1. What joints are in the
knee?
Tibiofemoral, patellofemoral, and tibiofibular.
2. What anatomic structures cause referred
pain to the knee?
Lumbar spine, hip, sacroiliac joint, and the
ankle or foot, (back, hips, or rest of lower extremity)
3. How should knee ROM be measured and
recorded?
ROM should be measured from the lateral side of the
patient�s leg with a goniometer. Full extension, an angle between the femur
and tibia of 00, should be recorded as 00. Full flexion is recorded as a
positive number, somewhere between 00 and 1350. If the patient�s leg cannot be
fully extended, the number of degrees possible short of full extension is
recorded as a positive number. For example, the patient who lacks 100 of full
extension who is able to flex to 1000 should be recorded as having a ROM +
10-1100. If patient�s knee comes to hypertension, then the amount past 00
should be recorded as a negative number. For example, if the subject
hyperextends approximately 50 and flexes to 1000, the ROM is recoded as
�5-1000.
4. What is a meniscus?
The
meniscus is a half moon shaped piece of cartilage that lies between the weight
bearing joint surfaces of the femur and the tibia. It is triangular in cross
section and is attached to the lining of the knee joint along its periphery.
There are two menisci in a normal knee; the outside one is called the lateral
meniscus, the inner one the medial meniscus.
5. What is the purpose of the knee
menisci?
Multiple purposes: Lubrication, nutrition, shock
absorption, and prevention of cartilage wear.
6. Why do meniscal injuries cause gradual
swelling and nonbloody effusions?
The menisci are primarily
avascular (without a blood supply), especially the inner two thirds.
7. What is the purpose of the
ACL?
To prevent anterior displacement of the tibia over the femur
(prevents instability of the knee joint)
8. What is a Baker�s cyst?
A
herniation of synovial tissue through a weakening posterior capsular wall
causing swelling in the popliteal fossa. It is a response to events happening
in the anterior aspect of the knee (front). It is not a "true" cyst and no
surgery is required nor does it need to be drained since fluid will just
reaccumulate posteriorly. Dealing with the problem in the knee joint will
typically take care of these.
9. What is patella baja?
Patella
baja (also called patella infera) indicates an abnormally low patella that
most often results from soft tissue contracture (scarring) and hypotonia of
the quadriceps muscle (abnormal weak function) following surgery or trauma to
knee. This typically leads to a stiff and less functional knee
10. What is patella alta?
A
high-riding patella in relation to the femur. Patella alta is also seen in
patellar tendon rupture. This can lead to pain, weakness, or inability to
extend the knee.
11. What is genu
recurvatum?
Hyperextension or excessive backward knee joint
mobility. This often results from individuals with generally lax
ligaments.
12. What is genu varum?
Bowleg or
excessive outward (lateral) deviation of the leg.
13. What is genu
valgum?
Knock-knee or excessive inward (medial) deviation of the
leg.
14. What is osteochondritis
dissecans?
Also know as OCD, is fragmentation of the articular
cartilage with subchondral bone, most commonly affecting the medial femoral
condyle or patella. It can be a result of trauma, but is often of unknown
(idiopathic) etiology. It predominantly occurs in adolescent males. The usual
presentation is stiffness and aching with an effusion. Sometimes it can be
treated non-surgically but may need to be treated operatively to prevent
further joint collapse.
15. What is a jumper�s
knee?
Jumper�s knee is insertional tendinopathy (inflammation
where the muscle joins the bone) of the quadriceps or the patellar tendons.
The site of involvement is most commonly the inferior pole of the patella in
20�40-year old patients. In patients over 40, the quadriceps tendon is
affected more frequently.
16. How do you treat a jumper�s
knee?
Nonoperative measures (RICE: rest, ice, compression,
elevation).
Nonsteroidal anti-inflammatory medication, such as aspirin or
ibuprofen.
Ice massage after activity (control the swelling and
inflammation).
