Surgical dislocation of the hip for reduction of acetabular fracture and evaluation of chondral damage

Journal of Orthopaedic Surgery 2014;22(1):18-23 Surgical dislocation of the hip for reduction of acetabular fracture and evaluation of chondral damage Lalit Maini, Sahil Batra, Sumit Arora, Shailendra Singh, Santosh Kumar, VK Gautam Department of Orthopaedic Surgery, The Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India ABSTRACT Purpose. To assess the outcome of open reduction and internal fixation combined with surgical dislocation of the hip for displaced acetabular fractures. Methods. 20 men and 2 women aged 20 to 55 (mean, 28) years underwent open reduction and internal fixation combined with surgical dislocation of the hip for displaced acetabular fracture. The most common fracture pattern was bicolumnar (n=12), followed by transverse (n=6) and T-type (n=4). Femoral head chondral lesions were classified as grade 0 (no defect) to grade 4 (osteochondral defect). Fracture fragments were fixed with titanium plates and screws, and the femoral head was redislocated to inspect for intraarticular screws. The association between functional status and acetabular fracture pattern and femoral head chondral lesions was explored. Results. Nine patients had chondral lesions in the femoral head (mostly in the anterosuperior zone), but none in the acetabulum. All femoral heads were viable. Reduction was anatomic in 6 patients and satisfactory in 16. Functional outcome was very good in 6 patients, good in 13, medium in 2, and fair in one. No patient developed avascular necrosis of the femoral head. Four patients had iatrogenic sciatic nerve palsy. One patient developed early degenerative hip arthritis and underwent total hip arthroplasty 14 months later. Conclusion. Surgical dislocation of the hip facilitated anatomic reduction and inspection of any chondral lesions. It did not result in avascular necrosis of the femoral head. Key words: acetabulum; femur head necrosis; fracture fixation INTRODUCTION Anatomic restoration of the articular surface for displaced acetabular fractures using open reduction and internal fixation achieves good outcomes. 1 7 The decision for surgical treatment, the surgical approach, and the accuracy of reduction are affected by the surgeon s expertise. 8 For bicolumnar, T-type, Address correspondence and reprint requests to: Sahil Batra, Department of Orthopaedic Surgery, The Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, 110002, India. Email: sahil.ortho.dhs@gmail.com

Vol. 22 No. 1, April 2014 Surgical dislocation of the hip for reduction of acetabular fracture 19 and transverse acetabular fractures, surgical dislocation of the femoral head enables inspection and repair of cartilaginous lesions of the labrum, acetabulum, and femoral head. 9 It also facilitates fracture reduction under direct vision and avoids intra-articular penetration of screws. In addition, it provides predictable mid-term outcomes, with no development of avascular necrosis of the femoral head. 9 However, its efficacy in restoring articular congruity and its safety pertaining to vascularity of the femoral head remain controversial. We assessed the outcome of open reduction and internal fixation combined with surgical dislocation of the hip for displaced acetabular fractures. MATERIALS AND METHODS This study was approved by the institutional review board of our hospital. Between August 2009 and July 2011, 20 men and 2 women aged 20 to 55 (mean, 28) years underwent open reduction and internal fixation combined with surgical dislocation of the hip for displaced acetabular fractures. 19 of them were younger than 40 years of age. Patients underwent surgery within 3 weeks of injury. Patients with associated posterior hip dislocation, anterior wall/ column fractures only, or ipsilateral femoral neck/ intertrochanteric fractures were excluded, as were those with an associated head injury, abdominal injuries requiring surgery, or Morel-Lavallée lesions. Those who had surgery through the ilio-inguinal approach or who were managed conservatively were also excluded. The most common fracture pattern 10 was bicolumnar (n=12, Fig. 1), followed by transverse (n=6) and T-type (n=4). The most common injury mechanism was high-energy road traffic accident. Fracture lines were redrawn on a bony pelvis model to determine the operative approach. A lateral incision centred over the greater trochanter (as used in the Kocher-Langenbeck approach) was made. The gluteus maximus fibres were split to expose the trochanteric bursa. The posterior border of the gluteus medius tendon and vastus lateralis tendon were identified. A digastric trochanteric flip osteotomy 1 was made using an oscillating saw, while keeping the whole vastus lateralis attachment and most of the gluteus medius attachment. Care was taken to preserve the short external rotators and the deep branch of the medial circumflex femoral artery by avoiding too medial an osteotomy. The trochanteric fragment of around 1.5 cm thickness, with the attached gluteus medius (a) (b) (c) (d) (e) (f) Figure 1 (a) Anteroposterior radiograph showing breech in the right ilio-pectineal and ilio-ischial lines with anterior column fragment free from acetabulum, (b) iliac oblique radiograph showing the displaced posterior column, (c) obturator oblique radiograph showing a `spur sign suggestive of a bicolumnar acetabular fracture, (d) axial, (e) sagittal, and (f) coronal computed tomographic scans showing the displaced posterior column.

