Millers - Sports Medicine - Section 1 Knee

Front 1

Origin and insertion of ACL

Back 1

The tibial insertion is a broad, irregular, oval area just anterior to and between the intercondylar eminences of the tibia. The femoral attachment is a semicircular area on the posteromedial aspect of the lateral femoral condyle

Front 2

Bundles of the ACL

Back 2

The ACL is often said to be composed of two “bundles”—an anteromedial bundle that is tight in flexion and a posterolateral bundle that is tight in extension. The ACL is composed of 90% type I collagen and 10% type III collagen.

Front 3

Size of the ACL

Back 3

ACL is approximately 33 mm long and 11 mm in diameter.

Front 4

blood supply to cruciate ligaments

Back 4

The blood supply to both cruciate ligaments is via branches of the middle geniculate artery and the fat pad.

Front 5

Origin and insertion of PCL

Back 5

The posterior cruciate ligament (PCL) originates from a broad, crescent-shaped area anterolaterally on the medial femoral condyle and inserts into a tibial sulcus that is below the articular surface

Front 6

meniscofemoral ligaments

Back 6

Variable meniscofemoral ligaments (Humphry's [anterior]; Wrisberg's [posterior]) originate from the posterior horn of the lateral meniscus and insert into the substance of the PCL.

Front 7

Bundles of the PCL

Back 7

It is also composed of two bundles—an anterolateral portion that is tight in flexion and a posteromedial portion that is tight in extension.

Front 8

Size of the PCL

Back 8

The PCL is approximately 38 mm in length and 13 mm in diameter.

Front 9

composition of the medial collateral ligament (MCL)

Back 9

Composed of superficial and deep fibers. The superficial MCL (tibial collateral ligament) lies deep to the gracilis and semitendinosus tendons; originates from the medial femoral epicondyle; and inserts onto the periosteum of the proximal tibia, deep to the pes anserinus. The anterior fibers of the superficial MCL tighten during the first 90 degrees of motion, while the posterior fibers tighten in extension. The deep portion of the ligament (medial capsular ligament) is a capsular thickening that blends with the superficial fibers and is intimately associated with the medial meniscus (coronary ligaments).

Front 10

The lateral collateral ligament (LCL),

Back 10

The lateral collateral ligament (LCL), or fibular collateral ligament, is a cordlike structure that originates on the lateral femoral epicondyle posterior and superior to the insertion of the popliteus tendon and inserts on the lateral aspect of the fibular head. Because it is located behind the axis of knee rotation, the LCL is tight in extension and lax in flexion.

Front 11

The posteromedial corner

Back 11

The posteromedial corner, a structure deep and posterior to the superficial MCL and contiguous with the deep MCL, is important to rotary stability. The posteromedial corner consists of the capsular thickening of the multiple insertions of the semimembranosus; the posterior oblique ligament (POL), which originates on the adductor tubercle; and the oblique popliteal ligament, or thickening of the posterior capsule.

Front 12

posterolateral corner

Back 12

The posterolateral corner is becoming increasingly important in treating the multiple ligament–injured knee. It consists of the biceps, iliotibial band, and popliteus (which originates on the back of the tibia and inserts medial, anterior, and distal to the LCL); the popliteofibular ligament; the lateral capsule; the arcuate ligament (which is contiguous with the oblique popliteal ligament medially); and the fabellofibular ligament (the lateral two are really just thickenings of the joint capsule).

Front 13

Menisci

Back 13

The menisci are crescent-shaped, fibrocartilaginous structures that are triangular in cross section. They are composed predominantly of type 1 collagen. Only the peripheral 20-30% of the medial meniscus and 10-25% of the lateral meniscus are vascularized (medial and lateral genicular arteries, respectively). The medial meniscus is more C shaped, and the lateral meniscus is more circular in shape. These structures deepen the articular surfaces of the tibial plateau and have a role in stability, lubrication, and nutrition. They are connected anteriorly by the transverse (intermeniscal) ligament and are attached peripherally via the coronary ligaments.