Strengthening the quadriceps (helps to balance the forces
across the patella)
Hamstring stretching (take pressure off the anterior
structures of the knee).
Neoprene sleeves or braces (similar to the ones
used for tennis elbow )
Surgery is reserved for patients who experience
pain for 6 to 12 months despite close adherence to treatment patients who have
suffered a complete tendon rupture.
17. What is Osgood-Schlatter�s
disease?
Apophysitis (abnormality) at the insertion of the
patellar tendon into the tibial tubercle. Osgood-Schlatter disease is probably
the most frequent cause of knee pain in children and it is always
characterized by activity-related pain that occurs a few inches below the
knee-cap on the front of the knee. It usually responds to rest and gradual
ressumption of activities and does not require surgery.
18. What is a plica?
The extra
synovium ("remnants") present in the knee joint. During fetal development, the
knee is divided into three separate compartments. As the fetus develops these
compartments develop into one large cavity (synovial membrane). The majority
of people have remnants of these three cavities referred to as a plica. Most
often the plica is on the medial (inside) of the knee at the level of the
medial femoral condyle. Most individuals are not adversely affected by the
presence of plicas. The plica only becomes a problem when there is an
inflammation (thickening) in the synovial sack and it begins to catch on the
femur as the knee moves, (plica syndrome).
19. What is
arthrofibrosis?
Arthrofibrosis is a relatively common complication
after total knee arthroplasty with a reported overall incidence of
approximately 10%. It can occur after any knee surgery and sometimes after
injuring the knee without surgery. It is defined as painful stiffness with
scarring and soft tissue proliferation, which results in a reduction in knee
range of movement and patient dissatisfaction. There are several risk factors
associated with arthrofibrosis. Pre-operative risk factors include limited
range of motion, underlying diagnosis (alcohol abuse, obesity), and history of
prior surgery. Intra-operative risk factors include surgical technical issues
such as improper flexion-extension gap balancing, oversizing or malpositioning
of components, inadequate femoral or tibial resection, excessive joint line
elevation, creation of an anterior tibial slope, and inadequate resection of
osteophytes. Post-operative factors include poor patient motivation,
infection,
20. How is arthrofibrosis typically
treated?
The basic therapy regimen is early and intensive
physiotherapy combined with sufficient analgesia. The next therapeutic steps
for persisting arthrofibrosis include closed manipulation under anesthesia and
open lysis of intrarticular adhesions. Arthroscopic interventions for lysis of
adhesions should be limited to local fibrosis and therapy resistant cases. The
choice of revision total knee arthroplasty may be often associated with
recurrence of fibrosis. However, revision total knee arthroplasty is preferred
for stiffness from malpositioned or oversized components. The management of
arthrofibrosis by individualized rehabilitation program that may involve
prolonged oral analgesia, continued physical therapy, emotional support, and
sufficient patient education remains the accepted treatment option for
arthrofibrosis after total knee arthroplasty
21. Does a positive Lachman�s test always mean
anterior cruciate ligament (ACL) injury?
No, laxity may be
symmetric in the other knee. It is important to compare both knees in most
conditions.
22. What is O�Donoghue�s
triad?
This is characterized by injuries to the medial meniscus,
medial collateral ligament (MCL), and anterior cruciate ligamwnt (ACL). It is
caused by a valgus force to a flexed, rotated knee.
23. Describe the typical signs and symptoms of
patellofemoral pain.
-
Anterior knee pain with gradual onset that
worsens with repetitive knee flexion
-
Pain with prolonged sitting or upon arising
after sitting (positive theater sign)
-
Pain with squatting or with descending
stairs
24. Name the most common tests for an ACL
injury.
Lachman, anterior drawer sign, and pivot shift test.
