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Re-operations following Austin Moore hemiarthroplasty: a district hospital experience
Injury, Int. J. Care Injured 32 (2001) 465– 467 www.elsevier.com/locate/injury
Re-operations following Austin Moore hemiarthroplasty: a district hospital experience N. Tellisi *, K.H.A. Wahab Orthopaedics Department, Good Hope Hospital, 28 Rectory Road, Sutton Coldfield, Birmingham B75 7RR, UK Accepted 2 March 2001
Abstract The Austin Moore prosthesis is commonly used for displaced femoral neck fractures. In this study the rate of re-operation following Austin Moore hemiarthroplasty was studied. Ten out of 88 cases (11.36%) were re-operated on within the first year following the original operations. The indications for re-operation were infection (4.5%), dislocation (3.4%) and loose prosthesis (3.4%). The rate of infection found in this study was higher than other published series and could be attributed to the lack of laminar flow ventilation system and the use of cotton drapes and surgical gowns while performing these operations. We recommend that Austin Moore hemiarthroplasty should be carried out in theatres equipped with a laminar flow ventilation system and to use waterproof gowns and drapes to limit the number of deep infections and therefore lower the re-operation rate. © 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction Hip fractures in the elderly are increasing, representing a challenge to the National Health Service. The incidence of hip fractures in the UK is between 45 000 and 57 000 cases per annum [1,2], occupying 20% of orthopaedic beds [3]. Surgical treatment in the form of internal fixation or endoprosthesis is the preferred form of management. For displaced femoral neck fractures, hemiarthroplasty is thought to be superior to internal fixation, which is associated with a high incidence of fixation failure, nonunion and avascular necrosis. Studies that compared the two methods of treatment showed disappointing results in the internal fixation group [4,5,26]. Alho et al. 1999 reported a re-operation rate of 14% following internal fixation for displaced femoral neck fractures [6]. These figures are modest compared to those quoted by Marti who reported a re-operation rate in the region of 23 – 31% [7]. Other studies that looked into the use of internal fixation in undisplaced femoral neck fractures quoted a similar re-operation rate [4,8]. Advocates of internal fixation argue that the main cause for fixation failure is poor * Corresponding author. E-mail address: [email protected] (N. Tellisi).
reduction and fixation techniques [5]. Those who support endoprosthesis, on the other hand, regard hemiarthroplasty as a better option for treating displaced femoral neck fractures, because it eliminates the possibility of revision surgery if fixation fails. Moreover, hemiarthroplasty procedures do not require intra-operative X-ray facilities, which are essential to perform internal fixation. This makes hemiarthroplasty preferable in locations where theatre X-ray facilities are scarce. This study examines the frequency and cause of re-operation following Austin Moore hemiarthroplasty, in order to improve the quality of care and reduce the complication rate.
2. Patients and methods The results of Austin Moore hemiarthroplasty in 88 consecutive patients with displaced femoral neck fractures were reviewed. The patients were admitted between January 1995 and December 1995. The study was conducted by reviewing case notes and radiographs, and the data collected included: age, sex, classification of the fracture, date of operation, surgical approach, indication and date of re-operation. The average follow-up of this study was 5 years (12 months –5 years).
0020-1383/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 0 1 ) 0 0 0 2 7 - 4
N. Tellisi, K.H.A. Wahab / Injury, Int. J. Care Injured 32 (2001) 465–467
466
All the cases were performed using the lateral Hardinge approach [9] and received three doses of prophylactic antibiotics in the form of Cefuroxime 1.5 g on induction and 750 mg at 8 and 16 h post-operation. All the operations in this study were performed by middle grades on the regular trauma list, except on weekends where surgery was performed in emergency theatre but not beyond 22:00 h.
3. Results There were 71 females and 17 males with a mean age of 80, S.D. 10.04 and S.E. 0.7098. The mean age of the male group was 77.93, S.D. 10.89 and S.E. 1.660. The female mean age was 81.58, S.D. 9.684 and S.E. 0.7728. Of the 88 cases, there were 10 re-operations at a rate of 11.36%. Dislocation occurred in three cases at a rate of 3.4%. One case was treated by exchange to a better fitting prosthesis with a satisfactory result. One to a total hip replacement and a third to a Girdlestone arthroplasty. There were four cases of deep infection at a rate of 4.5%. In three cases the infection was treated by debridment and conversion to Girdlestone arthroplasty. In one case the infection was controlled by intravenous antibiotics and debridment and the prosthesis was retained with satisfactory results. Loosening developed in three cases at a rate of 3.4%. All the three cases were revised to total hip arthroplasty (Table 1).