Front 14

Collagen in Menisci

Back 14

Type 1

Front 15

Vascularity of Menisci

Back 15

Only the peripheral 20-30% of the medial meniscus and 10-25% of the lateral meniscus are vascularized (medial and lateral genicular arteries, respectively)

Front 16

Shape of Menisci

Back 16

The medial meniscus is more C shaped, and the lateral meniscus is more circular in shape

Front 17

Comparison of size / shape of medial & lateral femoral condyles

Back 17

The anteroposterior dimensions of the lateral femoral condyle are greater than those of the medial condyle. The alignment of the condyles is also different; the lateral condyle is relatively straight, but the medial condyle is curved (allowing the medial tibial plateau to rotate externally in full extension—the “screw-home mechanism”). The lateral condyle can also be identified by its terminal sulcus and groove of the popliteus insertion

Front 18

The patella is restrained in the trochlea by what?

Back 18

The patella is restrained in the trochlea by the valgus axis of the quadriceps mechanism (Q angle), the oblique fibers of the vastus medialis (VMO) and lateralis muscles (and their extensions—the patella retinaculum), and the patellofemoral ligaments

Front 19

The role of the ligaments of the knee is to ?

Back 19

The role of the ligaments of the knee is to provide passive restraints to abnormal motion

Front 20

The motion of the knee joint and interplay of ligaments

Back 20

The motion of the knee joint and interplay of ligaments have been described as a four-bar cruciate linkage system (Fig. 4–5). As the knee flexes, the center of joint rotation (intersection of the cruciate ligaments) moves posteriorly, causing rolling and gliding at the articulating surfaces. The concept of ligament “isometry” remains controversial.

Front 21

Meniscal biomechanics

Back 21

The collagen fibers of the menisci are arranged radially and longitudinally. The longitudinal fibers help dissipate the hoop stresses in the menisci, and the combination of fibers allows the meniscus to expand under compressive forces and increase the contact area of the joint. The lateral meniscus has twice the excursion of the medial meniscus during knee range of motion (ROM) and rotation. Studies have shown that an ACL deficiency may result in abnormal meniscal strain, particularly in the posterior horn of the medial meniscus.

Front 22

The main restraint to lateral displacement of the patella

Back 22

The MPFL

Front 23

MEDIAL STRUCTURES OF THE KNEE: Layers & Components

Back 23

I Sartorius and fascia
II Superficial MCL, posterior oblique ligament, semimembranosus
III Deep MCL, capsule


Note: The gracilis, semitendinosus, and saphenous nerves run between layers I and II.

Front 24

LATERAL STRUCTURES OF THE KNEE: Layer & Components

Back 24

I Iliotibial tract, biceps, fascia
II Patellar retinaculum, patellofemoral ligament
III Arcuate ligament, fabellofibular ligament, capsule, LCL

Note: The inferior lateral geniculate artery is deep to the LCL and is at risk with aggressive meniscal resection

Front 25

Age of patient and knee injuries

Back 25

older patients are more likely to have degenerative conditions

Front 26

KEY HISTORICAL POINTS THAT INDICATE MECHANISM for knee injuries

Pain after sitting/climbing stairs
Locking/pain with squatting
Non–contact injury with “pop”
Contact injury with “pop”
Acute swelling
Knee “gives way”
Anterior force—dorsiflexed foot
Anterior force—plantar-flexed foot
Dashboard injury
Hyperextension, varus, and tibial external rotation

Back 26

Pain after sitting/climbing stairs Patellofemoral etiology
Locking/pain with squatting Meniscal tear
Non–contact injury with “pop” ACL tear, patellar dislocation
Contact injury with “pop” Collateral ligament, meniscus, fracture
Acute swelling ACL, peripheral meniscal tear, osteochondral fracture, capsule tear
Knee “gives way” Ligamentous laxity, patellar instability
Anterior force—dorsiflexed foot Patellar injury
Anterior force—plantar-flexed foot PCL injury
Dashboard injury PCL or patellar injury
Hyperextension, varus, and tibial external rotation Posterolateral corner injury

Front 27

Insall-Salvati index:

Back 27

Ratio, or index, of patella tendon length (LT) to patella length (LP) should be 1.0. An index of 1.2 is alta and 0.8 is baja.

Front 28

The benefits of arthroscopic versus open techniques on the knee

Back 28

include smaller incisions, less morbidity, improved visualization, and decreased recovery time.