During the Lachman test, the knee is flexed approximately 20 degrees and the
proximal tibia is pulled forward to assess excessive translation (more than
3-4 mm). The anterior drawer test follows the same principle but the knee is
flexed at 90 degrees. The pivot shift test is performed with the leg in
extension. The examiner supports the leg by the upper tibia and flexes the
knee while applying a slight valgus stress to the knee (pushing the knee
towards the midline). In a knee with an ACL injury, the femur sags backward on
the tibia (or conversely, the tibia moves forward on the femur), creating a
subluxation of the lateral tibiofemoral compartment. At approximately 30
degrees of flexion, the subluxed tibia suddenly reduces and externally rotates
about the femur. The subluxation and the sudden reduction of the knee joint
during flexion are termed the "pivot shift."
25. Name the cause and acute signs of a
posterior cruciate ligament (PCL) injury?
The most common
mechanism of injury of the PCL is the so-called "dashboard injury" (when the
knee is bent, and an object forcefully hits the tibia backwards). Another
mechanism of injury is hyperflexion of the knee, with the foot held pointing
downwards. The acute signs include swelling in the popliteal space with
bruising present during the first 36 to 48 hours, and NO effusion due to the
extrarticular nature of the PCL. Pain and instability are also common.
26. Name the acute signs of ACL
injury.
First, one usually hears a loud ripping sound ("pop")
which is usually followed by a rapidly developing effusion (fluid accumulation
of the knee)
27. What are the degrees of MCL
strains?
Grade 1 (first degree)�valgus stress results in medial
pain but no increased laxity.
Grade 2 (second degree)�valgus stress
demonstrates increased laxity, and an endpoint is appreciated.
Grade 3
(third degree)�valgus stress demonstrates increased laxity with no appreciable
endpoint. This indicates rupture of the ligament and the surrounding capsular
structures.
28. How much laxity is there in MCL and
lateral collateral ligament (LCL) injuries?
Grade 1 0�5
mm
Grade 2 6�10 mm
Grade 3 11�15 mm
29. How do patients with iliotibial band
syndrome (ITB) present?
The patient with iliotibial band syndrome
reports pain at the lateral aspect of the knee joint. The pain is worse after
strenuous activity, particularly running downhill and climbing stairs. On
physical examination, tenderness is present at the lateral epicondyle of the
femur, approximately 3 cm proximal to the joint line. Soft tissue swelling may
be present, but there is no joint effusion.
30. Can meniscal injuries be treated without
surgery?
Yes. Initially, the RICE (rest, ice, compression, and
elevation) acronym is prescribed. In fact, most meniscal tears can be treated
without the need of surgical intervention.
31. When is surgical treatment indicated for a
meniscal tear?
-
Locking, or inability to fully extend the knee
because of mechanical blockage
-
Motion restricted despite a trial of
physical therapy
-
Instability, which may predispose to further
intra-articular damage
-
Persistant Baker�s cyst resulting from a
meniscal tear
-
Pain not improving with physical therapy and
symptomatic treatment.
32. What is the rationale for the use of knee
injections?
There are two types of injections used to treat
symptoms of knee osteoarthritis: joint chondroprotective agents
(viscosupplementation) and corticosteroids. Viscosupplementation therapy
involves injecting a gel-like substance directly into the knee joint. These
injections help to restore the lubrication lost by damaged cartilage and may
have anabolic (beneficial) effects on articular cartilage. Usually people who
respond to this form of treatment will experience some improvement for six to
twelve months but sometimes longer. Cortisone injections are reserved for
people with a severely inflamed knee with uncontrolled pain. Cortisone
injections can provide rapid relief from a tender, swollen osteoarthritic knee
which has failed to respond to other forms of treatment. The benefit of an
injection may last anywhere from a few days to more than 6 months. They can be
repeated safely every few months.
33.What are the types and indications for the
use of a knee brace?
According to the American Academy of
Orthopaedic Surgeons, knee braces can be classified
as:
(1)prophylactic--braces intended to prevent or reduce the severity of
knee injuries in contact sports; These braces are often not recommended due to
increased number of due to excessive preloading of the medial collateral
ligament, limited speed and athleticism, false sense of security for
previously injured knee, and brace-related contact injuries to other
players.
