Background：
A prospective clinical trial was conducted to evaluate the conjunctive use of an extramedullary device and the bridge-plating technique in the treatment of comminuted subtrochanteric fractures with major extension into the femoral shaft.
Methods：
A Winquist criteria was used to classify 3 fracture patterns. The type 3 fractures were excluded from this study because of great extent of the fracture zone for which the bridge-plating technique is not indicated. There were 14 men and 6 women, with a mean age of 49 (range, 17-76) years. A dynamic hip screw (DHS) with a long side plate was chosen as the fixation device because of the small learning curve.
Results：
The fractures united at a mean of 7.6 (range, 3-15) months postoperatively. Mobility was scored at 9 points in 18 patients and 6 points in 2 patients (Mobility score of Parker & Palmer). Pain was absent in 14, mild in 3, and moderate in 3 patients. Two limbs were shortened by 1 and 1.5 cm, respectively.
Conclusion：
Our results indicate that DHS fixation using the bridge-plating technique leads to union of all comminuted Winquist types 1 and 2 fractures without major complications, and it is a valuable alternative to new intramedullary devices. This procedure offers the significant advantage of being less technically demanding.
(Chang Gung Med J 2002;25:803-10)
Keywords：
bridge-plating osteosynthesis, subtrochanteric fracture, dynamic hip screw.

The subtrochanteric region extends from the upper border of the lesser trochanter to 5 cm distal to it.(1,2) This region is subjected to high compressive forces medially and tensile forces laterally, which can lead to fatigue failure of implants. It represents a transition zone from the cancellous bone of the trochanteric area to the cortical bone of the femoral shaft and is slow to heal when injured. The treatment of the comminuted fracture of the subtrochanteric region is problematic. Only a durable and long implant that is firmly anchored above and below the fracture region will allow early weight bearing.(3) The best treatment for such kind of fractures is biological indirect reduction and splinting by a new generation of intramedullary nails, yet it is technically demanding.(4-7)
The DHS (dynamic hip screw, Synthes, Basel, Switzerland) is widely used in the treatment of trochanteric fractures. It provides a firm upper anchorage with a 12.5 mm lag screw in the femoral head proximally and a long side plate (up to 260 mm in length) securely fixed in the femoral shaft distally. But it requires large exposures. The preservation of blood supply with untouched fragment might accelerate union. The treatment should aim at restoration of bone length, axial and torsional alignment. The fragments are not directly manipulated, and their soft tissue attachment is not disturbed; instead the area of comminution is bridged with a plate, which is fixed to the proximal and distal fragments.(8-13) A prospective clinical trial was conducted to evaluate the conjunctive use of the DHS and bridge-plating technique for the treatment of comminuted subtrochanteric fractures.

METHODS

Between January 1997 and September 1998, 20 patients with comminuted subtrochanteric fractures underwent bridge-plating osteosynthesis using DHS. All fractures were caused by high-velocity accidents. Sixteen patients were involved in motor-vehicle accidents, and 4 had fallen from a height. Eleven had multiple traumas. Eighteen fractures were closed, and 2 were open. The Winquist criteria was used to classify the fracture patterns: Type 1, true subtrochanteric fractures, with the proximal fragment intact to a level below the lesser trochanter; type 2, the greater trochanter and piriform fossa intact, but the lesser trochanter fractured; and type 3, the subtrochanteric fracture extending into the greater trochanter and piriform fossa, with or without loss of continuity of the lesser trochanter (Fig. 1).(14) Type 3 fractures were excluded from this study because of the great extent of the fracture zone for which the bridge-plating technique is not indicated. There were 14 men and 6 women with a mean age of 49 (range, 17-76) years in the present study.
The DHS entry site, and the proper length of the plate were judged from the radiographs of the opposite limb. Operations were carried out by the senior surgeon under general or spinal anesthesia. Traction was applied to the injured leg by a supracondylar Kirschner wire, or by a padded holder on the foot. A padded perineal post was used for countertraction. The unaffected limb was placed in hip abduction and knee flexion. Closed reduction was performed under fluoroscopic guide. A lateral approach was used as described previously.(15) The vastus lateralis was mobilized from the linea aspera and reflected anteriorly, revealing only the lateral aspect of the proximal femur. Hoffman retractors were placed only on the proximal and distal main fragments and not in the area of comminution. The DHS with 135o side plate was mounted to the lag screw, tightened, and secured to the distal fragment with bone holding forceps. The fragments lying medially were indirectly reduced by overtraction and careful manipulation of the larger ones with the aim of bringing them close to the plate and fixing them by interfragment screws. Small fragments were left undisturbed. Axial alignment, rotation, and length were checked, and the plate was fixed by at least 3 screws. Regardless of the severity of comminution, no initial bone graft was used in any patient.
Postoperative management consisted of active exercise of the quadriceps and early ambulation unless associated with other injuries or the poor general conditions. Partial weight bearing (20-30 kg) was allowed as soon as the patient could tolerate it, and full weight bearing was begun after 3 to 6 months based on the degree of comminution of the fracture. Patients were evaluated at 4- to 8-week intervals until fracture union and at 3- to 6-month intervals thereafter. The operation time, blood loss, ambulation level, the union time, and complications were recorded.
The activities of daily living and level of pain were assessed 12 months after fractures. Walking ability was evaluated according to the criteria of Parker (Table 1).(16) Pain was scored as absent when no painkiller were used, mild when only occasional oral painkiller were used, moderate when they were used regularly, or severe when the pain was difficult to treat with oral painkillers or when narcotic analgesics were used regularly.