Front 29

Portals for knee arthroscopy

Back 29

Standard portals include superomedial and superolateral outflow portals (made with the knee in extension but may not be necessary with newer pump systems) and inferomedial and inferolateral portals (made with the knee in flexion) for instrument placement and the arthroscope, respectively (Fig. 4–8). Accessory portals, sometimes helpful for visualizing the posterior horns of the menisci and PCL, include the posteromedial portal (1 cm above the joint line behind the MCL [be careful to avoid saphenous nerve branches]) and the posterolateral portal (1 cm above the joint line between the LCL and biceps tendon [avoiding the common peroneal nerve]). The transpatellar portal (1 cm distal to the patella, splitting the patellar tendon fibers) can be used for central viewing or grabbing but should be avoided in patients requiring subsequent autogenous patellar tendon harvesting. Other, less commonly used portals include the medial and lateral midpatellar portals; the proximal superomedial and superolateral portals (4 cm proximal to the patella), which are used for patellofemoral compartment visualization; and the far medial and far lateral portals, which are used for accessory instrument placement (loose-body removal).Standard portals include superomedial and superolateral outflow portals (made with the knee in extension but may not be necessary with newer pump systems) and inferomedial and inferolateral portals (made with the knee in flexion) for instrument placement and the arthroscope, respectively (Fig. 4–8). Accessory portals, sometimes helpful for visualizing the posterior horns of the menisci and PCL, include the posteromedial portal (1 cm above the joint line behind the MCL [be careful to avoid saphenous nerve branches]) and the posterolateral portal (1 cm above the joint line between the LCL and biceps tendon [avoiding the common peroneal nerve]). The transpatellar portal (1 cm distal to the patella, splitting the patellar tendon fibers) can be used for central viewing or grabbing but should be avoided in patients requiring subsequent autogenous patellar tendon harvesting. Other, less commonly used portals include the medial and lateral midpatellar portals; the proximal superomedial and superolateral portals (4 cm proximal to the patella), which are used for patellofemoral compartment visualization; and the far medial and far lateral portals, which are used for accessory instrument placement (loose-body removal).

Front 30

Arthroscopic complications of knee artroscopy

Back 30

The most common arthroscopic complication is iatrogenic articular cartilage damage. Additional complications include instrument breakage, hemarthrosis, infection, and neurovascular injury.

Front 31

Evaluation of the knee by knee arthroscopy

Back 31

A systematic examination of the knee should include evaluation of the patellofemoral joint, medial and lateral gutters, medial and lateral compartments, and the intercondylar notch. The posteromedial corner can be best visualized with a 70-degree arthroscope placed through the notch (modified Gillquist's view) or a posteromedial portal. Each knee arthroscopy should include an evaluation of the suprapatellar pouch; patellofemoral joint and tracking; medial and lateral gutters; medial compartment, including the medial meniscus and the articular surface; the lateral compartment, including the lateral meniscus and the articular surface; and the intercondylar notch to visualize the ACL and PCL.

Front 32

the most common injury to the knee that requires surgery

Back 32

Meniscal tears

Front 33

Which is more common, tears of the medial or lateral meniscus

Back 33

The medial meniscus is torn approximately three times more often than the lateral meniscus

Front 34

Traumatic vs. degenerative meniscal tears

Back 34

Traumatic meniscal tears are common in young patients with sports-related injuries. Degenerative tears usually occur in older patients and can have an insidious onset.

Front 35

When to initiate treatment of mensical tears

Back 35

Treatment—In the absence of intermittent swelling, catching, locking, or giving way, meniscal tears, particularly those degenerative in nature, may be treated conservatively. Younger patients with acute tears, tears causing mechanical symptoms, and those that fail to improve with conservative measures may benefit from operative treatment.

Front 36

Partial meniscectomy

Back 36

Tears that are not amenable to repair (i.e., peripheral, longitudinal tears), excluding those that do not require any treatment (i.e., partial-thickness tears, those >5 mm in length, and those that cannot be displaced >1-2 mm), are best treated by partial meniscectomy.

In general, complex, degenerative, and central/radial tears are treated with resection of a minimal amount of normal meniscus. A motorized shaver is helpful for creating a smooth transition zone (Fig. 4–10). The role of lasers or other devices for this purpose is still under investigation. There is some concern about possible iatrogenic chondral injury caused by lasers and other thermal devices.

