De Novo Reconstruction of a Hybrid Patella by Staged Fabrication of a Microvascular Bone Transplant with an Osteointegrated Prosthetic Socket

Abstract

Total patellectomy is sometimes unavoidable but usually results in severely impaired function, pain, and instability in the affected knee. Any patellar prosthetic solutions rely on a certain amount of remaining bone and therefore are not applicable after total patellectomy. Traditionally, reconstruction of a neopatella by avascular or allogeneic bone grafts is hampered by mechanical failure, resorption, or infection. We developed a new, 3-stage approach to reconstruct a hybrid patella composed of a revascularized scapula tip transplant fabricated with a prosthetic socket. The procedure is safe and provides optimal healing and prosthetic osteointegration through viable bone and dynamic stability to the considerable load a patella has to bear in unrestricted mobility. The technique also demonstrates successful integration of orthopedic prosthetic devices into current flap fabrication concepts.

Fig. 1.

Right scapular tip burred to receive a patellar prosthetic socket. The Roux hook retracts the latissimus dorsi, the 4-pronged hook retracts the partially elevated teres major muscle.

Fig. 2.

Elevated hybrid flap still pedicled on the angular branch of the thoracodorsal vessels.

Fig. 3.

The polyethylene gliding surface fixed to the prosthetic socket of the hybrid flap with polymethylmethacrylate (PMMA) cement according to the manufacturer (Zimmer Biomet, Warsaw, Ind.). Note the size 0-PDS marionette sutures to fix the hybrid flap underneath the patellar ligament.

Fig. 4.

Hybrid flap fixed in place through paramedian tenotomy. Note the length of the pedicle to be anastomosed to the descending genicular vessels directly.