You are in: eMedicine Specialties > Orthopedic Surgery > KNEE Quadriceps Tendon RuptureArticle Last Updated: Mar 7, 2008AUTHOR AND EDITOR INFORMATIONAuthor: James Lyle, MD, Consulting Surgeon, Department of Orthopedic Surgery, Hughston Clinic James Lyle is a member of the following medical societies: Christian Medical & Dental Society Coauthor(s): Lynn A Crosby, MD, FACS, Chief of Shoulder Division, Professor, Department of Orthopedic Surgery, Wright State University School of Medicine Editors: Phillip J Marone, MD, Clinical Professor, Department of Orthopedic Surgery, Jefferson Medical College; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Shepard R Hurwitz, MD, Executive Director, American Board of Orthopaedic Surgery; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Carlos J Lavernia, MD, FAAOS, Adjunct Clinical Professor, Department of Orthopedic Surgery, University of Miami School of Medicine; Medical Director, Orthopedic Institute at Mercy Hospital Author and Editor Disclosure Synonyms and related keywords: extensor mechanism disruption, tooth sign, patellar tendon ruptures, jumper's knee, unilateral quadriceps tendon ruptures, bilateral quadriceps tendon ruptures, quadriceps tendon tear INTRODUCTIONRuptures of the quadriceps tendon occur relatively infrequently and usually occur in patients older than 40 years. A strong association exists with numerous systemic diseases and prior degenerative changes in the knee extensor mechanism. Ruptures most often occur unilaterally. Bilateral ruptures are highly correlated with systemic disease but have been reported in healthy patients who do not have predisposing factors.1, 2, 3, 4, 5, 6 Patellar tendon ruptures are less common than are quadriceps ruptures and tend to occur in patients younger than 40 years. In rare cases, partial ruptures of the quadriceps tendon are seen in young athletes with end-stage jumper's knee.7, 8, 9, 10 Jumper's knee usually involves the patellar tendon, although in 25% of cases, the quadriceps is involved. To obtain the best results, the early diagnosis and repair of complete quadriceps ruptures are essential.11 If intervention is delayed, repair is more difficult and results may be compromised. For excellent patient education resources, visit eMedicine's Sprains and Strains—First Aid and Emergency Center and Foot, Ankle, Knee, and Hip Center. Also, see eMedicine's patient education articles Ruptured Tendon, Tendinitis, Knee Pain Overview, and Knee Injury. History of the ProcedureGalen first reported the extensor mechanism injury around 130-201 CE. He described a young man injured during a wrestling match. Several other authors wrote on the subject during the 1700s and 1800s, including Ruysch, Louis Petit, Dupuytren, and Samuel. Treatment was nonoperative. In 1878, Lister was the first to report on surgical repair. In 1887, McBurney reported on the first surgical repair in the United States. The injury was a direct blow to the knee, and the tendon was repaired using catgut and silver wire. After several other reports on surgical repair of extensor mechanism injuries were published in the early 1900s, operative management became standard. In 1949, Steiner and Palmer reported the first case of bilateral, simultaneous ruptures of the quadriceps tendons. Since then, several large series of patients undergoing quadriceps tendon repair have been published. These include works by Scuderi in 1958, Ramsey and Muller in 1970,12 Siwek and Rao in 1981,13 Larsen and Lund in 1986,14 Rasul and Fischer in 1993,15 Rougraff and colleagues in 1996,16 and Konrath and co-authors in 1998.17 Many case reports of bilateral quadriceps ruptures have been published in the last few decades.1, 2, 3, 4, 5, 6 ProblemComplete quadriceps tendon rupture is a disabling injury, and operative repair is required to obtain an optimal result. FrequencyUnilateral ruptures are relatively rare when all types of knee injuries are considered; bilateral ruptures are even less common. However, quadriceps tendon ruptures are more common than are patellar tendon ruptures, although quadriceps tendon ruptures are more likely to be misdiagnosed.18 As mentioned previously, quadriceps tendon rupture usually occurs in patients with predisposing factors who are older than 40 years, but these ruptures may be seen in nearly any age group. Siwek and Rao reviewed 69 cases reported in the literature from 1880-1978 and found that 88% of the ruptures were in patients aged 40 years or older.13 To the authors' knowledge, the youngest patient was a 13-year-old who had been immobilized in a long-leg cast prior to injury. In contrast, partial ruptures occur in young athletes.7, 8, 9, 10 Raatikainen and colleagues reported an average age of 28 years in a series of patients with partial tears.19 Partial and complete tears occur predominantly in males. EtiologyQuadriceps tendon rupture usually occurs during a rapid, eccentric contraction of the quadriceps muscle, with the foot planted and the knee partially flexed. This injury commonly occurs during falls. Other mechanisms of injury include direct blows, lacerations, and iatrogenic causes. McMaster showed that normal tendons in rabbits do not rupture under stress. Instead, linear stress causes disruption at the musculotendinous junction, the muscle belly, or the tendinous insertion into bone. Harkness demonstrated that approximately 30 kg/mm2 of longitudinal stress may be applied to normal quadriceps tendons prior to failure. Additionally, many ruptures occur after relatively trivial trauma. Therefore, tendon rupture usually occurs through a pathologic area of the tendon. Many conditions have been reported to contribute to degeneration of the quadriceps tendon, including the following:
