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Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and preliminary results
Accepted Manuscript Title: Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and Preliminary results Authors: Ye Ye, Chen Ke, Tian Kewei, Li Wuyin, Cyril Mauffrey, David J. Hak PII: DOI: Reference:
S0020-1383(17)30530-2 http://dx.doi.org/doi:10.1016/j.injury.2017.08.017 JINJ 7347
To appear in:
Injury, Int. J. Care Injured
Accepted date:
6-8-2017
Please cite this article as: Ye Ye, Ke Chen, Kewei Tian, Wuyin Li, Mauffrey Cyril, Hak David J.Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and Preliminary results.Injury http://dx.doi.org/10.1016/j.injury.2017.08.017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and Preliminary results Ye Ye1 Chen Ke1 Tian Kewei1 Li Wuyin1 Cyril Mauffrey, MD, FACS2; David J. Hak, MD, MBA, FACS 2 Keywords: Buttress plate， Cannulated screws， Vertical unstable femoral neck fracture ; Pauwels type 3 fracture Corresponding authors at: Denver Health medical center, 777 Bannock street, 80204, Denver, CO, USA Keywords: Buttress plate， Cannulated screws， Vertical unstable femoral neck fracture , Pauwels type 3 fracture
1 2
Hip Injury Department, Henan Provincial Luoyang Orthopedic Hospital, Luoyang City, China Department of Orthopedic Surgery, University of Colorado/Denver Health Medical Center, Denver, CO USA
1
Objective: To evaluate the outcome and complications of unstable Pauwels type 3 femoral neck fractures treated with a combination fixation of three cannulated screws and a medial buttress plate. Patients and methods: From October 2015 to June 2016, 28 patients under 60 years of age with Pauwels type 3 femoral neck fracture were treated with open reduction and internal fixation using a direct anterior approach.
Fracture consisted of three
cannulated screws augmented with a medial buttress plate. All reductions achieved Garden’s alignment index grade one. Touch down weight bearing was permitted postoperatively for 6 weeks, and subsequently advanced to full weight bearing. One patient was lost to follow-up, which the remaining 27 patients were followed at 1 week, 6 weeks, 3 months, 6 months and 12 months post-operatively. Result: Union without femoral neck shortening was achieved in 89 % of cases. Implant failure was seen in 3 cases and was associated femoral neck shortening. Reduction loss with backing out of the cannulated screws occurred in these cases, and in one case there was also plate and screw breakage. There were no cases of avascular necrosis identified at a mean follow-up was 13.6 months Conclusion: At short time follow-up, treatment of Pauwels type 3 femoral neck fractures using cannulated screws combined with medial buttress plate improves the fracture union rate compared to historical series using cannulated screws alone. The method of medial buttress plate augmentation does not appear to increase any implant related complications, including avascular necrosis.
2
3
Introduction Femoral neck fractures in young adults usually result from high-energy trauma.
1
These injuries may involve a vertical fracture pattern resulting in a high shear load at the fracture site, and this may be associated with internal fixation failure rates.
2
Pauwels classified femoral neck fractures based on the degree of verticality of fracture line, with the higher grade category having a more vertical orientation. 3 Pauwels type 3 femoral neck fractures are the most vertical, and fixation of these fractures is associated with high shear loads leading to nonunion rates ranging from 16% to 59% and osteonecrosis rates ranging from 11% to 86%.
2, 4
Anatomic reduction and stable
internal fixation are necessary to achieve satisfactory femoral neck fracture treatment.5 Fixation options include cannulated screws, sliding hip screw with or without an additional derotation screw, cephalomedullary nails, and proximal femoral locking plates. Among Orthopedic trauma surgeons there is no consensus that a single fixation option is superior for treating these injuries.6 A recent meta-analysis of femoral neck fractures in young adults reported an overall reoperation rate of 18 %, nonunion rate of 9 %, avascular necrosis rate of 14 %, and an implant failure rate of nearly 10 %.7 A review of 62 Pauwels type 3 femoral neck fractures (37 of which were treated with cannulated screws and 25 with a fixedangle device) reported a nonunion rate of 16 %, and avascular necrosis rate of 11 % .2 In this series the nonunion rate was 19% for fractures treated with cannulated screws alone and 8% for those treated with a fixed-angle device.
