The patella (kneecap) is one of the three bones that make up the knee. It begins within the quadriceps tendon and ends where the patella tendon begins. The patella tendon inserts at the tibial tubercle – sometimes known as the knob of the knee. It protects the knee from a direct blow and is positioned to maximize the mechanical efficiency of quadriceps muscles. The patellofemoral joint is formed by the patella and the front part of the distal femur – called the trochlear groove. In a healthy patellofemoral joint, there is symmetrical contact of the patella upon the trochlear groove.
One common malfunction of the patellofemoral joint, sometimes known as chondromalacia, or softening of the cartilage of the patella (kneecap), is associated with anterior (front) knee pain, difficulty walking up stairs and pain after prolonged sitting. Some patients also report an uncomfortable grinding sensation in the kneecap. The condition is aggravated when the knee is bent for extended periods. It is a condition that causes the slick cartilage surface of the patella to soften. This can arise from excessive pressure across the patellofemoral joint, as in obese individuals and those with a combination of weak quadriceps and tight hamstrings.
The other common malfunction of the patellofemoral joint is called patella instability. In this condition, the patella may not symmetrically strike the femur, but rather to the outside of the groove. In the most severe cases, the patella may dislocate off the side of the femur and require a manipulation to realign. More often, the abnormal patella only partially dislocates. This is called subluxation. When this happens, pain is felt in the front of the knee and may cause an unstable sensation within the kneecap. The knee may pop or feel as though it is unable to support weight. Examination may reveal a knock-kneed tendency in the lower limbs. The medical term for this is “valgus.” Also common is a condition called Patella Alta. In this situation the patella tendon is too long, and the knee cap rides too high on the femur. Somewhat less commonly, an abnormal amount of twisting of the femur or tibia is present. This is called torsion. These patients have swelling, and tenderness around the kneecap. Regularly they become apprehensive and fearful if the kneecap is moved to the outside.
Over time, these deformities – combined with an injury or other factors – may cause the cartilage surfaces to break down. When this happens, patients will complain of anterior knee pain, which grows progressively worse with daily activities. The result is arthritis of the patellofemoral joint.
As always, the best treatment is non-surgical. In the acute stage, ice and elevation in the form of the Cryo/Cuff®, both compresses and cools the inflamed area. Medications such as Ibuprofen, as well as nutritional supplements, are helpful. Occasionally a knee brace is used, but the best brace is always a strong, stabilizing quadriceps muscle.
Patients are advised to lose unnecessary weight and perform a series of exercises including hamstring stretching, stretching of the iliotibial band, stretching of the gastrosoleus muscle and strengthening of the abductor muscles of the hip – as well as closed chain quadriceps drills using the Step Box. The Step Box is a simple and inexpensive device used for the performance of closed chain knee extension exercises on both legs – six sets of 25 reps each day. As strength increases, reps increase to 50. When patients are able to do 50 reps at two inches of excursion, excursion is moved to four inches, and then six and on to eight as each level is comfortably achieved. Later a program of biking and more difficult closed chain exercises are added.
Patella Realignment Surgery
Patella Realignment Surgery is indicated for patients who have ongoing anterior knee pain, subluxation or dislocations of the patella, and/or patellofemoral arthritis that is non responsive to conservative treatment.
About the Procedure
Throughout the past century, over 100 different surgical procedures for the correction of patella pain and instability have been described. Unfortunately, the results of these procedures led to continuing pain and arthritis. Most surgeons had their “preferred” procedure that they learned during their early training. Over the past decade we became indebted to Drs. Robert Teitge and David DeJour, who taught us that “one size” does not fit all. Surgical procedures to correct patella problems must be tailored to each individual patient.
Preoperative planning is necessary if an excellent result is to be expected. It starts with a careful physical examination and observation of the patient’s gait. Ordinary weight bearing X-rays are taken. This gives us an idea of limb alignment and whether or not arthritis is present. A lateral view determines the height of the patella. Orthoradiograms, which are X-rays that show the frontal and side alignment of the entire limb from hip to ankle, help determine alignment in the frontal and sagittal (side view) plane. A CT or MRI scan is also performed. This will determine if torsional malalignment is present. The scan will also determine at what angle of flexion the knee cap strikes the trochlear groove and whether or not the trochlear groove is deep enough. This is important because as the knee cap strikes the femur, the knee cap becomes fixed in place. Lastly, the offset between the trochlear groove (where the patella strikes) and the tibial tubercle (knob of the knee) is measured. This ideal offset is between 10 and 15 millimeters. Over 20 millimeters requires correction.