RESULTS

Nine were Winquest type 1, and 11 type 2 fractures. Fourteen were operated on the day of admission or the next day. The median length of stay in hospital was 11 (range, 6-17) days. The operation time averaged 60 (range, 50-80) minutes, and blood loss 450 (range, 200-700) ml (Table 2).
Union was defined as callus formation at the fracture site, with the fracture line visible for less than a quarter of the circumference. All fractures united after a mean of 7.6 (range, 3-15) months without additional procedures (Fig. 2, 3). Two patients underwent implant removal because of hip pain after complete union. The patients started to have ambulation training at an average of 2.7 (range, 1-7) days after surgery. Full weight bearing was delayed for 3 months in all patients. Mobility was scored as 9 points in 18 patients and 6 points in 2 patients 12 months after fractures. At the same time, pain was absent in 14, mild in 3, and moderate in 3 patients.
Two patients had superficial wound infection and were treated with parenteral antibiotics for 1 week. No additional surgery was performed in these 2 patients. There was no significant varus/valgus malunion but 2 limbs were shortened with by 1 and 1.5 cm respectively and no patient had significant rotational malalignment as determined by clinical examination.

DISCUSSION

In general, 7% to 20% of the proximal femur fracture occurred over the subtrochanteric region.(1,17-19) The treatment of the comminuted subtrochanteric fractures remains a challenge, and there are few reported.(5,20,21) No single treatment option has generally been accepted as the method of choice. There were high rates of delayed union, malunion, and implant failure.(1,22) Classification of these fractures based on therapeutic criteria has undergone modifications through the years.(23,24) The adapted classification system in the present study was developed for general fractures of the long bones. It entails the specific fracture anatomy included in the present study.
The advocated treatment for these fracture patterns is a locked nail for Winquist types 1 and 2 fractures and a dynamic condylar screw or angle blade plate with a long side plate for Winquist type 3 fractures.(23,25-28) Rigid intramedullary devices include the Zickle nail, Russell-Taylor reconstruction nail, and long Gamma nail. Advantages listed for these devices include their load-sharing capacity, decreased operative time, and the possibility of performing a closed reduction.(5,29-31) There are favorable results with intramedullary nailing in extensive proximal femoral fractures, but other experts have noted unacceptably high complication rates with this device. Disadvantages are technical difficulties, the requirement of an intact trochanteric mass, and trouble in controlling rotation and shortening.(6,7,17) Unreamed intramedullary nails have reduced but not eliminated cardiopulmonary complications.(15) Thus, there is still debate whether to nail femur fractures in patients in shock and concomitant chest trauma. It has been suggested that long bone fractures of these patients should be plated or stabilized with an external fixator.
The underlying premise of this study was to evaluate the use of a commonly available extramedullary device for comminuted and extensive subtrochanteric fractures, combined with the bridge- or so-called biological plating technique. The DHS was chosen because it is an easier and safer fixation procedure than the dynamic condylar screw and the angle blade plate. A DHS has been widely used in the treatment of stable peritrochanteric fractures and has been very successful. In contrast to the literature, this study demonstrates a more-expanded use of the DHS with a long side plate. In our experience, the DHS with a long side plate can be used for comminuted subtrochanteric fractures as distal as 20 cm below the lesser trochanter. Some of the problems that have been pointed out with the DHS in the treatment of highly unstable peritrochanteric fractures are worth considering and include the basic problems of lag screw cutout, varus angulation, limb shortening, and femoral shaft medialization. These problems did not occur in our series partially due to delayed full weight bearing for at least 3 months after operation in our patients. In our series, trochanteric fractures with subtrochanteric extension (Winquist type 3 fractures) were treated with a modified trochanteric stabilizing plate and were excluded from this study. In agreement with the majority of the current literature, medial cortex reconstruction and initial bone grafting were not performed in our patients. It appears from this study that better results are achieved by preservation of medial soft tissue, and that a bone graft is unnecessary in comminuted fractures treated with the bridge-plating technique.(1,10) The essence of the concept of bridge plating introduced by Perren is an indirect reduction technique, and the philosophy emphasizes maximal exploitation of implants and reduction tools to avoid unnecessary intraoperative soft-tissue stripping and to achieve stable and satisfactory (although not necessarily anatomic) reduction.(1,10) This is in some contrast to the previous concept of rigid internal fixation of metaphyseal and diaphyseal fractures. Although not all series give details of all scored items, the results in the present study are quite comparable with those using the new intramedullary devices reported in the literature.(20,21,32)
In conclusion, our findings indicate that DHS fixation using the bridge-plating technique leads to union of all comminuted Winquist types 1 and 2 fractures without major complications, and that it is a valuable alternative to new intramedullary devices. This procedure offers significant advantages of being less technically demanding and more cost effective. The absence of ununited fractures and implant fatigue failure indicates the direct benefits of the bridge-plating technique, and it is comparable with new intramedullary nailing.