4
To improve fixation stability, Mir and Collinge hypothesized applying the concept of buttress plate fixation to the treatment of vertical femoral neck fractures.8 A buttress plate placed in an anti-glide function can be applied antero-inferiorly over the fracture line and act to resist the shear forces seen in vertical femoral neck fractures. 9 This approach uses a modified Smith-Peterson approach that provides direct fracture site visualization for anatomical reduction and facilitates placement of a medial buttress plate. 10
Surgical technique The patient is placed in a supine position on a radiolucent table. A C-arm or Garm is used for intraoperative x-ray control to obtain an AP and true lateral view of the proximal femur. The direct anterior (modified Smith-Petersen) approach is used for this procedure. 10 This is an internervous approach between the femoral nerve and superior gluteal nerve and it can provide excellent visualization of the entire femoral neck for fracture reduction and medial buttress plate placement. A 10 to 15 cm skin incision begins approximately 2 cm lateral and 2 cm distal to the anterior superior iliac spine (ASIS). The incision is carried distally toward the lateral aspect of the knee.(Figure 1) Care should be taken to avoid possible damage to the lateral femoral cutaneous nerve (LFCN). The interval between the sartorius and the tensor fascia lata (Smith-Peterson interval) is bluntly dissected. The ascending branch of the lateral femoral circumflex artery (LFCA) is identified and ligated.(Figure 2) According to Ganz’s research, the deep branch of medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head. 11 LFCA and it’s branch are in the middle of the approach 5
and ligation of these vessels will not jeopardize the blood supply to femoral head. The internervous plane between the gluteus medius and rectus femoris is then identified. The hip capsule is exposed anterolaterally by mobilizing the gluteus minimus and tensor fascia lata laterally and the iliopsoas and rectus femoris medially. A ‘‘T’’- shaped capsulotomy is made sharply through the anterior capsule. The incision of capsular along the acetabular rim should not go too posterior to avoid possible damage to the MFCA entry point. After capsulotomy the hematoma is evacuated. One or two k-wires can be placed into the anterior femoral head and used as a joystick to manipulate the femoral head to assist in achieving anatomic reduction. Direct fracture visualization can help the surgeon to control the reduction quality. The reduction is confirmed by biplanar fluoroscopy and the cannulated screw guide wires introduced into femoral head through another small incision over the lateral aspect of the proximal femur. We usually choose partially threaded 7.3-mm cannulated screws and prefer to implant them in an inverted triangle configuration. After cannulated screw fracture is completed, the hip is flexed and externally rotated. (Figure 3) This position exposes the medial aspect of femoral neck and lesser trochanter in the operative field. (Figure 4) A 4 to 6 hole 1/3 tubular plate is contoured to fit the medial arch of the femoral neck and secured with 3.5-mm cortical screws. We typically under-contour the plate, since when it is fixed onto femoral neck the screws can push it to cortex and produce more buttress force against the medial femoral neck cortex. A screw is usually first placed in the middle aspect of the plate in order to allow rotation of the plate if adjustment of position is needed. The ideal position of the plate should be in the medial aspect of the
6
femoral neck. On the lateral view it can sometimes appear in a more anterior-medial position due to the anteversion of femoral neck. The screw proximal to the fracture line should be directed cephalad into the femoral head to avoid crossing the fracture line. We typically then place a third screw in the distal aspect of the plate.
Patients and methods We treated 28 patients with Pauwels type 3 femoral neck fracture under 60 year old with cannulated screws and medial buttress plate fixation from October 2015 to June 2016. The mean age of patients was 42.1 years (range, 29 – 57 years); 25 cases (89.2%) were male. All cases except one were followed at 1 week, 6 weeks, 3 months, 6 months and 1 year post-operatively. Fracture healing and complications were assessed by plain radiographs. Union was defined as the absence of visible fracture line on both the AP and lateral radiographs. Nonunion was identified as clearly visible fracture line one year postoperatively. (Figure 5)
Any degree of necrosis from
Steinberg stage 2 upwards on any of the follow-up radiographs was defined as avascular
necrosis.12
Results The mean follow-up was 13.6 months (range, 12 – 18 months). The operation was performed by the lead author (YY) for 15 patients (53.5%), a consultant orthopaedic surgeon for 11 patients (39.2%) and a trainee surgeon for 2 patients
7
(7.1%). The mean operative time was 71.4 minutes (range, 62 – 108 minutes). The mean blood loss was 270 ml (range 200ml - 450ml). The incidence of complications related to the fracture treatment are show in Table 1. No cases underwent revision during the follow-up period. In three cases the cannulated screws backed-out and in one of these cases the plate screws were found to have broken at 3 months follow-up. (Figure 6) This patient refused further follow-up or revision surgery because he had no apparent hip symptoms.
