Arthroscopy of the Lower Extremity

General principles

Arthroscopy of the knee can be done as the essential initial step before proceeding to operative arthroscopy or before an open arthrotomy. Anesthesia can be local, regional block, or general. If the procedure is uncomplicated and of short duration, it can be done using a regional block local anesthesia in cooperative patients, especially if the surgeon is experienced in arthroscopy. If local anesthesia is to be used, we prefer intravenous sedation for portal injection with 1% lidocaine and an intraarticular bolus of 30 mL of bupivacaine and 15 mL of lidocaine 20 minutes before starting the procedure. Diagnostic arthroscopy before arthrotomy or major intraarticular surgery generally is best done with the patient under general anesthesia, unless this type of anesthesia is contraindicated.

The procedure is performed in the operating room under strict sterile conditions. The seriousness of this surgical procedure must not be minimized. Although complications such as infection are infrequent (<1%), carelessness in surgical scrubbing, preparation, or draping or careless handling of the irrigating solutions, arthroscopes, and instruments can result in intraarticular infections just as devastating as those after arthrotomy. Sterilization of arthroscopy equipment and use of waterproof arthroscopy gowns and drapes are essential. Sealing the extremity proximal and distal to the arthroscopy site and use of a durable skin preparation (DuraPrep, 3M Healthcare, St. Paul, MN) and iodine-impregnated drape at the surgical site can help to minimize infections.

The scrub nurse uses a large table for instruments. This is positioned for the nurse’s convenience, usually on the same side as the knee having surgery. A Mayo stand is placed over the operating table at the upper part of the patient’s thighs, and the more commonly used instruments are placed on it. Power cords and light cables are attached to the appropriate sources and are placed on a side table. Irrigation bags are suspended from an intravenous stand at the head of the table and are raised 3 to 4 feet above the level of the patient. The use of an arthroscopic pump for inflow through the arthroscope sheath or a separate sheath helps keep flow and pressure constant. The pump may eliminate the need for a tourniquet, making arthroscopy using local anesthesia feasible.

A tourniquet is placed around the thigh but is not inflated in diagnostic arthroscopy unless troublesome bleeding occurs. Inflation of the tourniquet blanches the synovium and other vascularized tissue and makes diagnostic evaluation of these structures more difficult. Meniscal vascularity and healing potential should be evaluated with the tourniquet deflated and the intraarticular hydrostatic pressure low. The tourniquet usually is inflated after exsanguination of the limb in acute traumatic disorders, or if the surgeon anticipates anything other than the simplest intraarticular surgical procedure. Tourniquet time should be minimized and not exceed 90 minutes for routine procedures to prevent possible deep vein thrombosis. For major complicated procedures, tourniquet times of up to 2 hours can be used, but times longer than this should be avoided to prevent ischemic neurovascular changes.

Stressing the knee to open up the various compartments is necessary for diagnostic or operative procedures. This can be accomplished by using a padded lateral post or a commercial leg-holding device. The use of a padded lateral post attached to the edge of the operating table can be effective for valgus stressing in or near full extension, but it does not control rotation. The commercial thigh holders are most effective, but some of their potential dangers must be kept in mind.

Patient positioning

When the patient is anesthetized, and a tourniquet and leg holder are applied if desired, the limb from the ankle to the tourniquet is thoroughly scrubbed and surgically prepared, just as for an open arthrotomy. Excellent commercial arthroscopy draping systems are available that isolate the foot and lower leg and the distal thigh just below the tourniquet and leg holder ( Fig. 51.1 ). Waterproof gowns also are imperative for the surgeon and assistant to prevent contamination.

The patient can be placed supine with the prepared and draped limb angled off the lateral aspect of the table. The use of a leg holder or a lateral post allows the surgeon to stand on the inside of the abducted leg, placing the patient’s foot and ankle on the surgeon’s hip and iliac crest area. Placing the surgeon’s outside foot on a small platform often helps maintain the patient’s foot in the correct position. This position frees both of the surgeon’s hands, and the surgeon can stress the leg into valgus by simply leaning against the leg in the leg holder. This maneuver opens up the medial compartment for examination and probing. When the patient is supine, examination of the lateral compartment requires the assistant to hold the leg in a figure-four position. The table-flat position can be used with the surgeon and assistant standing at the side of the table ( Fig. 51.2 ).

