PATIENT EVALUATION

History and Physical Examination

A detailed history should be obtained from the patient. The examiner must inquire about any previous trauma, infections, fractures, or surgery to the knee. It is important to get details about past treatments, including the duration of immobilization and postoperative rehabilitation. The surgeon should try to determine the cause of the stiffness. In many cases, potential causes of the stiff knee can be identified based on the patient’s history. The examiner also must determine whether there is any associated pain. If there is significant pain associated with the stiffness, then the location may provide a clue about the site of greatest entrapment. For example, a patient with an infrapatellar entrapment and stiffness will most often complain of anterior knee pain.

The physical examination should begin with a generalized inspection of the patient. Contralateral knee motion should be assessed. The examiner should evaluate the ipsilateral hip and ankle for any concurrent pathology. The patient may have an antalgic gait because of a painful knee that won’t fully extend. The affected knee should be inspected thoroughly. It is important to note any previous incisions or scar. As noted earlier, some patients are fibrotic healers and may produce abundant scar or keloids. Muscle atrophy is common and should be noted if present.

Palpation of the knee should follow. The temperature of the knee should be determined and compared with the contralateral knee. The surgeon will need to evaluate the knee for any intra-articular effusion present. Warmth and swelling are important findings that will guide treatment options. If a significant effusion is present, consideration should be given to knee aspiration to rule out infection as a possible cause. Range of motion should be measured with a goniometer in a consistent fashion that can be replicated during subsequent physical examinations. The contralateral knee range of motion should also be measured. A standard knee ligamentous examination should be carried out. The location of any pain elicited should be documented. Joint line tenderness may be present if the patient has significant arthritis or a concurrent meniscus tear.

One of the most important structures to examine in the stiff knee patient is the patella. The patella is the centerpiece of knee motion and is almost always involved in the stiff knee. Medial and lateral patella glide should be assessed. Medial and lateral patellar tilt should be measured and compared withthe contralateral side. Decreased medial or lateral tilt compared with the contralateral side is suggestive of medial or lateral gutter involvement. Anterior patellar tilt should also be assessed (Fig. 4-4). If the patient has infrapatellar entrapment, he or she will usually lose the anterior patellar tilt. With moderate to severe infrapatellar entrapment, the patient will usually develop a shelf sign, which denotes loss of the retropatellar tendon bursa and adherence of the patellar tendon to the tibia (Fig. 4-5).

FIGURE 4-4 Anterior patellar tilt (arrow).

FIGURE 4-5 Shelf sign. Shown is loss of the retropatellar tendon bursa with adherence of the patellar tendon to the tibia.

Diagnostic Imaging

A standard series of radiographs should be taken on initial evaluation of the stiff knee. Weight- bearing anteroposterior and 45-degree anteroposterior flexion views should be obtained to assess for any degenerative changes. Bilateral 30-degree lateral views should be obtained to evaluate for any degenerative changes as well as any patella baja. A Merchant or sunrise view of the knee should be obtained to evaluate patella tracking as well as any patellofemoral degenerative changes. Long leg alignment or scanograms should be obtained if any significant varus or valgus malalignment is suspected. Computed tomography and ultrasound have little use in the evaluation of the stiff knee, but magnetic resonance imaging (MRI) may be of some benefit. A MRI scan can evaluate the structures within the knee, including the location and integrity of any previously reconstructed ligament. It can also help quantify the degree of any cartilage loss or injury. Loose bodies within the intracondylar notch will be evident by MRI. An MRI scan will give a detailed evaluation of the fat pad, which may have contracted, calcified, or formed a pseudotendon (Fig. 4-6).

FIGURE 4-6 MRI scan of infrapatellar entrapment and pseudotendon formation.

TREATMENT

The key to treating arthrofibrosis of the knee successfully is identifying the cause. Once the cause has been identified, a treatment plan can be created and carried out to correct it. If the cause is not corrected and only the stiffness is treated, the arthrofibrosis will undoubtedly recur.

Indications and Contraindications

It is important for the surgeon to understand the indications and contraindications for arthroscopic or open lysis of adhesions (Box 4-1). The most common mistake is to operate too soon on a stiff knee. Although short-term range of motion may improve, this second hit only worsens the arthrofibrosis in the long run. The knee must not be warm and swollen when proceeding with any treatment. It may take from 2 to 12 months before the knee has returned to a noninflamed state. Regardless of the cause, the quadriceps muscle must be contracting normally prior to proceeding with surgery. If the patient does not have adequate quadriceps strength to maintain extension after the surgery, the procedure will have a poor outcome.