Femoral neck
shortening occurred in the other two patients in which cannulated screw back out occurred, but the fracture appeared radiographically healed in a malunited position. One of these patients reported mild pain with walking, while the other patient reported no symptoms. One patient complained of groin pain with deep hip joint flexion, but this resolved by 3 months post-operatively. In examining the patient’s radiographs and combined with the physical examination, this was felt potentially to be due to impingement between the high position plate and acetabulum or labrum when the hip is in deep flexion.(Figure 7) One patient reported LFCN injury symptoms that recovered in three months.
Discussion We found that buttress plate augmentation of cannulated screw fixation resulted in an 89 % union rate in a series of Pauwels type 3 femoral neck fractures treated by open reduction and internal fixation. This union rate is favorable comparable
8
to the literature for Pauwels type 3 fractures, in which nonunion rates ranging from 16% to 59% have been reported. 2, 4 We found no cases of avascular necrosis at short term follow-up, which is much lower than traditional treatment methods, but that may be due to the short follow up period and the small number of cases. Longer-term follow up examination is needed to determine the ultimate osteonecrosis rate among these patients. For Pauwels type 3 femoral neck fractures, the key to successful fracture treatment is for the fixation to resist the vertical shear force maintaining the reduction and fixation stability during the process of fracture healing without damaging the blood supply to the femoral head. A biomechanical analysis compared the strength of medial buttress augmented fixation with non-augmented fixation techniques in vertical shear femoral neck fractures.13 The constructs that were augmented with medial buttress fixation had significant higher stiffness and load to failure. One concern is whether this treatment approach might damage the femoral head blood supply. A classic study by Ganz has showed that the deep branch of MFCA provides the primary blood supply to the femoral head.11 The direct anterior approach to the hip has been widely accepted as the inter-nervous muscle sparing approach. The only structure damaged in this approach is the LFCA, which has been shown to have only limited relationship with the femoral head blood supply. In addition, the open surgical approach can evacuate the intracapsular hematoma that may contribute to the high pressure in the joint and may induce avascular necrosis of the femoral head. 14 The lack of avascular necrosis in our series at short term follow up supports that this 9
technique of open reduction and buttress plate fixation does not increase the osteonecrosis rate of the Pauwels type 3 fracture. For the plate choice we prefer to use a thin plate such as a 2.7mm or 3.5 mm third tubular plate. The plate thinness can reduce the possible irritation to the medial femoral neck structures and it still effectively buttresses the fracture. We do not use a reconstruction locking plate because the locked screws may prevent the dynamic compression between the fracture fragments post-operatively and increasing the risk of nonunion. In the combination fixation the plate function is only to resist the vertical shear stress and protect cannulated screw structure from failure before fracture union. Cannulated screws are still the most important implant in this fixation configuration. According to our short term follow-up, it does not increase any complication related to plate implant. The union rate is comparable to the best result in traditional methods. 7 Iatrogenic impingement should be avoided by careful attention to intra-operative plate placement, avoiding placing the buttress plate too superiorly or too anteriorly onto the femoral neck. Our study has a few notable limitations. The absence of a control group makes it difficult to make conclusions regarding the impact of this new technique and patientrelated factors that may affect outcome compared to the traditional techniques. The series is relatively small and the mean follow-up time of 13.6 months is not long enough to observe delayed development of avascular necrosis. Finally only plain radiographs were obtained and they are not sensitive to observe the early or minor necrosis in
10
femoral head. Strengths of this study are the high rate of follow-up and that all surgeons performing the operation were familiar with direct anterior approach.
Public disclosure of conflicts of interest to journals to which publications about the research are submitted or in public presentations of the research:
The Author(s) declare(s) that there is no conflict of interest.
David Hak, MD, MBA, FACS Interim Director Department of Orthopedics, Physical Medicine & Rehabilitation Denver Health Medical Center 777 Bannock Street MC 0188 Denver, Colorado 80204
[email protected] There is no “gold standard” for the treatment of Pauwels type 3 femoral neck fractures. For vertical fractures in young active patient the medial buttress plate has advantages in biomechanical testing and short time clinical follow up. This technique is likely most beneficial in young adults with vertical femoral neck fractures and its use should not be extrapolated to other fracture orientations or for femoral neck fractures in elderly patients. Future larger randomized trials comparing the new combination fixation with the tradition fixation would be beneficial in determining the indications and benefits of medial plate augmentation of femoral neck fracture fixation.
