Introduction
This guide is intended as a primer on the basics of knee replacement for
patients. It is by no means comprehensive, but my intent is to explain the risks
and benefits of this surgery and to outline the process surrounding the
procedure and recovery. As always, knowledge is power. The more you know,
the more you are able to be an active participant in your recovery and the less
anxiety you will experience during your surgery and rehabilitation. This
information is not intended to frighten, but to educate about risks associated with
knee replacement surgery. This information ensures that you are able to assist
your care team in watching for potential issues and that your consent for the
procedure is truly an INFORMED consent. Determining when/if surgery is
appropriate involves SHARED DECISION MAKING between patient and
surgeon.
My Philosophy
My philosophy of practice is a focus on specialization, attention to detail, and
appropriate use of the latest technologies and protocols to obtain the best
possible results.
I am committed to providing good information to patients so that they can
make the best decisions about their care.
Risks
Infection: Infection is one of the most dreaded complications of knee
replacement surgery. In most large studies, the rate of infection after knee
replacement is noted to be approximately 1%. Infection of a prosthetic knee
may require multiple additional surgeries to treat (including removal of the
prosthesis) and in extreme cases can even lead to amputation (less than 0.2%
of knee replacement cases). Infection risk can be increased by multiple factors
such as: obesity, smoking, diabetes and other immune suppressing conditions.
Each patient’s risk factors will be evaluated and managed in conjunction with
their primary care physician and in some instances surgery may be deferred if
risks are felt to be excessive. Multiple steps are taken to prevent infection
including pre-surgical skin cleansing, meticulous sterile technique in the OR,
appropriate use of intravenous antibiotics before and after surgery, multiple
antiseptic washes during surgery and use of watertight antimicrobial dressings.
We are constantly updating our process of infection-prevention and seeking
ways to minimize these unfortunate occurrences.
Stiffness: The primary determinant of range-of-motion after knee replacement
surgery is range-of-motion before knee replacement surgery. In other words, a
knee which has become very contracted prior to surgery is more likely to have
motion difficulties after surgery. Additionally, major surgeries of the knee require
careful attention to post-operative therapy/rehabilitation. This requires diligence
and very active participation by the patient in order to achieve a good result.
Depending on a physical therapist alone is not sufficient. However, there are some
instances where the surgeon, patient and therapist do everything correctly and the
knee still becomes stiff. The human body heals by means of scar tissue, and this
scar tissue sometimes results in stiffness of the knee. Approximately 3-4% of
patients may experience stiffness which requires a manipulation under anesthesia.
This is a procedure which typically takes place 1 or more months after surgery in
which the knee is manually bent while the patient is asleep under anesthesia. This
is sufficient to produce better motion for most patients. A very small percentage of
patients may have residual stiffness which becomes permanent or necessitates
additional surgeries.
“Mechanical” complications: Orthopaedic procedures are by their nature
different from other surgeries. These surgeries involve more than the removal of
diseased organs or tissues and typically include an attempt to reconstruct normal
anatomic structures. Patients live with the effect of our reconstructive efforts with
every step they take after surgery. Even surgeries performed with the best
intentions, the best hands and the best technologies sometimes have an imperfect
outcome. It is always possible for an extremity to become incorrectly aligned or
improperly rotated or for a joint to become unstable or for an implant to fail
prematurely. Fractures around the knee during surgery may occasionally occur
during knee replacement (the largest published series of these indicated a
prevalence of less than half of 1%). Similarly, ligaments or tendons may be torn or
cut. Putting an exact percentage on these types of issues is a bit difficult due to
their wide range and to the variance of what is considered acceptable by the
patient and their surgeon. Major issues of this type are relatively uncommon and
usually fixable. However, correcting these problems may require additional
surgeries and rehabilitation time.
Blood Clot: Deep vein thrombosis, or DVT, occurs when a blood clot forms in one
of the deep veins of the body. This can happen if a vein becomes damaged or if
the blood flow within a vein slows down or stops. While there are a number of risk
factors for developing a DVT, two of the most common are experiencing an injury
to your lower body and having surgery that involves your hips or legs. A DVT can
have serious consequences.
If a blood clot breaks free, it may travel through the bloodstream and block
blood flow to the lungs. Although rare, this complication - called a pulmonary
embolism - can be fatal. Even if a blood clot does not break free, it may
cause permanent damage to the valves in the vein. This damage can lead to
long-term problems in the leg such as pain, swelling, and leg sores.
