OPEN OR ARTHROSCOPIC LATERAL RELEASE

ARTHROSCOPIC SURGERY, PART I 1 THE KNEE

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OPEN OR ARTHROSCOPIC LATERAL RELEASE Indications, Techniques, and Rehabilitation Danny H. Ford, MD, and William R. Post, MD

Anterior knee pain is a very common complaint among active individuals and is sometimes resistant to nonoperative management. When operative treatment is indicated to relieve anterior knee pain, a careful evaluation of alignment, flexibility, and the degree of patellofemoral arthrosis is necessary to choose the correct operative procedure. Lateral release is often successful in relieving symptoms of anterior knee pain but is not the answer for all patients and should not be used as a first-step operation when arthrosis and malalignment are severe. The techniques used to perform lateral release are relatively simple but are not without important pitfalls. Attention to detail in diagnosis, surgical treatment, and postoperative rehabilitation is important for successful outcome. ANATOMY

The lateral retinaculum is a richly innervated, fibrous connective tissue structure located on the lateral side of the knee. It is composed of two anatomic layers: superficial and deep (Fig. 1).The superficial layer is composed of fibers from the iliotibial band and vastus lateralis muscle. Oblique fibers from the iliotibial band insert primarily into the lateral border of the patella and interdigitate with longitudinal fibers of the

From the Department of Orthopedics, Section of Sports Medicine and Shoulder Surgery, West Virginia University School of Medicine, Morgantown, West Virginia

CLINICS IN SPORTS MEDICINE VOLUME 16 * NUMBER 1 *JANUARY 1997

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Fibers blend with fibrous expansion of vastus lateralis

A

lliotibial tract Lateral joint line Vastus lateralis

f

Fibrous expansion of vastus lateralis eep transverse retinaculum Patellotibial band Superficial oblique retinaculum

Epicoi

B

Iliotibial tract

Figure 1. Anatomy of the lateral retinaculum. A, Superficial lateral extensor retinaculum. Note interdigitation of superficial oblique retinaculum fibers with vastus lateralis expansion on the patella. 6, Deep to the superficial oblique retinaculum. (From Fulkerson JP, Grossling HR: Anatomy of the knee joint lateral retinaculum. Clin OrIhop 153:183-188, 1980; with permission.)

vastus lateralis and patellar tendon. The deep layer is composed of dense transverse fibers that connect the deeper portion of the fascia lata directly to the lateral patella. Two distinct ligaments-the epicondylopatellar and patellotibial ligaments-are located at the superior and inferior borders of the deep layer, tethering the patella to the lateral epicondyle and anterolateral tibia, respectively.’O Through the contributions of the iliotibial band and fascia lata in the formation of the lateral retinaculum, a posterolateral force is exerted on the patella as the knee is flexed. This is consistent with the clinical observation that many patients with anterior knee pain tolerate prolonged knee flexion poorly. The posterolateral force exerted on the lateral patella by the lateral retinaculum is primarily posterior (Fig. 2).43This has important implications when considering lateral release because releasing the retinaculum removes a posterior restraint on the lateral patella. To a lesser degree, lateral restraint (subluxation) is decreased. Anatomically, lateral release has been shown to correct lateral patellar tilt more than lateral subluxati~n.~~

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Figure 2. Midpatellar CT image. Note the posterior component of the vectors representing forces generated by the lateral retinaculum. (From Post WR, Fulkerson JP: Arthritis of the patellofemoral joint. In Fu FH [ed]: Knee Surgery. Baltimore, Williams & Wilkins, 1994, pp 995-1024; with permission.)

LITERATURE REVIEW: WHEN TO DO A LATERAL RELEASE

The initial studies of lateral retinacular release were retrospective studies of patients with recurrent dislocation or subl~xation.~~, 55 Lateral release for the primary indication of pain and lateral retinacular tightness, rather than lateral instability, was first studied by Larson et al.25 Numerous studies of lateral release for subluxation and recurrent dislocation have been reported.2,6 , 7, 15,31,34, 52,53, 55 Most of these studies reported generally good results, although several reported on patients with less than 2-year follow-up. In retrospect, this is of some concern because more recent reports show a late deterioration of good results in patients whose primary diagnosis was instability. Similarly, Gecha and Torg12 reported that patients with patellar hypermobility are less likely to benefit from lateral release. a decline from 86% to 74% good and excellent M e t ~ a l fshowed ~~ results between 1 and 4 years postoperatively. Seventy-four percent of his patients had enough lateral subluxation to be evident on axial radiographs. Betz et a12 found 82% good or excellent results at 1 year follow-up, but they deteriorated to 29% at 4-year follow-up in patients whose primary diagnosis was patellar instability. Christensen et a16also found a decrease from 73% good results at 1.2 years to 30% at 4.6 years in patients with recurrent subluxation. Conversely, Christensen’s patients with anterior knee pain (without instability) did not deteriorate with time. The severity of articular degeneration is another factor that correlates directly with the outcome of lateral retinacular release. The Outerbridge classification is the most widely used method of describing articular degeneration4+