11
References 1. Robinson CM, Court-Brown CM, McQueen MM, Christie J. Hip fractures in adults younger than 50 years of age: epidemiology and results. Clin Orthop Relat Res. 1995; 312:238-246 2. Liporace F, Gaines R, Collinge C, Haidukewych GJ. Results of internal fxation of Pauwels type-3 vertical femoral neck fractures. J Bone Joint Surg Am. 2008; 90(8):1654-1659. 3. Pauwels F. Der Schenkelhalsbruch: Ein Mechanisches Problem. Stuttgart: Ferdinand Enke Verlag; 1935. 4. Protzman RR, Burkhalter WE. Femoral-neck fractures in young adults. J Bone Joint Surg Am. 1976; 58(5):689-695. 5. Panteli M, Rodham P, Giannoudis PV. Biomechanical rationale for implant choices in femoral neck fracture fixation in the non-elderly. Injury.2015;46(3):445–52. 6. Luttrell K, Beltran M, Collinge CA. Preoperative decision making in the treatment of high-angle “vertical” femoral neck fractures in young adult patients: an expert opinion survey of the Orthopaedic Trauma Association’s (OTA) membership. J Orthop Trauma. 2014; 28(9):e221-e225. 7. Slobogean GP, Sprague SA, Scott T, Bhandari M (2015) Complications following young femoral neck fractures. Injury 46(3):484–491.
12
8. Mir H, Collinge C. Application of a medial buttress plate may prevent many treatment failures seen after fxation of vertical femoral neck fractures in young adults. Med Hypotheses. 2015;84(5):429-433 9. Stacey S , Renninger C , Hak DJ , Mauffrey C .Tips and tricks for ORIF of displaced femoral neck fractures in the young adult patient .Eur J Orthop Surg Traumatol (2016) 26:355–363. 10. Molnar RB, Routt ML Jr: Open reduction of intracapsular hip fractures using a modifed Smith-Petersen surgical exposure.J Orthop Trauma 21:490–494, 2007. 11. Gautier E, Ganz K, Krugel N, et al. Anatomy of the medial femoral circumflex artery and its surgical implications. J Bone Joint Surg Br. 2000;82:679–683. 12. Steinberg ME, Hayken GD, Steinberg DR. A quantitative system for staging avascular necrosis. J Bone Joint Surg [Br] 1995;77-B:34–41. 13.Kunapuli SC, Schramski MJ, Lee AS, et al. Biomechanical analysis of augmented plate fxation for the treatment of vertical shear femoral neck fractures. J Orthop Trauma. 2015; 29(3):144-150 14. Swiontkowski MF, Winquist RA, Hansen ST Jr. Fractures of the femoral neck in patients between the ages of twelve and forty-nine years. J Bone Joint Surg Am. 1984 Jul;66(6):837-46.
13
Figure 1: Incision for anterior approach to the hip.
Figure 2: Identification and ligation of the LFCA ascending branch.
Figure 3: Flexion and external rotation of the hip to allow placement of the inferomedial plate.
Figure 4a: Medial view of the femoral neck fracture line.
Figure 4b: Inferomedial buttress plate position.
Figure 4c: Sawbones model showing position of the inferomedial plate.
Figure 5a: Pre-operative anteroposterior (AP) radiograph showing displaced femoral neck fracture
Figure 5b: AP radiograph 3 months post-operatively
Figure 5c: CT scan 3 months post-operatively demonstrating fracture union and no evidence of necrosis.
Figure 5d: AP radiograph 18 months post-operatively.
Figure 6: AP radiograph showing failure of fixation with backing out of screws, breakage of plate screws, and femoral neck shortening.
Figure 7a and 7b: AP and lateral radiographs of a patient that experienced hip pain with deep hip flexion.
Figure 7c: Sawbones model demonstrating possibility of acetabular/labral impingement with deep hip flexion.
