**3. Posterior capsular release**

#### **3.1 History and physical examination**

Flexion contractures are one of the main factors that adversely affect patient outcome and knee function following surgery. 5, 7, 8 A 5o loss of extension can cause a noticeable limp during ambulation and patellofemoral irritability, and a loss of 10o is poorly tolerated. 3 Deficits greater than 20o result in a significant leg-length discrepancy. 8 Contracture of the posterior capsule is the primary cause of extension loss, however anterior interval scarring, patellar entrapment, anterior cruciate ligament (ACL) graft malposition and hamstring tightness can also contribute. 5, 7, 8, 9

Patients with an extension deficit should be systematically evaluated for the multiple potential causes of a flexion contracture. A thorough history of any trauma or surgical procedures should be obtained. Knee range of motion should be carefully measured and the quality of the endpoint should be recorded. Flexion contractures exhibiting a firm endpoint tend to involve the posterior capsule, while a spongier endpoint typically indicates involvement of the patellofemoral mechanism or anterior interval.

MRI is the imaging modality of choice. Thickening or scarring of the posterior capsule, indicated by low T1 and T2 signal, may sometimes be observed.

#### **3.2 Posterior capsular release**

Surgical intervention is indicated in a patient with a 10-15 degree flexion contracture with an unyielding endpoint that has failed non-operative management, 10 however even smaller degrees of contracture may not be tolerated in the elite athletic population. Both open 9,10,11 and arthroscopic posterior capsular releases 12,13 have been described, however arthroscopic releases are more technically demanding.

The patient is positioned for standard arthroscopy, however the contralateral leg is placed in a well-leg holder and the foot of the bed is dropped. Care should be taken to place the tourniquet high on the thigh to allow adequate draping for the creation of a posteromedial and/or posterolateral portal (Figure 4). An arthroscopic pump is generally recommended to maintain a constant intra-articular pressure and ensure distension of the posterior capsule. Anterolateral and anteromedial arthroscopic portals are created near the edge of the patellar tendon to allow instrumentation to be used in the posterior compartment.

Arthroscopic Soft Tissue Releases of the Knee 263

Figure 4B

starts medially and proceeds laterally to the midline, in line with the PCL at the midcapsular level. The gastrocnemius muscle and tendon become visible as the capsule is

Mariani 13 described posteromedial and posterolateral arthroscopic capsular releases. The arthroscope may be placed in either posteromedial or posterolateral portals to visualize the contralateral compartment. Often there is a posterior septum that must first be released. A blunt trocar may be used to perforate the septum and then expanded with a shaver or radiofrequency probe. Posterior adhesions are removed until the femoral condyles become visible. A punch or radiofrequency probe is then directed toward the superior capsular attachments at the condyle. The capsule is then progressively released. The tendon of the gastrocnemius is then recognized and can also be released to allow for a greater posterior

Postoperatively, patients may be admitted to the hospital for pain management and initial physical therapy. An indwelling epidural catheter is often beneficial, in addition to oral and

Fig. 4. Posteromedial arthroscopic portal. A, The entry site (1) is between the posterior medial femoral condyle (2) and posterior medial tibial plateau (3) and created under direct visualization. B, View from the posterolateral portal toward the posteromedial aspect of the knee during capsular release. MFC: medial femoral condyle. MTP: medial tibial plateau.

released.

release.

The posteromedial compartment is visualized with a 30o arthroscope via the anterolateral portal by placing it between the medial femoral condyle and posterior cruciate ligament (PCL). 12 Often, a blunt arthroscopic obturator must first be used to break through scar tissue or adhesions, prior to inserting the arthroscope. 12 A spinal needle is placed under direct visualization from the posteromedial skin through the posteromedial capsule to localize the posteromedial arthroscopic portal (Figure 4). The portal is then created by making a small incision and advancing an arthroscopic cannula through the incision into the posteromedial compartment under direct visualization. Similarly, the arthroscope may be placed between the ACL and lateral femoral condyle to visualize the posterolateral compartment. A posterolateral portal can be created in a similar manner; however care must be taken to avoid the peroneal nerve, which lies on the posteromedial border of the biceps tendon. Incision must be anterior to the biceps and blunt dissection must be performed during portal placement.

