applied for 4 weeks. Partial weight-bearing mobilisation was started on postoperative day 1. The slab was removed after 4 weeks, and she was advised to wear a knee brace for 8 weeks.

Figure 2.

Postoperative radiographs of right knee. (A) Anteroposterior and (B) lateral radiographs postsurgery showing an anteroposteriorly placed partially threaded cannulated cancellous screw for the tibial tuberosity fragment. Undisplaced fracture is also noted passing through the stem. (C) Anteroposterior and (D) lateral radiographs at 12 weeks of follow-up postsurgery showing complete union of both fracture lines.

Outcome and follow-up

Follow-up radiographs revealed both fractures to have healed completely by 12 weeks following the procedure (figure 2C, D). Full weight-bearing walking was then initiated. The patient returned to preinjury functional levels by 4 months following the injury. At 6 months of follow-up, she was found to have a Knee injury and Osteoarthritis Outcome Score of 89.5 and knee range of movements of 0–100 degrees, which were at par with the recordings made prior to injury.

Discussion

The incidence of type IV tibial periprosthetic fractures involving the tibial tuberosity is extremely rare. Further, there is no literature available on the incidence of fractures involving more than one type, like in our case. This made our case extremely rare and a challenge to treat. Shukla et al in their recent scoping review of available literature on tibial periprosthetic fractures found that only 5.9% of tibial periprosthetic fractures were managed conservatively, whereas 58% were managed with open reduction and internal fixation with plating, and 11.2% were managed with revision TKA.⁸ There are no reported cases of management with screws alone.⁹ Type IV fractures have been reported to be managed with K-wire/cerclage wire, but these require hardware removal after the union.¹⁰ Type II fractures have been predominantly treated with plating.^{11 12} Dual plating has also been recommended for type II fractures.^{13 14} Revision TKA with stemmed components has been advocated when poor bone stock, comminution, far distal fracture configuration, old age, severe osteoporosis or difficulty in achieving stability with plates is present.¹⁵

As the fracture pattern we encountered was rare, there was little literary guidance available on the mode of treatment to be chosen in our case. The fracture adjacent to the stem was undisplaced, with a stable, well-aligned prosthesis. However, the tibial tuberosity fragment was displaced due to the pull of the attached patellar tendon and could not be reduced by closed methods. We, therefore, decided to treat the type IV fracture by open reduction and internal fixation with an anteroposterior cannulated cancellous screw. Both fractures were found to have healed by 12 weeks which was earlier than other reported series.^{13 14} It also had the benefit of decreased blood loss, decreased operative time, shorter hospital stay and lesser cost compared with plating of the tibia. Screw fixation rather than K-wires for the tibial tuberosity fracture avoided the need for hardware removal at later date. While further reports on such cases are required to establish a definitive guideline on the management of such fractures, our demonstration of this case could prove a viable treatment guide for such cases.

Patient’s perspective.

I had pain and was unable to walk after my fall. After the surgery I had pain while walking for 1 month, after which the pain settled down. Now I am able to walk without pain.

Learning points.

• Combination-type periprosthetic fractures are extremely rare and pose a new challenge.

• Our demonstrated treatment of a Felix type (II+IV)A periprosthetic fracture with screws and immobilisation could be a viable treatment option for such fractures.

• It has the benefit of decreased blood loss, decreased operative time, shorter hospital stay and lesser cost compared with plating of the tibia.

Ethics statements

Patient consent for publication

Obtained.