14
Figure 1:
Figure 2:
Figure 3:
15
Figure 4a:
Figure 4b:
Figure 4c:
16
Figure 5a:
Figure 5b:
Figure 5c:
Figure 5d:
17
Figure 6:
Figure 7a:
Figure 7b:
18
Figure 7c:
19
Table I. Incidence of complications related to the fracture
Complications
Numbers
Percentage
Uneventful fracture healing
25
89.3%
Avascular necrosis
0
0%
Superficial or deep wound infection
0
0%
Non-union
3
10.7%
Implant failure (cannulated screw back out /screw 3
10.7%
or plate breakage)
LFCN injury
1
3.6%
Impingement
1
3.6%
20
S0020-1383(17)30530-2 http://dx.doi.org/doi:10.1016/j.injury.2017.08.017 JINJ 7347
To appear in:
Injury, Int. J. Care Injured
Accepted date:
6-8-2017
Please cite this article as: Ye Ye, Ke Chen, Kewei Tian, Wuyin Li, Mauffrey Cyril, Hak David J.Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and Preliminary results.Injury http://dx.doi.org/10.1016/j.injury.2017.08.017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Medial buttress plate augmentation of cannulated screw fixation in vertically unstable femoral neck fractures: Surgical technique and Preliminary results Ye Ye1 Chen Ke1 Tian Kewei1 Li Wuyin1 Cyril Mauffrey, MD, FACS2; David J. Hak, MD, MBA, FACS 2 Keywords: Buttress plate， Cannulated screws， Vertical unstable femoral neck fracture ; Pauwels type 3 fracture Corresponding authors at: Denver Health medical center, 777 Bannock street, 80204, Denver, CO, USA Keywords: Buttress plate， Cannulated screws， Vertical unstable femoral neck fracture , Pauwels type 3 fracture
1 2
Hip Injury Department, Henan Provincial Luoyang Orthopedic Hospital, Luoyang City, China Department of Orthopedic Surgery, University of Colorado/Denver Health Medical Center, Denver, CO USA
1
Objective: To evaluate the outcome and complications of unstable Pauwels type 3 femoral neck fractures treated with a combination fixation of three cannulated screws and a medial buttress plate. Patients and methods: From October 2015 to June 2016, 28 patients under 60 years of age with Pauwels type 3 femoral neck fracture were treated with open reduction and internal fixation using a direct anterior approach.
Fracture consisted of three
cannulated screws augmented with a medial buttress plate. All reductions achieved Garden’s alignment index grade one. Touch down weight bearing was permitted postoperatively for 6 weeks, and subsequently advanced to full weight bearing. One patient was lost to follow-up, which the remaining 27 patients were followed at 1 week, 6 weeks, 3 months, 6 months and 12 months post-operatively. Result: Union without femoral neck shortening was achieved in 89 % of cases. Implant failure was seen in 3 cases and was associated femoral neck shortening. Reduction loss with backing out of the cannulated screws occurred in these cases, and in one case there was also plate and screw breakage. There were no cases of avascular necrosis identified at a mean follow-up was 13.6 months Conclusion: At short time follow-up, treatment of Pauwels type 3 femoral neck fractures using cannulated screws combined with medial buttress plate improves the fracture union rate compared to historical series using cannulated screws alone. The method of medial buttress plate augmentation does not appear to increase any implant related complications, including avascular necrosis.
2
3
Introduction Femoral neck fractures in young adults usually result from high-energy trauma.
1
These injuries may involve a vertical fracture pattern resulting in a high shear load at the fracture site, and this may be associated with internal fixation failure rates.
2
Pauwels classified femoral neck fractures based on the degree of verticality of fracture line, with the higher grade category having a more vertical orientation. 3 Pauwels type 3 femoral neck fractures are the most vertical, and fixation of these fractures is associated with high shear loads leading to nonunion rates ranging from 16% to 59% and osteonecrosis rates ranging from 11% to 86%.
2, 4
Anatomic reduction and stable
internal fixation are necessary to achieve satisfactory femoral neck fracture treatment.5 Fixation options include cannulated screws, sliding hip screw with or without an additional derotation screw, cephalomedullary nails, and proximal femoral locking plates. Among Orthopedic trauma surgeons there is no consensus that a single fixation option is superior for treating these injuries.6 A recent meta-analysis of femoral neck fractures in young adults reported an overall reoperation rate of 18 %, nonunion rate of 9 %, avascular necrosis rate of 14 %, and an implant failure rate of nearly 10 %.7 A review of 62 Pauwels type 3 femoral neck fractures (37 of which were treated with cannulated screws and 25 with a fixedangle device) reported a nonunion rate of 16 %, and avascular necrosis rate of 11 % .2 In this series the nonunion rate was 19% for fractures treated with cannulated screws alone and 8% for those treated with a fixed-angle device.