After all is measured, it is determined whether or not correction of bony deformities is necessary. If all the deformities are not addressed and an unanatomic operation creates secondary deformities, a poor result is guaranteed. If bony abnormalities are not present, soft tissue reconstructions, such as reconstruction of the medial and/or patellofemoral ligament, may be performed.
Lateral retinacular release, although commonly performed by community Orthopedists, is NEVER indicated. Release of the lateral retinaculum, also known as lateral release, has been shown to loosen the already unstable patella and cause the uncommonly seen medial dislocation of the patella. For this reason, the lateral release is no longer broadly used by patellofemoral specialists. Unfortunately, it is still performed in many communities. Equally ineffective is arthroscopic shaving, as well as microfracture of the patella- a procedure in which holes are made in the patella with a small drill or awl.
Dr. Sanders’ procedures include an examination under general anesthesia, in which the laxity of the patella to medial and lateral forces is documented, and a diagnostic and/or surgical arthroscopy is performed. Arthroscopy will directly identify and confirm the problem and correct any other intra-articular abnormalities such as torn menisci, a pathologic medial plica (a relatively painful but harmless developmental condition), as well as address chondral surface pathology.
Following the arthroscopy, the previously calculated correction of bony deformities in as many as four different planes is performed. Again these planes consist of the frontal plane, for valgus or varus correction (see tibial and femoral osteotomy). The height of the patella and its medial and lateral offsets are corrected through osteotomy of the tibial tubercle. The groove in the femur may require deepening, maltorsions of the femur and/or the tibia may also require attention. And finally, the ligament called the medial patellofemoral ligament may need to reconstructed. Although all of this can seem daunting to perform in a single surgery, recovery all occurs at the same time. Dr. Sanders does not believe in correcting one deformity at a time, prolonging treatments over years.
Postoperative Management after Patella Surgery
As in most knee surgeries, the postoperative rehabilitation is among the most critical components and Dr. Sanders begins this the day of surgery. These surgeries are typically performed on an outpatient basis. We have abandoned the used of the femoral nerve block, as while they provide effective pain relief in the first 24 hours, needle trauma or cytotoxicity from the medications commonly case neuriti8c pain and weakness that lasts in excess of three months. Patients are given the benefit of multimodal analgesia. By attacking the pain through several different pathways, fewer narcotics will be necessary, and subsequently, the negative side effects of narcotic use can be diminished or eliminated. These medications include an anti-inflammatory such as Meloxicam, a nonnarcotic analgesic such as Tramadol, acetaminophen, also known as Tylenol and gabapentin which calms down peripheral nerve pain. These medications are taken around the clock. The need for a narcotic analgesic, such as hydrocodone, is drastically diminished so fewer side effects such as effects such as nausea and/or constipation occur. Phenergan is prescribed to help with nausea. Taking two Tylenol every four hours is a good alternative.
And Tylenol PM (a preparation that includes benedryl) is encouraged over other medications in the event of sleep disturbance, which is common after such procedures. Ambien, which is also prescribed, is a stronger sleep aid. All patients will immediately begin an accelerated rehabilitation program the day of their procedure. This ensures the best results and a rapid recovery.
Avoiding Blood Clots
A risk of a fatal blood clot traveling to the lung can occur after knee surgery and preventative measures are taken. Previously, we utilized spinal anesthesia as it was believe to reduce the incidence of venus thromoboembolism. Unfortunately, comparative data did not support that. Dr. Sanders does not utilize a tourniquet on the limb for patella surgery. This measure both decreases the incidence of blood clots and results in pain relief on a standalone basis. Patients also receive mechanical measures to compress the veins of the opposite lower extremity while on the operating table and at home. Following surgery, mechanical pumps are placed on both legs. Patients are expected to be out of bed walking with assistance the afternoon of their surgery. Depending on a patient’s presurgical medical condition, blood thinning medications such as aspirin or Warfarin may be utilized. Aspirin is all that is necessary for the majority of patients.