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Grade I: Closed chondromalacia, pitting edematous cartilage Grade 11: Chondral fissuring and fragmentation (I 1.2 cm in diameter) Grade 111: Chondral fissuring and fragmentation (> 1.2 cm in diameter) Grade IV: Erosion to bone, eburnated bone, any size Grade I refers to softening without macroscopic fissures or fibrillations. Grades I1 and I11 refer to chondromalacia with macroscopic changes less than or greater than 1.2 cm in diameter, respectively. Grade IV refers to full-thickness defects with exposed bone of any size. Multiple reports have shown that patients with mild articular degeneration have better results after lateral release than patients with the more severe form. Osborne et a1@showed poor results in all patients with Outerbridge grades I11 and IV 3 years after lateral retinacular release. Christensen et a16 found good results in only 17% of similar patients with moderate or severe articular degeneration after more than 4 years. Ogilvie-Harris and Jackson38noted good results in 85% of a group of patients with Outerbridge grade I compared with only 65% in those with more significant articular degeneration. Shea and F ~ l k e r s o nreported ~~ on a group of patients with CT scan-documented alignment and arthroscopically documented articular condition. Treated by open lateral release, patients with CT scandocumented patellar tilt and minimal articular degeneration (Outerbridge grade 1/11) achieved 92% good and excellent results. Conversely, only 22% with patellar tilt and more severe chondrosis had satisfactory results. Based on review of available literature, the best candidates for lateral retinacular release have more complaints of anterior knee pain than recurrent instability, clinical findings consistent with lateral retinacular tightness, documented lateral patellar tilt with minimal subluxation, and mild (Outerbridge grade 1/11) articular degeneration. If patellofemoral malalignment has been documented and dedicated nonoperative management for a minimum of 3 months has failed, surgical realignment can be considered. Realignment operations, including lateral release, are contraindicated in patients without proven malalignment. If a patient with anterior knee pain does not fit these criteria, lateral release is not the procedure of choice. In these cases, the operative plan should be tailored to the specific disorder as indicated by clinical and radiologic e v a l u a t i ~ n For . ~ ~ example, patients with severe articular degeneration should have surgery that includes pressure-relieving anteriorization or anteromedialization, arthroplasty, or, in selected circumstances, patellectomy. Patients with anterior knee pain secondary to pathologic plicae or neuromas should have surgery directed at excision of the pathologic tissue. Rarely, nonoperative treatment of chronic patellar tendinitis fails and dkbridement of the focal area of tendinitis is indicated. Clearly, in

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patients with anterior knee pain, careful clinical evaluation is critical to ensure accurate patient selection and optimal results. HISTORY It is important to define patients' symptoms as clearly as possible. Patients with patellofemoral disorders may complain of both pain and instability; however, one usually predominates. Patients often experience dull, achy anterior knee pain exacerbated by prolonged knee flexion (e.g./ sitting or squatting) or resisted knee extension (e.g., stair climbing). Constant pain, which does not increase with activity, should raise suspicion of nonmechanical or referred pain. Activity-related patellofemoral pain is generally caused by mechanical disorders such as arthrosis or malalignment. Based on patient history, it is possible to suspect articular pain (e.g./ post-traumatic arthrosis) or soft-tissue pain (e.g., pathologic lateral patellar tilt). A patient who sustained high-energy blunt trauma to the patella in a previously asymptomatic knee usually has pain that is predominantly articular in origin. Any malalignment or flexibility deficits and associated soft-tissue pain that may be present probably have developed secondarily. Patients without a history of significant trauma or dislocation who present with anterior knee pain should be suspected of having underlying patellofemoral malalignment as the primary problem. Patients with genuine patellar instability have had actual patellar dislocation or can describe episodes of patellar subluxation. Real patellar subluxation usually is described by patients as a discrete lateral movement of the patella with a clear sensation of the patella going back into place. "Giving way" or buckling episodes do not indicate actual patellar instability and are often secondary to pain inhibition or weakness of the quadriceps muscle. If a patient reports actual patellar dislocation, however, malalignment should be considered part of the problem. Some patients have objective patellofemoral malalignment on the contralateral side, suggesting a predisposition to traumatic patellar instability. This should be suspected in patients who suffer patellar dislocation from relatively low-energy injuries, such as twisting while walking. Peripatellar soft-tissue pain may result from overuse tendinitis, pathologic plicae, postsurgical or post-traumatic neuromas, or other pathologic conditions. A history of overuse in work or recreational activities, previous surgery, and trauma may lead to these disorders. Patients who do not maintain adequate strength and flexibility for their functional demands can become victims of chronic overload and develop peripatellar soft-tissue pain. In patients who have had prior surgery, one should determine specifically if their complaints have changed since surgery. If so, one should be suspicious of iatrogenic malalignment (especially if the initial surgery may have included realignment, such as lateral release on a patient without malalignment) or postsurgical neuroma (if the nature of the pain changed and is less related to activity).

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PHYSICAL EXAMINATION Thorough physical examination is essential to the accurate diagnosis and treatment of patellofemoral disorders. The goals of physical examination are (1)to assess the relative contributions of soft-tissue peripatellar pathologic conditions and patellofemoral arthrosis to the patients' pain and (2) to evaluate bony and soft-tissue factors that potentially contribute to patellofemoral malalignment. Systematic palpation helps to determine the contributions of the peripatellar soft tissues (such as tendinitis, neuromas, and pathologic plicae) and patellofemoral articular degeneration to complaints of pain. Specific structures to palpate include all portions of the quadriceps and patellar tendons, retinacular tissues, medial femoral condyle and parapatellar area, and around any surgical or traumatic scars. Tenderness along the quadriceps and patellar tendon, particularly their origins and insertions, usually results from overuse tendinitis. Tendons may be subjected to overuse as a result of excessive functional demands in the absence of malalignment or they may be compromised by inefficient premorbid alignment before overuse. Both possibilities should be considered as the physical examination progresses. Patients with malalignment are often tender at points of intersection between structures such as the junction of the medial patellar tendon, inferior pole of the patella, and medial retinaculum. The diagnosis of pathologic hypertrophic plicae is based primarily on history and physical examination. Pathologic medial parapatellar plicae are palpable and tender over the medial femoral condyle and parapatellar area. Tenderness near surgical and traumatic scars may be secondary to neuromas. Pain resulting from articular degeneration may be confirmed by direct manual compression of the patella (without touching the peripatellar soft tissue) with the knee in various degrees of flexion. Direct compression generally produces pain at the degree of flexion at which articular lesions (patellar or trochlear) come into contact. Patellofemoral crepitus also suggests articular degeneration; however, crepitus is a more significant finding when absent or asymmetric in the contralateral knee, as it is common in many asymptomatic knees. Evaluation for patellofemoral malalignment should include observing the lower extremity for tibiofemoral valgus, rotational abnormalities, patellar tracking, leg-length discrepancy, foot position, and gait pattern. The degree of tibiofemoral valgus can be estimated by the Q angle, defined as the angle created by the anterior-superior iliac spine, the patella, and the tibial tubercle with the knee extended. An angle of 15" or less is considered normal. Angles greater than 20" should be considered abnormal. The tubercle sulcus angle is used to estimate the degree of lateralization of the patellar tendon insertion. Normally, the tibial tubercle is directly below the center of the patella when the knee is flexed to 90". Lateralization of the tubercle is considered abnormal if it exceeds lo", although normal population data are lacking for this test.22The Q and tubercle sulcus angles have some value as estimates of the degree