Two methods of arthroscopic capsular release have been described. Laprade et al. 12 described an isolated posteromedial release for flexion contractures. Separation of the posteromedial capsule from the posteromedial structures, including the medial gastrocnemius tendon and muscle, using a blunt arthroscopic obturator or a small periosteal elevator was recommended. An arthroscopic basket punch and shaver, with the shaver blade facing anteriorly, are then used to release the posteromedial capsule. The procedure

Figure 4A

The posteromedial compartment is visualized with a 30o arthroscope via the anterolateral portal by placing it between the medial femoral condyle and posterior cruciate ligament (PCL). 12 Often, a blunt arthroscopic obturator must first be used to break through scar tissue or adhesions, prior to inserting the arthroscope. 12 A spinal needle is placed under direct visualization from the posteromedial skin through the posteromedial capsule to localize the posteromedial arthroscopic portal (Figure 4). The portal is then created by making a small incision and advancing an arthroscopic cannula through the incision into the posteromedial compartment under direct visualization. Similarly, the arthroscope may be placed between the ACL and lateral femoral condyle to visualize the posterolateral compartment. A posterolateral portal can be created in a similar manner; however care must be taken to avoid the peroneal nerve, which lies on the posteromedial border of the biceps tendon. Incision must be anterior to the biceps and blunt dissection must be performed

Two methods of arthroscopic capsular release have been described. Laprade et al. 12 described an isolated posteromedial release for flexion contractures. Separation of the posteromedial capsule from the posteromedial structures, including the medial gastrocnemius tendon and muscle, using a blunt arthroscopic obturator or a small periosteal elevator was recommended. An arthroscopic basket punch and shaver, with the shaver blade facing anteriorly, are then used to release the posteromedial capsule. The procedure

Figure 4A

during portal placement.

Figure 4B

Fig. 4. Posteromedial arthroscopic portal. A, The entry site (1) is between the posterior medial femoral condyle (2) and posterior medial tibial plateau (3) and created under direct visualization. B, View from the posterolateral portal toward the posteromedial aspect of the knee during capsular release. MFC: medial femoral condyle. MTP: medial tibial plateau.

starts medially and proceeds laterally to the midline, in line with the PCL at the midcapsular level. The gastrocnemius muscle and tendon become visible as the capsule is released.

Mariani 13 described posteromedial and posterolateral arthroscopic capsular releases. The arthroscope may be placed in either posteromedial or posterolateral portals to visualize the contralateral compartment. Often there is a posterior septum that must first be released. A blunt trocar may be used to perforate the septum and then expanded with a shaver or radiofrequency probe. Posterior adhesions are removed until the femoral condyles become visible. A punch or radiofrequency probe is then directed toward the superior capsular attachments at the condyle. The capsule is then progressively released. The tendon of the gastrocnemius is then recognized and can also be released to allow for a greater posterior release.

Postoperatively, patients may be admitted to the hospital for pain management and initial physical therapy. An indwelling epidural catheter is often beneficial, in addition to oral and

Arthroscopic Soft Tissue Releases of the Knee 265

Fig. 5. Patellar tilt test. The patella is centralized in the femoral trochlea with the knee in full extension. The medial and lateral aspect of the patella is stabilized and the lateral aspect is elevated. Inability to elevate the lateral aspect of the patellar to neutral indicates a tight

Lateral release is indicated in patients who have failed physical therapy and have increased lateral facet pressure demonstrated either radiographically or clinically with a tight lateral retinaculum on tilt testing. 2,18,19 Isolated lateral release is contraindicated for patellar

A tight lateral retinaculum is confirmed on patellar tilt testing once the patient is under anesthesia. 20 Patellar tilt and areas of chondromalacia are also visually assessed and

lateral retinaculum.

**4.2 Lateral release** 

instability. 19,20,21

documented arthroscopically.

intravenous analgesics. Early, aggressive physical therapy is begun on the first postoperative day. A continuous passive motion machine is used and is alternated in cycles with extension splinting. Patients are advanced to weight bearing as tolerated and weaned from crutches when they are able to ambulate pain free. Patients are also placed on deep venous thrombosis prophylaxis for two weeks. At discharge, patients continue with outpatient physical therapy and nighttime extension splinting for at least 6 weeks.

