TENDINOPATHIES ABOUT THE KNEE

Be suspicious of popliteal tendinitis in long-distance runners and walkers who present with atypical posterolateral knee pain (23).
Often these individuals are involved in activities such as
cross-country running or backpacking where extensive downhill walking
or running occurs. Pain will usually present insidiously along the
lateral femoral condyle at the insertion of the popliteal tendon. This
lateral-sided knee pain can be reproduced with weight bearing and 15°
to 30° of knee flexion.

Physical examination will reveal point tenderness just
anterior and posterior to the lateral collateral ligament. Palpation of
the knee while in a “figure of four” position can help locate the area
of maximal tenderness. Close examination will locate the area of
tenderness just proximal to the lateral joint line. Often the symptoms
can be reproduced by externally rotating the tibia, which places
tension on the popliteus tendon.

Other possible etiologies, which can be ruled out by
careful history and examination, should include a lateral meniscus
tear, biceps femoris tendinitis, and iliotibial band friction syndrome.
In those cases where the etiology remains in question, magnetic
resonance imaging (MRI) or knee arthroscopy can be helpful in
identifying any intraarticular pathology or tendon rupture (19,20,46).

Treatment should start with restricting participation in
the inciting activity. Altering training habits such as running on the
other side of the road or uphill may help alleviate the symptoms. Oral
nonsteroidal antiinflammatory medicines are often helpful (23).
In recalcitrant cases, the use of a local steroid injection around the
tendon may be required. Other modalities such as ultrasound and deep
transverse tissue friction massage may prove beneficial. To maintain
aerobic conditioning, a program of cycling or deep-water aerobics
should be initiated. After resolution of the symptoms, running can be
gradually resumed.

Patellar tendinitis is also known as jumper’s knee, and
for good reason. The extreme demands placed on the patellar tendon by
the quadriceps muscle during explosive jumping, and especially
eccentric loading, result in microtears and focal degeneration of the
tendon at its bony insertion

along
the inferior pole of the patella. In younger individuals this is known
as Sinding-Larsen-Johansson disease and is usually self-limiting. The
poor blood supply within the tendon results in a slow rate of healing (5).
Therefore, the clinical history of patellar tendinitis is often a long
and protracted course, and one that may become a persistent and
recurrent problem in the adult population.

Continuing to pursue activities that aggravate the
injury will only worsen the degenerative changes within the tendon’s
origin. Histologic findings include pseudocyst formation at the
interface of bone and mineralized fibrocartilage along the inferior
pole of the patella (9). The fibrocartilage
exhibits thickening with myxomatous and hyalin metaplasia. Areas of
microtears within the tendon display mucoid degeneration and fibrinoid
necrosis (39). These findings are consistent with insertional tendinopathy.

Symptoms usually arrive gradually with no history of a
single inciting event. Typically, there is pain along the inferior pole
of the patella or within the patella tendon itself. Patients may relate
a history of participation in sports, such as basketball or volleyball,
that involve jumping and running. Rarely is there a history of trauma.
Palpation along the inferior pole will elicit tenderness. In some
instances there may be palpable enlargement and thickening of the
patellar tendon. In longstanding cases there may be crepitus with range
of motion of the knee.

During the examination, take note of any
musculotendinous imbalance. Heel cord, hamstring, and quadriceps
tightness have been implicated as sources for patellar tendinitis.
Also, vastus medialis oblique dysplasia and weakness of ankle
dorsiflexors are thought to be possible causes of patellar tendinitis (2).

Radiographs are often unrevealing. Both AP and lateral
views may show bony changes along the inferior pole of the patella such
as sclerosis and cyst formation. A lateral view may reveal mild patella
alta. Patella alta is thought to cause enhanced transmission of the
force developed by the quadriceps to the patellar tendon. A bone scan
will show increase uptake along the inferior pole. Magnetic resonance
imaging is the most revealing study. It will localize the degenerative
changes occurring both in the tendon and at the bone–tendon interface (14).

Treatment of patellar tendinitis involves activity
modification with a controlled exercise program. It is important to
remember that tendons are metabolically active and respond to stress
with increased fiber size, number, and tensile strength (7).
Initially, flexibility training and avoidance of activities that caused
the symptoms are begun. Once the symptoms have subsided, a training
program concentrating on eccentric exercises is started.

