Indications and Goals: Knee arthroscopy is now the standard of care for treating a variety of knee problems. Arthroscopic partial meniscectomy is the most popular procedure done in orthopedics. Other arthroscopic procedures include cruciate ligament reconstruction, articular cartilage procedures, synovectomy, loose body removal, and a variety of other procedures.

Procedure and Technique: Knee arthroscopy is accomplished with the patient supine. The use of a leg holder is optional. Most procedures can be done through two portals. The main viewing portal is via an inferolateral portal just lateral the edge of the patella tendon and just superior to the joint line. The main instrumentation portal is the inferomedial portal, just medial to the edge of the patella tendon and just superior to the joint line. Accessory portals include a superolateral portal, a trans-patellar tendon portal, a posteromedial portal, and others. A systematic, thorough evaluation of the knee joint involves inspecting and probing all compartments, both gutters, the intercondylar notch, and, when indicated, the posteromedial (and posterolateral) aspects of the knee. The knee is stressed to allow access for the arthroscope and instruments. A variety of mechanical instruments (various angled biters [baskets] and grabbers) and shavers are used to carry out knee arthroscopy.

Post-surgical Precautions/Rehabilitation: Post-surgical rehabilitation varies significantly based upon the specific procedures performed. Since arthroscopic surgery of the knee can range from a minor synovectomy to a meniscal repair or an articular cartilage transplant, guidelines for rehabilitation should be closely correlated to the surgeon’s preference and based upon tissue healing factors. All rehabilitative approaches, though varying in their timeline, will focus on the reduction of swelling, minimizing of quadriceps muscle atrophy, restoration of patellofemoral and tibiofemoral joint motion, and return of joint proprioceptive function.

Expected Outcomes: Generally speaking, arthroscopic procedures yield excellent results. However, specific assessment of outcomes must be procedurally based.

Return to Play: Return to sport participation can range from days in a professional athlete who simply had some soft tissue debridement or fluid aspiration to 6 months or more for anyone undergoing articular cartilage repairs.

Indications and Goals: An arthroscopy synovectomy (removal of the joint lining in the knee) can be done arthroscopically as well as open, provided that a thorough systematic approach is used through as many as six portals. Indications include pigmented villonodular synovitis (PVNS), synovial chondromatosis, rheumatoid arthritis, and a variety of other disorders. Synovial plicae, which are thickenings of the synovium, can sometimes become symptomatic and abrade the articular surfaces, especially the medial femoral condyle. Pathologic plicae, although rare, should be removed. Lateral release should also be a relatively uncommon procedure for the knee arthroscopist. Indications are limited to patients with refractory anterior knee pain and objective evidence of patellar tilting (lateral patellar compression syndrome).

Procedure and Technique: Arthroscopic synovectomy of the knee is accomplished with a large shaver. The entire synovium is shaved. Fortunately, the pathologic synovium is dark colored and it is relatively easy to see what needs to be removed. Typically, the superior joint is addressed first (using superomedial and superolateral portals), then the gutters, and then the anterior part of the knee. Additional portals are necessary to debride the posteromedial and posterolateral aspects of the knee. These portals are localized using a spinal needle as viewed through the notch. Medially, the saphenous vein and nerve branches need to be protected and laterally, the common peroneal nerve should be protected by staying anterior to these structures. Plicae can be easily resected with a combination of a biter and a shaver. A lateral release is usually accomplished under direct visualization using an electrocautery device. Care should be taken to avoid excessive bleeding (from the superolateral geniculate artery).

Post-surgical Precautions/Rehabilitation: Post-operative precautions following an isolated synovectomy involve a gradual progression to weight bearing, with range of motion exercises implemented immediately. The focus is on minimizing post-operative effusion and regaining neuromuscular control. With a lateral release performed, post-operative emphasis should be placed on quadriceps muscle activity and joint proprioception. Care should be taken early on to consider the use of a patella-stabilizing orthotic of some kind. It is also important to assess one’s posture and avoid a pronated foot, thus foot orthotics may be of assistance to minimize any excessive valgus forces placed on the knee.

Expected Outcomes: Anterior knee pain has been reported to subside post-operatively in the number of patients as compared to preoperative findings as much as 2 years post-operative. However, an isolated lateral retinacular release of the patella has not proven to be effective for long-term benefit of reducing patellar instability. It is not uncommon for a person who undergoes a lateral release to have repetitive episodes of complaints of instability and pain years later if in fact continued quadriceps strengthening has not been maintained.

Return to Play: A return to sport participation can occur with days to weeks with only a synovectomy being performed. However, with the lateral release procedure, restoration of quadriceps strength and function is required prior to any competitive return to sport. This may be as early as 1 month post-operatively but is often longer.

