Simon Lee1, Thomas H Wuerz1, Elizabeth Shewman1, Frank M McCormick2, Michael J Salata3, Marc J Philippon4, Shane J Nho5. 1. Rush University Medical Center, Chicago, Illinois, USA. 2. Holy Cross Orthopedic Institute, Ft Lauderdale, Florida, USA. 3. Case Western University, Cleveland, Ohio, USA. 4. The Steadman Clinic and Steadman Philippon Research Institute, Vail, Colorado, USA. 5. Rush University Medical Center, Chicago, Illinois, USA Shane.nho@rushortho.com.
Abstract
BACKGROUND: Labral reconstruction using iliotibial band (ITB) autografts and semitendinosus (Semi-T) allografts has recently been described in cases of labral deficiency. PURPOSE/HYPOTHESIS: To characterize the joint biomechanics with a labrum-intact, labrum-deficient, and labrum-reconstructed acetabulum in a hip cadaveric model. The hypothesis was that labral resection would decrease contact area, increase contact pressure, and increase peak force, while subsequent labral reconstruction with ITB autografts or Semi-T allografts would restore these values toward the native intact labral state. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen human cadaveric hips were analyzed utilizing thin-film piezoresistive load sensors to measure contact area, contact pressure, and peak force (1) with the native intact labrum, (2) after segmental labral resection, and (3) after graft labral reconstruction with either ITB autografts or Semi-T allografts. Each specimen was examined at 20° of extension and 60° of flexion. Statistical analysis was conducted through 1-way analysis of variance with post hoc Games-Howell tests. RESULTS: For the ITB group, labral resection significantly decreased contact area (at 20°: 73.2%±5.38%, P=.0010; at 60°: 78.5%±6.93%, P=.0063) and increased contact pressure (at 20°: 106.7%±4.15%, P=.0387; at 60°: 103.9%±1.15%, P=.0428). In addition, ITB reconstruction improved contact area (at 20°: 87.2%±12.3%, P=.0130; at 60°: 90.5%±8.81%, P=.0079) and contact pressure (at 20°: 98.5%±5.71%, P=.0476; at 60°: 96.6%±1.13%, P=.0056) from the resected state. Contact pressure at 60° of flexion was significantly lower compared with the native labrum (P=.0420). For the Semi-T group, labral resection significantly decreased contact area (at 20°: 68.1%±12.57%, P=.0002; at 60°: 67.5%±6.70%, P=.0002) and increased contact pressure (at 20°: 105.3%±3.73%, P=.0304; at 60°: 106.8%±4.04%, P=.0231). Semi-T reconstruction improved contact area (at 20°: 87.9%±7.95%, P=.0087; at 60°: 92.9%±13.2%, P=.0014) and contact pressure (at 20°: 97.1%±3.18%, P=.0017; at 60°: 97.4%±4.39%, P=.0027) from the resected state. Comparative analysis demonstrated no statistically significant differences between either graft reconstruction in relation to contact area, contact pressure, or peak force. CONCLUSION: Segmental anterosuperior labral resection results in significantly decreased contact areas and increased contact pressures, while labral reconstruction partially restores time-zero acetabular contact areas and pressures as compared with the resected state. Although labral reconstruction improved the measured biomechanical properties as compared with the resected state, some of these properties remained significantly different compared with the native intact labrum. CLINICAL RELEVANCE: Labral reconstruction appears to improve femoroacetabular joint biomechanics as compared with the labrum-resected state; these improved biomechanics may translate into increased joint function clinically.
BACKGROUND: Labral reconstruction using iliotibial band (ITB) autografts and semitendinosus (Semi-T) allografts has recently been described in cases of labral deficiency. PURPOSE/HYPOTHESIS: To characterize the joint biomechanics with a labrum-intact, labrum-deficient, and labrum-reconstructed acetabulum in a hip cadaveric model. The hypothesis was that labral resection would decrease contact area, increase contact pressure, and increase peak force, while subsequent labral reconstruction with ITB autografts or Semi-T allografts would restore these values toward the native intact labral state. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen human cadaveric hips were analyzed utilizing thin-film piezoresistive load sensors to measure contact area, contact pressure, and peak force (1) with the native intact labrum, (2) after segmental labral resection, and (3) after graft labral reconstruction with either ITB autografts or Semi-T allografts. Each specimen was examined at 20° of extension and 60° of flexion. Statistical analysis was conducted through 1-way analysis of variance with post hoc Games-Howell tests. RESULTS: For the ITB group, labral resection significantly decreased contact area (at 20°: 73.2%±5.38%, P=.0010; at 60°: 78.5%±6.93%, P=.0063) and increased contact pressure (at 20°: 106.7%±4.15%, P=.0387; at 60°: 103.9%±1.15%, P=.0428). In addition, ITB reconstruction improved contact area (at 20°: 87.2%±12.3%, P=.0130; at 60°: 90.5%±8.81%, P=.0079) and contact pressure (at 20°: 98.5%±5.71%, P=.0476; at 60°: 96.6%±1.13%, P=.0056) from the resected state. Contact pressure at 60° of flexion was significantly lower compared with the native labrum (P=.0420). For the Semi-T group, labral resection significantly decreased contact area (at 20°: 68.1%±12.57%, P=.0002; at 60°: 67.5%±6.70%, P=.0002) and increased contact pressure (at 20°: 105.3%±3.73%, P=.0304; at 60°: 106.8%±4.04%, P=.0231). Semi-T reconstruction improved contact area (at 20°: 87.9%±7.95%, P=.0087; at 60°: 92.9%±13.2%, P=.0014) and contact pressure (at 20°: 97.1%±3.18%, P=.0017; at 60°: 97.4%±4.39%, P=.0027) from the resected state. Comparative analysis demonstrated no statistically significant differences between either graft reconstruction in relation to contact area, contact pressure, or peak force. CONCLUSION: Segmental anterosuperior labral resection results in significantly decreased contact areas and increased contact pressures, while labral reconstruction partially restores time-zero acetabular contact areas and pressures as compared with the resected state. Although labral reconstruction improved the measured biomechanical properties as compared with the resected state, some of these properties remained significantly different compared with the native intact labrum. CLINICAL RELEVANCE: Labral reconstruction appears to improve femoroacetabular joint biomechanics as compared with the labrum-resected state; these improved biomechanics may translate into increased joint function clinically.
Authors: C Signorelli; T Bonanzinga; N Lopomo; S Zaffagnini; M Marcacci; M Safran Journal: Knee Surg Sports Traumatol Arthrosc Date: 2015-11-14 Impact factor: 4.342
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