Thomas M. DeBerardino and Brett D. Owens
DEFINITION
Complete tears of the patella tendon are best classified into acute versus chronic.
Partial tears often can be managed nonoperatively. The functional integrity of the extensor mechanism is the key to determining the need for surgical repair.
This chapter focuses on the surgical treatment of complete tendon disruption.
ANATOMY
The patella tendon is approximately 30 mm wide × 50 mm long, with a thickness of 5 to 7 mm.1
The origin on the inferior pole of the patella is juxtaposed to the articular cartilage on the deep side and becomes confluent with the periosteum of the patella anteriorly.2
The tibial insertion is narrower and invests the entirety of the tibial tubercle.
The overlying peritenon is thought to be the cellular source for healing of tendon injuries.
PATHOGENESIS
Tendon rupture usually is the result of underlying tendinosis.6
There is some evidence of genetic predisposition to tendon rupture.
Certain conditions predispose individuals to tendon rupture, including renal dialysis, chronic corticosteroid use, fluoroquinolone antibiotics, and corticosteroid use.
NATURAL HISTORY
The natural history of an untreated patella tendon is complete extensor mechanism dysfunction.
Untreated acute ruptures result in chronic lesions that are more difficult to manage surgically. These often require reconstructive procedures and have inferior functional results.
PATIENT HISTORY AND PHYSICAL FINDINGS
Patients with acute tendon tears may report an audible “pop” or the sensation of their knee giving way.
Patients with chronic injuries may report ambulatory difficulty and pain. These injuries often are treated with bracing before definitive evaluation.
The loss of active knee extension is the key physical examination finding when evaluating for patella tendon rupture.
Loss of tension in the patella tendon with the knee at 90 degrees of flexion and patella alta are indirect signs of rupture.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Plain radiographs may reveal patella alta, avulsion fractures, Osgood-Schlatter lesions, or other concomitant knee injuries.
MRI scans may be helpful in determining the exact location of the rupture and evaluating concomitant intraarticular knee lesions.
DIFFERENTIAL DIAGNOSIS
Quadriceps tendon rupture
Patella fracture
Tibial tubercle avulsion fracture
NONOPERATIVE MANAGEMENT
Nonoperative management should be considered only for patients who are not surgical candidates because of medical comorbidities.
SURGICAL MANAGEMENT
Although not considered to be a surgical emergency, prompt surgical management of acute patella tendon ruptures is recommended.
Preoperative Planning
Repairs of chronic injuries often require allograft tissue availability and careful surgical planning.
Significant patella alta may require proximal release in conjunction with the repair.
Positioning
Supine postioning is recommended.
Use of a tourniquet may preclude proper repair tensioning in chronic injuries.
Prepping and draping of both lower extremities allows use of contralateral limb as a template for patella positioning.
Approach
An anterior approach is used, regardless of the repair technique.
A midline longitudinal incision is made over the patella tendon.
The peritenon is incised longitudinally and dissected away from the underlying tendon.
TECHNIQUES
ACUTE REPAIR
Midsubstance
Grossly pathologic tendon tissue is aggressively débrided.
The full length of the patella tendon is exposed.
Two Krackow locking stitches are placed in each tendon stump with no. 2 or no. 5 Fiberwire (Arthrex, Inc., Naples FL; TECH FIG 1).
Any required retinacular repair stitches are placed with absorbable suture before the tendon repair.
The four proximal core sutures are tied to the four distal core sutures with the knee in full extension.
Integrity of the repair is evaluated by checking the maximal flexion possible prior to gap formation.
The peritenon is closed with absorbable suture.
Proximal Avulsion
Grossly pathologic tendon or bone is removed.
Exposure of the inferior pole of the patella is performed.
If the transosseous drill hole technique is preferred, superficial exposure of the superior pole of the patella is required.
A smaller exposure is required for suture anchor technique.
Three suture anchors are placed in the inferior pole of the patella, equally spaced along the anatomic tendon footprint.
We prefer the 5.0 Bio-Corkscrew FT Suture Anchor (Arthrex, Inc., Naples, FL) loaded with no. 2 Fiberwire (Arthrex, Inc., Naples, FL).
TECH FIG 1 • Repair of acute midsubstance tear.
The suture is pulled through the anchor eyelet to produce long and short suture arms.
The long suture arm is passed down and back up the tendon stump in a locking Krackow fashion (TECH FIG 2).
The tendon is manually reduced to the inferior pole of the patella, and the slack is taken out by the short arm of suture pulled through the eyelet.
Each suture pair is tied securely to complete the repair.
Repair integrity is evaluated by checking the maximal flexion possible before gap formation.
The peritenon is closed with absorbable suture.
Distal Avulsion
Grossly pathologic tendon or bone is removed.
The tibial tubercle is exposed.
Two suture anchors are placed in the tibial tubercle.
We prefer the 5.0 Biocorkscrew FT Anchor loaded with no. 2 Fiberwire (Arthrex, Inc., Naples, FL).
The suture is pulled through the anchor eyelet to produce long and short suture arms. The long suture arm is passed up and back down the tendon stump in a locking Krackow fashion (TECH FIG 3).
The tendon is manually reduced to the tibial tubercle, and the slack is taken out by the short arm of suture pulled through the eyelet.
Each suture pair is tied securely to complete the repair.
Repair integrity is evaluated by checking maximal flexion possible before gap formation.
The peritenon is closed with absorbable suture.
