Case report: proximal tibiofibular joint instability-a forgotten cause in revision total knee arthroplasty?

Abstract

Background: Proximal tibiofibular joint instability (PTJI) is a rare condition, particularly in total knee arthroplasty (TKA) revision, with only one prior case reported. This case highlights the importance of considering PTJI in patients with chronic lateral knee pain and instability following TKA and demonstrates a novel stabilization approach for managing this challenging condition.

Case description: A 73-year-old female with a history of multiple knee surgeries presented to our clinic due to increasing lateral knee pain radiating along the syndesmosis, aggravated by activities like squatting. Clinical examination revealed anteroposterior subluxation of the fibular head, suggesting PTJI. Radiological findings confirmed tibial component loosening, and the diagnosis of aseptic loosening with PTJI was made. Given her complex surgical history, a two-stage revision was planned. The first stage involved prosthesis removal, bacteriological sampling, and spacer placement. The second stage included revision TKA and proximal tibiofibular joint (PTFJ) stabilization using a Twin Tail Tight-Rope™ system and Arthrex endobutton, preserving joint mobility and restoring functional stability. A hinged revision knee prosthesis was then implanted. The patient had an uneventful recovery. At 1-year follow-up, the pain score was 1/10 and she achieved good mobility. Radiographs showed satisfactory implant positioning. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) score of 15/96 indicated a successful outcome.

Conclusions: PTJI is rare and is not typically associated with TKA. This case report highlights a unique presentation of PTJI in a multi-revised TKA, raising concerns about the potential role of repeated proximal tibial resections in ligamentous instability of the PTFJ. The specific localization of pain and its resolution following PTFJ fixation support this hypothesis. Therefore, careful assessment of the PTFJ should be considered in TKA revisions, particularly in cases involving extensive lateral tibial resections.

Keywords: Proximal tibiofibular joint instability (PTJI); case report; complications in total knee arthroplasty (complications in TKA); ligamentous injury; revision knee surgery.

Figure 1

X-ray follow-up. (A) Native knee. (B) Unicompartmental knee arthroplasty. (C) Unicompartmental knee arthroplasty with a loose tibia. (D) Conversion to a total knee arthroplasty with a stem.

Figure 2

X-ray follow-up. (A) Total knee arthroplasty with a loose tibial component. (B) Conversion to a revision prosthesis. (C) Change of the tibial component. (D) Change of the prosthesis with stabilisation of the proximal tibiofibular joint.

Figure 3

Scintigraphy. (A) Axial, (B) coronal, (C,D) sagittal views of the scintigraphy showing tibia component loosening, and activity around the proximal fibula.

Figure 4

Intra operative image. The tibial cut is too low, resulting in the absence of the proximal tibiofibular ligament. The Twin Tail Tight-Rope™ is passing through the fibula head, with two strands across the tibia, avoiding the medullary canal.

Figure 5

Illustration of the stabilisation system.

Figure 6

Post-operative X-ray. (A) Anteroposterior at 6 weeks. (B) Lateral at 6 weeks. (C) Anteroposterior at 1 year. (D) Lateral at 1 year.