Front 37

Meniscal repair

Back 37

Should be done for all peripheral longitudinal tears, especially in young patients and in conjunction with an ACL reconstruction. Augmentation techniques (fibrin clot, vascular access channels, synovial rasping) may extend the indications for repair. Four techniques are commonly used: open, “outside-in,” “inside-out,” and “all-inside” (Fig. 4–11). Newer techniques for all-inside repairs (arrows, darts, staples, screws, etc.) are popular because of their ease of use; however, they are probably not as reliable as vertical mattress sutures. The latest generation of “all-inside” devices allows tensioning of the construct. Nevertheless, the gold standard for meniscal repair remains the inside-out technique with vertical mattress sutures. Regardless of the technique used, it is essential to protect the saphenous nerve branches during medial repairs and the peroneal nerve during lateral repairs

Front 38

Results of meniscal repair

Back 38

Several studies report 80–90% success rates with meniscal repairs. However, this depends upon location, type of tear, and chronicity. It is generally accepted that the results of meniscal repair are best with acute peripheral tears in young patients with concurrent ACL reconstruction. Generally, a 90% success rate can be achieved with meniscal repair performed in conjunction with an ACL reconstruction, 60% success with a repair in which there is an intact ACL, and 30% with a repair in which there is an ACL-deficient knee

Front 39

Meniscal cysts

Back 39

Occur primarily in conjunction with horizontal cleavage tears of the lateral meniscus (Fig. 4–13). Operative treatment consisting of arthroscopic partial meniscectomy and decompression through the tear (sometimes including “needling” of the cyst) has been shown to be effective. En bloc excision is no longer favored for most meniscal cysts. Popliteal (Baker's) cysts are commonly related to meniscal disorders and usually resolve with treatment of the primary disorder. They are usually located between the semimembranosus and medial head of the gastrocnemius.

Front 40

Usual location of meniscal cysts

Back 40

They are usually located between the semimembranosus and medial head of the gastrocnemius.

Front 41

Discoid menisci

Back 41

(“popping knee syndrome”)—

Can be classified as (1) incomplete, (2) complete, or (3) Wrisberg's variant

Patients may develop mechanical symptoms, or “popping,” with the knee in extension. Plain radiographs may demonstrate a widened joint space, squaring of the lateral femoral condyle, cupping of the lateral tibial plateau, and a hypoplastic lateral intercondylar spine. MRI (three consecutive sagittal images demonstrating a contiguous lateral meniscus) can be helpful and may also demonstrate associated tears. Treatment includes partial meniscectomy (saucerization) for tears, meniscal repair for peripheral detachments (Wrisberg's variant), and simple observation for discoid menisci without tears.

Front 42

Meniscal transplantation

Back 42

Remains controversial but may be indicated for young patients who have had near-total meniscectomy (especially lateral meniscectomy) and who have early symptomatic chondrosis. Relative contraindications include diffuse grades III-IV chondral lesions, kissing lesions (chondral lesions adjacent to each other on the femur and tibia), advanced patient age, and joint space narrowing. ACL deficiency as well as limb alignment needs to be addressed to increase the success rates of meniscal transplants. Pain relief is the most consistent benefit, with most studies having short- to mid-term (5-year) data available. Three-phase bone scans can be used diagnostically in patients who fit inclusion criteria to help determine if they are good surgical candidates. Allograft tissue needs to be appropriately sized and is typically harvested under a sterile technique, appropriately screened, and frozen. Techniques for implantation include the use of individual bone plugs for the anterior and posterior horns and the use of a bone bridge, especially laterally.

Front 43

Bone bruises following ACL tear

Back 43

Bone bruises (trabecular microfractures) occur in more than half of acute ACL injuries and are typically located near the sulcus terminalis on the lateral femoral condyle and the posterolateral aspect of the tibia. Although the long-term significance of these injuries is unknown, they may be related to late cartilage degeneration.

Front 44

Is ACL tear more common in men or women and why?

Back 44

The ACL injury rate is higher in female than male individuals and is thought to be due to smaller notches, smaller ligaments, and different landing biomechanics in this group

Front 45

When is the in situe force of the ACL highest

Back 45

The in situ force of the ACL is highest at 30 degrees of flexion in response to anterior tibial load.

Front 46

History and physical examination of ACL tears

Back 46

ACL injuries are often the result of noncontact pivoting injuries and are commonly associated with an audible “pop” with an immediate hemarthrosis.