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of the theoretical skeletal malalignment, but there is no substantial proof that they correlate with anterior knee pain, clinical symptoms of malalignment, or the results of treatment. Patellar tracking should be observed from extension through flexion and also during squatting. Close attention should be paid to the rotation of the entire extremity and foot position because foot position has been shown to affect standing judgment of patellofemoral alignment.39 Normally, the patella begins superior and lateral to the trochlea in full extension and should enter the trochlea smoothly in early flexion. An abrupt lateral-to-medial path of the patella (positive J-sign) suggests normal lateral tracking that may result from a tight lateral retinaculum or laxity of the medial soft-tissue restraints. If this sign is present, it suggests moderate or severe lateral subluxation, which may not be corrected completely by lateral release alone. Patellofemoral malalignment may result from abnormal laxity or excessive constraint in the peripatellar soft tissues. The integrity and tightness of the medial and lateral soft-tissue restraints can be evaluated by the medial and lateral glide and patellar tilt tests. The medial patellar glide test evaluates the lateral retinaculum. It should be performed with the knee in full extension. The examiner’s thumbs are placed on the lateral border of the patella while the medial side is held in neutral tilt with the forefingers. The patella is then pushed medially. Medial translation of less than one quadrant is considered abnormal and usually consistent with a tight lateral retinaculum. The lateral patella tilt test is a more direct method to check for lateral retinaculum tightness (Fig. 3). It is performed by pushing down on the medial border of the patella

Figure 3. Patellar tilt test performed by pushing down on the medial border of the patella. Patellar tilt should correct to neutral.

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while the knee is in full extension. Normally, the tilt corrects at least to neutral and often lo" or more past neutral. Medial retinacular laxity should be tested using the lateral glide test. The medial border of the patella is pushed laterally while the patella is held in neutral tilt with the knee in full extension. Lateral translation of approximately three quadrants or more is consistent with medial retinacular laxity. If the patient reacts with apprehension to gentle lateral displacement of the medial border of the patella while the knee is in full extension and recognizes the sensation of impending dislocation, the "apprehension sign" is considered positive and instability is confirmed as an important part of the patient's presentation. Muscle flexibility testing is also important in evaluating patellar malalignment. Normal patellar tracking results from a combination of adequate soft-tissue restraints and dynamic muscular control. Limited flexibility in muscle groups of the lower extremity can alter the function of the patellofemoral joint significantly by exerting direct or indirect forces on the patella. Tight hip flexors and external rotators affect the position of the extremity during weight bearing and the direction of patellofemoral load. Tight quadriceps increase patellofemoral joint reaction forces and are associated with patellar tendinitis. Hamstring tightness may cause functional knee flexion contracture, which increases patellofemoral joint reaction forces. Because the iliotibial band exerts a posterolateral moment on the patella with increasing knee flexion, flexibility deficits contribute to patellar tilt. Gastrocnemius or soleus muscle tightness also may contribute to patellofemoral malalignment. With gastrocsoleus stiffness and a functional decrease in ankle dorsiflexion, compensatory subtalar pronation occurs. Increased pronation causes excessive internal rotation of the tibia and contributes to malalignment. Because of the complex biomechanics of the lower extremity, flexibility deficits are very important in treatment of patellofemoral malalignment and anterior knee pain. When detected, flexibility deficits are an important focus of nonoperative management. RADIOGRAPHIC STUDIES

Standing anteroposterior and lateral views of the knee should be obtained to check for signs of articular damage, patella alta and baja, and other associated conditions. Signs of articular degeneration include joint space narrowing, subchondral sclerosis, osteophytes, and cyst formation. The Insall-Salvati ratio of patellar tendon length to patellar length should be used to test for patella alta or baja.18 Ratios greater than 1.2 or less than 0.8 indicate a pathologic condition. Axial tangential views of the patellofemoral joint are useful in evaluating patellar alignment. An axial image of the patellofemoral joint in 45" of knee flexion ("Merchant's view") is used to measure the congruence angle, an estimation of lateral subluxation (Fig. 4). An angle of 4" laterally or 14" medially are considered normal. Laurin's axial

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0 Lateral

Figure 4. The congruence angle. Angle BAC is the sulcus angle. Line A 0 bisects the sulcus angle. DAO is the congruence angle. (From Merchant AC, Mercer RL, Jacobsen RH, et al: Roentgenographic analysis of patellofemoral congruence. J Bone Joint Surg Am 56:1395, 1974; with permission.)

patellar view, taken at 20" of flexion, measures lateral patellar tilt (Fig. 5).26It is considered normal if it opens laterally and abnormal if it opens medially or parallel. Unfortunately, two problems are inherent in the use of axial radiographs. Image overlap occurs because the radiographic beam is rarely precisely tangential to the patellofemoral joint. Thus, the apparent shape and position of the patella and trochlea are actually a summation of shadows from bone proximal and distal to the portion of the patella that articulates at that degree of flexion. A second problem is that some patients with symptoms and physical findings of patellofemoral malalignment may show no evidence of malalignment on axial radiographs. In early flexion, patellar tracking is more dependent on the soft-tissue

Figure 5. Lateral patellofemoral angle should open laterally if normal. M = medial; L = lateral. (From Fulkerson JP, Hungerford DS: Disorders of the Patellofemoral Joint, ed 2. Baltimore, Williams & Wilkins, 1990, p 50; with permission.)