Indications and Goals: Meniscectomy is indicated for meniscal tears that are not repairable. These tears include complex or degenerative tears, most flap tears, and radial tears. Patients may relate a history of a twisting injury and may complain of mechanical symptoms (locking, catching, popping, etc.). Findings on examination include joint line tenderness and pain with provocative maneuvers (McMurray testing, compression testing, duck walk, etc.). Plain radiographs are helpful to evaluate the degree of associated osteoarthritis (standing radiographs are mandatory). Magnetic resonance imaging (MRI) is very helpful in confirming the diagnosis and gives some idea regarding the repairability of a meniscal tear.

Procedure and Technique: Partial meniscectomy is accomplished using a variety of biters (baskets) and shavers. Since development of late arthritis is directly related to the amount of meniscus removed, the minimal amount necessary to result in a stable rim is resected. The articular cartilage of the affected compartment should be protected by adequately stressing the joint and using careful technique and smaller shavers. Associated meniscal cysts, when present, can be debrided from inside-out.

Post-surgical Precautions/Rehabilitation: Despite the fact that some peer-reviewed literature show little evidence that formal rehabilitation is necessary to return patients to normal function following a meniscectomy, formally guided rehabilitation following a partial meniscectomy can speed up the recovery timeline for someone returning to sport participation. Emphasis is placed on minimizing joint effusion, restoring joint range of motion, regaining quadriceps control, and gradually ambulating with weight as tolerated to achieve optimal outcomes. Since no tissue is repaired in an isolated meniscectomy, rehabilitation can be progressive and integrates neuromuscular training early post-operative. Assistive devices only need to be used in some circumstances and only for the first few days. Otherwise, ambulation with full weight bearing should be promoted.

Expected Outcomes: Outcomes following partial meniscectomies are relatively good. Some resultant joint osteoarthritis may occur years post-operative, with a larger size of meniscal resection, and those performed on females, showing the most consistent associations with increased radiographic evidence of osteoarthritis. Furthermore, greater articular cartilage degeneration assessed at surgery, increased sizes of meniscal resection, greater laxity of the anterior cruciate ligament (ACL), and prior surgery on the index knee were the strongest predictors of worse functional outcomes. There appears to be no difference in functional outcome between medial or lateral meniscectomies, though radiologic results are significantly worse after lateral meniscectomy. It appears as though improved outcomes can be predicted for some patients. With an isolated medial meniscal tear, better outcomes may result, given one or more of the following: Less than 35 years old, a vertical tear, no cartilage damage, and an intact meniscal rim at the end of the meniscectomy. With an isolated lateral meniscal tear, a better prognosis can be predicted if the patient is young and has an intact meniscal rim at the end of the meniscectomy.

Return to Play: Following restoration of quadriceps tone and control of post-operative effusion, a return to activity can occur reasonably quick, ranging from weeks to months based upon one’s required level of function.

Indications and Goals: Meniscal tears should be repaired rather than removed whenever there is a reasonable chance of success. The ideal candidate for meniscal repair is a peripheral longitudinal tear that is undergoing concurrent ACL reconstruction. Examination and imaging findings are similar to that described for meniscectomy. The goal is to restore meniscal integrity and function to avoid the development of late arthritis.

Procedure and Technique: There are a variety of techniques for meniscal repair including open, inside-out, outside-in, and all-inside repairs. The gold standard for meniscal repair is inside-out repair, and this should be accomplished if there is any doubt about the integrity of the repair. Inside-out repair is accomplished using long needles that are placed through special contoured cannulae. A posteromedial or posterolateral incision is made in order to “capture” the needles as they are passed through the knee. A variety of all-inside devices have been developed to make meniscal repair easier for the surgeon, but because of associate complications, not always better for the patient. Newer devices allow the surgeon to tension the repair. These new devices approach but do not equal the results of inside-out repair. The use of adjunctive techniques to improve healing rates of meniscal repair includes rasping and the use of fibrin clot.

Post-surgical Precautions/Rehabilitation: Rehabilitation following meniscal repairs should focus on minimizing joint swelling, regaining knee joint range of motion, and emphasizing quadriceps strengthening exercise—all of which can be initiated on the first day post-operatively. Excessive weight bearing and joint compressive forces that could disrupt the healing meniscus repair are avoided, oftentimes with the use of crutches for up to 4 weeks. Modifications based upon the type, size, and location of meniscal tear and other concomitant procedures may be required. Full return to weight-bearing activity may take between 4 to 6 months.