Associated injuries, including meniscal tears (75%), are common. Lateral meniscal tears are more common than medial tears acutely, while medial tears occur more often in the chronic ACL-deficient knee.

The Lachman test is the most sensitive examination for acute ACL injuries. The pivot shift or jerk is helpful in evaluating an ACL-deficient knee, especially with an examination under anesthesia. The KT-1000 and KT-2000 are useful in quantifying laxity.

Front 47

the most sensitive examination for acute ACL injuries.

Back 47

The Lachman test

Front 48

Treatment of ACL tears

Back 48

Intra-articular reconstruction is currently favored for patients who meet the criteria indicated in Figure 4–14.

Graft selection depends on patient factors and surgeon preference and usually includes (1) a bone-patella, tendon-bone autograft; (2) a four-strand hamstring autograft, (3) a quadriceps tendon autograft, and (4) an allograft. Primary repair of ACL tears is not currently recommended. Myofibroblasts “coat” the end of the ACL stumps, making primary healing impossible. Significant controversy exists regarding the double-bundle ACL reconstruction.

Front 49

SCHENCK CLASSIFICATION OF KNEE DISLOCATIONS

Back 49

KDI ACL + MCL or LCL
KDII ACL + PCL
KDIII ACL + PCL + one collateral ligament
 KDIIIM MCL
 KDIIIL LCL
KDIV ACL + PCL + MCL + LCL

Front 50

Partial ACL tears

Back 50

The existence and treatment of “partial” ACL tears are controversial, although clinical examination and functional stability remain the most important factors for determining the need for reconstruction. One-bundle tears can occur and may be addressed with reconstruction of the injured bundle and preservation of the intact bundle.

Front 51

Postoperative rehabilitation

Back 51

Rehabilitation has evolved, and early motion (emphasis on extension) and weight bearing are encouraged in most protocols. Closed-chain rehabilitation has been emphasized because it allows physiologic co-contraction of the musculature around the knee. No difference has been found between accelerated and nonaccelerated rehabilitation programs. Postoperative bracing has not been proven to be beneficial after ACL reconstruction except in downhill skiers.

Front 52

Complications in ACL surgery

Back 52

are usually a result of aberrant tunnel placement (often the femoral tunnel is placed too far anteriorly, limiting flexion) and early surgery (resulting in knee stiffness). Arthrofibrosis, which can occur often with acute ACL reconstruction, and aberrant hardware placement (interference screw divergence of >30 degrees [for endoscopic femoral tunnels] and >15 degrees [for tibial tunnels]) can also result in complications.

Front 53

PCL injury - History

Back 53

Injuries occur most commonly as a result of a direct blow to the anterior tibia with the knee flexed (the “dashboard injury”), hyperflexion, or hyperextension. A fall onto the ground with a plantar-flexed foot is also a mechanism of injury for PCL tears.

Front 54

Physical examination and classification of PCL injury

Back 54

The key examination is the posterior drawer test with an absent or posteriorly directed tibial “step-off.” In grade I there is an isolated PCL injury in which the tibia remains anterior to the femoral condyles. In grade II there is usually an isolated, complete injury in which the anterior an tibia becomes flush with the femoral condyles. In grade III the tibia is posterior to the femoral condyles.

Front 55

classification of PCL injury

Back 55

In grade I there is an isolated PCL injury in which the tibia remains anterior to the femoral condyles. In grade II there is usually an isolated, complete injury in which the anterior an tibia becomes flush with the femoral condyles. In grade III the tibia is posterior to the femoral condyles.

Front 56

Treatment of PCL injury

Back 56

a. Nonoperative treatment is favored for most isolated grades I and II PCL injuries.
b. Grade III injuries indicate a combined injury, usually to the posterolateral corner.
c. Bony avulsion fractures can be repaired primarily with good results, although primary repair of midsubstance PCL (and ACL) injuries has not been successful.
d. Chronic PCL deficiency can result in late chondrosis of the patellofemoral compartment and/or medial femoral condyle.
e. PCL reconstruction is recommended for functionally unstable or combined injuries (Fig. 4–16). Generally, the results of PCL reconstruction are not as good as those of ACL reconstruction, and there is often some residual posterior laxity. For a successful reconstruction, concomitant ligament injuries must be addressed. There are many published techniques for PCL reconstruction, and they can generally be divided into tibial inlay versus transtibial, and single-bundle versus double-bundle. There are biomechanical advantages to the tibial inlay, such as a decrease in the “killer turn” and decreased attenuation of the graft. Double-bundle techniques may improve biomechanical function in both extension and flexion, but a clinical advantage to those techniques has not yet been shown. The anterolateral bundle is the most important for posterior stability at 90 degrees of flexion and should be tensioned in flexion, while the posteromedial bundle has a reciprocal function and should be tensioned in extension.

