Hip resurfacing arthroplasty is a recognised treatment option for young patients with osteonecrosis of the femoral head and may have advantages over a total hip replacement. However, resurfacing for osteonecrosis occurring as a complication of femoral neck fracture may be challenging to treat due to the presence of fixation devices. We describe the case of a patient with a history of Ewing’s sarcoma of the proximal femur who presented with an ipsilateral occult femoral neck fracture treated initially with cannulated screw fixation. The patient subsequently developed symptomatic osteonecrosis and underwent hip resurfacing arthroplasty. Intra-operatively, the track of the superior cannulated screw provided an appropriate track for guide wire insertion and overdrilling to accept the peg of the femoral component. At 24 months follow up the patient is pain free with no problems encountered. The use of hip resurfacing arthroplasty in this clinical scenario has not to date been described and in our experience, the presence of cannulated screws was not found to be a contraindication to resurfacing arthroplasty.Disruption of the vascularity to the femoral head has been implicated in osteonecrosis and can be due to a mechanical interruption following trauma, thrombotic occlusion or extravascular compression from fat emboli as seen with corticosteroid use and alcohol excess1. Osteonecrosis can be a debilitating event in young patients and in the later stages of the disease, hip arthroplasty is a standard treatment option (1,2) We report a case of hip resurfacing for osteonecrosis following a femoral neck fracture which had been treated with cannulated screws.
A 50-year-old male presented with hip and thigh pain on weight bearing following a stumble in the road. He had a history of Ewing’s Sarcoma of the femoral diaphysis at age 5 years treated with radiotherapy. At age 18 years he had suffered from a pathological fracture of the ipsilateral femoral shaft which was treated non-operatively, but since then he had been very active and could, for example, play football. Other significant medical history included alcohol excess with a consumption of 40 units per week.
- On examination, there was significant post-radiotherapy induration of the soft tissues of the thigh, from the level of the lesser trochanter to the distal thigh. There was considerable pain on passive hip movement. Anteroposterior and lateral radiographs of the pelvis, affected hip and femoral shaft revealed no obvious proximal femoral fracture and initially a fracture of the femoral shaft was suspected because of a linear shadow in the proximal diaphysis, but review of earlier films showed that this had been present for some years (Fig. 1). Magnetic Resonance Imaging of the hip confirmed the presence of a non-displaced occult femoral neck fracture with marrow changes visible on T1 and T2 weighted images (Fig. 2). Signal changes were also seen in the diaphysis at the previous site of the Ewing’s sarcoma, but no fracture was seen in this area. A Technetium methylene diphosphonate (Tc99m-MDP) radionuclide bone scan revealed increased uptake in the femoral neck and shaft. In light of the patient’s pain and continuing disability the fracture was fixed with two 6.5mm stainless steel AO cannulated screws placed under general anaesthesia and fluoroscopic control. Care was taken not to breach the articular surface of the femur. Fracture reduction was maintained throughout the procedure. The patient was discharged protected weightbearing for 3 months. He was mobilising pain free and unrestricted at 6 months. Radiographs showed evidence of fracture union and the lesion in the femoral shaft remained unchanged.
Three and a half years later, the patient presented with progressive pain in the same hip on weight bearing. Anteroposterior and lateral radiographs views of the hip showed evidence of avascular necrosis with femoral head collapse (Fig 3). Having failed conservative treatment, the patient underwent a hip resurfacing arthroplasty (Birmingham Hip Resurfacing, Smith and Nephew®). The procedure was performed with the patient in the lateral position through a posterior approach, as is the preference of the senior author. A large defect in the superior quadrant of the femoral head was identified, removed and sent to histology. The acetabular component was inserted in a standard fashion. When preparing the femur, the superior cannulated screw was removed. The resultant track was appropriately orientated for passage of the guide-wire and subsequent overdrilling to accommodate the peg of the femoral component. Following milling of the femoral head the bone stock was deemed sufficient to support the implant. The lower screw was left in situ, and was sufficiently recessed so as to not to be in contact with the metal of the femoral component.
Histological examination of the femoral head confirmed the clinical diagnosis of osteonecrosis. Recovery was uncomplicated, and the patient was discharged on the fourth postoperative day, fully weight bearing on crutches with low molecular weight heparin thromboprophylaxis. At 24 months the patient continues to mobilise without pain and radiographs of the hip are satisfactory (Fig. 4).
Anteroposterior radiographs of left hip on arrival. No obvious intracapasular fracture evident. Note the chronic post radiotherapy changes to femoral shaft and thin soft tissue envelope of the thigh.
T1 weighted magnetic resonance imaging highlights trabecular changes in femoral neck indicative of an occult femoral neck fracture.
Anteroposterior radiographs of the left hip showing cannulated screws in situ and evidence of osteonecrosis with subchondral sclerosis and collapse of femoral head in the superior portion.
Anteroposterior radiographs of left hip at 24 months post removal of superior cannulated screw and resurfacing arthroplasty.
