Low Prevalence of Anterior and Posterior Cruciate Ligament Injuries in Patients With Achondroplasia.

BACKGROUND: Anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injuries and their subsequent reconstructions are common in the general population, but there has been no research regarding ACL or PCL injuries in patients with achondroplasia, the most common skeletal dysplasia. Our goals were to (1) evaluate the prevalence of ACL and PCL injuries in adolescents and adults with achondroplasia, (2) compare this prevalence with that reported for the general population, (3) determine how many patients with ACL or PCL injuries underwent ligament reconstruction as treatment, and (4) determine patient activity levels as they relate to the rate of ACL/PCL injuries and reconstructions. METHODS: We reviewed medical records of 430 patients with achondroplasia seen in the senior author's clinic from 2002 through 2014. Demographic data were reviewed, as well as any documentation of ACL or PCL injury or reconstruction. We called all 430 patients by telephone, and 148 agreed to participate in our survey, whereas 1 declined. We asked these patients about their history of ACL or PCL injury or reconstruction, as well as current and past physical activity levels. RESULTS: No ACL or PCL injuries were found on chart review. One patient reached by telephone reported an ACL injury that did not require reconstruction. This yielded a theoretical prevalence of 3/430 (0.7%). Of the 148 patients surveyed, 43 (29%) reported low physical activity, 75 (51%) reported moderate physical activity, and 26 (17%) reported high physical activity. There was no significant difference in the rate of ACL injury when stratified by physical activity level (P=0.102). CONCLUSIONS: ACL and PCL injuries and reconstructions are extremely rare in patients with achondroplasia, which cannot be completely ascribed to a low level of physical activity. One possible explanation is that patients with achondroplasia, on an average, have a more anterior tibial slope compared with those without achondroplasia, which decreases the force generated within the ACL and may protect against ACL injury. Further research is needed to explore possible causes. LEVEL OF EVIDENCE: Level IV-retrospective review.

Prevalence of Scoliosis and Thoracolumbar Kyphosis in Patients With Achondroplasia.

STUDY DESIGN: Retrospective chart review, case series. OBJECTIVES: To determine the prevalence of scoliosis and kyphosis in patients with achondroplasia. SUMMARY OF BACKGROUND DATA: There is little published research on the prevalence of scoliosis and thoracolumbar kyphosis in patients with achondroplasia. METHODS: The authors retrospectively reviewed charts of 459 patients with achondroplasia who were seen by the senior author, an orthopedic surgeon, from 1999 through 2013, at a tertiary referral center. After excluding patients who presented after spinal surgery and those who were referred for specific non-spinal issues, 326 patients were included (71%). Cobb angles were measured on lateral and posteroanterior radiographs. Scoliosis was defined as curvature on posteroanterior radiographs greater than 10°; thoracolumbar kyphosis was defined as any kyphotic curvature with an apex between T11 and L2. These data were then stratified by sex, age group (0-2, 3-12, 13-19, 20-40, and >40 years), and severity: within normal limits (≤10°), mild (>10°-25°), moderate (26°-50°), and severe (>50°). RESULTS: The study population consisted of 176 males and 150 females with a mean age of 18 years. Scoliosis was observed in 60%. Thoracolumbar kyphosis was observed in 79%, with 52% exhibiting moderate to severe curvature. CONCLUSIONS: In these patients, the rates of scoliosis and kyphosis were 60% and 79%, respectively, which are much higher than the rates reported in the literature for the general population of children. LEVEL OF EVIDENCE: Level 3 or 4.

Laminectomy in patients with achondroplasia: the impact of time to surgery on long-term function.

STUDY DESIGN: Retrospective analysis, survey. OBJECTIVE: To describe a cohort of individuals with achondroplasia undergoing thoracolumbar laminectomy and to examine if shorter time to surgery was related to improvement in long-term functional outcome. SUMMARY OF BACKGROUND DATA: Data on the long-term benefits of laminectomy are mixed for such patients. Earlier intervention may be associated with greater likelihood of long-term benefit, but quantified data are lacking. METHODS: We retrospectively studied 49 patients with achondroplasia who underwent primary laminectomy for spinal stenosis. Patients completed a questionnaire to assess symptoms, walking distance, and independence (per Modified Rankin Scale), before surgery and currently. Responses were analyzed for the likelihood of improved walking distance or Rankin level. RESULTS: Our patients had the following mean values: age, 37.7 ± 10.6 years; body mass index, 31.8 ± 5.5; symptom duration, 74.0 ± 100.1 months; preoperative symptom severity score, 2.7 ± 1.0 points; mean changes in blocks walked, +0.39 ± 2.0; and Rankin level, +0.08 ± 1.47. Patients with a time-to-surgery interval of <6 months were 7.13 times (95% confidence interval [CI], 1.39-36.66) more likely to experience improvement in walking distance and 4.00 times (95% CI, 1.05-15.21) more likely to experience Rankin level improvement than patients whose interval was >6 months. Intervals of up to 12 and 24 months were associated with increased likelihoods of 4.95 (95% CI, 1.41-17.41) and 3.43 (95% CI, 1.05-11.22), respectively, of improved walking distance compared with those with longer time-to surgery intervals, but those Rankin level improvements were not statistically significant. CONCLUSION: Time from symptom onset to surgery in patients with achondroplasia is an important predictor of long-term functional outcome. For sustained long-term postsurgical improvement, the window of opportunity might be relatively narrow. Patients with achondroplasia should seek medical advice for spinal stenotic symptoms as soon as possible.