Front 57

MCL injury - History and physical examination

Back 57

Occurs as a result of valgus stress to the knee. Pain and instability with valgus stress testing at 30 degrees of flexion (and not in full extension) is diagnostic. Opening in full extension usually signifies other concurrent injuries (ACL and PCL). Injuries most commonly occur at the femoral insertion of the ligament.

Front 58

Treatment of MCL injury

Back 58

Nonoperative treatment (hinged knee brace) is highly successful for isolated MCL injuries. Prophylactic bracing may be helpful for football players, especially interior linemen. Advancement and reinforcement of the ligament are rarely necessary for chronic injuries that do not respond to conservative treatment (Fig. 4–17). Chronic injuries may have calcification at the medial femoral condyle insertion (Pellegrini-Stieda sign). Pellegrini-Stieda syndrome, which can occur with chronic MCL injury, usually responds to a brief period of immobilization followed by progressive motion

Front 59

LCL injury

Back 59

Varus instability in 30 degrees of flexion is diagnostic only for an isolated LCL ligament injury. Isolated injuries to the LCL ligament are uncommon and should be managed nonoperatively if laxity is mild

Front 60

Posterolateral corner injury - History

Back 60

These injuries are rarely isolated but are usually associated with other ligamentous injuries (especially the PCL). Because of poor results with chronic reconstructions, acute repair combined with reconstruction is advocated. Examination for increased external rotation, the external rotation recurvatum test, the posterolateral drawer test, and the reverse pivot shift test are important.

Front 61

Posterolateral corner injury - Treatment

Back 61

Early anatomic repair is often successful, but these injuries are frequently missed. Procedures recommended for chronic injuries include posterolateral corner advancement (only if structures are attenuated but intact); popliteal bypass (not currently favored); two- and three-tailed reconstruction; biceps tenodesis; and (more recently) “split” grafts and anatomic reconstructions, which are used to reconstruct both the LCL and the popliteal/posterolateral corner

Front 62

Multiple-ligament injury - History and physical examination

Back 62

Combined ligamentous injuries (especially ACL-PCL injuries) can be a result of a knee dislocation, and neurovascular injury must be suspected. The incidence of vascular injury after anterior knee dislocation is 30-50%. Liberal use of vascular studies is recommended early (Fig. 4–21). In one study, serial examinations including ankle-brachial index (ABI) >90% over 48 hours were used to determine whether an arteriogram was necessary. The authors noted success with this technique and noted that a four-ligament injury was associated with a higher rate of vascular injury. Dislocations are classified based on the direction of tibial displacemen

Front 63

Treatment of Multiple-ligament injury

Back 63

Treatment is usually operative. Emergent surgical indications include popliteal artery injury, compartment syndrome, open dislocations, and irreducible dislocations. Most surgeons recommend delaying surgery 1-2 weeks to ensure that there is no vascular injury. The use of the arthroscope, especially with a pump, must be limited during these procedures because of the risk of fluid extravasation. Avulsion injuries can be repaired primarily; however, interstitial injuries must be reconstructed. Early motion is critical to avoid a stiff knee after these combined procedures, which has a high incidence.

Front 64

Osteochondritis dissecans (OCD)

Back 64

1. Introduction—Involves subchondral bone and overlying cartilage separation, most likely as a result of occult trauma. The lesion most often involves the lateral aspect of the medial femoral condyle. The lateral femoral condyle is involved in 15-20% of cases, and OCD is rarely seen in the patella. Spontaneous resolution is seen in the majority of the juvenile cases, in about 50% in the adolescent group, and rarely in the adult.
2. Diagnosis—Patients usually have poorly localized, vague complaints. Radiographs, nuclear imaging, and MRI can be helpful in determining the size, location, and characteristics of the lesion.
3. Treatment and prognosis—Children with open growth plates have the best prognosis, and often these lesions can be simply observed. In situ lesions can be treated with retrograde drilling. Detached lesions may require abrasion chondroplasty or newer, more aggressive techniques. OCD in adults is usually symptomatic and leads to arthritis if left untreated.