(2) functional--braces designed to provide stability for unstable
knees;
(3) rehabilitative--braces designed to allow protected and
controlled motion during the rehabilitation of injured knees.
(4)
patellofemoral braces, which are designed to improve patellar tracking and
relieve anterior knee pain.
34. What are the surgical options for
osteoarthritis of the knee?
Arthroscopic debridement. This
includes irrigation and removal of loose bodies from the knee.
Cartilage
transplantation. For small isolated areas, portions of autologous articular
cartilage can be grafted into the defect.
Osteotomies of the distal femur
or proximal tibia are used for isolated lateral or medial compartment
arthritis
Unicompartmental knee arthroplasty can be performed for isolated
lateral or medial compartment arthritis
Patellofemoral replacement replaces
just the patello-femoral joint (anterior part of the knee)
Total knee
arthroplasty is used for severe arthritis. Other options depend on the
location and severity of the arthritis and include:
35.What is a total knee
arthroplasty?
In a total knee arthroplasty, the surfaces of the
distal femur, proximal tibia, and often the patella, are replaced. This is
performed with a femoral component and a tibial base plate made of a metal
alloy, usually cobalt-chromium or titanium. The tibial component has a
polyethylene plastic piece that is fixed to the metal base plate and
articulates with the femur.
36.What is minimally invasive total knee
replacement surgery?
There are many definitions of minimally
invasive knee surgery including a skin incision under 14 cm (ranging between 6
and 14 cm), and minimization of soft-tissue dissection (including quadriceps
sparing).
37. What are different surgical approaches to
the knee?
The conventional medial parapatellar arthrotomy splits
and detaches a portion of the quadriceps tendon from the patella.
The
midvastus approach involves detaching the vastus medialis fibers that are
attached distal to the patella and then splitting the muscle parallel with
these fibers from the superior pole of the patella down to their origin on the
femur.
The subvastus approach (unlike the medial parapatellar approach)
preserves the extensor mechanism and its vascularity. This approach is
performed by dissecting around the inner thigh muscle through a natural plane,
instead of directly cutting through muscle and tendon (quadriceps) as in
traditional approaches.
A new lateral approach for total knee arthroplasty
has been recently described. This approach avoids the disruption of the
extensor mechanism by entering the joint through the Ilio-tibial band through
a lateral skin incision.
38. Are there proven advantages of performing
minimally invasive knee arthroplasties?
At this point there is
little evidence-based proof with conflicting reports. Some studies report,
cosmetic benefits, shorter rehabilitation periods, and higher patient
satisfaction. Other studies do not show this and have reported higher
complication rates.
39. What is computer assisted total knee
replacement surgery?
A method where the surgeon can use a computer
to aid during surgery. Often, there is no need for an intramedullary rod and
the need for intraoperative x-ray equipment is eliminated. It has been
reported to help yield optimal positioning of the components. There are
ongoing efforts aiming for a more surgeon-friendly device.
40. What are the indications for total knee
arthroplasty?
The primary indication is to relieve pain caused by
arthritis. Secondary goals are to restore functions and correct deformity.
Candidates should have degenerative changes on radiographs and failed other
methods of nonoperative and occasionally other types of operative care.
Nonoperative modalitites may include anti-inflammatory medications, assistive
devices, weight loss, behavioral modification, oral and intra-rticular
chondroprotective agents, and intra-articular corticosteroid injections. In
select cases, surgical options prior to total knee arthroplasty include
arthroscopy and osteotomies.
41. What happens to the ligaments in a total
knee arthroplasty?
In uncomplicated primary knee replacements,
collateral ligaments are preserved. Because these structures can tighten and
scar with arthritic deformity, they may need to be "released" to a certain
degree. This helps to balance the soft tissues to equalize tension in the
collateral ligaments and provide stability throughout the range of motion.