Treatment modalities such as ice, phonophoresis, and
ionophoresis may prove beneficial as second-stage treatments in
refractory cases. Ultrasound, deep tissue massage, and manual patellar
mobilization may help.

Infrapatellar straps placed across the tendon can
improve symptoms by altering the direction of mechanical force across
the bone–tendon interface at the inferior pole of the patella.
McConnell taping works in a similar manner but seems to have more
consistent results than use of an infrapatellar strap (27).

The use of steroid injections for treatment needs to be
undertaken with extreme caution. The patellar tendon is one of the
highest load-bearing tendons, and there are numerous cases of patellar
tendon rupture after steroid injection. If steroid injections are
performed, then forced rest is advocated.

In chronic cases that are unresponsive to nonoperative
management, an open procedure is warranted. Be cautious about surgical
intervention, as the results are unpredictable (9,39).
The MRI is useful in identifying the area of degenerative changes
within the tendon. This area of focal degeneration needs to be
debrided. After removal of the necrotic tissue, the tendon needs to be
fixed to the patella through drill holes with use of large, #2 or #5,
nonabsorbable suture. Multiple longitudinal incisions, in the direction
of the fibers, at the area of degenerative change may stimulate a
healing response and revascularity.

Return to activity is based on elimination of pain.
After strength and flexibility have been addressed, a gradual return to
sports can be started. Plyometrics can be helpful postoperatively.
Plyometrics activity should be instituted cautiously and with
supervision, however, as it may cause a relapse of symptoms.

Pain along the superior pole of the patella, at the
insertion of the quadriceps tendon, is quadriceps tendinitis. You would
expect quadriceps tendinitis to be analogous to patellar tendinitis;
however, it is seen much less frequently.

Pain often begins insidiously over the proximal pole of
the patella. There may be a history of changes in training habits
before the onset of symptoms. Palpation will reveal localized
tenderness over the proximal pole. Pain can be reproduced with
extension of the knee against resistance or with eccentric loading of
the quadriceps. During the examination, other associated findings such
as patellar malalignment or hamstring tightness may be present.

Radiographs usually reveal little (41),
but calcifications within the tendon may be identified. The
differential diagnosis should include a suprapatellar plica. A bone
scan or MRI may be helpful in ruling out other sources of pain. The MRI
is very helpful in localizing the affected area if operative
intervention is warranted.

Treatment is similar to that for patellar tendinitis.
This includes activity modification or active rest. Physical therapy
exercises directed toward patellar tendinitis are helpful. Modalities
such as ice, massage, ultrasound, iontophoresis,

and
phonophoresis can be instituted as second-stage treatments. The use of
nonsteroidal antiinflammatories may prove beneficial. A corticosteroid
injection into the quadriceps tendon is less risky than with patellar
tendinitis, but it should be used with extreme caution.

Surgical treatment is rarely needed. When conservative
therapy fails, the affected area needs to be localized with MRI. The
area of degenerative tissue is excised, and any heterotopic
calcifications are removed (9). Reattachment of
the quadriceps tendon to the superior pole of the patella is performed
with use of drill holes and large #2 or #5 nonabsorbable sutures of
suture anchors.

The criteria for return to sports are similar to those
for patellar tendinitis. Return to activity is based on the elimination
of pain. Once range of motion, strength, and flexibility have been
addressed, then a slow return to sports can be pursued.

Iliotibial band friction syndrome is a common tendinous
overuse syndrome of the knee. Activities that involve repetitive knee
flexion and extension will incite and aggravate the symptoms located
over the lateral side of the knee. This is commonly seen in
long-distance runners (29) and cyclists (24), where excessive friction between the iliotibial band and the lateral femoral condyle is the cause of the pain.

Point tenderness is located over the lateral femoral
condyle. Inflammation and hyperplasia develop within the synovium below
the iliotibial band, which is a lateral extension of the joint capsule (31).
There may be a catching or grating noted as the iliotibial band passes
over the lateral femoral epicondyle. Maximum discomfort is elicited by
flexing the knee to about 30° (32). As this
angle of knee flexion is encountered, the iliotibial band is passing
posteriorly directly over the prominent lateral femoral condyle. During
the physical examination, check for excessive tightness of the
iliotibial band. The Ober’s test has been described as a way to
determine if any iliotibial band tightness exists. Athletes should be
evaluated for other underlying factors that may predispose them to
iliotibial band friction syndrome such as genu varum, tibial torsion,
or excessive foot pronation.