4
To improve fixation stability, Mir and Collinge hypothesized applying the concept of buttress plate fixation to the treatment of vertical femoral neck fractures.8 A buttress plate placed in an anti-glide function can be applied antero-inferiorly over the fracture line and act to resist the shear forces seen in vertical femoral neck fractures. 9 This approach uses a modified Smith-Peterson approach that provides direct fracture site visualization for anatomical reduction and facilitates placement of a medial buttress plate. 10
Surgical technique The patient is placed in a supine position on a radiolucent table. A C-arm or Garm is used for intraoperative x-ray control to obtain an AP and true lateral view of the proximal femur. The direct anterior (modified Smith-Petersen) approach is used for this procedure. 10 This is an internervous approach between the femoral nerve and superior gluteal nerve and it can provide excellent visualization of the entire femoral neck for fracture reduction and medial buttress plate placement. A 10 to 15 cm skin incision begins approximately 2 cm lateral and 2 cm distal to the anterior superior iliac spine (ASIS). The incision is carried distally toward the lateral aspect of the knee.(Figure 1) Care should be taken to avoid possible damage to the lateral femoral cutaneous nerve (LFCN). The interval between the sartorius and the tensor fascia lata (Smith-Peterson interval) is bluntly dissected. The ascending branch of the lateral femoral circumflex artery (LFCA) is identified and ligated.(Figure 2) According to Ganz’s research, the deep branch of medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head. 11 LFCA and it’s branch are in the middle of the approach 5
and ligation of these vessels will not jeopardize the blood supply to femoral head. The internervous plane between the gluteus medius and rectus femoris is then identified. The hip capsule is exposed anterolaterally by mobilizing the gluteus minimus and tensor fascia lata laterally and the iliopsoas and rectus femoris medially. A ‘‘T’’- shaped capsulotomy is made sharply through the anterior capsule. The incision of capsular along the acetabular rim should not go too posterior to avoid possible damage to the MFCA entry point. After capsulotomy the hematoma is evacuated. One or two k-wires can be placed into the anterior femoral head and used as a joystick to manipulate the femoral head to assist in achieving anatomic reduction. Direct fracture visualization can help the surgeon to control the reduction quality. The reduction is confirmed by biplanar fluoroscopy and the cannulated screw guide wires introduced into femoral head through another small incision over the lateral aspect of the proximal femur. We usually choose partially threaded 7.3-mm cannulated screws and prefer to implant them in an inverted triangle configuration. After cannulated screw fracture is completed, the hip is flexed and externally rotated. (Figure 3) This position exposes the medial aspect of femoral neck and lesser trochanter in the operative field. (Figure 4) A 4 to 6 hole 1/3 tubular plate is contoured to fit the medial arch of the femoral neck and secured with 3.5-mm cortical screws. We typically under-contour the plate, since when it is fixed onto femoral neck the screws can push it to cortex and produce more buttress force against the medial femoral neck cortex. A screw is usually first placed in the middle aspect of the plate in order to allow rotation of the plate if adjustment of position is needed. The ideal position of the plate should be in the medial aspect of the
6
femoral neck. On the lateral view it can sometimes appear in a more anterior-medial position due to the anteversion of femoral neck. The screw proximal to the fracture line should be directed cephalad into the femoral head to avoid crossing the fracture line. We typically then place a third screw in the distal aspect of the plate.
Patients and methods We treated 28 patients with Pauwels type 3 femoral neck fracture under 60 year old with cannulated screws and medial buttress plate fixation from October 2015 to June 2016. The mean age of patients was 42.1 years (range, 29 – 57 years); 25 cases (89.2%) were male. All cases except one were followed at 1 week, 6 weeks, 3 months, 6 months and 1 year post-operatively. Fracture healing and complications were assessed by plain radiographs. Union was defined as the absence of visible fracture line on both the AP and lateral radiographs. Nonunion was identified as clearly visible fracture line one year postoperatively. (Figure 5)
Any degree of necrosis from
Steinberg stage 2 upwards on any of the follow-up radiographs was defined as avascular
necrosis.12
Results The mean follow-up was 13.6 months (range, 12 – 18 months). The operation was performed by the lead author (YY) for 15 patients (53.5%), a consultant orthopaedic surgeon for 11 patients (39.2%) and a trainee surgeon for 2 patients
7
(7.1%). The mean operative time was 71.4 minutes (range, 62 – 108 minutes). The mean blood loss was 270 ml (range 200ml - 450ml). The incidence of complications related to the fracture treatment are show in Table 1. No cases underwent revision during the follow-up period. In three cases the cannulated screws backed-out and in one of these cases the plate screws were found to have broken at 3 months follow-up. (Figure 6) This patient refused further follow-up or revision surgery because he had no apparent hip symptoms.