Occasionally ligaments may need to be tightened. Prostheses require removal of
the anterior cruciate ligament. The posterior cruciate ligament is left intact
or removed, depending on the type of prosthesis. Prostheses that require
removal of the posterior cruciate ligament are designed to substitute for its
function in flexion.
42. Should patients have both knees replaced
at once?
Many studies have shown that performing both knees at may
lessen the morbidity by having only one anesthesia setting. However, for
certain patients this may increase the morbidity and mortality for various
reasons including possibly the prolonged surgery. Patients where this is not
indicated are over 75 or 80 years of age, who may be at increased risk, and
certainly patients with cardiac problems.
43. What about replacing only one part of my
joint?
Various new techniques have been developed where an entire
knee replacement does not have to be performed. In a unicompartmental knee
arthroplasty, the surgeon can selectively replace a compartment such as a
lateral femoral condyle and lateral tibial plateau. A patellofemoral
arthroplasty is performed for the replacement of the patellofemoral joint.
44. What is a patellofemoral
arthroplasty?
A procedure in which the kneecap (patellar part),
and the trochlea (what articulates with the distal femur), are replaced.
Recently, many companies have developed new designs and there are recent
reports of better results which were not optimal historically. Presently,
about one percent of the knee replacements performed in the United States are
patellofemoral arthroplasties.
45. What is the role of pulsed electrical
fields in the treatment of osteoarthritis of the knee?
The limited
capacity of articular cartilage to heal has stimulated a number of approaches
to try to effectuate cartilage repair. Animal and clinical studies have
suggested that pulsed electrical stimulation may have beneficial effects on
articular cartilage healing. One company markets a product (Bionicare�,
Bionicare Medical Technologies, Sparks, MD) that appears to be a safe and
effective method for avoiding total knee arthroplasty in some patients and
relieving clinical signs and symptoms of osteoarthritis of the knee.
46.What is an "OATS" or
"mosaicplasty"?
Osteochondral autograft transfer system (OATS) is
a procedure employed for medium sized (approximately 1 to 1.5 square inches)
areas of isolated chondral damage (mosaicplasty is utilized for larger areas
of damage. The surgeon cores out a circle of damaged cartilage and replaces it
with a piece of normal cartilage from a less important part of the same knee,
or the contralateral knee (when performing a knee arthroplasty). The
underlying principal is that the transferred cartilage will grow to cover the
edges of the core with proper cartilage cells and not the weaker
fibrocartilage cells.
47. What are the OATS knee surgery
requirements?
-
The knee is stable with intact, fully functional
menisci and ligaments.
-
Normal knee alignment.
-
Normal joint space.
-
A patient with a body mass index (BMI) of less
than 35.
48. What is the rationale of osteotomies for
the treatment of knee arthritis?
An osteotomy is used to transfer
the weight-bearing forces from one part of the knee to another. It may be used
alone to change the weight-bearing forces or in conjunction with other
treatment methods such as arthroscopy to try to preserve the knee.
49. When can the patient resume sports
activities after an MCL injury?
When the patient�s strength is
near normal (90%) and the valgus instability is reduced to a point no longer
requiring a brace. The patient should be able to perform one-legged hopping,
jumping rope, and climbing stairs before returning to the playing field.
50. Should I use Cox 2
inhibitors?
A number of Cox-2 inhibitors have been taken off of
the market recently (Vioxx� (Rofecoxib), and Bextra� (Valdecoxib)). Presently,
at least one agent is still being used, and patients should feel safe about
Celecoxib (Celebrex�). One of the major side effects of these medications is
gastrointestinal (GI) and they should be used with caution if there is any GI
related past medical history. Patients with liver or kidney disease (ie;
alcoholics), or a history of serious allergic reactions (ie; Sulfas), should
be monitored closely for potential worsening of their conditions with the use
of the COX-2 inhibitors.