4. Discussion The overall re-operation rate found in this study (11.4%) was comparable to the published series [4,10,11]. The dislocation rate was 3.4%, which falls within the dislocation rates reported in the literature [12,13]. None of the dislocated hemiarthroplasties was treatable by closed reduction, therefore requiring revision to either a better fitting prosthesis or to total hip replacement. These findings, however, are in agreement with the figures published that described poor outcome following closed reduction of uncemented prosthesis
[14]. Loosening of the prosthesis was identified in three cases all of which developed in the first year following the initial surgery. It was found that both dislocation and loosening were due to loose prostheses and in two cases the femoral stem was rotated in the medullary canal. It is recognised that the medullary canal in the elderly is wide due to osteoporosis, and does not allow an accurate fit with the Austin Moore prosthesis stem, which is only available in two standard stem measurements. Moreover, surgical techniques and adequate measurement play an important role in determining the outcome. A study on uncemented prosthesis concluded that insertion of uncemented prosthesis is a technically demanding task and accurate femoral head measurement and femoral stem preparation are essential to achieve good outcome [15]. The re-operation rate due to infection in this series was 4.5%. This rate is high compared to published series [12,16–18], with a poor success rate in retaining the prosthesis when compared to the literature [16]. Infection was satisfactorily treated with debridment and intravenous antibiotics in one out of four cases, while the remaining cases required conversion to Girdlestone arthroplasty. The causative organisms were Staphylococcus aureus, and MRSA was isolated in two of the cases. All the cases of Austin Moore hemiarthroplasty were performed in a conventionally ventilated theatre with the use of cotton drapes and surgical gowns. This suggests that the lack of water-proof drapes and surgical gowns as well as the lack of laminar ventilation are contributory factors in the higher incidence of deep infection [19–21]. We suggest that infection rates could be lowered by performing Austin Moore hemiarthroplasty in theatres equipped with laminar flow ventilation and by the use of impermeable drapes and surgical gowns to minimise bacterial dispersal from the patient and the operating team. Studies have shown that cotton drapes and gowns are poor bacterial barriers even when new [21,22] unlike non-woven fabrics, which produced a lower level of microbial contamination. In addition, laminar flow ventilation has been shown by many studies to reduce the infection rate following hip operations [23,24]. It is also believed that the combined use
Table 1 Re-operations performed following Austin Moore hemiarthroplasty Complication
Procedure
No.
Bacteriology
Percentage
Infection
Wound debridment Girdlestone arthroplasty Revision of prosthesis Revision to THR Revision to THR
1 3 2 1 3
Staphylococcus aureus (MRSA was isolated in two cases)a No bacterial growtha
4.5
No bacterial growtha
3.4
Dislocation Loosening Total a
10
Bacteriology results based on deep wound swab at the time of re-operation.
3.4
11.4
N. Tellisi, K.H.A. Wahab / Injury, Int. J. Care Injured 32 (2001) 465–467
of impermeable gowns and laminar ventilation achieves ultraclean air conditions and a lower level of wound contamination [19,25]. As a result of this study, all hip surgery operations in our unit are now performed in theatres equipped with a laminar flow ventilation system, and water-proof drapes and surgical gowns have now replaced the cotton fabrics. A re-audit of the rate of infection following the introduction of these measures is underway to assess the outcome.