Femoral neck
shortening occurred in the other two patients in which cannulated screw back out occurred, but the fracture appeared radiographically healed in a malunited position. One of these patients reported mild pain with walking, while the other patient reported no symptoms. One patient complained of groin pain with deep hip joint flexion, but this resolved by 3 months post-operatively. In examining the patient’s radiographs and combined with the physical examination, this was felt potentially to be due to impingement between the high position plate and acetabulum or labrum when the hip is in deep flexion.(Figure 7) One patient reported LFCN injury symptoms that recovered in three months.
Discussion We found that buttress plate augmentation of cannulated screw fixation resulted in an 89 % union rate in a series of Pauwels type 3 femoral neck fractures treated by open reduction and internal fixation. This union rate is favorable comparable
8
to the literature for Pauwels type 3 fractures, in which nonunion rates ranging from 16% to 59% have been reported. 2, 4 We found no cases of avascular necrosis at short term follow-up, which is much lower than traditional treatment methods, but that may be due to the short follow up period and the small number of cases. Longer-term follow up examination is needed to determine the ultimate osteonecrosis rate among these patients. For Pauwels type 3 femoral neck fractures, the key to successful fracture treatment is for the fixation to resist the vertical shear force maintaining the reduction and fixation stability during the process of fracture healing without damaging the blood supply to the femoral head. A biomechanical analysis compared the strength of medial buttress augmented fixation with non-augmented fixation techniques in vertical shear femoral neck fractures.13 The constructs that were augmented with medial buttress fixation had significant higher stiffness and load to failure. One concern is whether this treatment approach might damage the femoral head blood supply. A classic study by Ganz has showed that the deep branch of MFCA provides the primary blood supply to the femoral head.11 The direct anterior approach to the hip has been widely accepted as the inter-nervous muscle sparing approach. The only structure damaged in this approach is the LFCA, which has been shown to have only limited relationship with the femoral head blood supply. In addition, the open surgical approach can evacuate the intracapsular hematoma that may contribute to the high pressure in the joint and may induce avascular necrosis of the femoral head. 14 The lack of avascular necrosis in our series at short term follow up supports that this 9
technique of open reduction and buttress plate fixation does not increase the osteonecrosis rate of the Pauwels type 3 fracture. For the plate choice we prefer to use a thin plate such as a 2.7mm or 3.5 mm third tubular plate. The plate thinness can reduce the possible irritation to the medial femoral neck structures and it still effectively buttresses the fracture. We do not use a reconstruction locking plate because the locked screws may prevent the dynamic compression between the fracture fragments post-operatively and increasing the risk of nonunion. In the combination fixation the plate function is only to resist the vertical shear stress and protect cannulated screw structure from failure before fracture union. Cannulated screws are still the most important implant in this fixation configuration. According to our short term follow-up, it does not increase any complication related to plate implant. The union rate is comparable to the best result in traditional methods. 7 Iatrogenic impingement should be avoided by careful attention to intra-operative plate placement, avoiding placing the buttress plate too superiorly or too anteriorly onto the femoral neck. Our study has a few notable limitations. The absence of a control group makes it difficult to make conclusions regarding the impact of this new technique and patientrelated factors that may affect outcome compared to the traditional techniques. The series is relatively small and the mean follow-up time of 13.6 months is not long enough to observe delayed development of avascular necrosis. Finally only plain radiographs were obtained and they are not sensitive to observe the early or minor necrosis in
10
femoral head. Strengths of this study are the high rate of follow-up and that all surgeons performing the operation were familiar with direct anterior approach.
Public disclosure of conflicts of interest to journals to which publications about the research are submitted or in public presentations of the research:
The Author(s) declare(s) that there is no conflict of interest.
David Hak, MD, MBA, FACS Interim Director Department of Orthopedics, Physical Medicine & Rehabilitation Denver Health Medical Center 777 Bannock Street MC 0188 Denver, Colorado 80204
[email protected] There is no “gold standard” for the treatment of Pauwels type 3 femoral neck fractures. For vertical fractures in young active patient the medial buttress plate has advantages in biomechanical testing and short time clinical follow up. This technique is likely most beneficial in young adults with vertical femoral neck fractures and its use should not be extrapolated to other fracture orientations or for femoral neck fractures in elderly patients. Future larger randomized trials comparing the new combination fixation with the tradition fixation would be beneficial in determining the indications and benefits of medial plate augmentation of femoral neck fracture fixation.