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tension from the retinacular constraints. As flexion proceeds, the patella normally is drawn more deeply into the bony trochlea. Therefore, axial radiographs may not be able to image the articulation early enough to detect subtle soft-tissue influences on patellar malalignment. Coronal midpatellar CT scanning offers a solution to these two problems. CT scans offer excellent visualization of the patellofemoral alignment at any degree of flexion without image overlap. Congruence, patellar tilt, and sulcus angles can be calculated. Studies have shown that CT images are more sensitive at 10" to 20" of knee flexion than axial radiographs in patients with patellar subl~xation.'~, 29, 48 Lateral patellar tilt less than 7" or evidence of lateral subluxation at 15" of flexion constitutes evidence of malalignment by CT criteria. Various angles of flexion also can be studied in order to understand the influence of progressive flexion on patellar subluxation and tilt. MR imaging also has been used to generate axial images of the patellofemoral joint. Unfortunately, precise criteria for measurement of alignment and normal population data have not been published for patellofemoral MR imaging. Kinematic MR imaging-rapidly viewed sequential static images in progressive angles of flexion-has been used to generate the impression of observing patellar motion. These images are acquired as multiple static images and, when viewed in sequence, 51 form a qualitative impression of patellar tracking.50, In general, radiographic studies should be used to confirm the clinical impression obtained from the history and physical examination. Plain radiographs generally should be part of a comprehensive initial knee evaluation to rule out unusual but important causes of knee pain, such as tumors and infections, before proceeding with extended nonoperative management. Axial CT images are useful when nonoperative management has failed and realignment surgery is being considered. If both lateral subluxation and lateral patellar tilt are present on plain axial films, they will be present also on CT images performed in lesser degrees of flexion. CT images, therefore, may not be necessary in cases of malalignment in which the diagnosis is obvious on plain axial radiographs. NONOPERATWE MANAGEMENT

The goals of nonoperative treatment of anterior knee pain are normal balanced strength and flexibility. Decreasing pain is an essential goal of early rehabilitation to reverse pain-mediated muscular inhibition of the quadriceps. Nonsteroidal anti-inflammatory medication, patellar taping, and other physical therapy modalities often can result in dramatic relief within several weeks. Initially, activity modification featuring relative rest and avoidance of prolonged flexed-knee posture are important. Exercises that do not cause symptoms yet maintain general fitness should be encouraged. Depending on the individual situation, examples of such activities include swimming, stationary bicycling, and

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other low-impact activities. Patients should avoid repetitive exercises that result in high patellofemoral joint reaction forces, such as stair climbing, during initial rehabilitation. As rehabilitation proceeds, focusing on restoring normal flexibility and muscular control is important. Patients with malalignment should focus on restoration of muscular control, especially strong vastus medialus obliquus contraction with initiation of quadriceps contraction. Patellar taping often helps to relieve pain and allows early pain-free quadriceps strengthening. Closed-chain exercises are often better tolerated and, because they are more closely related to function, should be featured in most patellofemoral rehabilitation programs. Rehabilitation programs should be designed individually. For example, when patellar tendinitis is present, quadriceps stretching and eccentric exercises should be emphasized. When patellar tendinitis is resistant to this approach, temporary use of counterforce straps can control pain until normal strength and flexibility are restored. In patients with localized inflammatory problems, such as patellar tendinitis or pathologic plicae, direct anti-inflammatory modalities, such as cryotherapy, phonophoresis, or iontophoresis, should be included. When patellofemoral arthrosis is a prominent feature, treatment should be directed at reducing joint reaction forces and soft-tissue abnormalities that result from prolonged pain and abnormal mechanics. Findings such as quadriceps, hamstring, iliotibial band, and gastrocsoleus muscle tightness are common in such patients and increase patellofemoral joint reaction forces. Often, patients with arthrosis are relatively asymptomatic with strengthening through flexion ranges that avoid direct compression of the most severe articular erosion. Patients may need to begin with isometric exercises within a nonpainful range of motion and progress as tolerated. If excessive pronation of the foot is contributing to malalignment, orthotics may be valuable, but generally they are not prescribed initially for all patients with evidence of hindfoot pronation. Almost all patients respond to a good therapy program, encouragement, and time. It is unusual enough for a patient to fail to improve with nonoperative management that one should reconsider whether the diagnosis of patellofemoral pain is actually correct before considering lateral release or other patellofemoral surgery. OPERATIVE MANAGEMENT BY LATERAL RETINACULAR RELEASE

Patients with radiographically documented lateral patellar tilt and mild or absent patellofemoral arthrosis are good candidates for lateral release. Lateral retinacular release can be performed by open or closed techniques. All techniques have the same goal of decreasing the posterolateral moment imposed on the lateral patella by an overly tight lateral retinaculum. Open techniques generally involve small incisions in the 4to 5-cm range and include simple division of the lateral retinaculum,

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excision of a small strip of the retinac~lum,5~ or lengthening of the retinaculum by Z-plasty of the transverse fibers of the retinac~lum.~ Closed or arthroscopic techniques use arthroscopic visualization to limit the incisions to several arthroscopic portals. Arthroscopically, techniques have been suggested using S C ~ S S O ~ S31,, ~34~ , arthroscopic blades: l5 or electrocautery to divide the r e t i n a c u l ~ mTourniquet .~~ use is not necessary with either technique. If a tourniquet is used, it definitely should be released before completion of the surgery and absolute hemostasis secured. Although there are relative advantages and disadvantages for each of the various techniques, each individual surgeon should choose the technique he or she can execute most effectively. All techniques can be accomplished as outpatient surgeries, and no differences in morbidity have been proved in the literature or perceived by the authors. Clearly, the actual surgical technique chosen is a secondary consideration to the need to accomplish, by whatever means, safe, effective, and efficient patellar realignment. OPEN LATERAL RETINACULAR RELEASE Relative Advantages and Disadvantages