The patient also can be placed supine on a standard operating table with the knee joint positioned slightly past the distal break point of the table. The end of the table is dropped so that both limbs dangle at 90 degrees. The opposite limb should be well padded to prevent potential pressure problems. Flexing the middle of the table and placing a padded bolster also flexes the hips to take the stretch off the femoral nerve and simultaneously flattens the lumbar spine. The use of a well-leg support for the uninvolved limb is another excellent technique. With either technique, it is recommended to wrap the uninvolved extremity with an elastic wrap or to use an elastic stocking to minimize venostasis ( Fig. 51.3 ).

Portal placement

Among the keys to success in arthroscopy are adequate light and distention of the joint and precise localization of the portals of entry for the arthroscope and accessory instruments. Without adequate illumination, clear vision is impossible; without adequate distention of the joint, the fat pad, synovium, and other soft tissues obliterate the view; and without precise location of the portals of entry, one would be unable to see adequately or to maneuver within all parts of the joint. Attempts to force a poorly placed arthroscope or instrument can result in articular scuffing, instrument damage, and other problems. Adequate illumination is ensured by proper care of the arthroscope and fiberoptic light cables, changing the light source bulbs when required, cleansing the arthroscope lens of film from frequent disinfectant soakings, and maintaining a clear irrigation medium. Any damage to the arthroscope tip, whether from motorized instrumentation or careless handling, can result in uneven light regulation and inability to focus the arthroscope properly. Precise entry portal location can be ensured best by carefully drawing the joint lines and soft-tissue and bony landmarks with a skin-marking pen before joint distention. All standard and optional portals are marked. Typically, the outlines of the patella and patellar tendon are drawn, medial and lateral joint lines are palpated with the fingertip and drawn, and the posterior contours of the medial and lateral femoral condyles are marked. The surgeon should recheck these outlines after distention to ensure proper placement.

When the portals are carefully marked, a small outflow, needle-type cannula can be placed superomedially or superolaterally with inflow through the arthroscope. This generally is necessary for large procedures, such as anterior cruciate ligament reconstruction when hemarthrosis is present. For smaller procedures, such as a meniscectomy, an outflow cannula might not always be necessary. Avoiding going through the vastus medialis obliquus may help to accelerate rehabilitation.

Standard portals

The standard portals for diagnostic arthroscopy are the anterolateral, anteromedial, posteromedial, and superolateral ( Fig. 51.4 ).

Anterolateral Portal

If allowed only one approach for diagnostic arthroscopy of the knee joint, most arthroscopic surgeons would choose the anterolateral portal. With the use of a 4-mm-diameter, 30-degree oblique forelens arthroscope through the anterolateral portal, almost all of the structures within the knee joint can be seen. Through this portal, the posterior cruciate ligament (PCL), the anterior portion of the lateral meniscus, and, in tight knees, the periphery of the posterior horn of the medial meniscus cannot be viewed adequately, however. This portal is located approximately 1 cm above the lateral joint line and approximately 1 cm lateral to the margin of the patellar tendon. Palpation of the inferior pole of the patella helps to ensure that the anterior portals are not placed too high; the portal should be approximately 1 cm inferior to the patella. If the portal is placed too near the joint line, the anterior horn of the lateral meniscus can be lacerated or otherwise damaged. Also, an arthroscope inserted through such a portal can pass either through or beneath the anterior horn of the lateral meniscus, resulting in damage to the anterior horn or difficulty in maneuvering the arthroscope within the joint because it is bound down by the overlying meniscus. A portal placement too superior to the joint line allows the arthroscope to enter the space between the femoral and tibial condyles and prevents viewing of the posterior horns of the menisci and other posterior structures ( Fig. 51.5 ). An arthroscope placed immediately adjacent to the edge of the patellar tendon can penetrate the fat pad, causing difficulty in viewing and in maneuvering the arthroscope within the joint.