Preventing Swelling and Excessive Pain
A Cryo/Cuff® (cold therapy device) is placed over the compressive stocking on the recovering limb the first day post-surgery and remains for several weeks to further minimize the amount of swelling and pain. Initially, the Cryo/Cuff® should be removed only when performing active exercises. Otherwise, it should be maintained at all times. With less swelling and pain, motion is regained faster. Initially, the leg is then elevated above the heart by flexing the hip and knee to 90 degrees and supporting the positon with folded sheets under the calf. This guarantees that the patient will have adequate flexion of the knee to walk comfortably and obviates the expense and need for a continuous passive motion machine. Pet lovers can also enjoy the emotional support of their dogs and cats lying next to them! (Dr. Sanders has three Labradors)
The best way to keep pain and swelling manageable is almost complete bed rest and elevation of the recovering leg for the first five days. Patients should be up only for the purpose of constructive fully exercises several times per day. They may most certainly leave the bed to use the washroom and to take their meals at the table. Leaving the house is best avoided the first week.
Regaining Mobility and Strength
The Recovering Knee, Day of Surgery through Postoperative Day 14
Movement is one of the most important elements in a rapid recovery and return to full mobility. A number of different devices and exercises are introduced to patients through an accelerated program in the advancement towards recovery.
Established in three phases, the first device used in this rapid recovery process is the Cryo/Cuff®, which compresses the knee and keeps it cold. On the first night after surgery, the knee is kept bent at 90 degrees to decrease bleeding. Starting on the morning thereafter, 55 minutes of the hour is spent with the limb elevated eight inches above the heart and fully straight.
Ten of these 55 minutes patients work on active quadriceps exercise. To complete this exercise, the foot rests on a pillow with nothing under the back crease of the knee. Patients should attempt to push the back crease of the knee down towards the bed, move the toes upward towards the head and lift the leg ten inches straight up into the air. It is maintained there for a count of five. This exercise is repeated 10 to 25 times.
While charging the water for the Cryo/Cuff®, patients do a “Cannonball” exercise as they grasp the back of both knees and bring them to the chest. The knees will bend on their own. During this time, no energy should be expended. Patients are encouraged to concentrate on deep breathing and long exhales.
The second half of Phase One: Postoperative days 8 through 42
On the eighth day following surgery, patients are generally able to resume regular sedentary activities and have a nearly normal gait, often times without any assistive devices in those cases where osteotomy of a bone was not necessary. Those patients will continue to use crutches or a walker, taking a nominal amount of weight on the limb. The length of time that patients use a walker or crutches is dependent on bone healing but usually averages about six weeks. Patients should continue their active exercises four times per day. The stationary bike is added at this time. Patients are instructed to stay on the bike one hour per day, every day – gradually increasing the resistance until the target heart rate for their age is reached. A follow-up appointment is made at this time. Skin sutures or staples are removed at 21 days.
Those patients who have not had bone surgery may continue their exercise program by adding the Step Box. This simple device is used for the performance of closed chain knee extension exercises, beginning with four sets of 25 reps of two-inch excursions until fatigue each day, progressively increasing until 50 reps can be performed. The same routine is then continued with a four-inch excursion. After the same goal is reached, the excursion is increased to six, then eight inches. Patients must remember to do at least four sets per day.
Postoperative Days 42 through 90
At this time, those patients who have had osteotomies may start taking full weight on their leg and gradually reduce until the complete elimination of the use of external ambulatory aids. These osteotomy patients continue their exercise program by adding the Step Box. This simple device is used for the performance of closed chain knee extension exercises, beginning with four sets of 25 reps of two-inch excursions until fatigue each day, progressively increasing until 50 reps can be performed. The same routine is then continued with a four-inch excursion. After the same goal is reached, the excursion is increased to six, then eight inches. Patients must remember to do at least four sets per day. All patients must continue to work the stationary bike into their rehabilitation routine, while also continuing the Step Box at increasingly longer excursions through the end of the fourth week. Patients are encouraged to take the recovery one step at a time, rather than over exerting and suffering a setback.
Postoperative Day 90 – until discharge from active treatment
Certified trainers or Physical therapists work one-on-one with the patients to continue a program of sports rehabilitation emphasizing strengthening and stretching of the hip abductors and quadriceps muscles as well as hamstring strengthening and stretching, illiotibial band stretching and gastrosoleus stretching. Aerobic fitness is also part of this rehabilitation program. An exercise routine that can easily be done both at home independently, as well as at a gym or clinic under supervision is created for each patient. During months three and four, patients may begin returning to sports at a restricted level. Patients are periodically evaluated through the remaining year.