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Contains fulltext : 183948.pdf (publisher's version ) (Open Access)

Contains fulltext : 183948.pdf (publisher's version ) (Open Access)

PURPOSE: Anterior cruciate ligament (ACL) rupture is increasingly common in adolescents. Time between ACL rupture and surgical reconstruction, surgical wait time, is related to concurrent meniscal tear incidence and possibly tear pattern. This study defines the relationship between meniscal tear characteristics and surgical wait time in adolescents with ACL rupture. METHODS: One-hundred and twenty-one consecutive adolescent (median age 16.1 years, range 9-19 years) ACL rupture patients undergoing primary ACL reconstruction were studied. All had documented surgical wait time, preoperative and 6-month post-operative outcome (Lysholm and pedi-IKDC) scores, and intraoperative meniscus tear characteristics. Meniscal tear severity was graded according to the Lawrence and Anderson system: non-surgical: grade 1; reparable: grade 2-3; irreparable: grade 4-5. Significant tears were defined as at least grade 2. RESULTS: Average age at surgery was 16.1 years. 48.7 % had surgical wait time greater than 6 months. 42.5 % of menisci were torn. With surgical wait time <6 months, there were more lateral than medial tears (48 vs 21 %, p = 0.001). With surgical wait time >6 months, medial tear incidence increased (50 vs 21 %, p < 0.001), there were more significant tears (63 vs 42 %, OR 2.3, p = 0.02), and preoperative Lysholm and pedi-IKDC scores were lower (58 vs 74, p < 0.001; 52 vs 61, p < 0.007). Scores were lower in patients with meniscus tears (63.8 vs 69.3, n.s.; 53.9 vs 60.5, p = .04). Patients with public insurance had risks of surgical wait time greater than 3 months (OR 12.4, p < 0.001) and 6 months (OR 7.8, p < 0.001), and of a significant meniscus tear (OR 2.5, p = 0.03). Six-month post-operative pedi-IKDC scores improved more in meniscus tear patients (28.4 vs 21, p = 0.05). CONCLUSIONS

We perform site-specific diagnostic evaluation of hard biological tissues via highly nonlinear solitary waves. Solitary waves are compact-supported tunable pulses with extremely high energy density, which can be efficiently formed in a chain of ordered granular particles defined as 1D granular crystals. We transmit a single pulse of solitary waves into specific areas of artificial biological systems via direct mechanical contact with a granular crystal sensor. We then record the solitary waves backscattered from a targeted bone area to assess its mechanical stiffness. By taking advantage of the coupling between nonlinear granular media and biological systems, we demonstrate that reflected solitary waves are highly sensitive to site-specific mechanical properties of hard biological tissues. The efficacy of the diagnostic approach is investigated by comparing the stiffness measurements with nominal elastic moduli of polyurethane foams that mimic osteoporotic bone. We also perform numerical investigations via a discrete element (DE) model, simulating propagation and attenuation of solitary waves at the interfaces. The site-specific evaluation technique via solitary waves has the potential for clinical applications, such as assisting appropriate intraoperative decision during joint replacement or spinal surgery for better surgical outcome.

Pseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity. We therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes. Tissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups. The tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group. Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrit

Pseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity. We therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes. Tissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups. The tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group. Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrit