Review Question - QID 219564

The patient sustained a complete quadriceps tendon rupture and has a history of long-standing inflammatory arthropathy, which has been shown to be an independent risk factor for failure of primary quadriceps tendon repair.

Quadriceps tendon ruptures represent a traumatic disruption of the quadriceps insertion on the superior pole of the patella, most often due to eccentric loading of the extensor mechanism in an individual with a planted foot and slightly bent knee. They typically occur in patient's aged >40 years, more frequently in males than females (up to > 8:1), with inflammatory arthropathy (particularly Rheumatoid arthritis) serving as a risk factor for rupture. Patients with a complete rupture present clinically with a palpable defect within 2cm of the superior pole of the patella and are unable to initiate or sustain a straight leg raise. Partial tears can be treated non-operatively in a hinged knee brace, but complete ruptures requite surgical repair with tendinous re-attachment to the patella. Repair techniques vary and include the use of transosseous suture fixation and suture anchor fixation; however, suture anchor fixation has been shown in the literature to result in decreased gap formation and increased ultimate loads to failure of the repaired construct.

Roberts et al. reviewed the rates and risk factors for failure of surgical repair of the knee extensor mechanism. The authors performed a retrospective cohort study of 294 patients and 303 extensor mechanism repairs (113 of which were quad tendon repairs) and found 6 failures (5%) in the quad tendon repair group. In the quad tendon repair group specifically, the authors found a history of inflammatory arthritis to be significantly correlated with repair failure. They concluded that inflammatory arthritis in patients with quad tendon ruptures is an independent risk factor for failure of a subsequent primary repair.

Negrin et al. reviewed the differences in demographic data and long-term outcome after surgical treatment of extensor mechanism ruptures of the knee. The authors reviewed the data of 130 patients (93 with quad tendon ruptures) from a level I trauma center over a 15-year time period and found that 8% of the quad tendon repairs suffered wound healing disorders/septic complications, while an additional 8% sustained a re-rupture. They concluded that quad tendon repair patients suffering a re-rupture had a significantly worse outcome in all scores except for the KSS-Knee score.

Figure A is a T1-weighted sagittal MRI slice demonstrating a complete rupture of the quadriceps tendon. Figure B is a lateral radiograph demonstrating primary quadriceps tendon repair with suture anchor fixation.

Incorrect Answers:
Answer 1: Even with suture anchor fixation immediate post-operative ROM should be limited to avoid repair failure, especially in patients that are at high risk for re-rupture.
Answer 2: Post-operative strength loss of up to 33-50% of initial quadriceps strength can be expected after repair, with nearly 50% of patients unable to return to their prior level of sport.
Answer 4: Suture anchor fixation has been shown to decrease gap formation and increase the ultimate load to failure of the repaired construct, thereby increasing (not decreasing) pull-out strength.
Answer 5: Non-operative management is not suitable for a patient with a complete quadriceps tendon rupture and an incompetent extensor mechanism.