The Role Of Pinning In Subcapital Fractures

Edward J. Harvey M.D., MSc
Montreal, QC

Displaced subcapital hip fractures represent a consistent problem in orthopaedic surgery. Assorted reasons for choosing a modality of treatment include ease of surgery, cost, morbidity and mortality, risk of AVN, re-operation rates and functional disability.

The physiologically young patient has traditionally been treated with internal fixation. There is little evidence-based literature to change that treatment plan. Currently, open or closed reduction and internal fixation with three or four screws are accepted therapies. Capsulotomy does not seem to be clinically relevant. Historically, expedient surgery has been advocated to avoid osteonecrosis. However, there is probably a low rate of AVN. Also, only about 20% of patients with AVN require further surgery. However, AVN is not painless in the high-demand patient post internal fixation. Some data suggests that urgent reduction and fracture fixation within 12 hours after a displaced fracture may be associated with a reduced rate of radiographic signs of avascular necrosis1. Pinning in the physiologically young patient is always indicated and none of the criteria such as cost, morbidity and mortality, re-operation rates and functional disability suggest otherwise.

Is there a place for internal fixation in the elderly patient? Many studies have attempted to determine the best treatment. In general2-5, they found that in patients with fractures of the femoral neck, arthroplasty of some type led to fewer treatment failures and better function than did internal fixation. More patients in the arthroplasty groups had complications. Mortality rates usually did not differ between the two treatment groups. One of the longer follow-up prospective cohorts3 commented that both internal fixation and hemiarthroplasty resulted in a poor outcome with respect to pain and mobility with a revision rate over 20%. There was no significant difference in the mortality or function of the survivors4. Internal fixation resulted in fewer postoperative complications, a shorter hospital stay and a reduced cost of treatment. The re-operation rate for internal fixation was higher. Other studies have noted a high initial re-operation rate for internal fixation but also a higher than expected rate for arthroplasty.

Internal fixation, however, is the clear optimal therapy in the demented or bedridden patient who requires surgery for pain relief. When mental dysfunction was present6, the dislocation rate after arthroplasty was 32%, whereas the re-operation rate after osteosynthesis was 5%. The opposite pattern of complications was found in patients from the same surgical practise with normal mental function (12% vs. 60%).

More importantly perhaps than the results of the prospective trials - why is there a difference in treatment outcome between the geriatric and the young patient? Why does a young high-demand patient do better with internal fixation? Definitely nutritional status, ability to use crutches effectively and surgeon desire for fixation to work do help the younger patient. Understanding the other differences may allow us to optimize the internal fixation for the older patient. There are the obvious problems with bone quality. These problems have been addressed with some success in fractures at other joints. Theoretically, if this limitation is overcome, then the elderly patient would tolerate the other complications of internal fixation, perhaps better than the young patient. This is a lower demand patient that theoretically may tolerate AVN of the femoral head slightly better. Is there a difference in bone blood flow in these patients? Bone perfusion does decrease significantly in the proximal femur in healthy subjects and the healing response is lessened. There is a decrease in the number of osteoblasts and hematopoietic cells, an increase in empty lacunae, and a degeneration of marrow with aging. This may dictate a larger zone of osteonecrosis and detrimental healing outcome. Perhaps internal fixation augmented by either a fixed angle component or resorbable cement containing BMPs could be of use here. Only more research will shed light on the relevance of this.

More immediately, some authors7,8 have suggested there is complacency in the reduction of the fractures in these patients. All the prospective randomized trials in the literature have not discussed efficacy of reduction of the fractures.

The subgroup of patients with comminution undoubtedly were more difficult to reduce and more prone to fail. If this group is removed from the prospective trials then there may be better results for internal fixation.

Internal fixation is currently the treatment of choice for displaced femoral neck fractures if: the patient is physiologically young, if the patient is demented, or if the femoral neck fracture can be reduced anatomically and fixed in a timely and structurally stable manner in the elderly patient.

References

1. Jain R., Koo M., Kreder H.J., Schemitsch E.H., et al. Comparison of early and delayed fixation of subcapital hip fractures in patients sixty years of age or less. J Bone Joint Surg Am. 2002 Sep; 84-A(9):1605-12.

2. Rogmark C., Carlsson A., Johnell O. et al. 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 Mar; 84(2): 183-8.

3. Ravikumar K.J., Marsh G. Internal fixation versus hemiarthroplasty versus total hip arthroplasty for displaced subcapital fractures of femur--13 year results of a prospective randomised study. Injury. 2000 Dec;31(10):793-7.

4. Parker M.J. Internal fixation or arthroplasty for displaced subcapital fractures in the elderly? Injury. 1992;23(8):521-4.

5. Skinner P., Riley D., Ellery J., et al. Displaced subcapital fractures of the femur: a prospective randomized comparison of internal fixation, hemiarthroplasty and total hip replacement. Injury. 1989 Sep;20(5):291-3.

6. Johansson T., Jacobsson S.A., Ivarsson I., et al. Internal fixation versus total hip arthroplasty in the treatment of displaced femoral neck fractures: a prospective randomized study of 100 hips. Acta Orthop Scand. 2000 Dec;71(6):597-602.

7. Sochart D.H. Poor results following internal fixation of displaced subcapital femoral fractures: complacency in fracture reduction. Arch Orthop Trauma Surg. 1998;117(6-7):379-82.

8. Chua D., Jaglal S.B., Schatzker J. Predictors of early failure of fixation in the treatment of displaced subcapital hip fractures. J Orthop Trauma. 1998 May; 12(4): 230-4.

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