Infrapatellar entrapment is an extremely difficult condition to treat arthroscopically. Although a mild degree of infrapatellar entrapment may respond to arthroscopic release, moderate to severe cases usually require an open release, with or without a retropatellar interposition patch. To correct patella infera, elevate the patellar tendon away from the anterior tibia, and restore the alpha angle, it is sometimes necessary to move the tubercle both superiorly and anteriorly. The DeLee-Paulos osteotomy is designed to accomplish this. A large shingle of anterior tibia (including the tubercle) is created. A 5-mm deep cut is made above the tubercle. A second 15-mm deep cut approximately 3 cm distal to the tubercle is also made. These two cuts are connected medially to laterally and the bone fragment is then moved superiorly, enough to correct the patella baja. As the bone fragment moves superiorly, it automatically proceeds anteriorly. It is fixated with one to two screws. The defect created by the osteotomy is then bone-grafted (Fig. 4-7).

FIGURE 4-7 DeLee-Paulos osteotomy for patella infera.

Conservative Management

Prevention is the best treatment for arthrofibrosis. Range-of-motion (ROM) exercises should be initiated as soon as possible after surgery. Other postoperative measures that can be taken to prevent stiffness include immediate quadriceps exercises, patellar mobility exercises, and obtaining early extension. Once arthrofibrosis has occurred, conservative treatment is based on the degree of involvement. Mild to moderate motion loss is treated initially with more active and passive ROM exercises, patellar glides, anti-inflammatories, analgesics for pain control, and extension bracing at night. If moderate to severe motion loss is present, it is critical to stop any painful treatments. Painful aggressive therapy at this point will only worsen the problem. A tapered dose of oral steroids may also be used for those who do not have contraindications. Muscle stimulation may be used and can be helpful. The most important part of this waiting period, during which the knee is still swollen and warm, is to avoid aggressive physical therapy and forceful manipulation. Swimming and cycling are activities that may be started during this time, with low risk of worsening the vicious cycle of pain, inflammation, and stiffness.

Arthroscopic Technique

Before considering surgery, the patient must have minimal swelling, no warmth, improving pain, and good quadriceps function. Common findings at the time of surgery usually include degeneration of the articular cartilage, abundant fibrous tissue, soft tissue transformation, and patella infera.¹⁰ The surgeon must be prepared to address these at the time of surgery if found.

Anesthesia

In the ideal situation, the patient is placed under general anesthesia with a regional nerve block and indwelling catheter. This allows for good pain control postoperatively, resulting in better patient compliance with immediate postoperative rehabilitation. An alternative strategy is to use epidural anesthesia with an epidural catheter for intraoperative and postoperative pain control.¹¹

Equipment

Standard knee arthroscopy equipment is used. We have 30- and 70-degree arthroscopes available for adequate visualization, and 4.5- and 5.5-mm full-radius arthroscopic shavers are frequently used. An electrocautery hook is used for scar releases. Arthroscopic biters and graspers should be present in case any concurrent pathology is found at the time of arthroscopy.

Positioning

We position the patient supine on the operating room table in a slight Trendelenberg. A small bump is placed under the ipsilateral hip. A nonsterile tourniquet is placed on the operative leg as high as possible. A foot rest is applied to the end of the operating room table to allow for maintained flexion during the procedure. A lateral post is used. Ideally, the surgeon will have an assistant available to help with leg positioning during the procedure.

Capsular Distention

We use a similar technique as described by Millett and Steadman.¹² We distend the capsule initially with 60 mL of normal saline through a superolateral injection. Fluid should follow easily into the suprapatellar pouch. If resistance is felt, the needle is redirected until the knee is easily distended. An additional 60 mL of normal saline is then injected slowly to allow for some additional distention of the contracted capsule.

