Arthroscopic Lysis of Adhesions for the Stiff Total Knee Arthroplasty

Abstract

The management of the stiff knee after total knee arthroplasty is controversial. Manipulation under anesthesia and open lysis of adhesions are techniques that can theoretically address the fibrous scar tissue, but their efficacy has been shown to be variable. We describe the technique of arthroscopic lysis of adhesions for the stiff knee after total knee arthroplasty. The advantages of this technique include minimally invasive debridement of scar tissue within defined compartments of the knee and evaluation for the presence and treatment of focal lesions (e.g., loose bodies or impinging synovial or soft tissue). The total arc of motion can be improved with a systematic arthroscopic approach.

Arthrofibrosis of the knee can be debilitating to patients who have undergone total knee arthroplasty (TKA). It occurs in 3% to 6% of patients undergoing TKA and can be painful and disabling.¹ Excessive scarring of the joint causes dense fibrous connective tissue to build up intra-articularly, resulting in decreased range of motion.^2,3 Stiffness of the knee joint and limited flexion can interfere with walking and the patient's activities of daily living. Nonoperative treatment options include pain management, physical therapy, and manipulation under anesthesia. When these options fail, operative treatments include lysis of adhesions (open or arthroscopic), explantation of components, and revision surgery.^1,3,4

Arthroscopic lysis of adhesions is a less invasive surgical procedure that can be used to address both focal and diffuse arthrofibrosis.⁵ Adhesions typically form between the capsule and femoral condyles, as well as in the anterior interval, the infrapatellar fat pad, and the pretibial recess. The arthroscopic approach allows release of adhesions throughout the suprapatellar pouch, the intercondylar notch, and the lateral and medial gutters. Typically, sharp punch and motorized shaver instruments and a radiofrequency device are needed to debride the dense fibrous tissue. Lateral patellar retinacular release can also be performed to improve patellar tracking if patellar mobility is tight with the patellar tilt test or if the capsular closure is deemed to be too tight. (This is best examined with a 70° arthroscope in the superolateral portal). Although posterior capsular adhesions are difficult to address with the arthroscopic approach,⁶ an arthroscopic posterior cruciate ligament (PCL) recession can be performed in cruciate-retaining knees that show PCL tightness (e.g., <90° of flexion for >1 year postoperatively).⁷ Intra-articular loose bodies and focal soft-tissue lesions can also be addressed during arthroscopy.^1,4,8

Relatively few studies have been published on the surgical outcome after arthroscopic lysis of adhesions, but recent studies have shown promising results regarding improvements in patients' knee motion.^3,4,6,8,9 Studies comparing total motion regained after arthroscopic lysis compared with manipulation under anesthesia have shown modest improvement with arthroscopic intervention.^3,8

Surgical Technique

The technique is demonstrated in Video 1. After induction of general anesthesia, an examination under anesthesia is performed to document the true total arc of knee motion. Standard inferomedial, inferolateral, and superolateral arthroscopic portals are used. The inflow cannula is inserted through the superolateral portal, and the knee is maximally distended with saline solution. All instruments are inserted carefully so as not to scratch the femoral component or polyethylene insert surfaces. Optional 5-mm plastic cannulas (5 × 76–mm Universal Cannula; Smith & Nephew, Andover, MA) can be used to safely maintain the working portals if desired. The arthroscope is first introduced into the intercondylar notch from the inferolateral portal, and a shaver (e.g., 4.5-mm Incisor Plus; Smith & Nephew) or radiofrequency probe (e.g., VAPR; DePuy Mitek, Raynham, MA) is introduced through an inferomedial portal with the knee in mid flexion. First, the granulation tissue connecting the PCL and the Hoffa fat pad is removed to gain visibility of the femoral component (Fig 1). If the knee is excessively scarred, normal landmarks can be difficult to appreciate. Furthermore, the reflection off of the femoral component can make proper orientation difficult initially. The shaver is gradually swept medially and laterally to gain anterior access to the peripatellar tissue and the suprapatellar pouch. The suprapatellar pouch is cleared up to and including the deep quadriceps fascia (Fig 2). The lysis continues medially and laterally with the radiofrequency probe where the spaces within the gutters are re-established. It is often easy to appreciate the scarred layer between the capsule and femoral condyles. The anterior portals are used interchangeably for the arthroscope and instrumentation as needed for visualization and access. A lateral (or medial) retinacular release is performed to improve patellar tracking if needed. (This is best examined with a 70° arthroscope in the superolateral portal.) The infrapatellar fat pad is released and mobilized from the anterior tibia to re-establish the pretibial recess. The intercondylar notch is exposed (Fig 3). The PCL is released from its femoral origin if it was determined to be tight preoperatively in a cruciate-retaining knee arthroplasty. Inspection of the femoral component, the implant-cement-bone interface, and the polyethylene liner is performed, followed by thorough irrigation of the knee to remove any remaining free bodies and debris. Progression through the procedure must be methodical to address all accessible sites of scarring. The arthroscope is then removed, and the examination of knee motion is repeated to assess improvement. If a manipulation under anesthesia is needed, a gentle manipulation is carried out only using slight pressure on the tubercle to avoid fracture or disruption of the extensor mechanism. Routine wound closure is performed, and sterile dressings are applied. Continuous passive motion or active range of motion is initiated immediately postoperatively. The key points to arthroscopic lysis of adhesions for the stiff knee arthroplasty are summarized in Table 1.

