Small versus large diameter closed-section femoral nails for the treatment of femoral shaft fractures: is there a difference?

Effect of Nail Size, Insertion, and Δ Canal-Nail on the Development of a Nonunion After Intramedullary Nailing of Femoral Shaft Fractures

OBJECTIVE

To determine whether intramedullary nail (IMN) diameter, antegrade versus retrograde insertion, or the difference between the canal and IMN diameter affect femoral shaft fracture healing.

DESIGN

Retrospective analysis of a prospective database.

SETTING

Level One Regional Trauma Center.

PATIENTS/PARTICIPANTS

Seven hundred thirty-three femoral shaft fractures (OTA/AO 32) treated with an IMN between 1999 and 2017. After exclusion criteria, 484 fractures remained in the final analysis.

INTERVENTION

Closed section, cannulated, interlocked, titanium alloy IMN using a reamed insertion technique.

MAIN OUTCOME MEASUREMENTS

Nonunion, IMN size (10, 11.5, and 13 mm), antegrade versus retrograde insertion, Δ canal-nail diameter (ΔD) after reaming (<1, 1-2, or >2 mm).

RESULTS

IMN diameters used were as follows: 314/10 mm (64%), 137/11.5 mm (28%), and 33/13 mm (8%). Forty-five percent were placed in antegrade versus 55% retrograde. Four hundred fifty-six fractures (94.2%) healed uneventfully. There were no IMN failures. 10/484 IMNs (2%) had broken interlocking screws; only 4 were associated with a NU. Average time to union was 23 weeks (12-119). Twenty-eight (5.8%) developed NU. There was no statistical correlation between (1) the NU rate and IMN diameter: 10 mm, 6.3%; 11.5 mm, 5.1%; 13 mm, 3% (P = 0.8, power = 0.85), (2) the NU rate and ΔD: 7.1% <1 mm, 5.6% 1-2 mm, 20% >2 mm (P = 0.36), (3) the NU rate and fracture location: Prox = 11%, Mid = 5%, Dist = 3% (P = 0.13), or (4) the NU rate and antegrade (7.2%) versus retrograde (4.2%) insertion (P = 0.24).

CONCLUSION

Similar healing rates occurred regardless of IMN diameter, Δ canal-nail diameter after reaming, or insertion site. This indicates that a closed section, cannulated, interlocked, titanium alloy IMN with a diameter of 10 mm can be considered the standard diameter for the treatment of acute femoral shaft fractures, regardless of entry point. This should be associated with less reaming and therefore shorter operative times, and possibly less hospital implant inventories as well. Larger diameter IMN should be reserved for revision surgery.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Intramedullary nailing: evolutions of femoral intramedullary nailing: first to fourth generations

Intramedullary femoral nailing is the gold standard for femoral shaft fixation but only in the past 27 years. This rapid replacement of closed traction and cast techniques in North America was a controversial and contentious evolution in surgery. As we enter the fourth generation of implant design, capabilities, and surgical technique, it is important to understand the driving forces for this technology. These forces included changes in radiographic imaging capabilities, biomaterial design and computer-assisted manufacturing, and the recognition of the importance of mobilization of the trauma patient to avoid systemic complications and optimize functional recovery.

Unreamed femoral nailing

Sixty one femoral fractures treated with ACE unreamed titanium nail (AIM femoral nail, ACE Medical, Los Angeles, CA) were studied. Ten patients died before bony union and three were lost to follow up. Forty eight fractures were followed up for an average of 11.2 months (4-31 months). All fractures united except one in which plating and bone grafting was performed at 6 months due to failure of progression of union. The mean time to bony union was 6.2 months. There was no implant failure but one distal interlocking bolt broke at 6 weeks. No incidence of adult respiratory distress syndrome (ARDS) was observed. Malunion was seen in one patient whereas three cases had shortening of more than 2 cm. Our results show that unreamed femoral nailing using titanium nail is a safe and effective procedure for the treatment of femoral shaft fractures.

Development of small diameter intramedullary nails made from ISO 5832-9 stainless steel

BACKGROUND

In order to improve strength in small diameter intramedullary nails, a system was designed in which the implants were manufactured from 30% coldworked ISO 5832-9 stainless steel.

METHODS

Nail diameters were 9 and 10 mm for the femur, and 8 and 9 mm for the tibia. The nails were solid rods and the screws were partially threaded. Pre-clinical bending yield tests established that the 8-, 9- and 10-mm diameter rods had strengths comparable, respectively, with 10-, 12- and 14-mm diameter Grosse-Kempf nails. Forty-eight femoral and 98 tibial shaft acute fractures were treated with this system. Postoperatively, patients were allowed to gently bear weight as tolerated.