Expected Outcomes: Results vary, based upon the size of the repair, the devices used to repair the meniscus, the potential healing properties of the individual, and the overall compliance associated with a rehabilitation program that carefully monitors limited weight bearing and joint compressive forces early on. Failures, or re-tears of the repair, range from 5% to 45%, with a higher rate of failure of tears in the medial versus lateral meniscus. Although the RTP is longer, surgeons should be encouraged to repair meniscal tears whenever possible.

Return to Play: Return to sport participation may take up to 6 months safely following a meniscal repair. It is not uncommon for athletes to feel “ready” to play sooner. However, full healing of the meniscal repair may not have yet taken place, and a return to competitive sport with increased knee joint compressive loads too soon may place the repair at risk for failure. Athletes returning to sports that may involve excessive amounts of knee hyperflexion, such as soccer, may be at an increased risk for reinjury.

Indications and Goals: Meniscal allograft transplantation is a technically difficult procedure with few long-term results available in the literature. It appears that the transplanted meniscus may have a limited lifespan and may only delay the onset of late arthritis. Nevertheless, symptomatic younger patients following complete meniscectomy, particularly of the lateral compartment, may benefit from this procedure. It is important to make sure that mechanical alignment and knee stability is restored either before or at the same time as the transplant procedure.

Procedure and Technique: Two different surgical techniques are popular. The trough or key-hole technique (typically done for lateral meniscal transplants) involves preserving a block of bone between the horns of the meniscus and then “sliding” it into a trough created for receiving the graft. The bone-plug technique (typically done for medial meniscal transplants) involves creating separate small bone plugs for each horn and passing them into tunnels. It is important to recreate the normal anatomy of horn insertion for both techniques. After the anterior and posterior horns are secured, sutures are placed as described for meniscal repair.

Post-surgical Precautions/Rehabilitation: The rehabilitation process for a meniscal transplantation is very similar to that of a meniscal repair. The main focus is on reducing joint compression forces, while restoring range of motion and keeping effusion to a minimum. Muscular reduction can be initiated day one post-operative. Modifications based upon the type of meniscal tear and other concomitant procedures may be required. Full return to weight-bearing activity may take between 4 and 6 months. It is critical not to rush the patient through early episodes of weight bearing that will increase joint compressive loads on the healing tissue.

Expected Outcomes: Pain relief and functional improvement are often seen, and the partial restoration of meniscal function provided by this procedure may slow down the degenerative arthritic process. Continued advances with the technique may yield more long-term benefits. It appears that the success of the results are dependent upon reestablishing normal knee alignment and stability, implanting a secure fixate graft, and limiting an individual’s return to light activities only.

Return to Play: This procedure is considered a salvage option and is not typically recommended for competitive athletes. Return to activities for recreational athletes should follow complete bony healing of the meniscal horns and periphery of the meniscus—which may be at least 6 months post-operatively.

Indications and Goals: There are a variety of procedures available for treating focal chondral defects. Patients may or may not recall a specific injury. Pain, mechanical symptoms, or an effusion may be the only findings. Plain films are often normal; joint space narrowing and other findings of diffuse osteoarthritis may suggest that advanced procedures are not indicated. MRI is improving; however, it is often still difficult to diagnose focal chondral defects pre-operatively.

Procedure and Technique: There are four commonly performed procedures: Microfracture, autograft osteochondral plug transfer, autologous chondrocyte implantation (ACI), and allograft osteochondral transplantation.

Microfracture: Marrow stimulation techniques, such as microfracture, involves puncturing the subchondral bone to allow pluripotent marrow cells to escape and cover the surface of the bone with a “superclot.” This will mature into fibrocartilage over time. It is important to first remove the calcified cartilage layer (usually with a curette and shaver) and then make a series of subchondral holes with angled awls at 2 to 3 mm intervals. The holes are made by aligning the awl perpendicular to the surface and inserting it deep enough to allow escape of blood and marrow elements.

Autograft Osteochondral Plug Transfer: This technique involves moving articular cartilage from an area that has less requirement for this cartilage (lower contact pressure) into an articular cartilage defect. The defect is evaluated and the geometry of the plug transferred is planned. Cylindrical cutting tools are used to harvest osteochondral plugs (typically from superolateral), a matching harvest tool is used to create a recipient site, and the plug(s) are inserted into the prepared recipient site. It is critical to have perpendicular access for both plug harvest and transfer. The defect is filled with plugs and the intervening area is microfractured or debrided to allow it to serve as “grout” for the cobblestone plugs.

ACI: This procedure involves a two-step process that includes first harvesting articular cartilage from a low-contact pressure area and then processing and culturing the chondrocytes, which are then injected under a periosteal patch at a second procedure. Periosteum is typically harvested from the proximal tibia and secured over the defect with fine absorbable suture. The chondrocyte cells are then injected under the patch which is sealed with fibrin glue. These cells then seed the resulting neocartilage.