Anteromedial Portal

The anteromedial portal is most commonly used for additional viewing of the lateral compartment and for insertion of a probe for palpation of the medial and lateral compartment structures. This portal is located similarly to the anterolateral portal: 1 cm above the medial joint line, 1 cm inferior to the tip of the patella, and 1 cm medial to the edge of the patellar tendon. Precise placement can be confirmed by using a percutaneous spinal needle visualized from the anterolateral portal. A no. 11 blade with the cutting edge pointed away from the meniscus is visualized while making the portal.

Posteromedial Portal

The posteromedial portal is located in a small triangular soft spot formed by the posteromedial edge of the femoral condyle and the posteromedial edge of the tibia. Before distention of the joint, this small triangle can be palpated easily with the knee flexed to 90 degrees. The landmarks should be drawn on the skin before beginning the diagnostic arthroscopy. The posteromedial compartment is small, but any arthroscope can be inserted into it with proper care and technique. In this portal, a 30-degree angled arthroscope offers optimal viewing of all the structures in the posteromedial compartment. Three guidelines aid in the establishment of this portal: (1) the knee must be maximally distended with irrigating solution so that the posteromedial compartment balloons out like a bubble when the knee is flexed to 90 degrees; (2) the knee must be flexed as close to 90 degrees as possible; and (3) the bony landmarks must be drawn before the joint is distended. The location of the portals should be approximately 1 cm above the posteromedial joint line and approximately 1 cm posterior to the posteromedial margin of the femoral condyle. This portal is useful for repair or removal of displaced posterior horn meniscal tears and for removal of posterior loose bodies that cannot be displaced into the medial compartment and removed through an anterior portal. It is always used in PCL reconstruction.

Superolateral Portal

The superolateral portal is most useful diagnostically for viewing the dynamics of the patellofemoral articulation. It also is the best approach for visualization of the patellar tendon using a 70-degree scope. This portal is located just lateral to the quadriceps tendon and about 2.5 cm superior to the superolateral corner of the patella. With the arthroscope in this portal, the patellofemoral joint can be viewed with a 30- or 70-degree arthroscope, allowing evaluation of patellar tracking, patellar congruity, and lateral overhang of the patella as the knee is carried from extension into varying degrees of flexion.

Insertion of scope

If the tourniquet is not to be inflated unless troublesome bleeding occurs, the portal sites should be infiltrated with 4 to 5 mL of a local anesthetic agent mixed with epinephrine, which reduces bleeding and postoperative pain. The use of more than 4 to 5 mL is not advised because a larger bolus, especially in the anterolateral and anteromedial portals, can distend the fat pads sufficiently to make viewing difficult. If inflation of the tourniquet is planned, the portals usually are not infiltrated.

Classification of meniscal tears

Classification of the types of meniscal tears encountered during diagnostic arthroscopy of the knee is essential in planning the subsequent arthroscopic resection or repair. Although numerous classifications of meniscal tears have been described, that of O’Connor has proved useful: (1) longitudinal tears; (2) horizontal tears; (3) oblique tears; (4) radial tears ( Fig. 51.7 ); and (5) variations, which include flap tears, complex tears, and degenerative meniscal tears.

• Longitudinal tears most commonly occur as a result of trauma to a reasonably normal meniscus. The tear usually is vertically oriented and may extend completely through the thickness of the meniscus or may extend only partially or incompletely through it. The tear is oriented parallel to the edge of the meniscus; if the tear is complete, a displaceable inner fragment frequently is produced. When the inner fragment displaces over into the intercondylar notch, it commonly is referred to as a bucket-handle tear ( Fig. 51.8 ). If the tear is near the meniscocapsular attachment of the meniscus, it commonly is referred to as a peripheral tear. A peripheral vertical tear in zone I, referred to as a red-red tear, and a tear between zone I and II, referred to as a red-white tear, are in the vascularized portion of the meniscus ( Fig. 51.9 ). These peripheral tears should be repaired when feasible.

