Surgical Treatment of Chronic Patellar Tendon Rupture: A Case Series Study

Backhrounds Patellar tendon can tolerate a force up to 17.5 times body weight. It is thesecond strongest tendon in the body after the Achilles tendon. Within the patellar tendonis the largest sesamoid bone in the body, the patella. The patellar tendon inserts to thetibial tuberosity (3-1). Rupture is less common in the patellar tendon than in the quadricepstendon. Eccentric contraction of the quadriceps muscle with partial flexion of the knee andfoot on the ground is the most common mechanism that causes rupture of the patellartendon. Degenerative changes may be presented due to repetitive micro-trauma before rupture. Trauma, total knee arthroplasty, anterior cruciate ligament reconstruction withbone-patellar tendon-bone graft, intramedullary nailing of tibia and corticosteroid therapy,and systemic or local injection may cause patellar tendon rupture (5 ,4).Methods This retrospective study included adult patients with chronic patellar tendonrupture, either at mid-substance or due to avulsion from patella or tibial tuberosity,whowere treated surgically by the senior author. A search of the hospital records from2006 to 2013 was done to identify these patients. Late or chronic cases were considered asthose that had been done three or more months after injury (8 ,7). Preoperative subjectiveinternational knee documentation committee (IKDC) (9) and modified Cincinnati kneescores (10) were collected from hospital documents. Records of complications such asinfection, knee stiffness, rerupture, hospitalization for manipulation or surgical releaseand device failure or removal were evaluated. All patients came back for a final visit totake lateral knee radiography and complete subjective IKDC and Modified Cincinnati scoreforms. Conditions of patella Alta or Baja were determined according to the Insall-Salvatiindex (11).Results From 2006 to 2013, ten patients with chronic patellar tendon rupture wereoperated by the senior author at the hospital of a referral center in the capital city. Twopatients had bilateral injuries; one was male and the other was female. The mean timefrom injury to surgery was 23 months (range 132 - 3). Seven cases of injury had been dueto traffic accidents and three cases due to a fall. Both patients with bilateral injury hadsustained injuries in a highenergy traffic accident. The mean age of the patients was 34.4years (range 58 - 18). Six ruptures were in the right knee and six in the left. The mean followuptime was 6.2 years (range 9 - 3). Augmentationwasmadewith both semitendinosus (ST)and gracilis (G) autografts in six of the knees and the only semitendinosus autograft wasused in two knees, one knee treated with Achilles tendon allograft and one with tibialisanterior (TA) tendon allograft. In two of the knees with good remaining tendon tissuewithout quadriceps, the muscle retraction direct repair was made without tendon graftaugmentation. In nine knees, reinforce-ment was made with a cerclage wire and in threeknees with fiberwire between the patella and tibial tubercle.Conclusions All chronic patellar tendon ruptures had enough tissue for direct repair. In all but exceptional cases, tendon graft should be added to the procedure, preferablyautogenously semitendinosus and gracilis; alternatively, an allograft could be applied. Allpatellar tendon repairs must be reinforced by cerclage wire between the patella and tibialtuberosity. Intraoperative lateral knee radiography is strongly recommended to determinepatellar position. A period of four weeks of knee immobilization is recommended witha long leg or cylinder cast. Cast immobilization does not compromise a range of motionof the knee joint. After cast removal, a hinged knee brace should be fitted that permitsresumption of ROM 15 - 10 degrees/week. Routine removal of the cerclage wire is notrecommended. Broken wire only needs to be removed in symptomatic cases. All patientsmust be informed preoperatively about