Roger Erivan1, Pierre-Alain Matthieu2, Bertrand Boyer3, Nicolas Reina4, Michel Rhame5, René-Christopher Rouchy6, Sébastien Moreau7, Thomas Sanchez8, Olivier Roche9, Jacques Caton10, Jean-Louis Rouvillain11, Gilles Missenard12, Nassima Ramdane13, Aurélien Mulliez14, Stéphane Descamps15, Stéphane Boisgard15. 1. CNRS, SIGMA Clermont, ICCF, université Clermont Auvergne, CHU Clermont-Ferrand, 58, rue Montalembert, 63000 Clermont-Ferrand, France. Electronic address: rerivan@chu-clermontferrand.fr. 2. Département d'orthopédie-traumatologie, CHU Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France. 3. Inserm, U1059, 42270 Saint-Étienne, France; Université Saint-Étienne, 42270 Saint-Étienne, France; Service d'orthopédie, hôpital La Charité, hôpital Nord, CHU Saint-Étienne, 44, rue Pointe Cadet, 42055 Saint-Étienne, France. 4. Hôpital Pierre-Paul-Riquet, Institut Locomoteur, CHU de Toulouse, Allée Jean Dausset, 31059 Toulouse, France. 5. Department of orthopaedic surgery and traumatology, Hautepierre hospital, Strasbourg university hospitals group, 1, avenue Molière, 67098 Strasbourg, France. 6. Service de chirurgie orthopédique et de traumatologie du sport, urgences, hôpital Sud, CHU de Grenoble, 19, avenue de Kimberley, 38130 Échirolles, France. 7. Hôpital Raymond Poincaré, CHU Paris Garches, 104, boulevard Raymond Poincaré, 92380 Garches, France. 8. Chirurgie orthopédique et traumatologie du membre inférieur, CHU Lapeyronie, 371, avenue du Doyen Gaston Giraud, 34000 Montpellier, France. 9. Centre Chirurgical Emile Gallé, CHRU Nancy, 49, rue Hermite, 54000 Nancy, France. 10. Institut de chirurgie orthopédique Lyon, 103, rue Coste, 69300 Caluire-et-Cuire, France. 11. Service de chirurgie orthopédique et traumatologique, CHU La Meynard CS90632, 97261 Fort-de-France, Martinique, France. 12. Orthopaedic department, tumor and spine unit, Bicêtre university hospital, AP-HP, 78, rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France; JE 2494 université Paris-Sud Orsay, 01405 Orsay, France. 13. Unité de méthodologie - biostatistique et Data Management, CHRU de Lille, 59037 Lille, France. 14. Délégation à la recherche clinique et aux innovations (DRCI), CHU Clermont-Ferrand, 63000 Clermont-Ferrand, France. 15. CNRS, SIGMA Clermont, ICCF, université Clermont Auvergne, CHU Clermont-Ferrand, 58, rue Montalembert, 63000 Clermont-Ferrand, France.
Abstract
BACKGROUND: In the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors. HYPOTHESIS: Acetabular reconstruction can be performed equally well with frozen or processed morselized allografts. MATERIALS AND METHODS: This retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years±1.89 [5-12.32]) than that of the processed grafts (8.22 years±1.77 [5.05-15.48]) (p=0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years±14.2 [17-80]) than in the processed group (57.5 years±13.0 [12-94]) (p<0.001) and were also younger at the time of THA revision (67.8 years±12.2 [36.9-89.3] versus 70 years±11.7 [25-94.5]) (p=0.041). RESULTS: There were more complications overall in the frozen allograft group (46/242=19.0%) than the processed allograft group (35/256=13.2%) (p=0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p=0.001). Conversely, the dislocation rate (16/242=6.6% vs. 17/266=6.4%) (p=0.844) and infection rate (18/242=7.4% vs. 15/266=5.7%) (p=0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p=0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p=0.006) and a relative risk of 1.95 (95% CI: 1.26-2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23-4.70) (p=0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52-6.51) (p=0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26-8.26) (p=0.022). DISCUSSION: Our hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior. LEVEL OF EVIDENCE: III, comparative retrospective study.
BACKGROUND: In the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors. HYPOTHESIS: Acetabular reconstruction can be performed equally well with frozen or processed morselized allografts. MATERIALS AND METHODS: This retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years±1.89 [5-12.32]) than that of the processed grafts (8.22 years±1.77 [5.05-15.48]) (p=0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years±14.2 [17-80]) than in the processed group (57.5 years±13.0 [12-94]) (p<0.001) and were also younger at the time of THA revision (67.8 years±12.2 [36.9-89.3] versus 70 years±11.7 [25-94.5]) (p=0.041). RESULTS: There were more complications overall in the frozen allograft group (46/242=19.0%) than the processed allograft group (35/256=13.2%) (p=0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p=0.001). Conversely, the dislocation rate (16/242=6.6% vs. 17/266=6.4%) (p=0.844) and infection rate (18/242=7.4% vs. 15/266=5.7%) (p=0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p=0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p=0.006) and a relative risk of 1.95 (95% CI: 1.26-2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23-4.70) (p=0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52-6.51) (p=0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26-8.26) (p=0.022). DISCUSSION: Our hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior. LEVEL OF EVIDENCE: III, comparative retrospective study.