RESULTS

There was one broken nail, occurring 10 months after femoral nailing. There were six broken screws, occurring between 3 and 6 months postoperatively in two patients and after more than 6 months in four patients. The broken screws had no adverse clinical effect. Five patients required late bone grafting or exchange nailing, and 15 patients required dynamization.

CONCLUSION

This design of small diameter locked intramedullary nails was strong enough to allow early weightbearing.

[From fat emboli to fat embolism syndrome]

The occurrence of a fat embolism syndrome (FES) can be explained by two hypothetic mechanisms. In the mechanical hypothesis, bone marrow enters into the cardiovascular system during an intramedullary peak pressure. This peak could occur during either long bone fracture and/or intramedullary nailing or cemented or noncemented arthroplasty. According to the biochemical hypothesis, the FES could occur in nontraumatic conditions such as lipid emulsion infusion or sickle cell disease. The C-reactive protein is a possible factor for destabilizing plasma fat (chylomicrons or Intralipid liposomes). Treatment with heparin has been reported to interfere with lipid metabolism through a "creaming" phenomenon. Plasma fatty acids increase lipid peroxidation, with potential severe oxidative stress of lung. Vascular lung injury is increased by granulocytes and the clotting cascade is activated by neutral fat. After a symptom-free period, the full clinical picture is characterized by pulmonary insufficiency with hypoxaemia, neurological impairment, pyrexia and petechial haemorrhages. The accurate incidence cannot be assessed as many subclinical forms remain unrecognized. Transoesophageal echocardiography with color-flow Doppler allows considerable insight into the sequence of embolic events and patent foramen ovale (PFO). A PFO induces an increase in right-to-left shunt in case of an elevated intrapulmonary pressure. PFO might elicit systemic manifestations of the FES, particularly with neurological impairment. Carotid ultrasonography helps to visualize embolism. Magnetic resonance imaging of cerebral fat emboli is a better diagnostic tool for detecting brain embolism than computerized tomography. Quantification of cells containing fat droplets in bronchoalveolar lavage material could also be helpful. Pulmonary microvascular cytology analysis of capillary blood samples obtained through a pulmonary artery catheter in combination with blood gas changes are of value for earlier stage FES. Prophylactic and therapeutic measures are aimed to counteract the various mechanisms leading to FES. The decrease in time delay of fracture management is probably the most effective prophylactic means. A reaming procedure can be noxious, particularly in a patient with a severe thoracic trauma. The insertion without reaming of a small diameter nail, plating or external fixation have several advantages. Albumin infusion is recommended for restoration of blood volume and binding of fatty acids. Among pharmacologic measures, only corticosteroids have a proven benefit, not only for prophylaxis but also for therapy. Aprotinin and heparin are beneficial in counteracting blood cell aggregation. A prophylactic use of vena cava filters has been advocated. Prevention or early treatment of hypovolaemia and hypoxaemia are essential.

Thoracic trauma and early intramedullary nailing of femur fractures: are we doing harm?

INTRODUCTION

It has been reported that early intramedullary nailing (IMN) of a femur fracture in the presence of thoracic injury increases morbidity and mortality. The purpose of the present study was to determine if IMN < or = 24 hours after multisystem injury (Injury Severity Score (ISS) > 16) is associated with a poor hospital outcome in the presence of blunt thoracic trauma (Abbreviated Injury Scale (AIS) thorax score > or = 2).

METHODS

Retrospective cohort study at a single adult trauma center.

RESULTS

In a 6-year period, 149 blunt trauma patients had both an ISS > 16 and a femur fracture managed by IMN. These 149 patients were divided into four groups based on thoracic injury (T = AIS thorax score > or = 2; N = AIS thorax score < 2) and the timing of IMN (E = < or = 24 hours; L = > 24 hours). There were 68 TE, 57 NE, 15 TL, and 9 NL patients. The TE and NE groups were similar in age and ISS. TE and NE groups had similar durations of ventilation, critical care, hospital stay, and mortality. Furthermore, TE patients were no more likely to be intubated after IMN than NE patients. TE patients were matched with similar patients without a femur fracture and found to have similar hospital outcomes.

CONCLUSIONS

This study has not demonstrated an increased morbidity or mortality associated with early IMN in the presence of thoracic trauma.