Fig 1.

Arthroscopic view of right knee, infrapatellar pouch, with arthroscope in inferolateral portal and shaver in inferomedial portal. Granulation tissue and scar tissue are being debrided to expose the femoral component (one should note the reflection of the shaver on the femoral arthroplasty component).

Fig 2.

Arthroscopic view of right knee, suprapatellar pouch, with arthroscope in inferomedial portal and shaver in inferolateral portal. Scar tissue is debrided up to and including the deep quadriceps fascia.

Fig 3.

Arthroscopic view of right knee, intercondylar notch, with arthroscope in inferolateral portal and radiofrequency probe in inferomedial portal. Scar tissue is being debrided to expose the PCL.

Table 1.

Key Points to Arthroscopic Lysis of Adhesions for Stiff TKA

Tips

Perform pre-procedure manipulation under anesthesia with the distal fulcrum at the tibial tubercle to avoid fracture or disruption of the extensor mechanism.

Use all portals (and accessory portals) interchangeably for optimum access.

Use a plastic cannula to maintain the portals and protect the prosthetic surface from scratches.

Prescribe immediate physical therapy or continuous passive motion machine use postoperatively.

Pearls

Loss of flexion indicates scar tissue in the suprapatellar pouch, anterior interval/pretibial recess, or intercondylar notch or a tight PCL.

Loss of extension indicates a tight posterior capsule, posterior osteophytes, or PCL stump scarring (difficult to adequately treat arthroscopically).

Sharp punch and motorized shaver instruments are needed to debride the dense fibrous tissue, but one must be careful not to damage the prosthetic surfaces with the instruments.

Mirror images on the femoral component may make proper orientation difficult.

Pitfalls

Not using inflow to distend the tight capsule

Scratching the metal prosthesis or polyethylene insert

Failing to release tight scar tissue in all involved compartments

Indications

Painless stiff knee arthroplasty (<90° total arc of motion) that has not improved after 6 mo of conservative management

Focal fibrous nodules (e.g., patellar clunk)

Loose bodies

Contraindications

Complex regional pain syndrome

Arthrofibrosis due to improper implant placement

Risks

Damage to metal prosthesis or polyethylene insert

Hemarthrosis

Extensor mechanism injury

Fracture

Neurovascular injury

Discussion

The pathogenesis of arthrofibrosis is not fully understood.⁵ Various inflammatory cytokines contribute to the proliferation of fibroblasts, vascular ingrowth, production of collagen, and subsequent scarring. Risk factors include soft-tissue injury, timing of surgery, delayed postoperative rehabilitation, prolonged immobilization, infection, complex regional pain syndrome, and technical errors at surgery. Anterior interval scarring, contracture of the posterior capsule or suprapatellar pouch, and diffuse arthrofibrosis may contribute to knee stiffness. Extra-articular factors such as muscular fibrosis and contracture, heterotopic ossification, or myositis ossificans can contribute to knee stiffness.

Arthrofibrosis and stiffness after TKA often respond poorly to conventional treatment, which may include physical therapy, pain management, manipulation under anesthesia, exchange of implants, or open arthrolysis. Thus an arthroscopic approach to arthrolysis of the stiff knee is an attractive option. The advantages of arthroscopic arthrolysis include direct visualization with a less invasive approach to release adhesions within multiple knee compartments, including the suprapatellar pouch, the intercondylar notch, the pretibial recess, and the medial and lateral gutters. Furthermore, loose bodies can be identified and removed easily, and synovial or soft-tissue impinging lesions can be directly treated. The risks of an arthroscopic approach include superficial wound infection or sinus, as well as intra-articular bleeding, which may lead to persistent stiffness and pain.^5,6 Furthermore, it is very difficult to correct flexion contractures with arthroscopic techniques because of difficulty in accessing the posterior capsule. Moreover, arthroscopy cannot address stiffness due to malpositioned or loose components.

The management of the stiff knee after TKA is controversial. An algorithm for treatment is illustrated in Figure 4. The indications for arthroscopic arthrolysis can be variable. However, although arthroscopy of the prosthetic knee can be technically challenging, with a systematic approach to address all sites of fibrosis and other intra-articular lesions, arthroscopic lysis of adhesions can be effective in treating the stiff knee after arthroplasty.

Fig 4.

Algorithm for treating knee stiffness after total joint arthroplasty. (postop, postoperatively; TKR, total knee replacement.)

Supplementary Data

Video 1

A case of a stiff right knee after TKA. An examination under anesthesia confirms preoperative range of motion. Systematic arthroscopic lysis of adhesions is performed to address all accessible intra-articular sites of scarring. Postoperative motion is documented after the arthroscopic lysis.