[12]
[13]
[14] [15]
[16]
References [1] Audit Commission. United they stand: co-ordinating care for elderly patients with hip fracture. London: HMSO, 1995. [2] Hollingworth W, Todd JC, Parker MJ. The cost of treating hip fractures in the twenty-first century. J Public Health Med 1995;17(3):269 – 76. [3] Working Party for the Royal College of Physicians. Fractured neck of femur, prevention and management. J R Coll Physicians Lond 1989;23(1):8 – 12. [4] Skinner P, Riley D, Ellery J, Beaumont A, Coumine R, Shafighian B. Displaced subcapital fractures of the femur: a prospective randomized comparison of internal fixation, hemiarthroplasty and total hip replacement. Injury 1989;5(20):291 – 3. [5] Sochart HD. Poor fixation following fixation of displaced subcapital femoral fractures: Complacency in fracture reduction. Arch Orthop Trauma Surg 1998;117:379 – 82. [6] Alho A, Benterud GJ, Soloveiva S. Internally fixed femoral neck fractures: early prediction of failure in 203 elderly patients with displaced fractures. Acta Orthop Scand 1999;2(70):141 – 4. [7] Marti KR, Dunki Jacobs BP. Proximal femoral fractures. London: Medical Press, 1993. [8] Hui ACW, Anderson GH, Choudry R, Boyle J, Gregg PJ. Internal fixation or hemiarthroplasty for undisplaced fractures of the femoral neck in octogenarians. J Bone Joint Surg Br 1994;76B(6):891 – 4. [9] Hardinge K. The direct lateral approach to the hip. J Bone Joint Surg Br 1982;64-B(1):17 –9. [10] Gebhard JS, Amstutz HC, Zinar DM, Rorey FJ. A comparison of total hip replacement and hemiarthroplasty for treatment of acute fracture of the femoral neck. Clin Orthop 1992;282:123 – 31. [11] Lu-yao GL, Keller RB, Littenberg B, Wennberg JE. Outcome after displaced fractures of the femoral neck. A meta-analysis of
.
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
467
one hundred and six published reports. J Bone Joint Surg Br 1994;76(1):15 – 25. Jalovaara P, Heikki V. Quality of life after primary hemiarthroplasty for femoral fracture. Acta Orthop Scand 1991;62(2):208 – 17. Unwin AJ, Thomas M. Dislocation after hemiarthroplasty of the hip: a comparison of the dislocation rate after posterior and lateral approaches to the hip. Ann R Coll Surg Engl 1994;76(5):327 – 9. Maxwell HA, Turner PG. Dislocation of Austin Moore: is closed reduction justified? J R Coll Surg Edinb 1994;39(6):370 –1. Pryor GA. A study of the influence of technical adequacy on the clinical result of Austin Moore hemiarthroplasty. Injury 1990;21(6):361 – 5. Kuokkanen MOH, Suominen KP, Korkala LO. The late outcome of femoral neck fractures. Int Orthop 1990;14:377 –14380. Mackay DC, Harrison WJ, Bates JH, Dickenson D. Audit of deep wound infection following hip fracture surgery. J R Coll Surg Edinb 2000;45(1):56 – 9. Rao J, Parker MJ. Austin Moore hemiarthroplasty for hip fractures: An eight year follow up of a consecutive series of 500 patients. J Bone Joint Surg Br 2000;82-B:Suppl 164. Blomgren G, Hoborn J, Nystrom B. Reduction of contamination at total hip replacement by special working clothes. J Bone Joint Surg Br 1990;72-B:985 – 7. Bregman RBO, Hoborn J, Nachemson LA. Patient draping and staff clothing in the operating theatre: A microbiological study. Scand J Infect Dis 1985;17:421 – 6. Mitchell JN, Evans D, Kerr A. Reduction of skin bacteria in theatre air with comfortable, non-woven disposable clothing for operating-theatre staff. BMJ 1978;1:696 – 8. Nagai I, Kadota M, Takechi M, Kumamoto R, Nakano S, Jitsukawa S. Studies on the bacterial permeability of non-woven fabrics and cotton fabrics. J Hosp Infect 1985;7:261 – 8. Fitzgerald RH Jr, Bechtol CO, Eftekhar N, Nelson JP. Reduction of deep sepsis after total hip replacement. Arch Surg 1979;7(114):803 – 4. Ha’eri GB, Wiley AM. Total hip replacement in a laminar flow environment with special reference to deep infections. Clin Orthop 1980;148:163. Ahl T, Dalen N, Jorbeck H, Hoborn J. Air contamination during hip and knee arthroplasties. Horizontal laminar flow randomized vs. conventional ventilation. Acta Orthop Scand 1995;66(1):17 – 20. Sikorski JM, Barrington R. Internal fixation versus hemiarthroplasty for displaced subcapital fracture of the femur. A prospective randomised study. J Bone Joint Surg Br 1981;63-B(3):357 – 61.