  
  

• Horizontal tears tend to be more common in older patients, with the horizontal cleavage plane occurring from shear, which divides the superior and inferior surfaces of the meniscus. These are more commonly seen in the posterior half of the medial meniscus or the midsegment of the lateral meniscus. Many flap tears and complex tears begin with a horizontal cleavage component.

• Oblique tears are full-thickness tears running obliquely from the inner edge of the meniscus out into the body of the meniscus. If the base of the tear is posterior, it is referred to as a posterior oblique tear; the base of an anterior oblique tear is in the anterior horn of the meniscus ( Fig. 51.10 ).

  

• Radial tears, similar to oblique tears, are vertically oriented, extending from the inner edge of the meniscus toward its periphery, and can be complete or incomplete, depending on the extent of involvement. These probably are similar in pathogenesis to oblique tears ( Fig. 51.11 ). Tears posterior to the popliteal tendon may heal on their own or with local stimulation techniques ( Fig. 51.12 ).

  
  

• The possible variations include flap tears, complex tears, and degenerative meniscal tears. Flap tears are similar to oblique tears but usually have a horizontal cleavage element rather than being purely vertical in orientation. Tears containing a horizontal element often are referred to as superior or inferior flap tears, depending on where the flap is based on the surface of the meniscus.

• Complex tears may contain elements of all of the just-mentioned types of tears and are more common in chronic meniscal lesions or in older degenerative menisci. These generally are caused by chronic, long-standing, altered mechanics of the meniscus, and the initial tear occurring in the meniscus may not be identifiable after several different planes of tearing have resulted.

• Degenerative tears often refer to complex tears. These present with marked irregularity and complex tearing within the meniscus. These are most often seen in older patients.

Types of meniscal excisions

O’Connor separated meniscal excisions into three categories depending on the amount of meniscal tissue to be removed ( Fig. 51.13 ).

General principles

• ▪

  Preserve functional meniscus; resect and contour the damaged tissue.

• ▪

  When possible, repair horizontal tears in the vascular zone and longitudinal and radial tears in young patients.

• ▪

  Repair the meniscus to protect the cartilage; protect the cartilage to repair the meniscus.

• ▪

  Release the superficial medial collateral ligament with a spinal needle to allow joint opening and prevent articular damage when necessary to repair.

• ▪

  Finally, check for a hypermobile lateral meniscus and any of the “3 Rs”: rips, ramps, and roots. Wrisberg rips are tears of the attachment over the popliteus tendon that allows displacement of the lateral meniscus. A ramp lesion is a peripheral, posterior horn, medial meniscal tear associated with the pivot shift from an acute ACL tear. A posterior root tear must be identified and repaired in non-arthritic knees to prevent cartilage overload and degeneration.

• ▪

  For partial meniscectomy use instrumentation in the ipsilateral portal with a straight or 15-degree up-curve instrument. For anterior tears, use curved or side-cutting instruments from the contralateral portal. Repairs are best performed outside-in for anterior tears and all-inside or inside-out for posterior tears, preferably from a contralateral portal to direct needles away from neurovascular structures.

Surgery for specific meniscal tears

As discussed earlier, tears of the menisci can be (1) longitudinal, either intrameniscal or peripheral, complete or incomplete, displaced (bucket-handle) or nondisplaced; (2) horizontal; (3) oblique; (4) radial; (5) flap; (6) complex; or (7) degenerative. No standard technique can be used in every case. The following techniques are useful in dealing with each of these types of tears through the anteroinferior portals. Even partial meniscectomy has been shown to increase joint wear; reasonable judgment must be used in planning meniscal surgery to preserve functional meniscal tissue. Planning begins in the preoperative period, ensuring the patient is fully informed as to the possibility of a partial meniscectomy versus meniscal repair and the postoperative course involved with each. Also, having the appropriate equipment and a thorough understanding of the incision and repair techniques are imperative.

As a whole, tears of the lateral meniscus are less common than tears of the medial meniscus. The radial tear configuration is almost unique to the lateral meniscus, occurring rarely in the medial meniscus. Also, the occasional discoid meniscus rarely is encountered in the medial compartment.