11
References 1. Robinson CM, Court-Brown CM, McQueen MM, Christie J. Hip fractures in adults younger than 50 years of age: epidemiology and results. Clin Orthop Relat Res. 1995; 312:238-246 2. Liporace F, Gaines R, Collinge C, Haidukewych GJ. Results of internal fxation of Pauwels type-3 vertical femoral neck fractures. J Bone Joint Surg Am. 2008; 90(8):1654-1659. 3. Pauwels F. Der Schenkelhalsbruch: Ein Mechanisches Problem. Stuttgart: Ferdinand Enke Verlag; 1935. 4. Protzman RR, Burkhalter WE. Femoral-neck fractures in young adults. J Bone Joint Surg Am. 1976; 58(5):689-695. 5. Panteli M, Rodham P, Giannoudis PV. Biomechanical rationale for implant choices in femoral neck fracture fixation in the non-elderly. Injury.2015;46(3):445–52. 6. Luttrell K, Beltran M, Collinge CA. Preoperative decision making in the treatment of high-angle “vertical” femoral neck fractures in young adult patients: an expert opinion survey of the Orthopaedic Trauma Association’s (OTA) membership. J Orthop Trauma. 2014; 28(9):e221-e225. 7. Slobogean GP, Sprague SA, Scott T, Bhandari M (2015) Complications following young femoral neck fractures. Injury 46(3):484–491.
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8. Mir H, Collinge C. Application of a medial buttress plate may prevent many treatment failures seen after fxation of vertical femoral neck fractures in young adults. Med Hypotheses. 2015;84(5):429-433 9. Stacey S , Renninger C , Hak DJ , Mauffrey C .Tips and tricks for ORIF of displaced femoral neck fractures in the young adult patient .Eur J Orthop Surg Traumatol (2016) 26:355–363. 10. Molnar RB, Routt ML Jr: Open reduction of intracapsular hip fractures using a modifed Smith-Petersen surgical exposure.J Orthop Trauma 21:490–494, 2007. 11. Gautier E, Ganz K, Krugel N, et al. Anatomy of the medial femoral circumflex artery and its surgical implications. J Bone Joint Surg Br. 2000;82:679–683. 12. Steinberg ME, Hayken GD, Steinberg DR. A quantitative system for staging avascular necrosis. J Bone Joint Surg [Br] 1995;77-B:34–41. 13.Kunapuli SC, Schramski MJ, Lee AS, et al. Biomechanical analysis of augmented plate fxation for the treatment of vertical shear femoral neck fractures. J Orthop Trauma. 2015; 29(3):144-150 14. Swiontkowski MF, Winquist RA, Hansen ST Jr. Fractures of the femoral neck in patients between the ages of twelve and forty-nine years. J Bone Joint Surg Am. 1984 Jul;66(6):837-46.
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Figure 1: Incision for anterior approach to the hip.
Figure 2: Identification and ligation of the LFCA ascending branch.
Figure 3: Flexion and external rotation of the hip to allow placement of the inferomedial plate.
Figure 4a: Medial view of the femoral neck fracture line.
Figure 4b: Inferomedial buttress plate position.
Figure 4c: Sawbones model showing position of the inferomedial plate.
Figure 5a: Pre-operative anteroposterior (AP) radiograph showing displaced femoral neck fracture
Figure 5b: AP radiograph 3 months post-operatively
Figure 5c: CT scan 3 months post-operatively demonstrating fracture union and no evidence of necrosis.
Figure 5d: AP radiograph 18 months post-operatively.
Figure 6: AP radiograph showing failure of fixation with backing out of screws, breakage of plate screws, and femoral neck shortening.
Figure 7a and 7b: AP and lateral radiographs of a patient that experienced hip pain with deep hip flexion.
Figure 7c: Sawbones model demonstrating possibility of acetabular/labral impingement with deep hip flexion.
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Figure 1:
Figure 2:
Figure 3:
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Figure 4a:
Figure 4b:
Figure 4c:
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Figure 5a:
Figure 5b:
Figure 5c:
Figure 5d:
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Figure 6:
Figure 7a:
Figure 7b:
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Figure 7c:
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Table I. Incidence of complications related to the fracture
Complications
Numbers
Percentage
Uneventful fracture healing
25
89.3%
Avascular necrosis
0
0%
Superficial or deep wound infection
0
0%
Non-union
3
10.7%
Implant failure (cannulated screw back out /screw 3
10.7%
or plate breakage)
LFCN injury
1
3.6%
Impingement
1
3.6%
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