Femoral fractures in the elderly treated with an unreamed titanium nail

Injury Vol. 29, No. 4, pp. 287-291, 1998 0 1998 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0020-1383/98 $19.00 + 0.00

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PII: SOO20-1383(97)00203-9

Femoral fractures in the elderly treated with an unreamed titanium nail S. H. Zaki, S. Shamsi and M. S. Butt Department

of Trauma and Orthopaedics,

Russells Hall Hospital, West Midlands, UK

We present a review of 28 femoral fractures in 28 elderly patients treated with nn unreamed titanium inframedullary nail (AIM femoral nail, ACE medical, Figure 1). The series included 11 male and 17 female pa fienfs with an average age of 74.5 yr (rrmge 63.5-93 yr). One fracture was open and the rest, closed (six pathological). Average follow up was 6 months (range 4.5-21 months). Mean time to bony union zoos 19 weeks (k3.5). The union rate was 91 per cent with two delayed unions; one was a subfrochanferic pathological fracture and the other a diaphyseal fracfure. Shortening of 2 cm occurred in one patient and one had malrotafion. There was no implant failure in our series either with the screws or the nails. We feel that titanium unreamed intramedullary femoral nailing is an effective way of treating subtrochanferic and shaft fractures of the femur in old and frail patients. 0 1998 Elsevier Science Ltd. All rights reserved.

Injury,

Vol. 29, No. 4, 287-291,

1998

Introduction Intramedullary (IM) nailing is now a well established and standard method of treating femoral fractures. It has many theoretical and practical advantages compared with other methods: it affords predictable realignment, a ‘biological’ environment for fracture healing and early functional use of the limb’. The medulla can be reamed or unreamed. It has been argued that reaming allows increased torsional resistance owing to the increased diameter of the nail being used2,‘. Unreamed IM nailing may therefore lead to implant failure, especially in the case of nails manufactured with steel alloy when an axial load is transferred through the locked IM system before fracture consolidatior?. With the introduction of new material and improved biomechanical characteristic9, nails with smaller diameters but sufficient mechanical strength have

been

introduced.

One

of these

unreamed intramedullary nail. We began using a titanium locking Angeles,

is the titanium

alloy femoral internail (AIM femoral nail, ACE Medical, Los CA) in July 1995. Two prospective random-

(4

(b)

Figure 1. A IM femoral nail made of titanium alloy. The nail is cannuiated. Proximal locking can be done antegrade with (a) a 6.5 mm cortical screw, or (b) retrograde with a 6.5 mm cancellous screw. Distal interlocking is done with two cortical screws. The interlocking screws are also made of titanium alloy.

Injury: International Journal of the Care of the Injured Vol. 29, No. 4,199s

288 Table I. Subtrochanteric tion) n 16

fractures (Seinsheimer 2’ classifica-

Tvpe 1 Type 2 Tvpe 3 Type 4 Type 5 trials on treatment of femoral fractures in the elderly have already been published from the same centre7,X. Historically, small diameter femoral nails have suffered from increased frequency of nail breakage as well as greater incidence of fracture non-union and malunion”-“. The main purpose in this study was to determine the rate of implant failure in a group of elderly patients (mean age 74.5 yr). To date there is no study reviewing the results of titanium intramedullary unreamed nailing in this age group. ized

Materials and methods A total of 28 patients (28 fractures), 17 female and 11 male, were reviewed. The average age was 74.5 yr (range 63.5-93 yr). The average follow up was 6 months (range 4.5-21 months). The fractures included 16 subtrochanteric (4 pathological) (Table I), and 12 diaphyseal (2 pathological) (Table II). One fracture was open (Gustilo grade 2) the rest, closed. We excluded all subcapital, supracondylar and trochanteric (without subtrochanteric extension) fractures from our study. The fractures were caused by falls in 19, road traffic accidents in three and no injury (pathological) in six patients. In all cases the implant used was an unreamed titanium intramedullary femoral nail. Retrograde proximal interlocking was done in subtrochanteric fractures where medial cortical comminution or dissociation of lesser trochanter from the proximal fragment failed to provide enough purchase for the antegrade locking. standard antegrade interlocking was performed in all other fractures. The nailings were performed with the use of a fracture table with the patient supine. The diameter of the nail used was 9 mm in 21 patients and 10 mm in seven patients. Postoperatively, the patients were mobilized according to the degree of the fracture comminution. In stable fractures the patients were asked to start partial weight bearing for the initial 4-6 weeks progressing to full weight bearing as the bony union progressed. In patients with comminuted fractures an initial period of non-weight bearing for 6 weeks was followed by partial and then full weight bearing. Table II. Diaphyseal (shaft) Hansen 24classification II 12

Type 1 Type 2 Type 3 Type 4

fractures.