Repetitive motion has been implicated as the cause of jumper's knee. Rare iatrogenic cases have been reported. Examples include rupture after total knee arthroplasty (TKA), lateral retinacular release, meniscectomy, and anterior cruciate ligament (ACL) reconstruction with central-third patellar tendon graft. In addition, steroid injections are believed to weaken tendons. Quadriceps tendon ruptures have also reportedly occurred with knee and patellar dislocations. PathophysiologyQuadriceps tendon rupture usually occurs distally 0-2 cm from the superior pole of the patella, through pathologic tissue. Various systemic conditions may cause damage to the tendon vascular supply or may disrupt the tendon structure. Diabetes can cause arteriosclerotic changes in tendon vessels. Fibrinoid necrosis of tendons is seen with chronic synovitis. Hyperparathyroidism causes dystrophic calcifications and subperiosteal bone resorption at the tendon insertion. Obesity causes fatty degenerative changes in tendons and increases the forces on the tendon. Fatty degeneration, fibrinoid degeneration, and decreased collagen are seen with normal aging. Kannus and Jozsa examined histopathologic changes in 891 ruptured tendons; about 97% of the pathologic changes were degenerative.22 The degenerative changes included hypoxic degenerative tendinopathy, mucoid degeneration, tendolipomatosis, and calcifying tendinopathy. In the 82 quadriceps tendons, tendolipomatosis was the most common type of degeneration, seen in almost half of the tendons (see Image 1). No signs of inflammatory cells were noted in any of the specimens. In 62% of the ruptured tendons, pathologic changes of the tendon blood supply were seen, including vessel narrowing and thrombosis. These findings led the investigators to suggest that nutrition and decreased blood flow, resulting in local hypoxia and impaired metabolic activity, are key factors in tendon degeneration. ClinicalPatients typically present with acute knee pain, swelling, and functional loss following a stumble, fall, or giving way of the knee. There may be no history of prior knee pain. However, younger patients with jumper's knee usually have a history of chronic, activity-related pain above the patella that is exacerbated by jumping or kneeling. Specifically ask patients about any history of systemic disease, steroid use, infection, tumors, or prior surgeries. There may be a history of an audible pop at the time of injury. Begin the physical examination by noting any obesity. Patients with recent ruptures have difficulty ambulating. Usually, obvious suprapatellar swelling, ecchymosis, and tenderness are present. Carefully evaluate lacerations. There may be a palpable defect in the suprapatellar area and a low-lying patella, but swelling initially may obscure this finding. Testing for full, active extension against gravity is the most important aspect of the examination. This may make the defect more apparent. Extension lags of varying degrees are seen, depending on the amount of retinacular damage. In incomplete ruptures, the patient may be able to fully extend the knee from the supine position but not from the flexed position. If only tendinitis is present, no extension lag should be noted with any test position. Examine the contralateral knee to rule out bilateral rupture. If the patient is not seen in the acute phase, diagnosing the rupture becomes more difficult, and it can be easily missed. Ramsey and Muller reported misdiagnosis in 7 of 17 ruptures.12 Patients with quadriceps tears, especially elderly patients, have been identified as having had and having been treated for strokes, radiculopathy, and myelopathy. Many patients are thought to have only simple knee sprains during their examination in the emergency room and are not given appropriate, immediate follow-up. Pain and swelling decrease over time, and quadriceps function can improve. Patients may be able to ambulate but will do so with a gait demonstrating knee stiffness and elevation of the hip to accommodate the swing-through phase. In addition, patients may have frequent buckling of the knee and difficulty with stair climbing. Results of neurologic examination are normal except for decreased quadriceps motor function and an absent patellar reflex. Again, full, active knee extension against gravity is the key component of the physical examination. INDICATIONSEarly operative repair is indicated for all acute, complete quadriceps tendon ruptures, provided that the patient is a suitable surgical candidate. Surgery is also indicated for most chronic, complete quadriceps ruptures. Although repair/reconstruction is technically more difficult and results are inferior to those of early repair, successful results have been reported with surgery performed even as late as a year following injury. Partial tears may be treated nonoperatively unless they are refractory to a long course of conservative management. RELEVANT ANATOMYThe quadriceps muscle is composed of 4 muscle groups, including the vastus intermedius, vastus medialis, vastus lateralis, and rectus femoris. The quadriceps tendon is formed by the convergence of all 4 muscles just proximal to the superior patella. The tendon is