20 L Maini et al. Journal of Orthopaedic Surgery proximally and the vastus lateralis distally, was flipped anteriorly. The plane between the inferior border of the gluteus minimus and the cranial border of the piriformis was entered. The leg was progressively flexed and externally rotated to facilitate the release of the gluteus minimus, vastus lateralis, and vastus intermedius from the underlying bone and capsule. Dissection of the gluteus minimus exposed the anterosuperior joint capsule. A Z-shaped capsulotomy was performed close to the acetabular margin (the labrum was preserved) cranially and Figure 2 The acetabulum is inspected following surgical hip dislocation. posteriorly and directed towards the proximal femur anteriorly and inferiorly. This was modified, depending upon the anatomy of fracture fragments. The hip was dislocated anteriorly by adduction and external rotation of the leg. The femoral head ligament may be cut for complete dislocation. The femoral head and acetabulum were inspected for chondral lesions (Fig. 2). The retroacetabular area was accessed by entering the plane between the piriformis and superior gemellus, or the plane between the inferior gemellus and obturator externus, or alternatively, the tendons of the proximal external rotators were cut (with a minimum distance of 2 cm from the intertrochanteric crest to avoid injuring the deep branch of the medial femoral circumflex artery). Fracture fragments were fixed with titanium plates and screws, and the femoral head was redislocated to inspect for intra-articular screws. The trochanteric osteotomy was fixed with two 6.5-mm solid lag screws. Femoral head chondral lesions were classified as grade 0 (no defect), grade 1 (superficial chondral abrasion), grade 2 (partial thickness chondral defect), grade 3 (full thickness chondral defect with exposed intact subchondral bone), and grade 4 (osteochondral defect). 11 The femoral head was divided into 8 zones (medial anterosuperior, lateral anterosuperior, (a) (b) (c) (d) (e) (f) Figure 3 (a) Anteroposterior, (b) iliac oblique, and (c) obturator oblique radiographs after open reduction and internal fixation, (d) axial, (e) sagittal, and (f) coronal computed tomographic scans showing reduction of the posterior column with a congruent articular surface.

Vol. 22 No. 1, April 2014 Surgical dislocation of the hip for reduction of acetabular fracture 21 medial anteroinferior, lateral anteroinferior, medial posterosuperior, lateral posterosuperior, medial posteroinferior, lateral posteroinferior) and the lesion location was recorded. Vascularity of the femoral head was assessed by drilling a 2-mm hole in the femoral head neck junction. 12 Fresh pulsatile blood from the drill hole was indicative of an intact blood supply for the femoral head. Postoperatively, reduction status was evaluated (Fig. 3). 13 At day 5, hip mobilisation exercises were started. Patients were kept on skeletal traction for 3 weeks and non weight bearing for 6 to 12 weeks, depending on stability and fixation of the joint. Functional status was assessed every 3 months. 14 Radiographs were taken monthly for the initial 6 months and thereafter every 3 months. Full weight bearing was allowed after 12 to 20 weeks. Magnetic resonance imaging (MRI) was performed after 6 months to evaluate the vascularity of the femoral head (Fig. 4). RESULTS The mean intra-operative blood loss was about 800 (range, 350 1800) ml, and the mean units of blood transfused were 1.6 (range, 1 3). The mean surgical time was 2.5 (range, 1.5 4) hours. Nine patients had chondral lesions in the femoral head (mostly in the anterosuperior zone), but none in the acetabulum (Table 1). All femoral heads were viable. Reduction was anatomic in 6 patients and satisfactory in 16; no reduction was unsatisfactory (Fig. 3 and Table 1). The mean follow-up period was 19 (range, 12 36) months. At 12 months, the functional outcome was very good in 6 patients, good in 13, medium in 2, and fair in one; no patient had poor functional outcome (Table 1). Trochanteric osteotomy was healed in all patients. No patient developed avascular necrosis of the femoral head. Four patients had iatrogenic sciatic nerve palsy. One patient had wound infection at week 4 and underwent debridement. One patient developed early degenerative hip arthritis and underwent total hip arthroplasty 14 months later. Figure 4 Magnetic resonance imaging at 6 months showing normal signal intensity of the femoral head (an implant artefact is noted at the trochanteric region). DISCUSSION The Kocher-Langenbeck approach is commonly used for fixation of acetabular fractures, especially for Table 1 Femoral head chondral lesion grade, reduction outcome, and functional outcome according to type of acetabular fracture Parameter Type of acetabular fracture (no. of patients) Bicolumnar (n=12) Transverse (n=6) T-type (n=4) Femoral head chondral lesions Grade 0 7 4 2 Grade 1 2 1 1 Grade 2 2 1 0 Grade 3 1 0 1 Grade 4 0 0 0 Reduction Anatomic 1 3 2 Satisfactory 11 3 2 Unsatisfactory 0 0 0 Functional outcome at 12 months Very good 1 3 2 Good 9 3 1 Medium 1 0 1 Fair 1 0 0 Poor 0 0 0