Most lateral meniscal excisions or repairs are done with the knee in the figure-four position: the hip slightly flexed, abducted, and externally rotated; the knee flexed at 30 to 90 degrees; and the tibia internally rotated. This position can be achieved with the foot of the table extended or flexed. With the end of the table extended, the ankle is placed on the table surface or on the opposite lower leg. In this position, the hip falls into external rotation, and a varus stress can be applied by pushing downward on the flexed knee. The figure-four position also can reduce overall joint distention by collapsing the suprapatellar pouch, making viewing and the use of suction and motorized cutters and trimmers in the lateral compartment more difficult. Inflow through the arthroscopic sheath allows for best visualization.

Vertical Longitudinal (Bucket-Handle) Tears

This common tear usually occurs in young patients as a result of significant trauma. It frequently is associated with an anterior cruciate ligament injury, and the medial side is more commonly involved than the lateral side (approximately 3:1). Long tears that extend at least two thirds of the circumference of the meniscus produce an unstable fragment that locks into the joint by displacing in toward the notch ( Fig. 51.14 ). The patient typically has episodes of locking in which the knee can be neither fully extended nor flexed. The fragment may displace and reduce with an audible and palpable clunk. There is associated pain and effusion. Occasionally, the bucket-handle fragment permanently displaces into the intercondylar notch. In these situations, the patient is gradually able to resume most activities but knows that something is wrong with the knee. The fragment may become distorted and fixed in place. Other bucket-handle tears divide in their central portion, creating two separate flaps, one based anteriorly and the other posteriorly.

A patient with a suspected bucket-handle tear who may be a candidate for meniscal repair should have this possibility discussed before arthroscopy. The most common criteria for meniscal repair include (1) a vertical longitudinal tear more than 1 cm in length located within the vascular zone, (2) a tear that is unstable and displaceable into the joint ( Fig. 51.15A ), (3) an informed and cooperative patient who is active and younger than 40 years old, (4) a knee that either is stable or would be stabilized with a ligamentous reconstruction simultaneously, and (5) a bucket-handle portion and remaining meniscal rim that are in good condition. Chronically deformed or degenerative menisci are not good candidates for repair. Most investigators report that only 10% to 15% of meniscal tears can be repaired and that most such repairs are done in association with an anterior cruciate ligament reconstruction.

Bucket-handle tears that cannot be repaired can be treated with partial meniscectomy. Early reports suggested that preserving a meniscal rim eventually would lead to better long-term results, particularly in stable joints with a normal weight-bearing axis.

Partially displaceable tears usually are shorter and confined to the posterior half of the meniscus. Often, these shorter tears are located peripherally and can be repaired. Tears that are less than 5 to 7 mm in length and stable to probing during which the tear does not displace more than 1 mm can have the edges and perimeniscal synovium freshened with a meniscal rasp. Talley and Grana noted a 21% failure rate at short-term follow-up of 19 patients with stable partial-thickness medial meniscal tears that were treated with perimeniscal rasping. For lateral tears, 4% failed. These authors recommended repair of partial-thickness medial tears. We also believe that an aggressive treatment approach should be used for medial meniscal tears.

When the decision has been made to perform a partial meniscectomy, the choice must be made as to whether to use a two-portal or three-portal technique. If the meniscal fragment has displaced into the notch, it should be reduced using either a probe or a blunt trocar. If the meniscal fragment is large or chronic, the medial compartment may have to be opened with flexion and a valgus stress to permit reduction of the fragment. The technique for resecting a displaced bucket-handle tear and the technique for resecting a nondisplaced, short, vertical, longitudinal tear are essentially the same. In each situation, a probe should be introduced and the tear should be examined with the probe to determine the anterior and posterior extents. The probe also can be used to plan the subsequent cuts. This examination usually is most easily conducted with the arthroscope in the anterior portal contralateral to the tear and the probe in the ipsilateral portal.

