Defining a Safe Zone for All-Inside Lateral Meniscal Repairs in Pediatric Patients: A Magnetic Resonance Imaging Study.

PURPOSE: To establish a safe zone for all-inside meniscal fixation in pediatric patients by use of magnetic resonance imaging (MRI) measurements between the popliteal tendon (PT) and popliteal neurovascular bundle (PNVB). METHODS: Patients aged 5 to 16 years with normal or nearly normal knee MRI scans were included. They were grouped by age: group I, 5 to 7 years (n = 61); group II, 8 to 10 years (n = 59); group III, 11 to 13 years (n = 60); and group IV, 14 to 16 years (n = 70). At the level of the lateral meniscus, 2 lines starting at the lateral patellar tendon border and ending at the medial edge of the PT (D1) and the lateral edge of the PNVB (D2) were made on an axial knee MRI scan. A third line (D3) connected D1 to D2 at the meniscocapsular junction of the posterior horn of the lateral meniscus (PHLM). A fourth line (D4), derived geometrically, was parallel and 8 mm anterior to D3, simulating the anterior edge of the PHLM. RESULTS: Axial MRI scans of 250 pediatric patients (aged 5-16 years) were retrospectively reviewed. Analysis showed significant correlation between age and sex for D3 (P < .0001). For D3, there were significant differences among all age groups, except between groups III and IV. The average D3 by age group was 14.1 mm (standard deviation [SD], 3.1 mm) for group I, 15.8 mm (SD, 2.5 mm) for group II, 17.0 mm (SD, 3.3 mm) for group III, and 17.2 mm (SD, 3.1 mm) for group IV. The average D4 was 11.39 mm (SD, 2.6 mm), 13.24 mm (SD, 2.24 mm), 14.59 mm (SD, 2.89 mm), and 14.80 mm (SD, 2.79 mm), respectively. There were significant differences in D3 and D4 in male versus female patients (17.6 mm vs 15.7 mm, P < .001, and 14.9 mm vs 13.2 mm, P < .001, respectively), particularly in groups III and IV (17.0 mm vs 13.8 mm and 16.8 mm vs 13.9 mm, respectively). CONCLUSIONS: This study provides normative data of the distance between the PNVB and PT at the meniscocapsular junction (D3) and anterior edge of the PHLM (D4) with the knee in full extension. Combined with previous studies showing that the addition of knee flexion increases the distance between the meniscus and the neurovascular bundle, these data can be used by surgeons to improve the safety of PHLM repair in pediatric patients. LEVEL OF EVIDENCE: Level III, diagnostic study of nonconsecutive patients.

Prospective Study of Acute Opioid Use After Adolescent Anterior Cruciate Ligament Reconstruction Shows No Effect From Patient- or Surgical-Related Factors.

INTRODUCTION: Patient-reported pain scores and opioid use have not been quantified after outpatient adolescent anterior cruciate ligament reconstruction (ACLR). METHODS: Patients aged 12 to 18 years undergoing primary isolated ACLR, with or without meniscal treatment, were prospectively recruited. Patients actively taking opioids or with previous extended use of opioids were excluded. Two orthopaedic surgeons performed ACLR and determined the use of a hamstring or bone-patellar tendon-bone autograft. For postoperative pain management, patients were prescribed 40 tablets of hydrocodone/acetaminophen 5/325 mg. Patients were instructed to document daily pill consumption and side effects through a daily log for 6 weeks. Patients completed the American Pain Society Patient Outcome Questionnaire at the end of weeks 1 and 6. RESULTS: One hundred three patients were enrolled, with age: 12.5 to 18.9 years (mean 16.2 y ± 1.3), weight: 41.3 to 113.6 kg (mean 72.4 kg ± 17.2), and body mass index: 17.8 to 40.1 (mean 25.9 ± 4.9). Sixty-nine patients received a hamstring autograft, and 34 received a bone-patellar tendon-bone autograft. Fifty-six received additional meniscal procedures. The median number of postoperative opioids taken by patients was 17 (range 0 to 40). No notable differences were found in total pill consumption with regard to age, weight, body mass index, sex, block type, autograft type, or meniscal treatment at 1 week post-op or 6 weeks post-op. No correlation was found between the self-reported "worst pain in the past 24 hours" at the end of the first postoperative week or after 6 weeks (r = 0.112, P = 0.26, and r = 0.093, P = 0.36). No correlation was found between the level of satisfaction with pain treatment and total number of pills taken during the first postoperative week or at the end of 6 weeks (r = -0.090, P = 0.37, and r = -0.172, P = 0.08). CONCLUSION: Patients take most pain medication during the first postoperative week after adolescent ACLR, although patient and surgical variables had no notable influence on pill consumption. LEVEL OF EVIDENCE: Level IV, case series.