Portal Placement

The surgeon should be familiar and comfortable making multiple portals for the treatment of knee arthrofibrosis. We make a standard anterior lateral portal at the level of the inferior pole of the patella using a no. 11 blade scalpel. Once the camera is inserted and driven down into the medial compartment, we approximate the anteromedial portal using an 18-gauge spinal needle. The anteromedial portal should be medial to the patellar tendon and just superior to the anterior horn of the medial meniscus. Under direct visualization, we create the anteromedial portal using a no. 11 blade scalpel. A superolateral portal is created just superior and lateral to the superior pole of the patella. This portal should be at the inferior edge of the vastus lateralis. A superomedial portal may also be needed and is created just medial and superior to the superior pole of the patella. If posterior capsular release is required, a posteromedial portal is also created.

While looking in the posterior medial compartment, an 18-gauge spinal needle is inserted under direct visualization. The needle is inserted anterior to the medial head of the gastrocnemius to avoid the neurovascular structures. Once the portal site is approximated, a no. 11 blade scalpel is used to incise the skin. A hemostat may be needed to spread the subcutaneous tissue down to the level of the capsule. A blunt trocar is then inserted under direct visualization, creating the posteromedial portal. Occasionally, a posterolateral portal may be needed for complete release. We first insert a spinal needle under direct visualization anterior to the biceps femoris, anterior to the lateral head of the gastrocnemius, and posterior to the fibular collateral ligament. If the portal is too far posterior, the peroneal nerve is in danger. In a manner similar to that for the posteromedial portal, the skin is incised with a scalpel. A hemostat is used to dissect bluntly through the soft tissue down to the capsule. The capsule is then entered with a blunt-tipped trocar.

Locations of Entrapment

Suprapatellar Pouch.

It is important to examine the suprapatellar pouch for adhesions (see Fig. 4-1). Use electrocautery to lyse any adhesions or plica seen. If the suprapatellar pouch appears to be small, then scar tissue has likely encroached on the superior part of the pouch. It may be necessary to débride the superior part of the pouch with an arthroscopic shaver. The pouch should extend at least 3 cm proximal to the patella. If significant débridement using the arthroscopic shaver is required, we recommend cauterizing the tissue afterward to achieve hemostasis.

Medial and Lateral Gutters.

As with the suprapatellar pouch, the medial and lateral gutters should be inspected. Lyse any adhesions visualized in this area with electrocautery. Typically, the adhesions will form between the capsule and femoral condyle. If the medial or lateral patellofemoral ligament is contracted, release of these ligaments is usually required. If limited medial glide and lateral patellar tilt are present on physical examination, we usually proceed with a lateral retinacular release. Starting at the inferior aspect of the vastus lateralis, the lateral release is performed using an electrocautery hook. The release is carried down to the level of the anterior lateral portal site. Once the release is complete, the patella should be able to be tilted 45 to 70 degrees. Additionally, the patellotibial ligament may require release distal to the lateral portal. If limited lateral glide and limited medial tilt are present, a medial release may be performed as well.

Medial Compartment.

As with any knee arthroscopy, the surgeon should inspect the medial compartment and address any pathology found. In the severely contracted knee, significant chondromalacia may be present.

Infrapatellar Area.

Inspection of the fat pad should be performed. In severe arthrofibrosis, a dense wall of scar may be present, making it difficult to visualize the fat (see Fig. 4-2). The fat pad should never be fully resected. The fat pad should be released using electrocautery on the medial and lateral sides. It is also important to release scar and the fat pad from the anterior tibia. In a normal knee, a retropatellar recess or bursa is usually present. An anterior recess release should be performed by use of electrocautery. The wall of scar should be released just proximal and anterior to the anterior horns of the medial and lateral meniscus. The release should be carried out distally 1 cm below the articular surface of the tibial plateau. Occasionally, a distinct pseudopatellar tendon will form between the inferior pole of the patella and anterior tibia. Resection of this dense band of tissue may be necessary. Care should be taken to avoid overzealous resection in this area. If the tendon is exposed to bone, then recurrence is likely. If retropatellar tendon fibrosis is present, but not patella infera, the use of a barrier to prevent adhesions of the patellar tendon to the anterior tibia may be needed. A nonreactive barrier such as the Bard hernia patch is an excellent choice. It can be cut to the approximate size and sutured to the anterior tibia directly posterior to the patellar tendon. The polyethylene surface faces the tendon. The patch may be left in place and does not require removal (Fig. 4-8). Care should also be taken to avoid abrading or severely cauterizing the bone, because this will increase the chances of recurrence.