Open release is a part of concomitant open patellar realignment surgery, such as anteromedialization of the tibia1 tubercle, whenever lateral patellar tilt or lateral subluxation is present preoperatively. A primary advantage of open lateral release is that it may be performed safely and reproducibly by orthopedists who are not comfortable with advanced arthroscopic techniques. Other relative advantages include direct articular observation and palpation, better visualization and control of the anatomy, and a better opportunity to control hemostasis. Because hemarthrosis is the most common complication of lateral release, this is an important consideration. Comparing reported incidence of hemarthrosis after open and arthroscopic release (Table l), open release may be preferable. It should be remembered, however, that such comparisons among studies do not control many variables and hemarthrosis is not defined clearly in many studies. The only relative disadvantage to open release is the longer scar. The procedure can be performed readily, however, through a 3- to 4-cm incision, which is generally quite acceptable. Cosmesis is rarely a problem, surgery time is brief, and the results are well documented. Technique

Diagnostic arthroscopy is recommended to confirm the clinical impression of patellar malalignment; to rule out associated meniscal, synovial, and tibiofemoral pathologic conditions; and to evaluate the degree of patellofemoral articular degeneration. If patellofemoral degeneration

Merchant and Mercer3* 20 Larson et aIz5 56 Cedar and Larson5 64 Osborne and Fulford40 75 Krompinger and F u l k e r s ~ n ~ ~ 14 Bigos and McBride3 102 Dzioba et a19 60 Schonholz et 22 Christensen et a16 59 Johnson 21 38 Johnson et alZo 25 Shea and Fulkerson49 30 Micheli and S t a n i t ~ k i ~ ~ 41 Total 606

Author

No. of Patients in Study

Open

1 0 1 3 1 1 0 4 0 0 2 0 0 13

No. of Patients with Hemarthrosis 5 0 2 4 7 1 0 18 0 0 8 0 0 2

(Yo) Hemarthrosis Harwin and Stern McGinty and McCarthy31 Metcalf 34 Simpson and B a r r e P Malek 28 Henry et all5 Lankenner et aIz4 Betz et a12 Sherman et a152 Bray et a14 Jackson et al l9 Ogilvie-Harris and Jackson 38 Grana et al l 3 Dentis Dandy and Desai' Total

Author 25 45 93 55 67 100 34 39 45 50 39 120 43 21 40 816

No. of Patients in Study 2 2 9 23 10 9 2 1 0 0 2 4 1 1 0 66

8 4 10 42 15 9 6 3 0 0 5 3 2 5 0 8

No. of Patients with ("/I Hemarthrosis Hemarthrosis

Arthroscopic

Table 1. COMPARISON OF THE PREVALENCE OF HEMARTHROSIS AFTER OPEN OR ARTHROSCOPIC LATERAL RETINACULAR RELEASE

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is more severe than Outerbridge grade 11, one should consider concomitant anteriorization/anteromedializationof the tubercle. To perform isolated open lateral release, make a 3- to 4-cm longitudinal incision approximately 2 cm lateral to the patella. This should be incorporated with the inferolateral arthroscopic portal (to minimize skin incisions). The subcutaneous tissues are spread to reveal the superficial layer of the lateral retinaculum. Dissection of the subcutaneous fat is performed bluntly from the fascial layer proximal to the incision with a surgical sponge to get clear visualization of the retinaculum. This ensures excellent exposure before, during, and after the actual release. The skin and subcutaneous layers are lifted away from the exposed retinacular layer with an Army/Navy retractor to expose the fascial layer proximal to the incision. All layers of the lateral retinaculum and synovium are incised midway between the lateral border of the patella and the lateral femoral condyle for a distance of 3 to 4 cm. The insertion of the vastus lateralis tendon is palpated into the superolateral corner of the patella. It is a prominent tendon and is readily palpable from the intra-articular side. The fatty plane is identified between the vastus lateralis and vastus lateralis oblique muscles on the fascial side of the dissection to confirm the insertion site of the vastus lateralis. Mayo scissors are inserted into the superior apex of the retinacular incision and it is pushed proximally, completely dividing the lateral retinaculum and extending 4 to 5 cm proximal to the patella. It is important to be absolutely certain not to detach the vastus lateralis tendon because this has been associated with 36, 54 It is also critical to postoperative iatrogenic medial subluxation.l6> extend the release distal to the patella and to release any tight bands in the fat pad that are tethering the patella. The distal portion of the release ensures release of the patellotibial ligament, which has been shown to provide substantial lateral c ~ n s t r a i n tPost . ~ ~ and FulkersonMrecommend continuation of the release to the level of the tibia1 tubercle (Fig. 6A). When extending the release inferiorly, it is important to avoid injury to the anterior portion of the lateral meniscus by incising retinacular and capsular layers only. Any synovial adhesions to the infrapatellar fat pad should be released. Passive eversion of the patella to 90" should be possible, permitting direct inspection of the articular surface (Fig. 6B). If eversion to 90" is not possible, release is incomplete, usually distally. The skin incision can then be mobilized proximally or distally to see all portions of the release site and coagulate any bleeders under direct vision. Meticulous hemostasis is important. Treat articular pathologic conditions, if indicated, by excision of unstable chondral flaps. The benefit of articular abrasion or burring is unproven in the patellofemoral joint and not recommended routinely. The tourniquet, if used, should be released and absolute hemostasis should be obtained with particular attention to the lateral superior geniculate vessels. Subcutaneous and skin layers are then closed based on the surgeon's preference. Drains are not used routinely. Cox" recommends lengthening of the retinaculum by Z-plasty between the superficial and deeper layers, avoiding incision of the synovial