51. Who is at risk for peroneal nerve palsy
after a total knee arthroplasty?
The patient with a valgus knee
with a fixed flexion contracture is most at risk The peroneal nerve is at risk
when a retractor is placed on the lateral side of the knee during surgery.
However, injury from this is not a common occurrence. Neuropraxias more often
result from stretching of the nerve with correction of the limb
deformity..
52. What measures should be taken in the
immediate postoperative patient who is found to have new weakness or absence
of the foot and ankle dorsiflexors? (peroneal nerve palsy)
All
dressings should be removed, and the knee should be flexed to relieve tension
across the peroneal nerve. If there is no resolution of the palsy, surgical
exploration and decompression should be considered.
53. What patient-related factors have a
negative impact on results following a total knee
arthroplasty?
Total knee arthroplasty is technically difficult
after high tibial osteotomies, and the results are not as good as routine
primary total knee replacements. Diabetics and patients with rheumatoid
arthritis are at an increased risk for infection. Patients on Workmen�s
Compensation do not do as well as others. The worst results are seen in obese
men with osteoarthritis who are less than 60 years of age at the time of
surgery (10-year survival rate of total knee arthroplasty: 37%).
54.How long does pain last after total knee
arthroplasty?
This is extremely variable. Each patient needs to be
managed individually. In general, pain management can be summarized as
follows:
1-2 days postoperatively-Patients will have significant pain, and
most need intravenous or intramuscular narcotic analgesia. Most patients can
distinguish between postoperative pain and their preoperative arthritic pain.
New management protocols are being developed to minimize this pain.
3 days
postoperatively-The pain is usually controlled with oral analgesics.
2-3
weeks postoperatively-Some patients continue to require analgesics, whereas
others may be weaned off their medications.
It can take up to 6 months to a
year before the patient feels that the knee is fully recovered.
55.What is the weight-bearing status
immediately after total knee arthroplasty?
There are different
protocols, and it is important to discuss this with the operating physician.
In the most common situation, when cement is used to fix both the femoral and
tibial components, the patient are routinely allowed to bear weight as
tolerated. Rarely, fixation requires bony ingrowth and then partial weight
bearing may be utilized.
56.What other operative factors govern
postoperative rehabilitation?
It is important to consider the
operative approach when determining the weight-bearing status and the range of
motion (ROM) that will be permitted. In some difficult cases the surgeon may
need to osteotomize the tibial tubercle or cut the extensor mechanism to gain
adequate exposure. In these instances, the rehabilitation protocol needs to be
modified to allow the bone and muscle to heal.
57.Do all patients need thromboembolic event
prophylaxis after total knee arthroplasty?
All patients should
receive some type of thromboembolic event prophylaxis postoperatively. This
prophylaxis has been shown to decrease the incidence of deep venous thrombosis
and/or fatal pulmonary embolism. However, there is controversy over the best
regimens, which include mechanical efforts, early rehabilitation efforts and
pharmacological agent methods. Different pharmacological regimens include
aspirin, warfarin (Coumadin) and low-molecular-weight heparin. Mechanical
efforts include sequential pneumatic compression devices. Aspirin may also be
combined with hypotensive epidural anesthesia.
58.What is the benefit of continuous passive
motion (CPM) machines?
Although CPM may improve the amount of
flexion a patient is able to attain initially, there is no evidence of any
long-term benefit. Most surgeons do not use these machines in their
rehabilitation protocols.
59.What is a knee manipulation and when should
it be considered after a total knee arthroplasty?
There are no
strict rules but usually if the patient has only 700 of flexion by 14 days
postoperatively or less than 900 by 6 weeks manipulation of the knee shoul d
be considered.
60.What is the most reliable predictor of the
range of motion a patient will have after total knee
arthroplasty?