Re-operations following Austin Moore hemiarthroplasty: a district hospital experience N. Tellisi *, K.H.A. Wahab Orthopaedics Department, Good Hope Hospital, 28 Rectory Road, Sutton Coldfield, Birmingham B75 7RR, UK Accepted 2 March 2001
Abstract The Austin Moore prosthesis is commonly used for displaced femoral neck fractures. In this study the rate of re-operation following Austin Moore hemiarthroplasty was studied. Ten out of 88 cases (11.36%) were re-operated on within the first year following the original operations. The indications for re-operation were infection (4.5%), dislocation (3.4%) and loose prosthesis (3.4%). The rate of infection found in this study was higher than other published series and could be attributed to the lack of laminar flow ventilation system and the use of cotton drapes and surgical gowns while performing these operations. We recommend that Austin Moore hemiarthroplasty should be carried out in theatres equipped with a laminar flow ventilation system and to use waterproof gowns and drapes to limit the number of deep infections and therefore lower the re-operation rate. © 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction Hip fractures in the elderly are increasing, representing a challenge to the National Health Service. The incidence of hip fractures in the UK is between 45 000 and 57 000 cases per annum [1,2], occupying 20% of orthopaedic beds [3]. Surgical treatment in the form of internal fixation or endoprosthesis is the preferred form of management. For displaced femoral neck fractures, hemiarthroplasty is thought to be superior to internal fixation, which is associated with a high incidence of fixation failure, nonunion and avascular necrosis. Studies that compared the two methods of treatment showed disappointing results in the internal fixation group [4,5,26]. Alho et al. 1999 reported a re-operation rate of 14% following internal fixation for displaced femoral neck fractures [6]. These figures are modest compared to those quoted by Marti who reported a re-operation rate in the region of 23 – 31% [7]. Other studies that looked into the use of internal fixation in undisplaced femoral neck fractures quoted a similar re-operation rate [4,8]. Advocates of internal fixation argue that the main cause for fixation failure is poor * Corresponding author. E-mail address: [email protected] (N. Tellisi).
reduction and fixation techniques [5]. Those who support endoprosthesis, on the other hand, regard hemiarthroplasty as a better option for treating displaced femoral neck fractures, because it eliminates the possibility of revision surgery if fixation fails. Moreover, hemiarthroplasty procedures do not require intra-operative X-ray facilities, which are essential to perform internal fixation. This makes hemiarthroplasty preferable in locations where theatre X-ray facilities are scarce. This study examines the frequency and cause of re-operation following Austin Moore hemiarthroplasty, in order to improve the quality of care and reduce the complication rate.
2. Patients and methods The results of Austin Moore hemiarthroplasty in 88 consecutive patients with displaced femoral neck fractures were reviewed. The patients were admitted between January 1995 and December 1995. The study was conducted by reviewing case notes and radiographs, and the data collected included: age, sex, classification of the fracture, date of operation, surgical approach, indication and date of re-operation. The average follow-up of this study was 5 years (12 months –5 years).
0020-1383/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 0 1 ) 0 0 0 2 7 - 4
N. Tellisi, K.H.A. Wahab / Injury, Int. J. Care Injured 32 (2001) 465–467
466
All the cases were performed using the lateral Hardinge approach [9] and received three doses of prophylactic antibiotics in the form of Cefuroxime 1.5 g on induction and 750 mg at 8 and 16 h post-operation. All the operations in this study were performed by middle grades on the regular trauma list, except on weekends where surgery was performed in emergency theatre but not beyond 22:00 h.
3. Results There were 71 females and 17 males with a mean age of 80, S.D. 10.04 and S.E. 0.7098. The mean age of the male group was 77.93, S.D. 10.89 and S.E. 1.660. The female mean age was 81.58, S.D. 9.684 and S.E. 0.7728. Of the 88 cases, there were 10 re-operations at a rate of 11.36%. Dislocation occurred in three cases at a rate of 3.4%. One case was treated by exchange to a better fitting prosthesis with a satisfactory result. One to a total hip replacement and a third to a Girdlestone arthroplasty. There were four cases of deep infection at a rate of 4.5%. In three cases the infection was treated by debridment and conversion to Girdlestone arthroplasty. In one case the infection was controlled by intravenous antibiotics and debridment and the prosthesis was retained with satisfactory results. Loosening developed in three cases at a rate of 3.4%. All the three cases were revised to total hip arthroplasty (Table 1).