Front 65

Articular cartilage injury

Back 65

1. Overview—The distinction between articular cartilage injury and OCD is not often clear, but articular cartilage injury occurs as a result of rotational forces in direct trauma. It usually occurs on the medial femoral condyle. The lesions are classified according to their arthroscopic appearance.
2. Treatment—D?bridement and chondroplasty are currently recommended for symptomatic lesions. Displaced osteochondral fragments can sometimes be replaced and secured with small, recessed screws or absorbable pins. Several treatment options for discrete, isolated, full-thickness cartilage injuries are in clinical use. These include microfracture, periosteal patches (chondrocyte implantation), and osteochondral transfer (plugs) (Fig. 4–23). Donor-site problems and the creation of true articular cartilage at the recipient site are still challenges. Age, lesion size, patient demand level, alignment, meniscal integrity, and ligamentous stability must all be taken into consideration when deciding on the appropriate treatment option. There is still debate regarding the best treatment options.

Front 66

Spontaneous osteonecrosis of the knee (SONK)

Back 66

thought to represent a subchondral insufficiency fracture and is typically a self-limiting condition. SONK can follow knee arthroscopy in middle-aged females. It may be treated with limited weight bearing until it resolves

Front 67

Pigmented villonodular synovitis (PVNS)

Back 67

—Patients may present with pain and swelling and may have a palpable mass. There are nodular and diffuse types. The diffuse type has a higher recurrence rate. Synovectomy is effective, but there is a high recurrence rate. Arthroscopic techniques are as effective as traditional open procedures if a complete synovectomy with multiple portals is done.

Front 68

Synovial chondromatosis

Back 68

This proliferative disease of the synovium is associated with cartilaginous metaplasia, resulting in multiple intra-articular loose bodies.

Front 69

Plicae

Back 69

Synovial folds that are embryologic remnants. They are occasionally pathologic, particularly the medial patellar plica, which can cause abrasion of the medial femoral condyle and sometimes responds to arthroscopic excisio

Front 70

Tendon ruptures

Back 70

Quadriceps tendon ruptures are more common than patellar tendon ruptures and occur most often in patients over 40 years old with indirect trauma. Patellar tendon ruptures occur in younger patients (<40 years) with direct or indirect trauma. Both types of tendon rupture are more common in patients with underlying disorders of the tendon. A palpable defect and the inability to extend the knee are diagnostic. Patella alta is consistent with patella tendon rupture. Primary repair with temporary stabilization (McLaughlin wire or suture) is indicated.

Front 71

Patellar tendinitis

Back 71

(jumper's knee)—This condition, perhaps better termed “tendinosis,” is most common in athletes who participate in sports such as basketball and volleyball and is associated with pain and tenderness near the inferior border of the patella (worse in extension than flexion). Treatment includes nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy (strengthening and ultrasound), and orthoses (patella tendon strap). Surgery involving excision of necrotic tendon fibers is rarely indicated.

Front 72

Quadriceps tendinitis

Back 72

Less common than patellar tendinosis but just as painful. Patients may note painful clicking and localized pain at the superior border of the patella. Operative treatment is occasionally necessary.

Front 73

Prepatellar bursitis

Back 73

(housemaid's knee)— The most common form of bursitis of the knee and associated with a history of prolonged kneeling. Supportive treatment (knee pads, occasional steroid injections) and (rarely) bursal excision are recommended. Aspiration is advocated in wrestlers because of the kneeling on the flexed knee required for this sport.

Front 74

Iliotibial band friction syndrome

Back 74

—Can occur in runners (especially those running hills) and cyclists and is a result of abrasion between the iliotibial band and the lateral femoral condyle. Localized tenderness, worse with the knee flexed 30 degrees, is common. The Ober test (patient lies in a lateral decubitus position with hyperextension of the hip; the leg can be brought from abduction to adduction to demonstrate tightness of the iliotibial band) is helpful in making the diagnosis. Rehabilitation is usually successful. Surgical excision of an ellipse of the iliotibial band is occasionally necessary

Front 75

Semimembranosus tendinitis

Back 75

—Most common in male athletes in their early thirties, this condition can be diagnosed with MRI or nuclear imaging and often responds to stretching and strengthening. A steroid injection may be added if no improvement is seen.