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Figure 6. Suggested extent of lateral release. A, Incision (dotted line) begins proximally between the lateralis and vastus lateralis obliqus and extends distally to the tibia1 tubercle. 6, Passive eversion of the patella to 90" (arrow) should be possible. (From Post WR, Fulkerson JP: Surgery of the patellofemoral joint: Indications, effects, results, and recommendations. In Scott N (ed): The Knee. St. Louis, Mosby-Year Book, 1994, p 451; with permission.)

layer. Although this has the theoretical advantage of avoiding complete release and perhaps medial subluxation, it also demands that the surgeon judge the necessary tension correctly. Avoiding incision of the synovial layer may help to avoid hemarthrosis by not opening the true joint space, but to date this has not been proven. In addition, it should be considered that the synovium is densely innervated, and release of the synovial tissue (if one believes it is part of the pain generating the pathologic condition in this area) might be prudent. Because techniques involving complete open release have proved to be highly successful, the addition of another variable (retensioning the retinaculum) may be unnecessary. Nonetheless, the theoretical advantages of the technique should be noted because in revision situations in which unusual con-

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cerns exist regarding medial subluxation (perhaps due to a compromised vastus lateralis) special advantages may exist. ARTHROSCOPIC LATERAL RETINACULAR RELEASE Relative Advantages and Disadvantages

Advocates of arthroscopic release cite minimal morbidity, better cosmesis, reduced hospitalization, short postoperative rehabilitation, and no interference with subsequent surgical procedures as important advant a g e ~ .Of ~ ~the proposed benefits, the only certain one is cosmesis. Disadvantages of arthroscopic lateral release include the need for more specialized and expensive equipment and increased anesthetic and operating time for surgeons who do the procedure rarely. Hemostasis must be maintained via electrocautery and, as noted previously, the rate of hemarthrosis may be higher. Fluid extravasation, which can be extensive with arthroscopic release, is unique to the arthroscopic procedure and probably causes minimal morbidity. Arthroscopic lateral release is a reproducible procedure with low morbidity in the hands of experienced arthroscopists but has only cosmetic advantages over open release. Technique

Using standard arthroscopic portals, the entire knee is examined, with particular attention to patellar alignment and articular condition. In the authors’ experience, the superomedial portal as described by S ~ h r e i b e allows r ~ ~ the best visualization of the patellofemoral joint and the lateral retinaculum (Fig. 7). This portal allows excellent visualization of the patellofemoral joint and lateral retinaculum. When using specialized insulated arthroscopic cautery devices, electrocautery may be done in normal saline or Ringer’s irrigant. It is important to check the manufacturer’s recommendation, as some cautery devices may require replacing the normal saline irrigant with sterile water. It is very important to maintain proper orientation to ensure accurate release. Often the insertion of the vastus lateralis can be seen at the superolateral patella and followed proximally. It is helpful to palpate the vastus lateralis and place an 18-gauge spinal needle lateral to its patellar insertion and to confirm the location arthroscopically. This provides an extra landmark to prevent inadvertent iatrogenic injury. If desired, another needle can be placed at the superior extent of the planned release 4 to 5 cm proximal to the patella, just lateral to the vastus lateralis tendon. This serves as a visible marker for the proximal extent of the release. The electrocautery device is placed through a medial parapatellar portal. With the knee extended and under direct vision, the release is begun proximally, progressing to the inferolateral portal. The synovium and all layers of the retinaculum are released until subcutaneous fat is

OPEN OR ARTHROSCOPIC LATERAL RELEASE

:i/

distal lateral release /

45

1

Figure 7. The proximal portion of a release can be accomplished from an inferolateral portal. An accessory mid-medial portal is helpful to accomplish the distal release.

exposed. Any bleeders encountered are coagulated, with particular attention paid to the lateral superior geniculate vessels. Because the important patellotibial ligament may often extend distal to the inferolateral portal, the release should extend distal to the portal to prevent a tight residual band at the inferior extent of the arthroscopic release. At times, an accessory portal in the midmedial patellar retinaculum is perfect to allow the cautery device to extend the release distally. Patellar mobility should be checked. As with open release, passive eversion of the patella to 90" should be possible. If it is not, the most common reason is inadequate distal release, and this should be corrected intraoperatively. If a tourniquet is used, it should be deflated before completion of the surgery and hemostasis assured. POSTOPERATIVE MANAGEMENT AND REHABILITATION

After skin closure and a light dressing, the authors apply a Cryocuff (Aircast, Summit, NJ) to provide continuous cryotherapy and gentle compression during the first 48 hours. Quadriceps muscle sets, cocontraction of quadriceps/hamstrings, and straight-leg raise exercises are begun as soon as the patient is conscious. Early knee flexion is important to prevent scarring in the lateral release site. Stretching of the hamstrings and gastrocsoleus can be done in the first days after surgery. Because a light dressing has been applied, patellar mobility exercises can begin immediately. The authors think it is important to teach patients these exercises preoperatively and that they be motivated to begin them imme-

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FORD&POST

diately. If they understand this, they seem less apprehensive postoperatively. Patients may bear weight as tolerated with the assistance of crutches until they can walk normally. Patients use a knee immobilizer for ambulation until they have adequate quadriceps control to perform a straightleg raise without an extension lag. The Cryocuff can be used on a daily basis before and after exercise sessions for approximately 1 month and subsequently as needed. Most patients show improvement of patellofemoral pain and stability within 1 month. Improvement may continue for many months as quadriceps muscle strength improves and functional rehabilitation progresses. COMPLICATIONS

