|
Reading List: Femoral neck fractures by Mr Martyn Parker
Upadhyay A, Jain P, Mishra P, Maini L, Gautum VK, Dhaon BK. Delayed internal fixation of fractures of the neck of the femur in young adults: a prospective, randomised study comparing closed and open reduction. J Bone Joint Surg [Br] 2004;86-B:1035-40. The authors of this study have to be commended for undertaking a study of an unusual clinical situation that has not before been studied within the context of a randomised trial. Prior to this study clinicians faced with a young patient (age 15 to 50 years) with a displaced intracapsular fracture, had to use their own personal experience and the evidence from a limited number of case series, to guide their treatment. This trial was conducted to a good standard with a blinded method of randomisation (sealed envelopes), a minimum follow-up of two years and an X-ray observer blinded to the method of treatment.
The reader has to be aware that the findings should only apply to patients aged between 15 and 50 years. Of the patients used in this study, 83% were men and most injuries were from high-energy trauma. For those patients in which an accurate closed reduction could not be achieved (four in this series), open reduction was undertaken. The mean time between injury and surgery was 50 hours (6 to 136). Open reduction was via a Watson-Jones an anterior approach and a T-shaped incision into the capsule. As expected open reduction was associated with longer operative times (90 vs 41 minutes) and an increased incidence of wound healing complications (4 vs 1). No difference in the incidence of non-union (9/48 for closed reduction vs 7/44 for open reduction) or avascular necrosis (7/48 vs 8/44) was found.
The only previous randomised trial on this topic involved elderly patients and had to be abandoned early in favour of closed reduction, because of an increased mortality in the open reduction group.1 This study gives further support to the use of closed reduction in preference to open reduction for displaced intracapsular fractures. For those fractures in which the treatment is delayed or when an accurate closed reduction cannot be achieved open reduction is indicated.
1. Parker MJ, Banajee A. Surgical approaches and ancillary techniques for internal fixation of intracapsular proximal femoral fractures. (Cochrane Review). In: The Cochrane Library Issue 2, 2005. Chichester, UK: John Wiley & Sons, Ltd
Baumgaertner MR, Solberg BD. Awareness of tip-apex distance reduces failure of fixation of intracapsular proximal femoral fracures. J Bone Joint Surg [Br] 1997;79-B:969-71. This study should be commended as rather than being a comparison of different types of implant used for this fracture, it concentrates on a much more important aspect – the quality of surgical technique. It provides a simple method of assessing the technical adequacy of surgery.
Internal fixation of a trochanteric fracture with a sliding hip screw must be among the commonest type of internal fixation for a fracture used today. When failures of fixation occur the implant is often blamed. The essential finding from this study and the previous report from the same group,1 was that no cases of implant cut-out occurred if the tip to apex distance was less than 25 millimetres. This has to be the take home message of these two papers; that the greater the distance of the lag screw from the apex of the femoral head, the greater the risk of implant cut-out.
The formula to calculate the tip-apex distance can deter some clinicians from using this method (figure 1). Many centres now use only the prints from the x-ray image intensifier. If the magnification of these prints is known or calculated using the formula given, then the full formula need not be used each time. This means that a simple measurement of two distances with a ruler can be used to determine the technical adequacy of surgery and the risk of implant cut-out. Perhaps a routine record of this distance should be made in the post-operative notes and used for audit purposes.
The tip-apex distance has since been shown to be one of the most useful predictors of failure of fixation when using the sliding hip screw for trochanteric fractures.2 The only small problem with the measurement is that an inferior placement of the screw may increase slightly the tip to apex distance without increasing the risk of cut-out, and the measurement makes no allowance for this. This is a however a small criticism of a simple and useful technique.
References
1. Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg [Am] 1995;77-A:1058-64. Figure 1.
Corrected Tip to Apex distance = (X ap x D true/D ap) + (X lat x D true/ D lat)
X is tip to apex distance and D is diameter of lag screw in millimetres. D true is the actual diameter of the lag screw used.
Davison JNS, Calder SJ, Anderson GH, Ward G, Jagger C, Harper WM, Gregg PJ. Treatment for displaced intracapsular fracture of the proximal femur: a prospective, randomised trial in patients aged 65 to 79 years.
J Bone Joint Surg [Br] 2001;83-B:206-12. This randomised trial studied patients aged between 65 and 79 years with a displaced intracapsular fracture. Three different types of surgical treatment were compared, reduction and internal fixation with a sliding hip screw, a cemented Thompson hemiarthroplasty or a cemented Monk bipolar hemiarthroplasty. A total of 280 patients were randomised. Follow-up was for a minimum of two years. The final outcome measure of mortality was less for those treated by internal fixation. Functional outcome was assessed by the Harris Hip Score and showed no difference between the three groups. The ‘process’ outcome favoured hemiarthroplasty with a markedly increased re-operation rate for those treated by internal fixation.
