By: 21 October 2013

With the frequency of intertrochanteric fractures, T Mahmood, S Sadiq and F Arnaout set out to assess the efficacy of intra-medullary hip screws in place of more outdated fixation methods



IMHSIntertrochanteric fractures account for approximately half of all hip fractures in the elderly, with up to 60 percent of these fractures being classified as unstable.
The management of intertrochanteric fractures is traditionally with dynamic hip screw and plate fixation. However, there has been recent emphasis on the failure rates between stable and unstable fractures, with higher failure rates reported in the unstable reverse oblique and subtrochanteric fractures primarily due to mechanical failure.1-3 The Intramedullary Hip Screw (IMHS) was designed to overcome the problems implicit in the sliding-screw fixations. We report our experience with the IMHS (Smith and Nephew) for the fixation of unstable proximal femoral fractures.


Materials and methods

A retrospective analysis was undertaken, reviewing all patients who underwent IMHS fixation for proximal femoral shaft fractures at Worcestershire Royal Hospital between December 2003 and March 2007.


Ninety-one patients were identified between December 2003 and March 2007, of which 70 were female patients and 21 were male patients, with a mean age of 74 (range between 28 and 97).

Indications for IMHS nailing were reverse oblique fractures, subtrochanteric fractures and type 5 Evans-Jensen fractures.

Thirteen patients underwent IMHS nailing due to pathological fractures secondary to metastatic deposits. Two patients underwent prophylactic IMHS nailing due to impending metastatic fracture.

A systematic review was undertaken of all patient documentation and radiographs. The following parameters were noted: time taken to surgery, operating time, type of anaesthesia, total blood loss and volume of blood transfusion, and peri-operative complications.


A total of 91 patients underwent IMHS fixation for proximal femoral shaft fractures between December 2003 and March 2007. Fifty-one of these were left sided fractures and 40 were right sided fractures.

Operations were performed within a mean of 1.4 days (range 0-6 days) following admission. A total of 81 patients were operated on within two days of admission.

Operating time

Forty-three patients underwent operation under general anaesthetic, 34 patients had a combination of general anaesthetic and spinal anaesthesia and 14 patients had a combination of spinal anaesthesia with sedation. A mean average of 25 minutes was spent in the anaesthetic room (range 10-55 minutes). Mean operating time was 126 minutes (range 30-360 minutes). A mean average of 64 minutes was spent in recovery postoperatively (range 15-245 minutes).

Operating surgeon

In 28 (31 percent) cases the operating surgeon was a consultant, 63 (69 percent) operations were carried out by a registrar or middle grade, with 50 percent being performed under direct supervision by a consultant.

Nail sizes

Forty-six short and 45 long IMHS nails were used.

Blood loss

Average preoperative haemoglobin was 12.2g/dl (range 9.1-15.7g/dl). Mean average blood loss recorded intraoperatively was 689ml (range 150-1800ml). A total of 51 patients required blood transfusion, with 20 (39 percent) requiring more than three units.


Intraoperative complications: Three patients sustained a further fracture intraoperatively whilst undergoing insertion of a short IMHS nail without reaming at the tip of the nail site. In two cases this was revised to a long IMHS nail, one of which was identified and revised intraoperatively. In the third case a small vertical slit was identified on the postoperative films; this was managed conservatively.

Infection: There were no cases of postoperative wound infection. One patient developed a stitch granuloma, which was excised under local anaesthetic.

Lag screw cut-outs: There were a total of
four lag screw cut-outs. Two patients were revised to total hip replacements (THR).
One case was managed conservatively due to lack of symptoms and one patient died prior to revision surgery.

Re-operation: Re-operation rates were 4.4 percent (four patients). Two patients were revised to THR due to lag screw cut-outs. In one patient, a short IMHS nail was revised to a long IMHS nail due to identification of a fracture at the nail tip postoperatively. One patient was operated on due to non-union with a broken IMHS nail, this was revised to a proximal femoral nail.

Mortality: Thirty-four patients died in total, with six deaths occurring during hospital admission.

Length of hospital stay: Average hospital stay was 17 days with range of 4-72 days.

Follow-up: A total of 41 patients were followed up on an outpatient bases for a mean period of 29 weeks (range 5-100). Four patients had been referred to other hospitals. A total of six patients died during admission. There was no follow-up in 40 cases.

Fracture healing: In 40 patients there was complete healing of the fracture. There was one case of non-union with a broken short IMHS nail, this was revised to proximal femoral nail which led to subsequent fracture healing.

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The treatment of proximal femoral fractures has improved with the usage of modern sliding implants, however, considerable morbidity and mortality still exists especially in unstable fractures. Consequently, there has been some movement away from the conventional treatment with dynamic hip screw and plate compression towards newer techniques, which include the intramedullary hip screw (IMHS).

IMHS combines the sliding compression screw with intramedullary nails. Advantages of this technique include percutaneous insertion to minimise fracture zone insult and reduce perioperative blood loss, and the fact that there is decreased bending movement on the compression screw because shaft fixation is intramedullary.4
IMHS nails are available in short and long nail designs. The longer designs allow for the management of subtrochanteric fractures and intertrochanteric fractures with distal subtrochanteric extensions. Longer nails are particularly useful when distal fracture extension cannot be bypassed effectively with shorter implants.

There have been a number of promising reports in current literature with regards to the use of IMHS nails, with the documented evidence suggesting improved operating times and reduced blood loss.5 Barquet et al reported shorter surgical times and less blood loss in comparison to open plating techniques, with a 100 percent union rate and no cut-outs.6 Baumgaertner et al reported no significant differences between intramedullary hip screws and compression hip screws with regards to complications, with an increase in surgical time and blood loss for the compression hip screw group.7
The revision rate for IMHS is estimated to be up to six percent,8 with lag screw cut-out rates of up to four percent. This parallels our current study, which had a revision rate and a lag screw cut-out rate of 4.4 percent. Cutting out from the femoral head is a reflection of technical error in assessing the correct tip-apex distance as opposed to poor implant function. In our experience a tip-apex distance of less than 25mm is associated with a lower cut-out rate.

There have been some studies in the literature, reporting the increased incidence of femoral shaft fractures at the tip of the IMHS implant.9,10 This, however, has been attributed to the relative inexperience with such implants. Within our study there were three cases, in which intraoperative fractures were sustained, whilst inserting short IMHS nails. This was due to insertion of the IMHS nail without reaming, therefore we would advise a low threshold for reaming prior to insertion of an IMHS to avoid intra-operative fracture.

IMHS confers good functional outcome, with studies suggesting IMHS implants expedite the return to preoperative ambulatory function, with patients regaining their preoperative function within a mean period of four months.11

Our experience with intramedullary hip screws suggests it is a safe and effective device in the treatment of unstable and pathological proximal femoral fractures, and therefore should be considered as part of the operative treatment options for proximal femoral fractures.



Tariq Mahmood, Speciality Doctor in Trauma and Orthopaedics

Shahzad Sadiq, Consultant Trauma and Orthopaedic surgeon

Firas Arnaout, Speciality Doctor in Trauma and Orthopaedics


Department of Trauma and Orthopaedics

Worcester Royal Hospital Worcester



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