Other entities that must be included in the differential
diagnosis of lateral side knee pain include lateral meniscal pathology,
biceps and popliteus tendinitis, and patellofemoral syndrome. The MRI
can help confirm the diagnosis of iliotibial band friction syndrome in
patients with an appropriate clinical history (30).

Cessation of the inciting activity is the first course
of treatment. This, along with time and a stretching program, is often
successful in eliminating the symptoms. Alteration of training
activities and habits can be helpful. Cyclists may find relief by
changing the height of their saddle or their foot position on the
pedals. Runners can try altering stride length or changing the
direction of running on the track.

Symptomatic treatment should include oral antiinflammatory medications (43).
Use of other modalities such as ultrasound, phonophoresis,
ionophoresis, and deep tissue friction massage may be beneficial. If
the syndrome is recalcitrant to these measures, then complete activity
restriction is required. Rarely do athletes not respond to nonoperative
treatment.

If conservative measures are ineffective, then surgical
intervention is indicated. The surgical technique involves removing
inflamed tissue and doing an elliptical excision of the portion of the
iliotibial band that contacts the lateral femoral epicondyle when the
knee is flexed to 30°. Martens recommends removing a triangular section
of the iliotibial band that contacts the lateral epicondyle with the
knee in 60° of flexion (24). A gradual return to activities can be started at 3 weeks postoperatively.

The tendinous aponeurosis of the sartorius, gracilis,
and semitendinosus muscles makes up the pes anserinus. The per
anserinus bursa is located directly beneath this aponeurosis and lies
on top of the underlying superficial medial collateral ligament.

Repetitive flexion and extension of the knee can cause
irritation of the bursa or the overlying pes tendons. Point tenderness
along the anteromedial surface of the tibia, two fingerbreadths below
the joint line, is present on examination. In longstanding cases there
may be a palpable boggy fullness to the inflamed bursa. It can be
difficult to distinguish bursitis from tendinitis clinically, but
distinguishing them is unnecessary, as the two are treated in a similar
fashion. It is not uncommon to find medial compartment osteoarthritis
associated with pes anserinus bursitis (3).
Other entities that must be considered in the differential diagnosis
include medial meniscus tear or cyst, juxtaarticular bone cysts (26),
and medial collateral ligament injury. The MRI can prove helpful in
determining the etiology of pain along the medial side of the tibia (10).

Initial treatment involves active rest and avoidance of
irritating activities. At the same time, a stretching and conditioning
program is initiated, beginning with isometric exercises and electrical
muscle stimulation and incorporating resistive exercises as symptoms
allow. Ice and nonsteroidal antiinflammatory medication have proven
beneficial.

Further treatment modalities can include ultrasound (3), phonophoresis, iontophoresis, and deep tissue transverse

friction massage. Corticosteroid injections have also been successful in treating the symptoms (21,33). In refractory cases of chronic pes anserinus bursitis, a bursectomy may be necessary.

Semimembranosus tendinitis occurs near the tendon’s
insertion along the posteromedial corner of the knee. This insertion is
made up of a five-footed tendinous expansion that embraces the
posteriomedial side of the tibia and knee (13,18). Strenuous, repetitive activities can elicit pain along the posteromedial knee joint.

Palpation of the knee joint often reveals point
tenderness inferior to the posteromedial joint line and posterior to
the superficial collateral ligament. The examination should include a
comprehensive evaluation of the knee to rule out any intraarticular
pathology that can mimic or be the source of the resulting tendinitis.

Begin treatment with cessation of any inciting
activities. An exercise program with emphasis on hamstring and
quadriceps static stretching should be started. As tolerated, an
eccentric exercise program can be introduced.

Oral antiinflammatory medications have proven
beneficial. Also, modalities such as ultrasound, phonophoresis,
iontophoresis, and deep tissue massage can be helpful. A local
injection with cortisone and an anesthetic can be beneficial both in
differentiating the etiology and in treatment (37).

In chronic cases that fail conservative therapy, look
for intraarticular etiology. An MRI can be valuable for evaluating any
meniscal or articular cartilage pathology (13,18,40).
In patients who remain symptomatic with no intraarticular pathology,
surgery may be indicated. This involves a posteromedial approach to the
tendinous insertion of the semimembranosus. Removing overlying inflamed
soft tissue can initiate a “healing response.” Care should be taken to
avoid violating the tendon itself (47).