Front 76

Pes anserinus bursitis

Back 76

—This is characterized by localized pain, tenderness, and swelling over the proximal anteromedial tibia at the insertion site of the sartorius, gracilis, and semitendinosus (approximately 6 cm inferior to the joint line). It is treated conservatively with oral anti-inflammatory medication, localized injections, and activity modification.

Front 77

Patellofemoral arthritis

Back 77

—Injury and malalignment can contribute to patellar DJD. Lateral release may be beneficial early only if there is objective evidence of patellar tilting; however, other procedures may be required for advanced patellar arthritis. Options include anterior (Maquet) or anteromedial (Fulkerson) transfer of the tibial tubercle or patellectomy for severe cases. Patellofemoral arthroplasty has been introduced as another treatment option but remains controversial.

Front 78

Anterior fat pad syndrome

Back 78

(Hoffa's disease)—Trauma to the anterior fat pad can lead to fibrous changes and pinching of the fat pad, especially in patients with genu recurvatum. Activity modification, ice, knee padding, and injection can be helpful. Arthroscopic excision is occasionally beneficial.

Front 79

Complex regional pain syndrome (CRPD

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) (formerly known as reflex sympathetic dystrophy)—Characterized by pain out of proportion to physical findings, this condition is an exaggerated response to injury. Three stages, progressing from swelling, warmth, and hyperhidrosis to brawny edema and trophic changes and finally to glossy, cool, dry skin and stiffness, are typical. Patellar osteopenia and a “flamingo gait” are also common. Treatment includes nerve stimulation, NSAIDs, and sympathetic or epidural blocks, which can be both diagnostic and therapeutic.

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Lateral patellar facet compression syndrome

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—This problem is associated with a tight lateral retinaculum and excessive lateral tilt without excessive patellar mobility. Treatment includes activity modification, NSAIDs, and VMO strengthening. Arthroscopy and lateral release are occasionally required but indicated only in the setting of objective evidence of lateral tilt that has not responded to extensive nonoperative management. The best candidates have a neutral or negative tilt with a medial patellar glide of less than one quadrant and a lateral patellar glide of less than three quadrants. Arthroscopic visualization through a superior portal demonstrates that the patella does not articulate medially with 40 degrees of knee flexion.

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Abnormalities of patellar height

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—Patella alta (high-riding patella) and patella baja (low-riding patella) are determined based on various measurements made on lateral radiographs of the knee (see Fig. 4–7). Patella alta can be associated with patellar instability because the patella may not articulate with the sulcus, which normally constrains the patella. Patella baja is often the result of fat pad and tendon fibrosis and may require proximal transfer of the tubercle in refractory cases.

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Recurrent subluxation/dislocation of the patella

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can be characterized by lateral displacement of the patella, a shallow intercondylar sulcus, or patellar incongruence. When it is associated with femoral anteversion, genu valgum, and pronated feet, the symptoms can be exacerbated, especially in adolescents (“miserable malalignment syndrome”). Extensive rehabilitation is often curative. Females with previous instability are at increased risk. Several radiographic findings are somewhat helpful in diagnosing patellar malalignment (Fig. 4–26). Surgical procedures include proximal and/or distal realignment. Acute, first-time patella dislocations may be best treated with arthroscopic evaluation/d?bridement and acute repair of the medial patellofemoral ligament (usually at the medial epicondyle). This is still somewhat controversial. These patients should be evaluated with radiographs for fractures and loose bodies. If a loose body is suspected, an MRI can help make the diagnosis. The articular cartilage of the medial patellar facet is the most common donor site.

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Idiopathic chondromalacia patellae

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—Although this term has fallen into disfavor, articular damage and changes to the patella are common. Treatment is usually symptomatic and has a heavy emphasis on physical therapy. D?bridement procedures are of questionable benefit. The Outerbridge classification system is still in common use today

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Classification of Avulsion fractures of the intercondylar eminence of the tibia are described as types I through IV.

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a. Type I—<3 mm displacement
b. Type II—Avulsion and elevation of the anterior ⅓-?
c. Type III—Displacement of entire fragment
d. Type IV—Comminuted