When compared with the average population undergoing hip arthroplasty for osteoarthritis, patients with osteonecrosis tend to be younger, with greater functional demands and have a higher rate of revision(1-5) Resurfacing arthroplasty in young patients with osteonecrosis should be considered because the femoral bone stock can be preserved for future surgery if necessary( 1,2) Although, valid concerns have been raised over the feasible use of resurfacing in the presence of large femoral head defects secondary to avascular necrosis, favourable short term results have been reported in the presence of advanced femoral head changes (2,3,6,7) Mont et al.(2) found similar short term follow-up with respect to post-operative Harris Hip scores, revision rates and survivorship curves when comparing patients treated with hip resurfacing for osteonecrosis with a matched group of patients who had undergone resurfacing for osteoarthritis. Revell et al.(3)reported in their series that the majority of their cases were Ficat stages three and four and reported an overall survivorship of 93.2% with a mean follow-up of 6.1 years(3). Amstutz et al.(6) recently reported comparable results at 2 years and 12 years when hip resurfacing for osteonecrosis was compared with other indications. Akbar et al.7 reported an overall survivorship of 92% after a mean follow-up of 4.8 years in their cohort of cases who had undergone resurfacing arthroplasty for osteonecrosis. Therefore, the published results suggest that hip resurfacing is indeed an acceptable treatment for young patients with symptomatic and advanced osteonecrosis and we have shown that it is possible to perform this procedure for osteonecrosis following fixation of a femoral neck fracture with cannulated screws.
- This was an unusual clinical case, in which a further consideration was that previous radiotherapy to the proximal thigh may have made instrumentation of the proximal femur difficult and soft tissue healing uncertain. Resurfacing was dependent on adequate bony support around the femoral head and neck which was potentially compromised due to the osteonecrosis. However, had it not been possible to perform a resurfacing in this fashion, we had been prepared to perform a neck osteotomy followed by the placement of a more standard femoral component with the intention of bypassing the previously irradiated and therefore weakened femur to avoid the risk of fracture. It was fortuitous that the superior cannulated screw had been inserted in a position which was appropriate for the stem of the resurfacing implant: it was felt prudent to leave the lower screw in place in order not to leave a defect in the bone of the femoral neck.
The risk factors for osteonecrosis in this patient included subcapital fracture and alcohol excess, of which this patient had a history 1. It is likely that the development of avascular necrosis which developed was secondary to trauma, despite the fact that it was diagnosed forty two months post fracture. Asnis et al. (8) reported in their series of 141 displaced and undisplaced intracapsular fractures treated with cannulated screw fixation, a total of 26 patients developed Osteonecrosis; 9 of these cases were diagnosed at twenty five to sixty months follow-up and 4 cases manifested after sixty months (8). It appears unlikely that the original radiotherapy contributed to the development of osteonecrosis given that the proximal femur was outside the radiation field.
- Stainless steel cannulated screws have been successfully used in fixing intracapsular femoral neck fractures following resurfacing arthroplasty without detrimental effect to the cobalt chrome implant or supporting bone 9,10. However, we thought it prudent to avoid direct contact between the head of the retained screw and the femoral component.
In summary, we describe a case in which hip resurfacing arthroplasty and a large metal on metal articulation have been used to treat a young patient with post traumatic osteonecrosis, where the cannulated screw fixation was still in situ. Although the follow up is short at (24) months, the outcome is encouraging and we believe this technique may be of value in selected difficult cases.
- Lieberman J, Berry DJ, Mont MA, Aaron RK, Callaghan J, Rayadhyaksha A, Urbaniak JR. Osteonecrosis of the Hip: Management in the Twenty-first Century. J Bone Joint Surg Am. 2002;84:834-853.
- Mont MA, Seyler TM, Marker DR, Marulanda G, Delanois RE. Use of Metal-on-Metal Total Hip Resurfacing for the Treatment of Osteonecrosis of the Femoral Head J Bone Joint Surg Am. 2006;88:90-97.
- Revell M, McBryde CW, Bhatnagar S, Pynsent P, Treacy R. Metal on Metal hip resurfacing in osteonecrosis of the femoral head. J Bone Joint Surg Am. 2006;88:98-103
- Callaghan JJ, Forest EE, Sporer SM, Goetz DD, Johnston RC. Total hip arthroplasty in the young adult. Clin Orthop Relat Res. 1997;344:257-62.
- Dorr LD, Kane TJ 3rd, Conaty JP. Long-term results of cemented total hip arthroplasty in patients 45 years old or younger. A 16-year follow-up study. J Arthroplasty.1994;9:453-6.
- Hip Resurfacing results are as good as for other aetiologies at 2 years and 12 years. Clin Orthop Relat Res.
- Akbar M, Mont MA, Heisel C, Marker DR, Ulrich SD, Seyler TM. Resurfacing for osteonecrosis of the femoral head. Orthopade. 2008 Jul: 37(7):672-8
- Asnis SE, Wanek-Sgaglione L. Intracapsular fractures of the femoral neck. Results of cannulated screw fixation . J Bone Joint Surg Am. 1994;76:1793-1803.
- Mereddy P, Malik H, Geary N. Peri-prosthetic fracture neck of femur following metal-on-metal Birmingham hip resurfacing treated by internal fixation. Injury Extra. 2009 April: 40(4): 65-67
- Kutty S, Pettit P, Powell JN. Intracapsular fracture of the proximal femur after hip resurfacing treated by cannulated screws. J Bone Joint Surg Br 2009 91-B: 1100-1102.