Symptoms of DVT occur in the leg affected by the blood clot and include:
- Swelling (also normal after knee replacement)
- Pain or tenderness (also normal)
- Distended veins
- Red or discolored skin
- A firmness or thickening of the vein called a “cord”
Many patients, however, experience no symptoms at all. In some cases, a
pulmonary embolism may be the first sign of DVT. Symptoms of pulmonary
embolism include:
- Shortness of breath
- Sudden onset of chest pain
- Coughing
- Spitting up or vomiting blood
The incidence of DVTs which produce symptoms is felt to be less than 1%.
Our emphasis is always on PREVENTION of clots and the terrible
complications which they can cause. Strategies to prevent complications
include “mechanical” prevention with compression stockings or devices,
“pharmacologic” prevention with aspirin or other blood thinners and most
importantly EARLY MOBILIZATION after surgery.
Medical complications: Medical events such as heart attacks, strokes,
allergic reactions, seizures or complications of anesthesia are quite rare, but
can potentially occur with any operation. Most of these are related to
underlying health problems and this is one of the main reasons for
preoperative medical evaluation and optimization. These types of
complications are possible with any surgery and are not specific to
orthopedic procedures.
Nerve damage: Nerve damage after knee replacement can occur but is
uncommon. Published studies indicate that the rate of occurrence is significantly
less than 1%. When this does occur it is typically a palsy of the common peroneal
nerve. Damage to this nerve may result in a “drop foot” which may or may not
resolve as the patient recovers from surgery. Most commonly this is associated
with correction of large valgus (knock-knee) deformities. Numbness adjacent to
the incision is normal and occurs in virtually 100% of cases.
Bleeding/Blood vessel damage: All knee surgeries by necessity result in
bleeding. Improved surgical techniques and new medications have significantly
reduced blood loss from knee replacement surgery. Blood transfusions are
increasingly rare and most surgeries do not require use of a wound drain. Bruising
and swelling due to post-surgical bleeding vary. Increased risk of bleeding is
associated with the use of certain blood thinners. Return to the OR for evacuation
of a hematoma occurs in less than 1% of cases. Laceration or blockage of a
major artery in knee replacement is potentially devastating , but is rare and occurs
in less than 1 in 1000 cases.
Pain: Pain is certainly expected to accompany surgery. Managing this pain is a
top priority in order to facilitate early mobilization and rehabilitation. In some rare
cases pain may persist after surgery or pain may not be diminished to the degree
that the patient hoped or expected.
Metal Hypersensitivity/Allergy: Orthopaedic implants are made of metals which
are typically non-reactive in the body. A small number of patients (very difficult to
determine an accurate percentage) may develop a hypersensitivity to metals
contained in the implants such as nickel, cobalt or chromium. While rare, this
situation may require revision surgery. Please notify your Surgeon if you are
allergic to any metals or have a history of skin sensitivity to jewelry.
Medication: Recovery from knee replacement surgery typically requires some use
of narcotic pain medication. These medications may cause significant
constipation. It is important to be aware of this and use whatever dietary
adjustments or medications are needed to avoid severe problems. Additionally,
these medications are HIGHLY addictive. Please plan to reduce and eliminate
these medications as soon after surgery as possible.
Unforeseen Events: Despite our efforts to control every event associated with
surgery, some things are simply beyond our control. Complications may occur
which are so rare that they could not reasonably be predicted. (A good friend of
mine finished a procedure with illumination from a flashlight after the hospital in
which he was operating collapsed during a tornado!) Most common
complications are described previously in this manual, but others may occur as
well.
Overlapping Surgery: Overlapping surgery is not actually a risk of surgery, but is a
situation of which patients should be aware. “Overlapping” refers to a scenario in
which your surgeon performs all essential portions of the procedure but may be
performing another operation in a separate room at times while you are still “in the
operating room”. In my practice, this means that you may be transferred to and from
the OR without me being present and that the closure of your incision will be
performed by a trusted Physician Assistant (P.A.). My own knee incision was closed
by a P.A. from our practice, so I am 100% confident in this process. Students,
resident physicians or visiting surgeons may occasionally be present in the
operating room as observers but are not participants. All critical portions of the
procedure are performed by me alone! A study on this method was presented at the
American Association of Hip & Knee Surgeons 2017 annual meeting and it was
found to be equivalent to consecutive(non-overlapping surgeries) with NO increased
risk of complications.
Other Indicated Procedures: Surgical consent forms frequently include the phrase
“other indicated procedures”. This means that during the course of a surgical
procedure, circumstances may dictate that the best course of action is to deviate
from the original plan. In such a situation, the surgeon uses his/her best judgment to
determine a “plan B” that is best for the patient. When this happens more or less
may be done than was originally planned or implants may be used that are different
from what was originally discussed with the patient.