The best predictor of range of motion (ROM) after
knee arthroplasty is preoperatively ROM. Thus, the better the ROM before
surgery, the better it will be after surgery. On average, patients can achieve
105-1300 of flexion. At least 900 of flexion is desired for a good outcome,
and this should be obtained within the first 2 weeks after surgery.
61.Outline a rehabilitation program for the patient
with a total knee replacement.
| SCHEDULE |
REHAB PROGRAM |
| Day of surgery |
Deep breathing exercise, active ankle ROM |
| Postop day 1 |
Lower limb isometric exercises (quadriceps, hamstrings and gluteal sets), passive and active ROM exercises |
| Postop day 2 |
Active assisted ROM |
| Postop day 3 |
Progressive isotonic and isometric knee and hip muscle strengthening |
| |
Concentrate on terminal knee extension through active knee extension exercises |
62.What muscles should be targeted after total
knee arthroplasty?
The quadriceps muscles are significantly
weaker after total knee arthroplasty. This is, in part, related to the
exposure required. Tourniquet and ischemic time also may play a part in
muscular weakness. The quadriceps is important for stability during the stance
phase of gait. Isometric strengthening and active ROM should begin immediately
after surgery and be continued for the first 6 weeks. Resisted isokinetic or
isotonic strengthening should be added. Other muscles that should be
strengthened after total knee arthroplasties include the hamstrings,
gastrosoleus, and ankle dorsiflexors.
63. List the usual sequence of ambulatory aids after a
total knee replacement.
Parallel bars in inpatient physical
therapy
Crutches or a walker, depending on patient stability and
comfort
One crutch or cane
Most patients do not require assistive
devices by 6 to 12 weeks postoperatively
64.How should a patient ambulate stairs after a total
knee arthroplasty?
When ascending the stairs, the patient should lead with
the nonoperative leg followed by crutches and the operative limb, one step at
a time. When descending the stairs, the patient should lead with crutches and
the operative extremity, following by the nonoperative extremity.
65.What are the four goals of occupational therapy
after total knee arthroplasty?
1. To reestablish basic activities of daily
living (ADLs), with modifications that keep the patient�s range of motion
within restrictions
2. To teach joint protection
3. To review and
minimize the risks for falls
4. To provide equipment with training
66.How long is it before a patient will receive full
benefit after total knee arthroplasty?
By 3 months postoperatively,
patients usually have regained most of their strength and ROM. However, in
difficult cases or revision surgery it may be up to 1 year before the patient
receives full benefit from the procedure.
67. Can a patient return to sports after total knee
arthroplasty?
Yes. It is recommended that they refrain from high-impact
sports, such as running, singles tennis, and football because these may lead
to greater wear of the prosthesis. Low-impact activities include golf, doubles
tennis, walking, and riding a stationary cycle.
68. What is an "extensor lag"?
This refers to the
inability to fully extend the knee actively, although passively full extension
is possible. This results from lengthening of the extensor mechanism or
weakening of the quadriceps. Component malposition may also produce this
problem.
69. How does a flexion contracture differ from an
extensor lag?
A knee with a flexion contracture cannot be fully extended
wither actively or passively. This is due to a mechanical block of which there
are numerous causes, including scarred posterior capsule or other soft tissue
structures, including the hamstrings, or retained osteophytes that may cause
structures to tighten and thus block full extension. Component malposition
also can cause this problem.
70. What rehabilitation approach should be used to
treat a stiff knee post knee arthroplasty?
The authors recommend a
multi-modality approach which combines revising the joint, performing an
arthrolysis and excising any adhesions present with a strict rehabilitation
protocol. A customized device may also be used to gain extension or flexion
when physical therapy alone failed (moderate intensity isometric sets of
gluteal, quadriceps and ankle pumps, active assistive flexion and passive
extension exercises, active exercise of the hamstring muscles to relax the
quadriceps mechanism by reciprocal inhibition).
71. How does one test the stability of a total knee
arthroplasty?