This study is one of a number of recent randomised trials on this topic of internal fixation versus arthroplasty. Results of all these studies have now been summarised in a Cochrane review.1 As expected the ‘process’ outcomes favour arthroplasty, with the lower re-admission and re-operation rate. The more important outcomes of mortality and final function of the limb however favour internal fixation. This study was one of a few randomised trials that suggested mortality is less for internal fixation. This is an important finding, not present in all randomised trials on this subject. Unfortunately, the paper failed to give the actual number of patients who died, thereby preventing their study being used in any meta-analysis of the data. Not all the previous studies on this topic have demonstrated a difference in mortality and firm conclusions cannot be drawn from systematic reviews.1,2
Regarding the comparisons between bipolar and unipolar hemiarthroplasty this study presents the best trial we have to date on the role of bipolar hemiarthroplasty. Despite the lack of evidence, bipolar hemiarthroplasties are used extensively for the treatment of this injury. To date only seven randomised trials involving a total of 857 patients (187 in this study) have been undertaken comparing unipolar and bipolar hemiarthroplasties.3 No significant difference has been found for any outcome including residual pain and need for revision arthroplasty. No study to date has had enough patients to be able to demonstrate a difference. A study of 1000 patients is needed for a firm conclusion to be drawn. Thus the use of more expensive bipolar hemiarthroplasties remains questionable. The reader has to conclude that bipolar arthroplasties should only be used within the context of clinical studies to evaluate their effectiveness in comparison with unipolar hemiarthroplasties.
The type of hemiarthroplasty chosen by an individual orthopaedic surgeon is determined by personal preference rather than good scientific evidence. There are no randomised trials comparing the two most commonly used prostheses, the Moore and the Thompson. Only five trials with a total of 482 patients have compared a cemented with an uncemented prosthesis, with results tending to favour the cemented prosthesis. Two trials with a total of 269 patients have compared different types of hemiarthroplasty with a total hip replacement. These figures show our sad lack of sound evidence based knowledge on the type of arthroplasty we should be using for patients with hip fractures.
References
1. Masson M, Parker MJ, Fleischer S. Internal fixation versus arthroplasty for intracapsular proximal femoral fractures in adults (Cochrane Review). In: The Cochrane Library, Issue 2, 2003. Oxford: Update Software. Rogmark C, Carlsson A, Johnell O, Sernbo I. A prospective randomised trial of internal fixation versus arthroplasty for displaced fractures of the neck of the femur: functional outcome for 450 patients at two years. J Bone Joint Surg [Br] 2002;84-B:183-8. Tradition held that displaced intracapsular fractures in elderly patients were treated by reduction and internal fixation in the Scandinavian countries, whilst for much of the rest of Europe and America femoral head replacement was used. This fracture was termed the unsolved fracture, because of this controversy. During the past decade a number of randomised trials have been undertaken on this topic. This study by Rogmark et al represents one of the largest and comes from 12 centres in Sweden, the heart of the internal fixation protagonists. The method of internal fixation was mainly Hansson Hook pins, a method originating from this area of Sweden. The type of arthroplasty was a variety of different total hip replacements (103 patients) and hemiarthroplasties (89 cases). The selection of total hip replacement or hemiarthroplasty was based on a functional score.
No difference was seen in mortality between treatment methods, but pain and function were significantly better for those treated by arthroplasty; 93 failures out of 217 patients were recorded in the internal fixation group, with a total of 106 secondary operations being required. For the arthroplasty group the main complication was dislocation which occurred in 15 cases.
This study has led to one of the areas that has traditionally advocated internal fixation for all displaced intracapsular fracture to question this practice. The authors conclude that primary arthroplasty should be recommended for the treatment of displaced intracapsular fractures in those over 70 years of age.
All the other randomised trials on this topic have since been summarised in two systematic reviews.1,2 These summaries indicated that some, but not all, of the previously undertaken trials have shown a tendency to a reduced mortality after internal fixation and some studies such as this by Rogmark et al, have shown better function after arthroplasty. These conflicting findings suggest that both treatment methods have a place. Perhaps certain fracture types or individuals are better treated by one method. Until these specific situations are defined it remains an ‘unsolved fracture’. A systematic review of case series reports also came to similar conclusions.3 As is often the case, larger trials are required to resolve the controversy.
References
1. Masson M, Parker MJ, Fleischer S. Internal fixation versus arthroplasty for intracapsular proximal femoral fractures in adults (Cochrane Review). In: The Cochrane Library, Issue 2, 2003. Oxford: Update Software. Christie J, Burnett R, Potts HR, Pell ACH. Echocardiography of transatrial embolism during cemented and uncemented hemiarthroplasty of the hip. J Bone Joint Surg [Br] 1994;76-B:409-12. This is one of the early studies on echocardiography. Some of the first studies were during intra-medullary nailing,1 where similar phenomena were observed. When presented at the British Orthopaedic Association any surgeon such as myself who saw the video of the emboli passing across the heart was mesmerised. Most patients had a cascade of fine emboli less than 1 cm in diameter. Larger emboli over 1 cm in size were however common with cemented hemiarthroplasties. In one case a 1 cm by 7 cm embolism was seen passing through the right atrium on reduction of a cemented hemiarthroplasty. This embolism may have been a cast of the femoral or profunda femoris vein and surprisingly no clinical consequences were seen.
All hip fracture surgeons are aware of the sudden death of the patient on insertion of cement or the later development of fat embolism syndrome. This study demonstrated in a dramatic form the cause for these major complications. Memories of this video remain and should be used to remind all orthopaedic surgeons of the potential damage that they may inadvertently inflict on their patients.
A more recent study has measured the cardiac output and stroke volume for cemented and uncemented hemiarthroplasties.2 This showed that the introduction of cement did not affect the heart rate or blood pressure but caused a significant reduction in cardiac output and stroke volume. In essence when we put cement in the femur we should be aware that we are causing major and potentially fatal changes to occur in the cardiovascular system.
References
1. Pell ACH Christie J, Keating JF, Sutherland GR. The detection of fat embolism by transoesophageal echocardiography during reamed intramedullary nailing: a study of 24 patients with femoral and tibial fractures. J Bone Joint Surg [Br] 1993;75-B:921-5. Mr Martyn Parker, Consultant Orthopaedic Surgeon |
|