REFERENCES

1. Kinast C, Bolhofaner BR, Mast JW, Ganz R. Subtrochanteric fractures of the femur- results of treatment with the 95 condylar blade plate. Clin Orthop 1989; 238:122-30.
2. Parker MJ, Dutta BK, Sivaji C, Pryor GA. Subtrochanteric fractures of the femur. Injury 1997;28:91-5.
3. Tencer AF, Johnson KD, Johnson DW, Gill K. A biomechanical comparison of various methods of stabilization of subtrochanteric fractures of the femur. J Orthop Res 1984;2:297-305.
4. Stapert JL, Geesing CLM, Dunki PB, de Wit R, Vierhout PAM. First experience with the long Gamma nail. J Trauma 1993;34:394-400.
5. Barquet A, Francescoli L, Rienzi D, Lopez L. Intertrochanteric-subtrochanteric fractures: treatment with the long Gamma nail. J Orthop Trauma 2000;14:324-8.
6. Thomas WG, Villar RN. Subtrochanteric fractures: Zickle nail or nail-plate. J Bone Joint Surg Br 1986;68:255-9.
7. Waddell JP. Subtrochanteric fractures of the femur: a review of 130 patients. J Trauma 1979;582-92.
8. Johnson E. Combined direct and indirect reduction of comminuted four-part intra-articular T-type fractures of the distal femur. Clin Orthop 1988;231:154-62.
9. Bolhofner BR, Carmen B, Clifford P. The results of open reduction and internal fixation of distal femur fractures using a biologic (indirect) reduction technique. J Orthop Trauma 1996;10:372-7.
10. Perren SM. The concept of biological plating using the limited contact-dynamic compression plate (LC-DCP)-scientific background, design and application. Injury 1991;22:1-5.
11. Cerber C, Mast JW, Ganz R. Biological internal fixation of fractures. Acta Orthop Trauma Surg 1990;109:295-303.
12. Ostrum RF, Geel C. Indirect reduction and internal fixation of supracondylar femur fractures without bone graft. J Orthop Trauma 1995;9:278-84.
13. Krettek C, Schandelmaier P, Miclau T, Tscherne H. Minimally invasive percutaneous plate osteosynthesis (MIPPO) using the DCS in proximal and distal femoral fractures. Injury 1997;28:20-30.
14. Winquist RA. Locked femoral nailing. J Am Acad Orthop Surg 1993;1:95-105.
15. Chrisovitsion JP, Xenakis T, Papakostides KG, Skaltsoyannis N, Grestas A, Soucacos PN. Bridge plating osteosynthesis of 20 comminuted fractures of the femur. Acta Orthop Scand 1997;68:72-6.
16. Parker MJ, Palmer CR. A new mobility score for predicting mortality after hip fracture. J Bone Joint Surg Br 1993;75:797-8.
17. Schatzker J, Waddel JP. Subtrochanteric fractures of the femur. Orthop Clin North Am 1980;145:539-43.
18. Fielding WJ. Subtrochanteric fractures. Clin Orthop 1973;192:86-91.
19. Johonson LL, Lottes JO, Arnot JP. The utilization of the Holt nail for proximal femoral fractures. A study of 146 patients. J Bone Joint Surg Am 1968;50:67-71.