Winquist

and

3 4 3 2

Results Twenty two patients were followed up to full radiological and clinical union. These patients were seen at regular intervals in the clinic and their progress recorded both clinically and radiologically. Five patients died within a year of follow-up. Four out of these died within a period of 3-6 months after the operation due to multiple metastases. One patient died 8 months postoperatively: this patient has been included in the study as bony union had occurred prior to death. Two patients were lost to follow-up. In the fractures which united the average time to union was 19 weeks (k3.5). The time to union of the fracture was defined as the time from injury to full weight bearing without any pain and bridging of at least three cortices out of four on A.P. and lateral radiographs of the fracture site. Keeping in view the age group studied non-union/delayed union was defined as failure of clinical and radiological union at 26 weeks post injury. The average flexion of the hip was 90” (range 75-100) and of the knee 110” (range 80-130). There was one superficial infection which settled with antibiotics. Two patients had serous discharge from the drain site following drain removal which settled within 10 days without specific treatment. In none of the patients did comminution of the proximal fragment occur during the nailing procedure. Two patients failed to show clinical and radiological evidence of fracture union. One, a 72 yr old man with a subtrochanteric fracture underwent secondary bone grafting 24 weeks after nailing. A bone biopsy from the unhealed fracture site revealed a metastatic squamous cell carcinoma. He has been treated by local irradiation but bony union has not yet occurred. The other patient is a female of 68 whose shaft fracture had failed to unite 22 weeks after nailing. There has been no implant failure either involving the screws or the nails. Shortening of 2 cm developed in one patient. The shortening was measured clinically using a measuring tape taking the ASIS and medial malleolus as landmarks. This patient had a spiral fracture treated with an interlocking nail with just the proximal screw and no distal interlocking screw. A 20” external rotation deformity developed in one patient (Tuble II). The deformity was measured clinically, using a goniometer with the patient prone and knees flexed to 90”. This method of measuring malrotation is not very accurate but post-op CT evaluation was not clinically justifiable as no further surgery was deemed necessary. Both of the above complications were deemed to be technical errors. We report no systemic effects of IM nailing i.e. fat embolism syndrome/ARDS in our series.

Discussion All femoral fractures, not only fractures of the hip, have become more frequent owing to an increase in

Zaki et al.: Femoral fractures in the elderly

(4

289

(‘-‘I

Figure 2. (a) An 84 yr old woman fell in the street sustaining a comminuted IM nailing using the titanium unreamed nail with retrograde locking.

the elderly population I2. The pattern of fractures is different from that encountered in younger patients. These are low-velocity injuries, usually from a simple fall within the home, and result in oblique or spiral fractures, sometimes with a butterfly fragment. These patients have much to gain from internal fixation and early mobilization. To be effective however, the fixation provided has to be strong enough to allow early weight-bearing even in poor quality osteoporotic bone”. A question is whether they should be reamed or unreamed? Recent experimental and clinical studies have demonstrated that insertion of reamed large diameter femoral nails have several potentially harmful local and systemic side effects. An increase in mortality related to adult respiratory distress syndrome in patients with coincident pulmonary trauma, if reaming is carried out within the first 24 h, has been described14,‘“. Once reamed, the cortex does not regenerate. In a rat model, alterations in cortical and in total bone blood flow have been shownlh. With the advent of stiffer and stronger small diameter nails orthopaedic surgeons have been given a new tool in the armamentarium for the stabilization of femoral fractures. The smaller diameter nail reduces the potential complications of reaming17. The problem however has been the incidence of implant

subtrochanteric

fracture. (b) Seven months after

failure especially with the use unreamed IM nails made of steel alloy4,1H,‘y. IM nails of titanium alloy produce similar findings in bending tests with nails that are 4 mm smaller in diameter than first generation interlocking nails made of steel alloy 4~‘x . Laboratory fatigue testing has shown that the fatigue strength of the titanium alloy is more than twice that of cobalt chrome and four times that of stainless steel. Fatigue strength of titanium has shown to be among the highest of the implant metal alloys’“. The ideal implant material should have elasticity identical to that of bone so it will react as naturally as possible when subjected to physiological forces. The greater flexibility of titanium permits more load to be transmitted through a fractured bone during healing, thus reducing effects of stress shielding and resulting in less bone resorption than with stiffer implants. The elasticity of titanium alloy matches more closely that of bone than other implant materials4~hJX~2”. The majority (72 per cent) of the femoral fractures which we treated were in the subtrochanteric region where a combination of high stress concentration, poor cortical bone quality and comminution may induce implant failure’“. The group we followed were elderly, low demand patients in whom the physiological forces on the nail would be less than in

Injury: International Journal of the Care of the Injured Vol. 29, No. 4,1998

290

(4 Figure 3. (a) A 65 yr old male slipped titanium nail with retrograde locking.

on ice sustaining

the injury.

their younger counterparts. The bone in the elderly patients is, however, osteoporotic making the possibility of implant failure more likely. In our small series, there was no implant failure. This is in contrast to the reported failure rate of 4.7 per cent in G. K. nails”, and 3 per cent in AO/ASIF Universal Femoral nails’ and is similar to those of Kropfl et a1.2’ who had no implant failure in 81 unreamed femoral nailings. His patients were younger (av. age 36 yr) and more compliant than ours. In conducting this study we were encouraged by the use/results of titanium alloy nails and were curious to find out if they would give better results than other stiffer implants in treating fractures of femoral shaft in the elderly. Based on our study we feel that the titanium unreamed femoral nail provides enough stability for even smaller diameter nails (Y,lO mm) to be used for the IM nailing for femoral shaft fractures. They must however always be statically interlocked to maintain axial and rotational stability. The design of this nail is advantageous when dealing with femoral shaft fractures associated with ipsilateral intertrochanteric

(b) Five months

after IM nailing

using

the unreamed

and subtrochanteric fractures as the same nail can be used in the reconstruction mode (Figures 2 and 3).

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17 Boyer M. I., Ribeiro E. et al. Small versus large diameter closed-section femoral nails for the treatment of femoral shaft fractures: is there a difference? Journal of Trauma 1996; 41(2): 279-282.

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Paper

accepted

11 November

1997.

35: 709.

16 Grundness medullary

0. and Reikeras 0. Acute effects of intrareaming on bone blood flow in rats. Acta

Orthopaedica Scandinavia 1993; 64: 203.

Requests for reprints should be addressed to: Mr S. H. Zaki, Sp. Registrar Orthopaedics, Russells Hall Hospital, 55 Glen House, Dudley, DYl 2LU, West Midlands, UK.