Arthroscopic Microfracture and Chondroplasty

Published on 11/04/2015 by admin

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CHAPTER 22 Arthroscopic Microfracture and Chondroplasty

Introduction

Articular cartilage defects are one of the pathologies that are most commonly encountered during hip arthroscopy. Limited information is available regarding the best treatment of these lesions; however, microfracture has been demonstrated to be effective for the treatment of articular cartilage defects of the knee and other weight-bearing joints, and several small series and case reports have been published that have described the use of microfracture for the treatment of articular cartilage defects in the hip. Several investigators are conducting ongoing outcome studies with regard to this treatment.

There are many conditions that can cause chondral defects that necessitate microfracture and chondroplasty, and these conditions can be acute, chronic, traumatic, or atraumatic. Defects can be full or partial thickness. Acute causes include hip dislocation, hip subluxation, and direct blows to the hip. Chronic causes include labral pathology, femoral acetabular impingement, loose bodies, dysplasia of the hip, a history of slipped capital femoral epiphysis, avascular necrosis, and degenerative joint disease.

It is critical to note that the diagnosis of these lesions is often only established intraoperatively, and patients should be aware that labral pathology is often associated with articular cartilage damage. The postoperative rehabilitation process and the patient’s prognosis can be significantly different if such a lesion is discovered, and the patient and surgeon should be prepared for this possibility. A working knowledge of chondroplasty and microfracture will be helpful for any orthopedic surgeon who attempts to treat these diseases.

Brief history and physical examination

As with other musculoskeletal conditions, a careful history and physical examination are warranted. An understanding of the acuity and cause of the injury has important prognostic indications. Acute injuries (e.g., hip dislocations, subluxation events) are often associated with significant articular cartilage lesions that are sometimes asymptomatic. A direct lateral blow to the greater trochanter (e.g., a fall) can cause a medial impaction injury to the femoral head. A more gradual onset of pain or discomfort suggests a degenerative or impingement cause of the articular cartilage injury.

The location, frequency, and radiation of pain should be determined. Furthermore, alleviating or worsening symptoms or activities should be noted. Attention should be paid to any presence of mechanical symptoms (e.g., clicking, snapping, popping), because chondral defects can be associated with labral injuries. Defects associated with impingement may result in a history of pain with daily activities that involve hip flexion (e.g., prolonged sitting).

Physical examination features will be similar to those of other intra-articular pathologies, with pain usually experienced deep in the groin rather than posteriorly or laterally. The passive and active range of motion should be assessed. Specific testing for impingement symptoms should be performed, which includes the assessment of pain with combined hip flexion, internal rotation, and adduction. A loss of internal rotation with the hip flexed suggests a potential cam- or pincer-type deformity. Limited range of motion during the logrolling of the supine patient’s leg suggests either synovitis or another, more diffuse pathology (e.g., arthritis, synovial chondromatosis). Unfortunately, there is no single clinical examination that reveals the presence or absence of a chondral defect. If a specific area of the joint is suspected of being damaged, weight-bearing activity that loads the area of the defect may elicit symptoms.

Imaging and diagnostic studies

Plain radiographs may initially provide the most information. Degenerative joint disease, dysplasia, loose bodies, avascular necrosis (AVN), cam- or pincer-type impingement, and a history of slipped capital femoral epiphysis (SCFE) may be apparent on plain films. We recommend the use of a weight-bearing anteroposterior pelvic film and a frog-leg lateral view to evaluate bony morphology around the hip joint, with attention paid to the femoral head–neck offset and crossover lesions of the acetabulum in addition to the standard evaluation of loose bodies. A joint space narrowing of more than 2 mm to 3 mm is indicative of arthritis, and we would not recommend microfracture for this patient population. A pure cross-table lateral view has also been advocated by some authors to obtain additional information about the femoral head–neck offset.

Magnetic resonance imaging may be helpful to obtain a cause of the pain; however, many authors have noted that articular cartilage defects are frequently not clearly identified by the imaging sequences and resolutions that are often used (Keeney CORR 2004). Secondary signs of articular cartilage damage may be identified, such as subchondral bony cysts, bone edema (Figure 22-1), and joint effusions. High-resolution images may demonstrate distinct defects (Figure 22-2), articular cartilage thinning, or heterogeneity of the articular cartilage signal (Figure 22-3). The use of a surface coil with high-resolution, cartilage-sensitive images in the axial, coronal, and sagittal planes may provide a higher spatial resolution that could be helpful for diagnosis. Magnetic resonance arthrography improves the ability to evaluate the articular surface, but current techniques lack reliable sensitivity. In the future, the use of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) may provide additional information about the proteoglycan content of the articular cartilage.