Discoid Lateral Meniscus

Most discoid menisci are lateral; compared with other meniscal pathologic entities, discoid lateral meniscus is rare (0.4% to 5%). Bilateral discoid menisci generally are reported in less than 10% of patients. Discoid medial meniscus is reported to be present in less than 0.3% of knee arthroscopies. A discoid lateral meniscus may be discovered during a systematic examination of the knee in which another abnormality may be producing symptoms. The abnormality accounting for the symptoms should be appropriately corrected, and the discoid lateral meniscus should be left intact unless torn or degenerative. Careful evaluation of the superior and inferior surfaces of the meniscus is necessary to rule out a meniscal tear.

The most common method of classification of discoid lateral meniscus is that of Wantanabe et al., who described three types: complete or incomplete, based on the degree of coverage of the lateral tibial plateau, and the Wrisberg variant with absent or abnormal posterior meniscal tibial attachment. The current recommended treatment of a discoid lateral meniscus is based on this system of classification. Complete and incomplete lesions with tears of the discoid component are partially resected to a stable peripheral rim of lateral meniscus 6 to 8 mm wide. When healthy meniscal tissue is present, repair of the Wrisberg-type lateral meniscus is performed.

Good and excellent results have been reported in 55% to 94% of knees that have had a partial central meniscectomy or “saucerization.” Preexisting degenerative changes, female gender, and age older than 20 years are associated with unsatisfactory results. We found at long-term follow-up that a significant percentage of patients had lateral joint symptoms after partial central meniscectomy, and others have reported similar findings. We try to preserve, contour, balance, and repair healthy meniscal tissue.

Meniscal cyst

Meniscal cysts may develop from chronic medial or lateral degenerative meniscal tears; they most commonly involve the lateral meniscus. The site of the cyst usually can be differentiated intraarticularly by probing the meniscal tear fragments and opening the horizontal split in the meniscus with a small curved curet and passing it through the meniscal body into the central portion of the cyst. The cyst is curetted, and external digital palpation of the cyst is used to free up the cyst and decompress it into the joint. Suction may be used to remove the contents further. The meniscal fragments are removed and are cleaned up to relatively stable healthy meniscus.

Good to excellent results have been reported with arthroscopic partial meniscectomy and cyst decompression. If the cyst decompresses during the meniscectomy, no further treatment is needed for the cyst. If the cyst does not spontaneously decompress, it can be percutaneously aspirated and does not require open excision.

Arthroscopic repair of torn menisci

Although partial meniscectomy has yielded functionally better results than total meniscectomy, the ultimate outcome for partial meniscectomy remains suboptimal, with Fairbanks changes and functional deterioration much more frequent after partial and total meniscectomy than after meniscal repair. Multiple authors have found that joint deterioration after meniscectomy is accelerated with concomitant conditions of femoral and tibial chondromalacia, grade II or III anterior cruciate ligament instability, or tibiofemoral malalignment at the time of the initial meniscectomy. Partial lateral meniscectomies tend to do worse than partial medial meniscectomies. The lateral meniscus bears approximately 70% of the weight in that compartment, whereas the medial meniscus bears 50% of the weight in the medial compartment.

As noted earlier, only 10% to 15% of meniscal tears can be repaired, and these usually are associated with anterior cruciate ligament injuries. The only other positive correlations with healing have been found in patients who have a narrow peripheral meniscal rim (<4 mm) and when the repair is done within 8 weeks of injury. The length of the tear also has been associated with variations in healing, with failure to heal in over half of tears longer than 4 cm. The addition of a fibrin clot or marrow stimulation has been reported to increase the healing rate.

Arthroscopic repair techniques can be divided into four categories: (1) inside-out repairs; (2) outside-in repairs; (3) all-inside repairs; and (4) hybrid repairs, which combine the previous techniques. The inside-out technique can be done with double-lumen or single-lumen zone-specific repair cannulas, with absorbable or nonabsorbable sutures. The technique is rendered safe with the use of an incision for exposure of the capsule and placement of retractors for safe retrieval of suture needles. The outside-in technique is most suitable for repairs of the middle and the anterior thirds of the meniscus.