Allograft Osteochondral Transfer: This procedure is similar to autograft plug transfer except it utilizes a matched fresh allograft, and is generally reserved for larger defects.

Post-surgical Precautions/Rehabilitation: The main goal following articular cartilage repairs is to restore full function as soon as possible by facilitating a healing response while simultaneously protecting the healing articular cartilage from excessive joint forces. Continuous passive motion (CPM) can be very beneficial in the early post-operative period, though the literature is divided as of the outcomes involving CPM units. Rehabilitation programs will vary based on the type of articular cartilage lesion or defect, the patient’s overall goals and conditioning level, and the type of surgical procedure performed. In general, it may take up to 6 months before full weight-bearing running-like activities can be performed safely, and up to 1 year before complete healing has occurred. Patience compliance is critical for successful outcomes, particularly in the early post-operative phases.

Expected Outcomes: Generally, all of these procedures have reported satisfactory outcomes with success rates as high as 85% to 96% in the current literature. Microfracture appears to have the best success for smaller lesions in relatively low-demand patients as its success diminishes long-term in very active patients. Few true prospective randomized studies are available comparing techniques and to date no one procedure has been shown to be vastly superior to any of the others. The most consistent factor in determining successful outcome remains careful patient selection and individualizing treatment based on each specific patient case.

Return to Play: Typically, return to sport participation will take at the earliest 4 to 6 months post-operatively, and in many cases more like 6 to 12 months. The size of the lesion and the surgical technique used will be determining factors for return to participation timelines.

Indications and Goals: Anterior cruciate ligament injuries are typically a result of a non-contact pivoting injury. Patients may hear or feel a “pop” and an immediate effusion is common. If left untreated, patients may note recurrent instability (giving way), especially when attempting pivoting sports. Associated meniscal tears and chondral injuries are common. Examination typically includes a positive Lachman test and a pivot-shift test.

Procedure and Technique: Although several graft options are available, autologous hamstring and bone-patellar tendon-bone grafts are common. After debriding the ruptured ACL fibers, tunnels are drilled in the tibia and femur for the prepared graft(s). Although there is some controversy, most surgeons prefer to place the tibial tunnel in the posteromedial aspect of the ACL footprint and the femoral tunnel in the 10-10:30 position (using a clockface for orientation, right knee) with a 1 to 2 mm posterior wall. Special guides are available to assist in accurate tunnel placement. Double-bundle techniques with two tunnels in the femur (+/- two tunnels also in the tibia) have been described but have not been universally accepted.

Post-surgical Precautions/Rehabilitation: Since there are different techniques for performing an ACL reconstruction, the course of rehabilitation will depend upon the type of graft fixation utilized, whether or not the procedure was isolated at an ACL tear or involved other structural damage, and the goals of the patient. All rehabilitation interventions should also consider the physiology of tissue healing as well as the biomechanical principles of joint contact surface. Typically, ACL rehabilitation is broken into phases. The early post-operative phase focuses on pain management, scar management, the minimizing of knee joint swelling, quadriceps muscle volitional control, and gentle range of motion for the tibiofemoral and patellofemoral joints. Weight bearing can begin immediately post-operatively, with a weaning away from crutches within 1 to 2 weeks, dependent upon one’s neuromuscular control and proprioceptive awareness. Once the suture wounds are closed, hydrotherapy can be initiated in an effort to gradually add weight-bearing activities with reduced joint forces from buoyancy. Exercises to improve neuromuscular control can begin gradually from the first week post-operative, with attention to not stress the graft with highly resisted knee extension exercises. Functional knee bracing is an option, with the literature reviews mixed regarding the effects of functional knee braces. However, athletes may express a sense of confidence and perception of safety while wearing a functional knee brace during the returning phases of sport specific activity.

Expected Outcomes: Overall outcomes are very good for ACL reconstructions. The differences in how outcomes are defined also play a role in how results are reported in the literature. Published studies suggest that hamstring tendon autografts are better for reducing post-operative anterior knee pain, while evidence exists, though limited in nature, that bone-patellar tendon-bone autografts provide better stability. Meanwhile, hardware removal and arthrofibrosis rates are slightly higher when using bone-patellar tendon-bone grafts. Athletes have been allowed to return to play as early as 3 to 4 months, but not without complications (e.g., patella fracture and reinjury). Delay in RTP for 6 months, or even a year, may be more prudent.

Return to Play: A return to functional activities can occur between months 4 and 6 based upon the stresses required for the activity, the individual’s neuromuscular strength and proprioception, and confidence to return to activity.