#### **3.3 Results**

Laprade et al 12 reported the results of isolated arthroscopic posteromedial release in 15 patients with an average follow-up of 24 months. Preoperative knee extension averaged 15o and significantly improved to 0.7o at the final follow-up.

Mariani 13 reported the results of arthroscopic posterior capsular release in 18 patients. Extension deficits averaged 34o preoperatively and improved to 3o at final one year followup. Patients with more severe pre-operative flexion contractures need more aggressive releases of *both* the posteromedial and posterolateral capsule and possibly partial release of the gastrocnemius tendon if the results are not adequate.

#### **4. Lateral retinacular release**

#### **4.1 History and physical examination**

The patellofemoral joint is an intrinsically unstable articulation, stabilized dynamically by the vastus medialis obliqus (VMO) and statically by the medial patellofemoral ligament and lateral retinaculum. 14, 15, 16 Imbalance may arise because of weakness in the VMO or tightness from the lateral retinaculum. Axial alignment and bony morphology of the patellofemoral joint may also contribute to this imbalance.

Evaluation of anterior knee pain begins with a history of aggravating factors such as inclined ambulation, squatting, prolonged sitting, or going up and down stairs. If present, patellar instability needs to be identified, as this can affect surgical decision making.

Physical examination begins with inspection of patellar glide, or excursion, which should be examined in all directions. 17 The VMO can be inspected for atrophy or weakness, and the medial and lateral patellar facets should be palpated for tenderness. Patellar tilt should be carefully assessed. 17 The inability to elevate the lateral aspect of the patella to neutral with the knee in full extension and the patella centered in the trochlea indicates a tight lateral retinaculum and possible over-constraint of the patellar mechanism (Figure 5). A patellar apprehension test should also be performed to evaluate for instability at 30 of flexion.

Radiographic evaluation consists of standard weight bearing AP and lateral radiographs of the knee, as well as an axial view of the patellofemoral joint in 30o or 45o of flexion. Patellar tilt and subluxation, as well as trochlear and patellar bony morphology can be evaluated on the axial view. MRIs are not routinely indicated for isolated patellofemoral pathology unless the articular surface warrants evaluation or there is history of patellar instability.

Initial, non-operative treatment generally begins with physical therapy. Specific therapy is aimed at strengthening of the hip external rotators and abductors, VMO and core musculature, as well as patellar mobilization. Patellar taping using the McConnell method may also be beneficial. 18 Surgical intervention is only indicated after failure of nonoperative management.

intravenous analgesics. Early, aggressive physical therapy is begun on the first postoperative day. A continuous passive motion machine is used and is alternated in cycles with extension splinting. Patients are advanced to weight bearing as tolerated and weaned from crutches when they are able to ambulate pain free. Patients are also placed on deep venous thrombosis prophylaxis for two weeks. At discharge, patients continue with

Laprade et al 12 reported the results of isolated arthroscopic posteromedial release in 15 patients with an average follow-up of 24 months. Preoperative knee extension averaged 15o

Mariani 13 reported the results of arthroscopic posterior capsular release in 18 patients. Extension deficits averaged 34o preoperatively and improved to 3o at final one year followup. Patients with more severe pre-operative flexion contractures need more aggressive releases of *both* the posteromedial and posterolateral capsule and possibly partial release of

The patellofemoral joint is an intrinsically unstable articulation, stabilized dynamically by the vastus medialis obliqus (VMO) and statically by the medial patellofemoral ligament and lateral retinaculum. 14, 15, 16 Imbalance may arise because of weakness in the VMO or tightness from the lateral retinaculum. Axial alignment and bony morphology of the

Evaluation of anterior knee pain begins with a history of aggravating factors such as inclined ambulation, squatting, prolonged sitting, or going up and down stairs. If present,

Physical examination begins with inspection of patellar glide, or excursion, which should be examined in all directions. 17 The VMO can be inspected for atrophy or weakness, and the medial and lateral patellar facets should be palpated for tenderness. Patellar tilt should be carefully assessed. 17 The inability to elevate the lateral aspect of the patella to neutral with the knee in full extension and the patella centered in the trochlea indicates a tight lateral retinaculum and possible over-constraint of the patellar mechanism (Figure 5). A patellar apprehension test should also be performed to evaluate for instability at 30 of flexion. Radiographic evaluation consists of standard weight bearing AP and lateral radiographs of the knee, as well as an axial view of the patellofemoral joint in 30o or 45o of flexion. Patellar tilt and subluxation, as well as trochlear and patellar bony morphology can be evaluated on the axial view. MRIs are not routinely indicated for isolated patellofemoral pathology unless

patellar instability needs to be identified, as this can affect surgical decision making.

the articular surface warrants evaluation or there is history of patellar instability.