The most common complication of lateral retinacular release, whether performed by open or closed technique, is hemarthrosis. Arthroscopic electrocautery has the advantage of concomitant hemostasis and cutting, but thermal injury to the skin is a potential complicat i ~ n . Most * ~ studies have shown hemarthrosis to occur in less than 10% of cases; however, some authors have reported occurrence in from 15% to 42% of cases. The authors’ review of the literature is summarized in Table 1. The total prevalence of hemarthrosis after open release was 2% compared with 8% using arthroscopic techniques; however, not all studies were well controlled, and hemarthrosis was not always well defined and may not be equivalent in different studies. Whether open or arthroscopic lateral release is performed, meticulous hemostasis must be obtained with special attention paid to the lateral superior geniculate vessels. Patients may have recurrence, persistence, or even exacerbation of preoperative symptoms secondary to an incomplete lateral release or postoperative scarring in the site of the lateral release. This is particularly common if arthroscopic release is not carried distally enough. Careful physical examination is the key to diagnosing an incomplete lateral release. Limited patellar mobility and point tenderness (typically at the inferior extent of the previous release) suggests an incomplete lateral release. Radiographic studies may be normal. Treatment is carried out by release of the residual band or excision of scar tissue. Although rare, medial subluxation may result after lateral release. This complication most likely represents the result of a knee without malalignment treated by a realignment procedure such as lateral release. Diagnosis of medial subluxation is best made by physical examination by observation of a “reverse apprehension sign.”16,36, 54 Medial subluxation also has been associated with transection of the vastus lateralis tendon. Hypermobile patients with transection of the vastus lateralis can be diagnosed by the gravity subluxation test, in which such patients cannot actively correct passively induced medial patellar subluxation in the lateral decubitus position.37Treatment of iatrogenic medial subluxa-

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47

tion is not well established. In general, the treatment should include retinacular balancing and restoration of vastus lateralis integrity. The best treatment for this problem is prevention. The indications for lateral release should be limited to patients with proven lateral tilt, and the vastus lateralis should be protected during release. Other potential complications include infection, reflex sympathetic dystrophy, arthrofibrosis, and deep vein thrombosis. These are unusual and limited by careful patient selection, careful sterile technique, and close attention to postoperative rehabilitation.

SUMMARY

Careful patient selection, accurate surgical technique, and careful postoperative rehabilitation are all equally important to success in lateral release surgery. Whether the surgery is performed by open or arthroscopic technique, one must release all layers of the retinaculum, spare the vastus lateralis, extend the release far enough distally, check intraoperative patellar mobility, and obtain absolute hemostasis. Postoperative rehabilitation must stress pain control, early quadriceps contraction, patellar mobility, and knee motion. With attention to these details, successful lateral release surgery is likely in most patients with pathologic lateral patellar tilt and minimal patellofemoral arthrosis. ACKNOWLEDGMENT The authors would like to acknowledge Cyndi Owens and Cindy Thompson for assistance in manuscript preparation.

References 1. Aglietti P, Insall JH, Cerulli G: Patellar pain and incongruence. Clin Orthop 122:217224, 1983 2. Betz RR, Magill JT, Lonergan Rp: The percutaneous lateral retinacular release. Am J Sports Med 15:477482, 1987 3. Bigos SJ, Mcbride GG: The isolated lateral retinacular release in the treatment of patellofemoral disorders. Clin Orthop 186:75-80, 1984 4. Bray RC, Roth JH, Jacobson Rp: Arthroscopic lateral release for anterior knee pain: A study comparing patients who are claiming workers compensation with those who are not. Arthroscopy 3:237-247, 1987 5. Ceder LC, Larson RL Z-plasty lateral retinacular release for the treatment of patellar compression syndrome. Clin Orthop 144:llO-113, 1979 6. Christensen F, Soballe K, Snerum L: Treatment of chondromalacia patellae by lateral retinacular release of the patella. Clin Orthop 234:145-147, 1988 7. Dandy DJ, Desai SS: The results of arthroscopic release of the extensor mechanism for recurrent dislocation of the patella after 8 years. Arthroscopy 10:540-545, 1994 8. Denti M: Arthroscopic lateral retinacular release of the alar ligament Indications and long-term results. Ital J Orthop Traumatol4:527-532, 1990 9. Dzioba RB, Strokon A, Mulbry L Diagnostic arthroscopy and longitudinal open lateral