multilayered. The rectus femoris becomes tendinous 3-5 cm proximal to the patella and is the most superficial layer inserting on to the patella. Some of its fibers continue over the anterior patellar surface and contribute distally to the patellar tendon. The middle layer is composed of the vastus lateralis and vastus medialis. The vastus medialis, which is composed of the vastus medialis obliquus and the vastus medialis longus, becomes tendinous only a few millimeters from its insertion into the patella. The vastus lateralis becomes tendinous about 3 cm proximal to its insertion into the patella. The deep layer is composed of the vastus intermedius. The tendon has an average thickness of 8 mm and an average width of 35 mm. Peterson and colleagues found that the blood supply to the quadriceps tendon arises from the descending branches of the lateral circumflex femoral artery, branches of the descending geniculate artery, and branches of the medial and lateral superior geniculate arteries.23 The superficial layers are well vascularized. In the deep layer, however, there is an oval, avascular area that is 30 X 15 mm in size; it probably plays a significant role in tendon degeneration. CONTRAINDICATIONSNo contraindications for acute repair of quadriceps tendon ruptures exist provided that the patient is an adequate surgical candidate. For delayed repair/reconstruction, no contraindications for surgery appear to exist up to 1 year following injury. The authors are unaware of any literature on operative management performed later than 1 year following rupture. WORKUPLab Studies
Imaging Studies
See also the following related eMedicine topic: Histologic FindingsHistologic study is usually not included in the preoperative workup. See Pathophysiology for histologic details. TREATMENTMedical TherapyConservative treatment is indicated for partial tears. Immobilize the knee in full extension for 3-6 weeks. Straight-leg raises are started late in the immobilization phase. If these can be performed without discomfort for 10 days, immobilization can be progressively discontinued. Range-of-motion (ROM) exercises are then initiated and quadriceps strengthening is continued until the strength of the injured leg is equal to that of the contralateral leg. Surgical TherapyEarly surgical repair yields the best results for complete quadriceps tendon ruptures.29, 30 Many techniques have been described for the repair and augmentation of acute and neglected tears, including the following:
Intraoperative DetailsDirect repair of the tendon can be performed for most acute ruptures and for some neglected ruptures. A midline longitudinal incision is made exposing the rupture (see Image 4). The tear site is irrigated, and the torn tendon edges are debrided back to healthy tissue. Occasionally, if adequate tendon remains distally, an end-to-end repair can be performed. Several heavy, nonabsorbable mattress sutures are placed through the tendon, and absorbable sutures are used to re-approximate the retinaculum. Some authors advocate leaving the lateral retinaculum open for better patellar tracking. Usually, insufficient tendon remains distally or the tear is at the osteotendinous junction. In these cases, the tendon is repaired to a bony trough in the patella. Again, the proximal tendon edge is freshened. The superior pole of the patella is debrided of any remaining tendon, and a transverse bony trough is made. The trough should not be made near the anterior surface of the patella, to avoid patellar tilt. Three or 4 longitudinal holes are drilled about 1 cm apart from the bony trough to the inferior pole of the patella (see Image 5). Running, interlocked stitches are placed medial and lateral in the tendon using 5-0 nonabsorbable suture. The Bunnell-type weave and Krackow whipstitches are popular. The free suture ends are passed through the drill holes from proximal to distal with a suture passer (see Image 6). The tendon then is pulled by the sutures distally into the trough (see Image 7). Secure the sutures with a hemostat, and assess patellar rotation and tracking throughout the ROM of the knee. If satisfactory, tie the sutures distally and repair the retinaculum with absorbable sutures (see Image 8). Additionally, if a significant vastus intermedius stump remains, this may be used to augment the repair posteriorly. After routine subcutaneous and skin closure, apply a cylinder cast with the knee in full extension. If necessary, the repair may be reinforced with extra tissue by using the Scuderi technique. A triangular flap from the anterior portion of the tendon is fashioned, with the base about 5 cm proximal to the tear. The flap should be roughly 3-4 mm thick, 7.5 cm long on each side, and 5 cm wide at its base. The posterior portion of the tendon is left intact. The apex of the triangle is folded distally and sutured over the repair site. Bunnell pull-out wires are placed medially and laterally, running from the quadriceps tendon to the patellar tendon, exiting the skin distally. Following wound closure, the knee is cast in full extension. For chronic ruptures, a direct repair with augmentation using the Scuderi technique (if necessary) is attempted. The quadriceps tendon and muscle are freed from adhesions. If the tendon cannot be re-approximated to the patella, the Codivilla tendon lengthening technique can be used. A triangular flap is fashioned similar to that used in the Scuderi technique, except that the flap consists of the full