4. Discussion The overall re-operation rate found in this study (11.4%) was comparable to the published series [4,10,11]. The dislocation rate was 3.4%, which falls within the dislocation rates reported in the literature [12,13]. None of the dislocated hemiarthroplasties was treatable by closed reduction, therefore requiring revision to either a better fitting prosthesis or to total hip replacement. These findings, however, are in agreement with the figures published that described poor outcome following closed reduction of uncemented prosthesis
[14]. Loosening of the prosthesis was identified in three cases all of which developed in the first year following the initial surgery. It was found that both dislocation and loosening were due to loose prostheses and in two cases the femoral stem was rotated in the medullary canal. It is recognised that the medullary canal in the elderly is wide due to osteoporosis, and does not allow an accurate fit with the Austin Moore prosthesis stem, which is only available in two standard stem measurements. Moreover, surgical techniques and adequate measurement play an important role in determining the outcome. A study on uncemented prosthesis concluded that insertion of uncemented prosthesis is a technically demanding task and accurate femoral head measurement and femoral stem preparation are essential to achieve good outcome [15]. The re-operation rate due to infection in this series was 4.5%. This rate is high compared to published series [12,16–18], with a poor success rate in retaining the prosthesis when compared to the literature [16]. Infection was satisfactorily treated with debridment and intravenous antibiotics in one out of four cases, while the remaining cases required conversion to Girdlestone arthroplasty. The causative organisms were Staphylococcus aureus, and MRSA was isolated in two of the cases. All the cases of Austin Moore hemiarthroplasty were performed in a conventionally ventilated theatre with the use of cotton drapes and surgical gowns. This suggests that the lack of water-proof drapes and surgical gowns as well as the lack of laminar ventilation are contributory factors in the higher incidence of deep infection [19–21]. We suggest that infection rates could be lowered by performing Austin Moore hemiarthroplasty in theatres equipped with laminar flow ventilation and by the use of impermeable drapes and surgical gowns to minimise bacterial dispersal from the patient and the operating team. Studies have shown that cotton drapes and gowns are poor bacterial barriers even when new [21,22] unlike non-woven fabrics, which produced a lower level of microbial contamination. In addition, laminar flow ventilation has been shown by many studies to reduce the infection rate following hip operations [23,24]. It is also believed that the combined use
Table 1 Re-operations performed following Austin Moore hemiarthroplasty Complication
Procedure
No.
Bacteriology
Percentage
Infection
Wound debridment Girdlestone arthroplasty Revision of prosthesis Revision to THR Revision to THR
1 3 2 1 3
Staphylococcus aureus (MRSA was isolated in two cases)a No bacterial growtha
4.5
No bacterial growtha
3.4
Dislocation Loosening Total a
10
Bacteriology results based on deep wound swab at the time of re-operation.
3.4
11.4
N. Tellisi, K.H.A. Wahab / Injury, Int. J. Care Injured 32 (2001) 465–467
of impermeable gowns and laminar ventilation achieves ultraclean air conditions and a lower level of wound contamination [19,25]. As a result of this study, all hip surgery operations in our unit are now performed in theatres equipped with a laminar flow ventilation system, and water-proof drapes and surgical gowns have now replaced the cotton fabrics. A re-audit of the rate of infection following the introduction of these measures is underway to assess the outcome.