All-inside repair techniques have been simplified by the development of suture fixators, which have pre-tied knots. These devices provide secure fixation and decrease the potential for chondral injury present in earlier devices. They are best used for securing tears that are 2 to 4 mm from the peripheral attachment. Because of the ease and speed of repair, greatly reduced patient morbidity, and midterm results that are equal to or better than those with outside-in sutures, most of our repairs are done with all-inside devices. Indications for the different repair techniques are listed in Boxes 51.1 and 51.2 .

Regardless of the arthroscopic technique preferred by the surgeon, arthroscopic meniscal repairs consist of four important steps: (1) appropriate patient selection; the patient should have a documented meniscal tear that is able to heal, most often a single vertical longitudinal tear in the outer one third; (2) tear debridement and local synovial, meniscal, and capsular abrasion to stimulate a proliferative fibroblastic healing response; (3) use of marrow stimulation or orthobiologics to enhance healing; and (4) suture placement to reduce and stabilize the meniscus.

Tears can be categorized into (1) tears that can be rasped and left alone, (2) tears that definitely can be repaired, (3) tears that can be repaired under certain circumstances, and (4) tears that should be resected. Weiss et al. showed that peripheral tears of 7 mm or less heal without suture stabilization. Such tears should be probed to ensure less than 3 mm of displacement, and the tear and the meniscal synovium should be rasped to promote healing.

Tears that definitely can be repaired are single vertical tears in the peripheral vascular portion of the meniscus, the red-red zone at the meniscosynovial junction, or the red-white zone within 3 mm of the junction. These tears are displaceable, are more than 1 cm long, and involve minimal damage to the body of the meniscus. Generally, repair should be limited to patients aged 40 years or younger. A healing response is stimulated by rasping the tear and the perisynovial tissue. Tears that can be repaired under certain circumstances include tears 3 to 5 mm from the meniscosynovial junction. These tears, similar to all tears that can be repaired, should be evaluated with the tourniquet deflated to determine vascularity. In young, active patients with minimal damage to the meniscal body, suture repair in association with healing enhancement is most likely to be successful when anterior cruciate ligament reconstruction is performed concomitantly. If rasping produces bleeding, potential healing can be considered. Vascular access channels, achieved through meniscal trephination using an 18-gauge spinal needle to penetrate the peripheral meniscus to the synovium, can stimulate bleeding. When isolated tears are to be repaired, microfracture marrow stimulation of the intercondylar notch or addition of fibrin clot or platelet-rich plasma (PRP) should be considered. Resection is necessary for a meniscus with several tears, for tears involving damage or deformation of the body, and for tears that are definitely in an avascular (white-white) area (see Fig. 51.15C ). Although complete radial tears are uncommon, they present particularly perplexing problems. When within the meniscal body, these tears disrupt all circumferential fibers. Although radial tears near the origin of the posterior horn of the lateral meniscus have been shown to heal, the biomechanical functionality of these repairs is in doubt. However, long-term results of repair may be better than those of a subtotal meniscectomy, especially in young patients ( Table 51.1 ).

We often combine two or three basic arthroscopic techniques (suture-based meniscal fixator, inside-to-outside cannula technique, and outside-to-inside needle technique). If a large bucket-handle tear of the medial meniscus is suitable for repair, an initial stabilizing horizontal mattress suture can be inserted with a single-cannula or double-cannula technique in the midpoint of the tear near the posteromedial corner. Additional sutures can be placed posteriorly using the cannula technique from inside to outside or with a suture-based fixation device. The anterior portion of the tear, especially if this extends into the anterior half of the meniscus, is often best approached with an outside-to-inside technique.

If a patient has an unstable knee caused by an anterior cruciate ligament deficiency and a meniscal lesion that can be repaired, generally a ligament reconstruction and a meniscal repair should be done at the same time.

Radial tears and meniscal root tears

Radial tears that extend to the capsule may be repaired in young patients with otherwise healthy menisci. Synovial rasping followed by longitudinal repair, consisting of two longitudinal sutures on the superior surface and one on the inferior surface, is indicated in young patients willing to follow stringent postoperative protocol ( Fig. 51.32 ).