Medial/lateral (varus/valgus). The knee is stressed at
0degrees, 30degrees, 60degrees, and 90degrees of flexion. An opening of
greater than 5degrees to varus and valgus stressing is considered
excessive.
Anterior/posterior. The knee is tested with an anterior drawer
throughout the ROM. The position of greatest instability is noted. Normally in
a total knee arthroplasty there is 5-8 mm of displacement in this plane,
because the anterior cruciate ligament is sacrificed during the procedure.
BIBLIOGRAPHY
1. Eisle MA: A precise approach to
anterior knee pain. Phys Sports Med 19:127, 1991.
2. Ellen MI, Young JL,
Sarni JL: Musculoskeletal rehabilitation and sports medicine. Knee and lower
extremity injuries. Arch Phys Med Rehabil 80:S59�67, 1999.
3.Magee DJ: The
knee. In Orthopedic Physical Assessment, 2nd ed. Philadelphia, W.B. Saunders,
1992, pp 372�447.
4. Sheon RP, Moskowitz RW, Goldberg VM: Soft Tissue
Rheumatic Pain: Recognition, Management, and Prevention, 3rd ed. Baltimore,
Williams & Wilkins, 1996
5. Callaghan JJ, Dennis Da, Paprosky WG,
Rosenberg AG: Orthopaedic Knowledge Update. Hip and Knee Reconstruction.
Rosemont, IL, American Academy of Orthopaedic Surgeons, 1995.
6. Fu FH
(ed): Surgery of the Knee. Baltimore, Williams & Wilkins, 1994.
7.
Healy WL, Iorio R, Lemos MJ: Athletic activity after total knee arthroplasty.
Clin Orthop 380:65-71, 2000.
8. Insall JN, Kelly M: The total condylar
prosthesis. Clin Orthop 205:43-48, 1986.
9. Insall JN, Windsor RE, Scott
WN, et al (eds): Surgery of the Knee, 2nd ed. New York, Churchill Livingston,
1993.
10. Krackow KA (ed): The Technique of Total Knee Arthroplasty. St.
Louis, Mosby, 1990.
11. Lombardi AV Jr, Mallory TH, Eberle RW: constrained
knee arthroplasty. In Scott WN (ed): The Knee. St. Louis, Mosby, 1993, pp
1305-1323.
12. Mont MA, Antonaides S, Krackow KA, Hungerford DS: Total knee
replacement following high tibial osteotomy. Clin Orthop 299:125-130,
1993.
13. Mont MA, Alexander N, Krackow KA, Hubgerford DS: Total knee
arthroplasty after failed high tibial osteotomy. Orthop Clin North Am
23:515-525, 1994.
14. Mont MA, Mathur SK, Krackow KA, et al: Cementless
total knee arthroplasty in obese patients: A comparison to matched control
group. J Arthroplast 11:153-156, 1996.
15. Mont MA, Mayerson JA, Krackow
KA, Hubgerford DS: Total knee arthroplasty in patients receiving Worker�s
Compensation. J Bone Joint Surg 80A:1285-1290, 1998.
16. Rand JA (ed):
Total Knee Arthroplasty. New York, Raven Press, 1993.
17. Sema F, Mont MA,
Krackow KA, Hungerford DS: Total knee arthroplasty in diabetic patients: A
comparison to a matched control group. J Arthroplast 9:375-380, 1994.
18.
Johnson, G. Vazquez-Vela; Worland, R. L.; Keenan, J.; Norambuena, N. Patient
demographics as a predictor of the ten-year survival rate in primary total
knee replacement. J Bone Joint Surg Br. 2003 Jan;85:52-6
Authored by :German A. Marulanda, M.D., Michael A.
Mont, M.D., Thorsten M. Seyler, M.D., Michael E. Frey, M.D., and Charles
Msika, M.D.
Reprinted by permission from : Physical Medicine and
Rehabilitation Secrets 3�d Ed: O�Young,BJ,Young,MA,Stiens,SA (eds.)