[12]
[13]
[14] [15]
[16]
References [1] Audit Commission. United they stand: co-ordinating care for elderly patients with hip fracture. London: HMSO, 1995. [2] Hollingworth W, Todd JC, Parker MJ. The cost of treating hip fractures in the twenty-first century. J Public Health Med 1995;17(3):269 – 76. [3] Working Party for the Royal College of Physicians. Fractured neck of femur, prevention and management. J R Coll Physicians Lond 1989;23(1):8 – 12. [4] Skinner P, Riley D, Ellery J, Beaumont A, Coumine R, Shafighian B. Displaced subcapital fractures of the femur: a prospective randomized comparison of internal fixation, hemiarthroplasty and total hip replacement. Injury 1989;5(20):291 – 3. [5] Sochart HD. Poor fixation following fixation of displaced subcapital femoral fractures: Complacency in fracture reduction. Arch Orthop Trauma Surg 1998;117:379 – 82. [6] Alho A, Benterud GJ, Soloveiva S. Internally fixed femoral neck fractures: early prediction of failure in 203 elderly patients with displaced fractures. Acta Orthop Scand 1999;2(70):141 – 4. [7] Marti KR, Dunki Jacobs BP. Proximal femoral fractures. London: Medical Press, 1993. [8] Hui ACW, Anderson GH, Choudry R, Boyle J, Gregg PJ. Internal fixation or hemiarthroplasty for undisplaced fractures of the femoral neck in octogenarians. J Bone Joint Surg Br 1994;76B(6):891 – 4. [9] Hardinge K. The direct lateral approach to the hip. J Bone Joint Surg Br 1982;64-B(1):17 –9. [10] Gebhard JS, Amstutz HC, Zinar DM, Rorey FJ. A comparison of total hip replacement and hemiarthroplasty for treatment of acute fracture of the femoral neck. Clin Orthop 1992;282:123 – 31. [11] Lu-yao GL, Keller RB, Littenberg B, Wennberg JE. Outcome after displaced fractures of the femoral neck. A meta-analysis of
.
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
467
one hundred and six published reports. J Bone Joint Surg Br 1994;76(1):15 – 25. Jalovaara P, Heikki V. Quality of life after primary hemiarthroplasty for femoral fracture. Acta Orthop Scand 1991;62(2):208 – 17. Unwin AJ, Thomas M. Dislocation after hemiarthroplasty of the hip: a comparison of the dislocation rate after posterior and lateral approaches to the hip. Ann R Coll Surg Engl 1994;76(5):327 – 9. Maxwell HA, Turner PG. Dislocation of Austin Moore: is closed reduction justified? J R Coll Surg Edinb 1994;39(6):370 –1. Pryor GA. A study of the influence of technical adequacy on the clinical result of Austin Moore hemiarthroplasty. Injury 1990;21(6):361 – 5. Kuokkanen MOH, Suominen KP, Korkala LO. The late outcome of femoral neck fractures. Int Orthop 1990;14:377 –14380. Mackay DC, Harrison WJ, Bates JH, Dickenson D. Audit of deep wound infection following hip fracture surgery. J R Coll Surg Edinb 2000;45(1):56 – 9. Rao J, Parker MJ. Austin Moore hemiarthroplasty for hip fractures: An eight year follow up of a consecutive series of 500 patients. J Bone Joint Surg Br 2000;82-B:Suppl 164. Blomgren G, Hoborn J, Nystrom B. Reduction of contamination at total hip replacement by special working clothes. J Bone Joint Surg Br 1990;72-B:985 – 7. Bregman RBO, Hoborn J, Nachemson LA. Patient draping and staff clothing in the operating theatre: A microbiological study. Scand J Infect Dis 1985;17:421 – 6. Mitchell JN, Evans D, Kerr A. Reduction of skin bacteria in theatre air with comfortable, non-woven disposable clothing for operating-theatre staff. BMJ 1978;1:696 – 8. Nagai I, Kadota M, Takechi M, Kumamoto R, Nakano S, Jitsukawa S. Studies on the bacterial permeability of non-woven fabrics and cotton fabrics. J Hosp Infect 1985;7:261 – 8. Fitzgerald RH Jr, Bechtol CO, Eftekhar N, Nelson JP. Reduction of deep sepsis after total hip replacement. Arch Surg 1979;7(114):803 – 4. Ha’eri GB, Wiley AM. Total hip replacement in a laminar flow environment with special reference to deep infections. Clin Orthop 1980;148:163. Ahl T, Dalen N, Jorbeck H, Hoborn J. Air contamination during hip and knee arthroplasties. Horizontal laminar flow randomized vs. conventional ventilation. Acta Orthop Scand 1995;66(1):17 – 20. Sikorski JM, Barrington R. Internal fixation versus hemiarthroplasty for displaced subcapital fracture of the femur. A prospective randomised study. J Bone Joint Surg Br 1981;63-B(3):357 – 61.