20. Doorn R van, Stapert JWJL. The long Gamma nail in the treatment of 329 subtrochanteric fractures with major extension into the femoral shaft. Eur J Surg 2000; 166:240-6.
21. Hotz TK, Zellweger R, Kach KP. Minimal invasive treatment of proximal femur fractures with the long Gamma nail: indication, technique, results. J Trauma 1999;47:942-5.
22. Blatter G, Janssen M. Treatment of subtrochanteric fractures of the femur: reduction on the traction table and fixation with dynamic condylar screw. Arch Orthop Trauma Surg 1994;113:138-41.
23. Bucholz RW, Brunback RJ. Fractures of the shaft of the femur. In: Fractures in Adults, 4th ed, ed by Rockwood CA, Green DP, Bucholz RW, Heckman JD. Philadelphia: Lippincott-Raven, 1996:1827-918.
24. Gehrchen PM, Nielsen JO, Olesen B, Andresen BK. Seinsheimer's classification of subtrochanteric fractures. Poor reproducibility of 4 observers' evaluation of 50 cases. Acta Orthop Scand 1997;68:524-6.
25. Brien W, Wiss D, Decker V, Lehman T. Subtrochanteric femur fractures: a comparison of the Zickel nail, 95 degrees blade plate, and interlocking nail. J Orthop Trauma 1991;5:458-64.
26. Kang S, McAndrew MP, Johnson KD. The reconstruction locked nail for complex fractures of the proximal femur. J Orthop Trauma 1995;9:453-63.
27. Kyle RF, Cabanela ME, Russell TA. Fractures of the proximal part of the femur. Instruct Course Lect 1995; 44:227-53.
28. Sanders R, Regazzoni P. Treatment of subtrochanteric fractures using the dynamic condylar screw. J Orthop Trauma 1989;3:206-13.
29. AlhoA, Ekeland A, Grogaard B, Dokke JR. A locked hip screw-intramedullary nail (cephalomedullary nail) for the treatment of fractures of the proximal part of the femur combined with fractures of the femoral shaft. J Trauma 1996;40:10-6.
30. Bose WJ, Corces A, Anderson LD. A preliminary experience with the Russell-Taylor reconstruction nail for complex femoral fractures. J Trauma 1992;32:71-6.
31. Browner BD, Cole JD. Current status of locked intramedullary nailing: a review. J Orthop Trauma 1987; 1:183-95.
32. Valverde JA, Alonso MG, Porro JG, Rueda D, Larrauri PM, Soler JJ. Use of the Gamma nail in the treatment of fractures of the proximal femur. Clin Orthop 1998; 350:56-61.

From the Division of Trauma & Emergency, Department of Orthopedic Surgery; 1Division of Orthopedic Surgery, Department of Surgery, Chung Gung Memorial Hospital, Taipei; Chang Gung University, Taoyuan.
Received: Jun. 15, 2002; Accepted: Oct. 31, 2002
Address for reprints: Dr. Po-Cheng Lee, Division of Trauma & Emergency Surgery, Department of Orthopedic Surgery, Chung Gung Memorial Hospital. 5, Fu-Shin Street, Kweishan, Taoyuan 333, Taiwan, R.O.C. Tel: 886-3-3281200 ext. 2158; Fax: 886-3-3285818; E-mail: leebone@cgmh.org.
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