22 L Maini et al. Journal of Orthopaedic Surgery Study Approach used No. of cases Radiological reduction 13 Siebenrock et al. 1 Surgical dislocation of hip 12 Anatomic/ satisfactory: 100% 100% Matta 3 Kocher-Langenbeck (K-L) 262 Anatomic: 71% [n=112], ilio-inguinal (II) 76%; fair/poor: 24% [n=87], extended iliofemoral (n=59), and K-L+II (n=4) Tannast et al. 9 Surgical dislocation of hip 60 Anatomic/ satisfactory: 93% Matta and Merritt 13 Giannoudis et al. 12 K-L (n=53), II (n=24), extended iliofemoral (n=19), K-L+II (n=2), and nonoperative (n=23) K-L (n=1125), II (n=506), iliofemoral (n=287), other (n=393), and unknown (n=1359) 121 Anatomic/ satisfactory: 91% Functional Complication rate (%) outcome 14 Avascular Infection ossification Heterotropic Nerve necrosis injury 81.5%; fair/poor: 18.5% 80%; fair/poor: 20% 3670 Anatomic/ satisfactory: 85.6% 86%; fair/poor: 14% Hadjicostas and Thielemann 18 Surgical dislocation of hip 31 Anatomic/ satisfactory: 100% 80%; fair/poor: 20% Triantaphillopoulos K-L (n=65) and extended 75 Anatomic/ et al. 16 iliofemoral (n=10) satisfactory: 89.3% 80%; fair/poor: 20% Heeg et al. 20-54 Anatomic/ satisfactory: 67% 61%; fair/poor: 39% Naranje et al. 19 Surgical dislocation of hip 18 Anatomic/ satisfactory: 100% 94%; fair/poor: 6% Briffa et al. 17 K-L (n=122), II (n=115), 161 of Anatomic/ Stoppa (n=2), Triradiate 257 satisfactory: 86% 72%; fair/poor: 27 % (n=8), K-L+II (n=5), K-L+digastric slide/greater trochanteric osteotomy (n=4), extended iliofemoral (n=1) Mayo 15 K-L (n=58), II (n=86), and extended iliofemoral (n=26), with 7 having combined approaches Table 2 Comparison of studies on treatment for acetabular fractures 163 Anatomic/ satisfactory: 81% Present study Surgical dislocation of hip 22 Anatomic/ satisfactory: 100% 75%; fair/poor: 25% Excellent to good: 86%; medium to poor: 14% 0 0 33.3 8.3 3 4.9 18 3.2 0 0 3.4 1.7-3 7 5 5.6 4.4 25.6 8 6.4 6.4 6.4 3.2 8-25.3 1.3 11.2-50 - 5.5-33.3 0 11.8 11 10.5 14.2 0.6 4 20.2 3 0 4.5 0 18.2 posterior wall or column fractures, with or without transverse fractures. 15 17 This approach does not provide access to the entire acetabulum or femoral head. Digastric trochanteric flip osteotomy enables surgical dislocation of the hip and thus addresses marginal impaction of fractures, intra-articular assessment of fracture fragments, presence of intraarticular fragments, comminution of the posterior and superior wall, reduction of the associated anterior wall or anterior column fractures, extra-articular placement of anterior column screws, or presence of femoral head fracture. 1,9,18,19 Poor prognosis of comminuted fractures may be partly due to the difficulty in assessing fracture reduction. Surgical dislocation of the hip enables intra-articular reduction of free and impacted fragments and thus improves outcome. 1,9,19 Transverse acetabular fractures are usually reduced using standard reduction clamps, with the femoral head in its intra-articular position. The femoral head is then dislocated for assessment of fracture reduction. Free and impacted intra-articular fragments are reduced and fixed with screws or Kirschner wires. This approach is safe and has advantages over the standard Kocher-Langenbeck approach (Table 2). 9,18 20 It enables an extended anterior capsular incision with an anterior femoral head dislocation but preserves the main vascular supply to the femoral head. Exposure extends to the superior rim and a complete inspection of the joint and fracture reduction is possible. However, the lateral decubitus position may pose a difficulty for reducing large, displaced anterior column fractures, which may require an additional approach. It is not possible to apply constant traction and manual

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