TECH FIG 2 • Repair of acute proximal avulsion.
TECH FIG 3 • Repair of acute distal avulsion.
RECONSTRUCTION OF CHRONIC TEARS
Reconstruction of a chronic tear begins with aggressive débridement of dysplastic tissue.
Remaining tendon tissue is assessed for possible repair.
The tibial tubercle is exposed.
The Achilles allograft is prepared with 15-mm × 25-mm bone block.
A rectangular box is cut out of the tubercle with an oscillating microsurgical saw and osteotomes to receive the bone block.
The block is secured to the tubercle with 2-mm × 3.5-mm cortical screws (TECH FIG 4A).
Suture anchors are placed into the distal pole of the patella and onto the anterior cortex of the patella to secure allograft tendon to the patella (TECH FIG 4B).
The allograft tendon is draped over the quadriceps tendon and muscle fascia and secured with nonabsorbable suture.
TECH FIG 4 • Chronic reconstruction with Achilles tendon allograft. The bone block is inlayed into the tibial tubercle and fixed with screws or staples. The soft tissue end of the graft is sutured into the patella with suture anchors and into the quadriceps with heavy nonabsorbable sutures. A. Lateral view. B. AP view.
AUGMENTATION PROCEDURES
After the repair has been completed, it is assessed for any need for augmentation.
The following materials can be used for augmentation. They are placed in a box-stitch fashion through drill holes in the patella and tubercle (TECH FIG 5A):
Mersilene tape
No. 5 Fiberwire
No. 5 Ethibond
Steel wire
Cerclage cables
Tibialis tendon allograft
A semitendinosus autograft also may be harvested proximally (while leaving its distal insertion intact) and passed through a drill hole in the patella and either through a drill hole in the tubercle or potted into the proximal tibia if the length is insufficient (TECH FIG 5B).
TECH FIG 5 • Augmentation of the repair can be with a box-stitched suture (A) or a soft tissue graft (B).
POSTOPERATIVE CARE
Weight bearing is allowed with the knee braced in extension.
Early flexion allowances are determined intraoperatively by the quality of the tendon tissue and repair.
Active-assisted range of motion is advanced as tolerated with the goal of 90 degrees of flexion by 4 to 6 weeks and full motion by 10 to 12 weeks after repair.
Strengthening is initiated immediately with isometric quadriceps contractions and progressed to straight-leg raises at 6 weeks.
Return to unrestricted activities is delayed until 6 months.
OUTCOMES
Marder and Timmerman9 reported excellent results in 12 of 14 patients treated with acute repair without augmentation.
Larson and Simonian7 reported excellent results (mean Lysholm score, 97.5) in four cases of acute repair augmented with autologous semitendinosus graft placed in a looped fashion.
Lindy et al8 reported excellent results in 24 patients repaired acutely and augmented with Mersilene tape placed in a looped configuration.
Fujikawa5 reported good results with a patella tendon repair augmented with a synthetic figure-8 weave performed on six patella tendon ruptures. They noted that the augmentation device allowed for early mobilization and good functional outcome.
Two recent biomechanical studies show that an augmented repair is stronger than an unaugmented repair11 and that suture anchor repair is at least as strong as repair through drill holes.3
Two cases of successful treatment of chronic patella tendon ruptures with Achilles allograft reconstruction have been reported.4,10
COMPLICATIONS
Rerupture is the most worrisome complication.
Infection is uncommon but devastating.
Residual quadriceps weakness and extensor lag are more common with repairs of chronic injuries.
REFERENCES
1. Andrikoula S, Tokis A, Vasiliadis HS, et al. The extensor mechanism of the knee joint: an anatomical study. Knee Surg Sports Traumatol Arthrosc 2006;14:214–220.
2. Basso O, Johnson DP, Amis AA. The anatomy of the patellar tendon. Knee Surg Sports Traumatol Arthrosc 2001;9:2–5.
3. Bushnell BD, Byram IR, Weinhold PS, et al. The use of suture anchors in repair of the ruptured patellar tendon. Am J Sports Med 2006;34: 1492–1499.
4. Falconiero RP, Pallis MP. Chronic rupture of a patellar tendon: a technique for reconstruction with Achilles allograft. Arthroscopy 1996;12:623–626.
5. Fujikawa K, Ohtani T, Matsumoto H, et al. Reconstruction of the extensor apparatus of the knee with the Leeds-Keio ligament. J Bone Joint Surg Br 1994;76B:200–203.
6. Kannus P, Jozsa L. Histopathological changes preceding spontaneous rupture of a tendon. A controlled study of 891 patients. J Bone Joint Surg Am 1991;73A:1507–1525.
7. Larson RV, Simonian PT. Semitendinosus augmentation of acute patellar tendon repair with immediate mobilization. Am J Sports Med 1995;23:82–86.
8. Lindy PB, Boynton MD, Fadale PD. Repair of patellar tendon disruptions without hardware. J Orthop Trauma 1995;9:238–243.
9. Marder RA, Timmerman LA. Primary repair of patellar tendon rupture without augmentation. Am J Sports Med 1999;27:304–307.
10. McNally PD, Marcelli EA. Achilles allograft reconstruction of a chronic patellar tendon rupture. Arthroscopy 1998;14:340–344.
11. Ravalin RV, Mazzocca AD, Grady-Benson JC, et al. Biomechanical comparison of patellar tendon repairs in a cadaver model. Am J Sports Med 2002;30:469–473.