Initial, non-operative treatment generally begins with physical therapy. Specific therapy is aimed at strengthening of the hip external rotators and abductors, VMO and core musculature, as well as patellar mobilization. Patellar taping using the McConnell method may also be beneficial. 18 Surgical intervention is only indicated after failure of non-

outpatient physical therapy and nighttime extension splinting for at least 6 weeks.

and significantly improved to 0.7o at the final follow-up.

the gastrocnemius tendon if the results are not adequate.

patellofemoral joint may also contribute to this imbalance.

**4. Lateral retinacular release** 

operative management.

**4.1 History and physical examination** 

**3.3 Results** 

Fig. 5. Patellar tilt test. The patella is centralized in the femoral trochlea with the knee in full extension. The medial and lateral aspect of the patella is stabilized and the lateral aspect is elevated. Inability to elevate the lateral aspect of the patellar to neutral indicates a tight lateral retinaculum.

#### **4.2 Lateral release**

Lateral release is indicated in patients who have failed physical therapy and have increased lateral facet pressure demonstrated either radiographically or clinically with a tight lateral retinaculum on tilt testing. 2,18,19 Isolated lateral release is contraindicated for patellar instability. 19,20,21

A tight lateral retinaculum is confirmed on patellar tilt testing once the patient is under anesthesia. 20 Patellar tilt and areas of chondromalacia are also visually assessed and documented arthroscopically.

Arthroscopic Soft Tissue Releases of the Knee 267

A systematic evaluation as described by Kim, et al. allows for assessment and treatment of intra-articular sources of motion loss. 30 Capsular distension before arthroscopy is useful, as it re-establishes effective joint space, allows easier and safer insertion of instruments, enhances visualization, and may disrupt intra-articular adhesions. 31 Injection of sterile saline should be performed slowly to allow for capsular stretching and to avoid rupture of

Intra-articular volume capacity can be assessed by injecting the knee with 60cc's of sterile saline. 29,31 After injection, the 18 gauge needle is disconnected from the syringe. If the saline drips out of the needle, the capsule is under little tension and the intra-articular volume is considered normal (Figure 6B). If, however, the saline is expressed from the joint in a stream (Figure 6A), the capsule is under significant pressure indicating insufficient volume. The knee

Fig. 6. Assessment of intra-articular volume. The preoperative knee is injected with 60mL of sterile saline. A, Rapid outflow suggests insufficient intra-articular volume. B, Slow egress

the capsule, preventing extravasation of fluid during arthroscopy. 29,31

should then be evaluated for stuctures known to reduce interarticular volume. 29

**5.2 Arthroscopic lysis of adhesions** 

(drip) indicates normal volume.

Modern lateral releases are generally performed using an arthroscopic electrothermal probe to aid in hemostasis, since hemarthrosis is the most common complication of this procedure. 23 The anterolateral portal is often used as the working portal and the anteromedial portal as the viewing portal. Placement of the electrothermal probe through a superior portal is possible, but usually unnecessary. The lateral release is performed approximately 1cm posterior to the lateral border of the patella to avoid devascularization. A complete release begins at the level of the proximal pole of the patella and is continued distally to the level of the distal pole. Modified releases begin distal to the vastus lateralis insertion on the patella and are continued distally only far enough to achieve a neutral tilt test. The release is performed in layers to prevent over-release.

Complications of lateral releases are common, especially with excessive release, which continues beyond the fat and muscle layers or disrupts the vastus lateralis tendon insertion. Over-release can result in wound complications or medial patellar instability. Hemarthrosis is the most common complication; therefore meticulous hemostasis is required due to the proximity of the geniculate arteries. 23

Weight-bearing is generally limited for several days to decrease the incidence of hemorrhage and inflammation. Bracing after lateral release is not routinely used. Patellar mobilization is begun immediately after surgery in physical therapy, followed by quadriceps strengthening.