Root tears of the lateral meniscus may do well by rasping and allowing them to heal in situ. Unstable root tears of the posterior horn of the medial or lateral meniscus may be repaired to a freshened posterior bony bed using an anterior cruciate ligament guide to drill from the anterolateral tibia to the base of the root footprint. A suture shuttle device is used to pass simple sutures through the meniscus and then out through the bone tunnel; the sutures are then tied anteriorly. The repair also may be accomplished using a 2.7 suture anchor placed through a high posteromedial portal.

Meniscal replacement

Meniscal replacement continues to evolve using bone-plug techniques with better-defined indications and more asymptomatic results (> 90%). The question remains how much chondroprotective function a transplanted meniscus produces. In a meta-analysis evaluating meniscal transplants, lateral transplants performed better than medial transplants. At 5- to 10-year follow-up, approximately 85% of transplants survived; at longer than 10-year follow-up, survival rates of approximately 55% are reported.

The functional relief provided by meniscal transplant is clouded further by the fact that many of the patients had concomitant procedures for realignment, stabilization, or osteochondral transplant at the time of the meniscal transplant. Cryopreserved menisci have been shown to perform similar to fresh frozen menisci with similar risks, in particular that of acquired immunodeficiency syndrome (AIDS; 1 in 1.6 million). Investigational studies of biologic tissue scaffolds for partial or complete meniscal replacement are in progress. These grafts may provide more acceptable replacements in the future, but at this time results are short term and limited in number.

Meniscal allograft is indicated in a patient who has had a previous meniscectomy, who is age 50 years or younger, and who has symptoms localized to the tibiofemoral compartment and no advanced arthrosis as evidenced by flattening of the condyles or excessive osteophyte formation. A joint space of 2 mm or greater on standing posteroanterior view is necessary. Contraindications include malalignment, instability that the patient does not wish to have corrected, chondromalacia greater than grade III, and previous joint infection.

In addition, the patient should be motivated, well informed, and willing to decrease impact-loading activities. When deciding whether a fresh frozen or a cryopreserved meniscus is to be used, one should be familiar with the allograft procurement and ensure that a quality, young, healthy graft is secured. Best results are obtained with a meniscal allograft that has a bone block or a bone bridge attached. Sizing is best done on anteroposterior radiographs, and MRI may be used to determine meniscal coverage.

A technique used at the University of Pittsburgh is described. The technique is divided into four parts: graft preparation, tunnel placement, graft insertion, and graft fixation.

Loose bodies in the knee joint

Removal of loose bodies from the knee joint is especially suitable for arthroscopic techniques. A loose body may be a singular, isolated problem, or multiple loose bodies may indicate the presence of a more complex pathologic process, such as synovial chondromatosis. Every attempt should be made to identify the underlying process to manage the condition correctly.

Loose bodies can be classified into the following types:

• 1.

  Osteocartilaginous. These loose bodies are composed of bone and cartilage and are detectable radiographically. Osteocartilaginous loose bodies may originate from several sources, the most common being osteochondritis dissecans, osteochondral fractures, osteophytes, and synovial osteochondromatosis.

• 2.

  Cartilaginous. These radiolucent loose bodies usually are traumatic and originate from the articular surfaces of the patella or the femoral or tibial condyle.

• 3.

  Fibrous. These radiolucent loose bodies occur less frequently and result from hyalinized reactions originating usually from the synovium secondary to trauma or, more commonly, from chronic inflammatory conditions. Synovial villi become thickened and fibrotic, may become pedunculated, and may detach and fall into the joint as loose bodies. Chronic inflammations, such as tuberculosis, may produce multiple fibrinous loose bodies known as “rice bodies.”

• 4.

  Others. Intraarticular tumors, such as lipomas, and localized nodular synovitis may be pedunculated and by palpation feel like loose bodies or, in rare instances, drop free into the joint. Bullets, needles, and broken arthroscopic instruments also may appear as foreign loose bodies within the knee.