thickness of the tendon. Also, the base of the flap is more distal, about 1.5-2.0 cm proximal to the tear. The tendon and retinaculum then are advanced distally until re-approximation is possible. Suturing is performed as previously described. The flap is folded distally and sutured over the repair. The proximal aspect of the open triangle is repaired with absorbable suture. Pull-out wires are recommended to protect the repair. If a defect remains following Codivilla lengthening, options for additional augmentation include the vastus lateralis strip, fascia lata grafts, the sartorius rotational flap, and artificial graft material. If a long course of conservative management for partial quadriceps tendon ruptures fails, surgery may be necessary. Repair using patellar drill holes, as well as simple excision of the scar tissue and closure, has been advocated. Postoperative DetailsSutures or staples are removed at 2-3 weeks. Pull-out wires are removed at 3 weeks. Most authors prefer cylinder casting for 4-6 weeks. Immediate postoperative weight bearing as tolerated with a walker or crutches is allowed by many authors. Isometric quadriceps exercises may be started in the cast. When the cast is removed, ROM exercises are initiated along with continued quadriceps strengthening.33 A hinged knee brace may be used, with flexion gradually increased over time. Therapy is continued until strength and motion are comparable to those of the uninjured leg. The goal of therapy is to obtain full extension and flexion. A few authors have advocated immediate postoperative ROM exercises and delayed weight bearing. For chronic repairs, postoperative treatment is similar, but protection of the repair and rehabilitation can be longer. Postoperative care for partial tear repairs requires minimal immobilization and a shorter period of rehabilitation. Follow-upAthletes treated for partial or complete ruptures may return to play when several conditions are met, including the following:
COMPLICATIONSThe most common complications are loss of motion and extensor mechanism weakness. Infection, wound compromise, and skin breakdown from casting occasionally occur. Although uncommon, malalignment of the patella, including patella alta, patellar tilt, and patellar subluxation, is possible. Take care to restore normal alignment during surgery, because malalignment can lead to degenerative changes of the patellofemoral joint. Repeat rupture occurs infrequently. Rougraff and colleagues reported 2 repeat ruptures in 53 repairs, while Konrath and associates observed 1 repeat rupture in 50 repairs.17, 16 OUTCOME AND PROGNOSISStudies generally have reported good results following early repair of complete unilateral and bilateral quadriceps tendon ruptures.34 The type of repair, the location of the tear, the patient's age and sex, and the mechanism of injury do not appear to affect the results. Good ROM usually can be regained, but some persistent quadriceps weakness is fairly common. Most patients can return to their previous occupation, but many cannot return to their pre-injury activity level. In a large study, Konrath and associates found that 83% of patients returned to their previous occupations, 51% were unable to return to their pre-injury activity levels, and 53% had persistent quadriceps strength deficits (>20% compared with the uninjured leg).17 Patients had a mean thigh atrophy of 1.5 cm compared with that of the uninjured leg. Several studies have shown markedly worse results with delayed repairs. Rougraff and colleagues reported significantly poorer functional results, lower satisfaction scores, and lower isokinetic data in patients with delayed repair.16 Raatikainen and coworkers reported good results from simple debridement and repair of partial quadriceps tendon ruptures.19 FUTURE AND CONTROVERSIESSeveral authors advocate immediate postoperative motion to potentially increase ultimate ROM. Studies also have shown that mobilized tendons heal faster and are stronger than are immobilized tendons. In 2 studies, artificial graft was used to augment the repair and to allow early motion. Konrath and associates reported successful immediate motion without routine augmentation.17 However, other studies have shown that ROM is routinely regained after up to 6 weeks of immobilization. Rougraff and colleagues found that nearly all patients (including patients with delayed repairs) regained motion to within 2º of their uninjured leg.16 Additionally, their study provided the only comparison of immobilization and immediate motion in the literature to date; however, the immediate motion group was very small. No significant difference existed in the ultimate ROM between the groups. Future research comparing larger groups of patients treated with immobilization and early motion is needed to help resolve this issue. With the growing popularity of suture anchor fixation in other aspects of orthopedic surgery, more research will probably follow to better define the role of this technique in quadriceps tendon ruptures. Finally, care must be taken to educate all physicians on the importance of testing the integrity of the extensor mechanism in the injured knee. It is hoped that physician awareness will lead to fewer cases of misdiagnosis of extensor mechanism injuries. MULTIMEDIA
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Quadriceps Tendon Rupture excerpt Article Last Updated: Mar 7, 2008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||