Use of morselized allografts for acetabular reconstruction during THA revision: French multicenter study of 508 cases with 8 years' average follow-up

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.

Are orthopedic surgeons exposed to excessive eye irradiation? A prospective study of lens irradiation in orthopedics and traumatology

INTRODUCTION

Numerous studies in recent years highlighted an increased risk of pathologies related to ionizing radiation in caregivers. A new French decree was adopted on June 4, 2018, dividing by 7.5 the radiation dose authorized in the lens for exposed workers.

HYPOTHESIS

The hypothesis of the present study was that ocular irradiation in orthopedic surgeons was below the new legal threshold.

METHOD

The equivalent dose (mSv) received by the lens was prospectively assessed in 10 orthopedic surgeons (5 senior, 5 residents), using 3 passive dosimeters placed at the forehead and either temple. Each intervention of each operator was recorded, with dose per area in the operating room at each use of the fluoroscope.

RESULTS

All equivalent doses to the lens at the end of the 4 month study period were well below threshold. Doses were not significantly different between forehead and either temple (p=0.7, p=0.6 for the 2 temples). There was no difference according to side of the head (p=0.3). The dose received in the lens correlated with the dose delivered in the room (p=0.004). There were no significant differences in irradiation according to the surgeon's experience (p=0.2) or trauma activity rate (p=0.4).

DISCUSSION

No studies have reported equivalent doses to the lens exceeding the authorized limit. But none previously measured equivalent dose to the lens according to the axis of irradiation in the eyes. The present study showed that orthopedic surgeons received as much eye radiation laterally as frontally. Ocular radiation protection needs therefore to be as effective laterally as frontally. The surgeon's experience did not emerge as a protective factor against ocular irradiation.