Unlike patella fractures, ruptures of the patellar
tendon are not uncommon and are frequently encountered in athletes.
Rupture of the tendon is most often seen in middle-aged individuals who
may deny any history of preexisting symptoms. There are case reports of
patellar tendon rupture after procedures that violate the integrity of
the patellar tendon, such as total knee arthroplasty, or after
harvesting a patellar tendon graft for ACL reconstruction (25,35).
Often individuals will describe the sensation of a sudden “pop” when
force was applied to the extensor mechanism. With complete rupture of
the patellar tendon, there is inability to support body weight on the
affected side.

The amount of stress leading to rupture can vary
greatly. Zernicke et al. describe an incident in which a force of
approximately 17.5 times the body weight was produced by a power lifter
before rupture of the patellar tendon (50). In
other instances, only a trivial amount of force was applied before
rupture. In these cases there is often an underlying autoimmune
disorder that affects the integrity of the tendon (34,36,38,49).

The typical history of rupture involves application of a force across the extensor mechanism followed by a “pop” sensation (4,12,17,42).
There may or may not be a history consistent with chronic inflammatory
symptoms. Subsequently, injured individuals are unable to support
themselves on the injured limb. They may even report severe proximal
displacement of the patella.

On physical examination there will be a diffuse swelling
throughout the knee because of the capsular disruption. Tenderness will
be located at or below the inferior pole of the patella. The location
of the patellas will be asymmetric. Patella alta will be present on the
affected side. Patients may still have the ability to extend the knee
against gravity if a portion of the extensor retinaculum remains
intact. Typically there is a palpable defect in the patellar tendon at
or just below the inferior pole of the patella.

Radiographs will demonstrate patella alta, particularly
on the lateral view. If there is a question about tendon rupture,
flexion of the knee will make any displacement more pronounced on the
lateral view.

With patellar tendon rupture, surgical repair is
required and should be performed acutely or within a few days for
optimal results. There is no place for nonoperative treatment. Delaying
the surgical repair will result in contracture of the extensor
mechanism, which can seriously complicate the repair (22,45).

With untreated patellar tendon ruptures, the extensor
mechanism can contract so that it is difficult to position the patella
distally for repair. The clinical and radiographic exam can help
determine if the extensor mechanism can be positioned distally to allow
a primary repair. When there is inadequate length, skeletal traction
can be placed on the extensor mechanism to regain length as described
by Justis (15), Kelikian et al. (16), and others (45).
A transverse pin is placed in the patella to apply skeletal traction.
This traction can be maintained up to 4 weeks, until the inferior pole
of the patella is positioned about 2.5 cm superior to the tibial
plateau with the knee in extension. Once the patella has been brought
back to its appropriate position, the patellar tendon is primarily
repaired.

Unfortunately, there is often a large defect in the tendon that needs to be reconstructed. Justis (15) recommends use of the fascia lata, as do Siwek and Rao (45).
Weaving several strips of fascia lata through the two ends of the
tendon can bridge the defect. Kelikian suggests use of the
semitendinosus tendon (16).

Rupture of the quadriceps tendon is most often seen in elderly patients and in patients with chronic disease (1,44,45,48).
In a healthy population, quadriceps rupture is often seen in
middle-aged individuals. This population is somewhat older than that
seen for patellar tendon ruptures. David et al. described bilateral
quadriceps tendon rupture (6). They implied that anabolic steroid use leads to tendon failure.

The clinical examination is similar to that of a
patellar tendon rupture. Patients will be unable to extend the knee
actively. Often there is a palpable defect 1 to 2 cm proximal to the
superior pole of the patella. The patella will not retract distally;
however, the patellar tendon will feel lax on examination.

As with patellar tendon ruptures, early repair of the
quadriceps tendon is imperative if good functional restoration is to be
obtained (45). When the repair is delayed, the
extensor mechanism will retract proximally, which complicates the
repair. There is no place for nonoperative treatment of a complete
quadriceps tendon rupture except in nonambulatory patients.

To avoid contractures of the quadriceps tendon, perform the repair within a few days (11).
Often the tendon ruptures within its substance 1 to 2 cm from the
proximal pole of the patella. At the site of disruption degenerative
changes are usually noted (44). The operative
technique to repair an acute quadriceps tendon rupture is similar to
that used to repair a patellar tendon rupture (11).