JAAOS

JAAOS, Volume 21, No. 1


Adjacent Segment Disease Following Cervical Spine Surgery

Cervical spine surgery is broadly divided into fusion and nonfusion procedures. Anterior cervical diskectomy and fusion (ACDF) is a common procedure, although adjacent segment disease following the surgery is an ongoing clinical concern. Adjacent segment cervical disease occurs in approximately 3% of patients per year, with an expected incidence of 25% within the first 10 years following fusion. Nonfusion procedures such as anterior diskectomy and posterior foraminotomy do not decrease the rate of adjacent segment disease compared with ACDF. Recently, enthusiasm has developed for artificial disk replacement as a motion-sparing alternative to fusion. To date, however, multiple clinical trials and subsequent follow-up studies have failed to demonstrate significant reduction of adjacent segment disease when artificial disk replacement is performed instead of fusion.

      • Subspecialty:
      • Spine

    Anterior Cruciate Ligament Rupture: Differences Between Males and Females

    The rate of anterior cruciate ligament (ACL) rupture is three times higher in female athletes than in male athletes. Intrinsic factors such as increased quadriceps angle and increased posterior tibial slope may predispose girls and women to ACL injury. Compared with males, females have smaller notch widths and smaller ACL cross-sectional area; however, no conclusive correlation between ACL size and notch dimension exists, especially in relation to risk of ACL injury. Female athletes who land with the knees in inadequate flexion and in greater-than-normal valgus and external rotation are at increased risk of ACL injury. No conclusive link has been made between ACL injury and the menstrual cycle. Neuromuscular intervention protocols have been shown to reduce the rate of injury in girls and women. Females are more likely than males to have a narrow A-shaped intercondylar notch, and special surgical considerations are required in such cases. Following ACL reconstruction, female athletes are more likely than male athletes to rupture the contralateral ACL; however, males and females are equally likely to rupture the reconstructed knee. Although self-reported outcomes in the first 2 years following reconstruction are worse for females than for males, longer-term studies demonstrate no difference between males and females.

        • Subspecialty:
        • Sports Medicine

      Bone Graft and Bone Graft Substitutes in Spine Surgery: Current Concepts and Controversies

      Iliac crest bone graft has long been the standard adjunct used in spine fusion surgery. This graft provides osteogenic, osteoinductive, and osteoconductive elements that aid in creation of a fusion mass. However, morbidity associated with bone graft harvest has led surgeons to seek other potential adjuncts, including bone morphogenetic proteins, demineralized bone matrix, and graft expanders such as synthetic bone graft and allograft. Knowledge of fusion biology is required to understand the benefits and limitations of these agents, which promote fusion via one of four mechanisms: osteogenesis, osteoinduction, osteoconduction, and osteopromotion. Although bone morphogenetic proteins have shown a clear ability to aid in bone formation and successful fusion, recent concern regarding their safety has tempered enthusiasm regarding their use.

          • Subspecialty:
          • Spine

        Mucopolysaccharide Disorders in Orthopaedic Surgery

        The mucopolysaccharidoses (MPSs) are a family of disorders characterized by the accumulation of glycosaminoglycans, which is caused by enzyme deficiencies in the lysosomal metabolism of these normal cellular byproducts. Skeletal abnormalities are early and prominent features of MPS, and the orthopaedic surgeon is often the first healthcare provider to raise suspicion for this diagnosis. Recently developed medical therapies for the management of MPS (ie, hematopoietic stem cell transplantation, intravenous enzyme replacement therapy) have led to increased lifespan but have not had much effect on the development of skeletal deformities. Patients must be monitored carefully and treated surgically as necessary. Conditions that may require surgical management include cervical spine and atlantoaxial instability, gibbus deformity, hip dysplasia and osteonecrosis, genu valgum, and carpal tunnel syndrome. The orthopaedic surgeon should have a basic understanding of MPS and of the clinical presentation, musculoskeletal abnormalities, and radiographic findings associated with this group of disorders.

            • Subspecialty:
            • Pediatric Orthopaedics

          Posterior Malleolus Fracture

          Posterior malleolus fractures are a common component of ankle fractures. The morphology is variable; these fractures range from small posterolateral avulsion injuries to large displaced fracture fragments. The integrity of the posterior malleolus and its ligamentous attachment is important for tibiotalar load transfer, posterior talar stability, and rotatory ankle stability. Fixation of posterior malleolus fractures in the setting of rotational ankle injuries has certain benefits, such as restoring articular congruity and rotatory ankle stability, as well as preventing posterior talar translation, but current indications are unclear. Fragment size as a percentage of the anteroposterior dimension of the articular surface is often cited as an indication for fixation, although several factors may contribute to the decision, such as articular impaction, comminution, and syndesmotic stability. Outcome studies show that, in patients with ankle fractures, the presence of a posterior malleolus fracture negatively affects prognosis. Notable variability is evident in surgeon practice.

              • Subspecialty:
              • Trauma

              • Foot and Ankle

            Soft-tissue Management in Revision Total Shoulder Arthroplasty

            Revision total shoulder arthroplasty can be technically challenging. Results are inferior to those of primary arthroplasty, particularly when the indications for revision are related to soft-tissue problems. Patient selection is important. In the stiff arthroplasty, the surgeon must address rotator cuff and capsular contractures as well as exuberant soft-tissue adhesions. Unstable arthroplasty can be the result of asymmetric soft-tissue balancing or deficiencies (eg, subscapularis deficiency) that can lead to loss of the rotator cuff force couples and, subsequently, to instability on attempted glenohumeral motion. Infection must be considered in the workup of the failed total shoulder. In this era of ever-increasing use of shoulder arthroplasty, surgeons will be presented with growing numbers of patients who require revision surgery. An organized approach is needed to diagnose and manage the stiff or unstable total shoulder arthroplasty.

                • Subspecialty:
                • Shoulder and Elbow

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