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release: A safe and effective treatment for "Chondromalacia patella." Arthroscopy 1~131-135,1985 10. Fulkerson JP, Gossling H R Anatomy of the knee joint lateral retinaculum. Clin Orthop 153:183-188, 1980 11. Fulkerson JP, Kalenak A, Rosenburg TD, et al: Patellofemoral pain. Instr Course Lect XLI57-71, 1992 12. Gecha SR, Torg JS: Clinical prognosticators for the efficacy of retinacular release surgery to treat patellofemoral pain. Clin Orthop 253203-208, 1990 13. Grana WA, Hinkley 8, Hollinsworth S: Arthroscopic evaluation and treatment of patellar malalignment. Clin Orthop 186:122-128, 1984 14. Harwin SF, Stem RE: Subcutaneous lateral retinacular release for chondromalacia patellae: A preliminary report. Clin Orthop 156207-210, 1981 15. Henry JH, Goletz TH, Williamson B: Lateral retinacular release in patellofemoral subluxation. Am J Sports Med 14121-129, 1986 16. Hughston JC, Deese M Medial subluxation of the patella as a complication of lateral retinacular release. Am J Sports Med 16:383-388, 1988 17. Inoue M, Shino K, Hirose H, et al: Subluxation of the patella. J Bone Joint Surg Am 70:1331-1337, 1988 18. Insall J, Salvati E: Patella position in the normal knee joint. Radiology 101:lOl-104,1971 19. Jackson RW, Kunkel SS, Taylor GJ: Lateral retinacular release for patellofemoral pain in the older patient. Arthroscopy 7283-286, 1991 20. Johnson DC, Cler JW, Narten NC: The lateral patellar push test for predicting the success of the lateral retinacular release. Am Joumal of Arthroscopy 1:23-26, 1991 21. Johnson RP: Lateral facet syndrome of the patella. Clin Orthop 238:148-158, 1989 22. Kolowich PA, Paulos LE, Rosenberg TD, et al: Lateral release of the patella: Indications and contraindications. Am J Sports Med 18:359-365, 1990 23. Krompinger WJ, Fulkerson JP: Lateral retinacular release for intractable lateral retinacular pain. Clin Orthop 179:191-193, 1983 24. Lankenner PA, Micheli LJ, Clancy R, et al: Arthroscopic percutaneous lateral patellar retinacular release. Am J Sports Med 14:267-269, 1986 25. Larson RL, Cabaud HE, Slocum DB, et al: The patellar compression syndrome: Surgical treatment by lateral retinacular release. Clin Orthop 134158-167, 1978 26. Levesque HP, Dussault R, Laurin CA, et a1 The abnormal lateral patellofemoral angle. J Bone Joint Surg Am 60:55-60, 1978 27. Lord MJ, Maltry JA, Shall LM: Thermal injury resulting from arthroscopic lateral retinacular release by electrocautery: Report of three cases and a review of the literature. Arthroscopy 7:33-37, 1991 28. Malek MM: Arthroscopic lateral retinacular release. Orthopaedic Review 19:55-59,1985 29. Martinez S, Korobkin M, Fondren FB, et al: Diagnosis of patellofemoral malalignment by computed tomography. J Comput Assist Tomogr 71050-1053, 1983 30. Marumoto JM, Jordon C, Akins R A biomechanical comparison of lateral retinacular release. Am J Sports Med 23151-155, 1995 31. McGinty JB, Mccarthy JC: Endoscopic lateral retinacular release. Clin Orthop 156:120125, 1981 32. Merchant AC, Mercer RL Lateral release of the patella. Clin Orthop 10340-45, 1974 33. Merchant AC, Mercer RL, Jacobsen RH, et al: Roentgenographic analysis of patellofemoral congruence. J Bone Joint Surg Am 56:1391-1396, 1974 34. Metcalf RW An arthroscopic method for lateral release of the subluxating or dislocating patella. Clin Orthop 1679-18, 1982 35. Micheli LJ, Stanitski CL: Lateral patellar retinacular release. Am J Sports Med 9:330336, 1981 36. Miller PR, Lekin RM, Teitge RA: Medial dislocation of the patella. Skeletal Radio1 20429431, 1991 37. Nonweiler DE, Delee JC: The diagnosis and treatment of medial subluxation of the patella after lateral retinacular release. Am J Sports Med 226804336, 1994 38. Ogilvie-Harris DJ, Jackson RW: The arthroscopic treatment of chondromalacia patellae. J Bone Joint Surg Br 66:660-665, 1984

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39. Olerud C, Berg P: The variation of the Q angle with different positions of the foot. Clin Orthop 191:162-165,1984 40. Osbome AH, Fulford PC: Lateral release for chondromalacia patellae. J Bone Joint Surg Br 64:202-205, 1982 41. Outerbridge RE: The etiology of chondromalacia patellae. J Bone Joint Surg Br 43752757, 1961 42. Post WR Surgical decision making in patellofemoral pain and instability. Operative Techniques in Sports Medicine 2:273-284, 1994 43. Post WR, Fulkerson JP: Arthritis of the patellofemoral joint. In Fu FH (ed): Knee Surgery. Baltimore, Williams & Wilkins, 1994, pp 99.51024 44. Post WR, Fulkerson Jl? Surgery of the patellofemoral joint: Indications, effects, results, and recommendations. In Scott N (ed): The Knee. St. Louis, Mosby-Year Book, 1994, pp 441468 45. Post WR, Fulkerson JP, Shea KP: Patellofemoral malalignment and realignment in a cadaver model. Presented at the 19th Annual Meeting of the American Orthopedic Society of Sports Medicine, Sun Valley, ID, July 13, 1993 46. Schonholtz GJ, Zahn MG, Magee CM: Lateral ritinacular release of the patella. ArthrosCOPY 3~269-272,1987 47. Schieiber S N Proximal superomedial portal in arthroscopy of the knee. Arthroscopy 7246-251, 1991 48. Schutzer SF, Ramsby GR, Fulkerson JP: The evaluation of patellofemoral pain using computerized tomography. Clin Orthop 204286-293,1986 49. Shea KP, Fulkerson JP: Preoperative computed tomography scanning and arthroscopy in predicting outcome after lateral retinacular release. Arthroscopy 8:327-334, 1992 50. Shellock FG, Mink JH, Fox J M Patellofemoral joint: Kinematic MR imaging to assess tracking abnormalities. Radiology 168:551-553, 1988 51. Shellock FG, Mink JH, Deutsch AL, et al: Patellar tracking abnormalities: Clinical experience with kinematic MR imaging in 130 patients. Radiology 172:799-804, 1989 52. Sherman OH, Fox JM, Sperling H, et al: Patellar instability: Treatment by arthroscopic electrosurgical lateral release. Arthroscopy 3:152-160, 1987 53. Simpson LA, Barrett JP: Factors associated with poor results following arthroscopic subcutaneous lateral retinacular release. Clin Orthop 186165-171, 1984 54. Teitge RA: Iatrogenic medial patellar dislocation. Presented at the Annual Meeting of the American Academy of Orthopaedic Surgeons, Anaheim, CA, 1991 55. Willner P: Recurrent dislocation of the patella. Clin Orthop 69:213-215, 1970

Address reprint requests to William R. Post, MD Department of Orthopedics West Virginia University Robert C. Byrd Health Sciences Center PO Box 9196 Morgantown, WV 26506-9196