Complete avulsion of the patellar tendon from the tibial tubercle in an adult without predisposing factors

Abstract

IntroductionAcute traumatic patellar tendon rupture in the adult pop-ulation usually occurs in younger patients (\40 years old)during athletic activities in which the quadriceps contractseccentrically when the knee is flexed. Systemic disease andsteroid use may predispose to rupture [1, 2], which in thevast majority of cases involves the tendon’s origin at theinferior pole of the patella [2, 3]. Ruptures of the distalpatellar tendon are extremely rare. Only two cases ofpartial rupture of the distal insertion of the patellar tendonhave been reported, occurring in athletes [4].To the authors’ best knowledge, there have been noreports of complete avulsion of the patellar tendon of thetibial tubercle in the adult. We present a very atypical caseof complete distal avulsion of the patellar tendon in anotherwise healthy patient in the absence of predisposingfactors. The patient was informed that data regarding hercase would be submitted for publication.Case reportA 52-year-old female presented to our institution com-plaining of significant pain in her right knee. She hadsustained a ground level fall directly on the anterior surfaceof her right knee 3 days before presentation. She was ini-tially seen at an outside Emergency Room where she wastold that the radiographs were negative for a fracture. Shewas subsequently placed in a knee immobilizer, givencrutches to ambulate and told to follow up with an ortho-pedic surgeon. Her past medical history is significant forhypertension and anxiety. The patient denied any priortrauma, any pre-existing symptoms or history of systemicdisease, corticosteroid or quinolone use. On physical exam,there was significant swelling and ecchymosis present.There was tenderness to palpation directly over the tibialtubercle. The patient was unable to perform a straight-legraise. There was a palpable defect along the inferiorinsertion of the patellar tendon. Plain radiographs demon-strated patella alta with no identifiable fracture (Fig. 1a, b).An MRI scan was performed that revealed a completeavulsion of the distal patellar tendon from the tibialtubercle insertion with 6 cm of proximal retraction(Fig. 2). The patient was taken to the operating room, andafter evacuating out the traumatic hematoma, the patellartendon was easily identified (Fig. 3a, b). Two no. 5 Tycronsutures were then placed through the patellar tendon andrun distally using a locking Krackow stitch (Fig. 3c). Thetibial tubercle base was then roughened up using a 3-mmbur to create a bleeding base. Three drill holes were thenplaced through the tibial tubercle. A single G2 Mitekanchor was then placed slightly more proximal to whereour tendon was going to attach distally. With the knee infull extension, the patellar tendon was then tied back downto the tibial tubercle over bone tunnels. The limbs of the G2Mitek suture anchor were then secured to reinforce ourrepair and create a broader footprint along the tibialtubercle. Postoperatively, the patient was placed in a hin-ged brace locked in full extension. She was allowed to bearweight as tolerated. Physical therapy was initiated after6 weeks to work on a progressive range of motion andstrengthening. Two and a half months after the procedure,