From January 2015 to June 2018, 37 patients with PPFs underwent surgical treatment in our institution. The following inclusion criteria were used: older than 18 years; a clear preoperative X-ray, CT scan and three-dimensional reconstruction diagnosis; normal ankle joint function before injury; no previous surgery around the ankle joint; and a follow-up for more than 12 months. The following exclusion criteria were used: severe open fractures (Gustilo classification type II or III[16]), old fractures, pathological fractures, fractures with vascular and nerve injuries, poor cardiopulmonary function, inability to tolerate surgical treatment, and incomplete case data. According to the fracture internal fixation method, the patients were divided into the BP (11 patients, 6 males and 5 females) and APS (26 patients, 8 males and 18 females) groups. In the BP group, the average age was 50.64±18.91 (range, 21-81) years, and 5 fractures occured on the left, while 6 fractures occured on the right, with 5 high falling injuries, 4 traffic injuries and 2 falling injuries when descending stairs or exercising. According to the Klammer classification[12], 3 type I, 2 type II and 6 type III fractures were sustained. One case had no medial or lateral malleolar fracture, 3 cases had lateral malleolar fractures and 7 cases had medial and lateral malleolar fractures. The average time from injury to surgery was 5.73±3.29 (range, 2-12) days. In the APS group, the average age was 52.15±16.22 (range, 20-74) years, and 13 fractures occured on the left, while 13 fractures occured on the right, with 8 high falling injuries, 13 traffic injuries and 5 falling injuries when descending stairs or exercising. Ten type I, 4 type II and 12 type III fractures were sustained. Two cases had medial malleolar fractures, 3 cases had lateral malleolar fractures, and 21 cases had medial and lateral malleolar fractures. The average time from injury to surgery was 5.50±3.50 (range, 1-16) days. The basic information of the patients is shown in Table 1. All patients signed informed consent forms.
Table 1. Baseline characteristics of the patients: Group BP (buttress plate) and group APS (anteroposterior screw).
|
Group BP
n=11
|
Group APS
n=26
|
P Value
|
Gender
|
|
|
|
Male
|
6
|
8
|
0.268
|
Female
|
5
|
18
|
|
Average age, y
|
50.64±18.91
|
52.15±16.22
|
0.806
|
Side
|
|
|
|
Lift
|
5
|
13
|
1.000
|
Right
|
6
|
13
|
|
Injury cause
|
|
|
|
High falling injury
|
5
|
8
|
0.673
|
Traffic accident
|
4
|
13
|
|
Falling when descending stairs or exercising
|
2
|
5
|
|
Klammer Classification
|
|
|
|
I
|
3
|
10
|
0.809
|
II
|
2
|
4
|
|
III
|
6
|
12
|
|
Medial/Lateral malleolar fracture
|
|
|
|
None
|
1
|
0
|
0.196
|
Medial malleolar fracture
|
0
|
2
|
|
Lateral malleolar fracture
|
3
|
3
|
|
Medial and lateral malleolar fracture
|
7
|
21
|
|
Time from injury to surgery, d
|
5.73±3.29
|
5.50±3.50
|
0.855
|
Surgical techniques
According to X-rays and local edema following the injury, manipulative reduction and plaster external fixation or calcaneal traction were performed, and then the affected limb was elevated to reduce swelling. All patients were treated surgically after local swelling subsided. The operation was performed under general anesthesia or spinal anesthesia. Intravenous drip antibiotics were administered 30 minutes before the operation to prevent infection. All operations were performed by the same group of doctors.
BP group: Klammer type I patients were treated using a posterolateral approach (prone position), and Klammer type II and III patients were treated using a combined posterolateral and posteromedial approach (floating position). Balloon tourniquets were applied to all patients to control hemorrhage. First, a longitudinal incision was made from the posterior edge of the fibula to the midpoint of the lateral Achilles tendon. Blunt separation was performed layer by layer. Care was taken to protect the sural nerve and the small saphenous vein. The peroneal muscles were pulled to the posterolateral side and fully separated to expose the lower fibula segment. In patients with lateral malleolar fractures, the fracture end was exposed, the stump hematoma was cleared, the lateral malleolus was reset by traction, and a lag screw was placed in the vertical fracture line. A lateral plate was then placed on the lateral malleolus to complete fixation of the lateral malleolar fracture. The posterior fracture block was exposed along the gap between the flexor pollicis longus tendon and the peroneal tendons. The posterior inferior tibiofibular ligament was used as a fulcrum, and the posterior fracture fragment was lifted to the distal and lateral sides. Next, the posterior articular surface of the ankle was explored, and the free cartilage and fracture fragment were removed. If the articular surface had collapsed, reduction and bone grafting were performed. Klammer type II and III fractures combined with a posteromedial bone block could not be completely exposed through the posterolateral approach and therefore required the use of a combined posteromedial approach. A 5-6 cm incision was made from the posterior inner edge of the distal tibia. After the incision was made layer by layer, the tissue in the ankle canal was pulled back to the medial side. At this time, the medial-lateral combined incision could fully expose the posterior fracture fragment. After both the posteromedial and posterolateral fracture fragments were anatomically restored, the posterior BP was placed through the posterolateral incision and fixed with locking screws. For medial malleolar fractures, 1-2 cannulated screws were inserted through the posteromedial incision for definitive fixation.
APS group: All fractures were fixated with the patient in the supine position. The posterolateral incision was the same as that used in the BP group. If a lateral malleolar fracture was also present, the lateral malleolus was fixated first according to the BP group method, and then the posterior fracture block was exposed by the same method. The free small bone block and cartilage debris on the articular surface were cleaned. Dorsal flexion of the ankle joint, pressing the posterior fracture block downward and forward, was performed to flatten the joint surface. Through the ankle joint anterior incision (1-2 cm), Kirschner wires were inserted from anterior to posterior to temporarily fix the posterior fracture block. After satisfactory reduction under fluoroscopy, cannulated screws (2-3) were inserted along the Kirschner wire with, care to avoid irritating the soft tissues behind the ankle joint with screws that were too long. If the patient was also had a posteromedial fracture block, the APSs could not be fixed effectively. Therefore, a small posteromedial incision was made, and the posteromedial fracture block was fixed with screws from the posterior medial side. If the patient also had a medial malleolar fracture, the medial malleolus was fixed with 1-2 cannulated screws through a small incision in front of the medial malleolus. After fixation was completed, reduction and joint surface flatness were confirmed by fluoroscopy. The cotton test was routinely used to check the stability of the lower tibiofibular syndesmosis, and a lower tibiofibular syndesmosis screw was used to fix an unstable tibiofibular syndesmosis. All patients had lower tibiofibular screws, and the screws were removed 12 weeks after the operation. All patients in the APS group received plaster immobilization for 4 weeks after surgery.
Postoperative management and follow-up
Prophylactic antibiotics were administered for 24-48 hours after surgery, and elevation of the swollen affected limb was maintained. The drainage tube was removed 2-3 days after the operation, and the dressing was changed every 2-3 days to observe wound healing. Ankle functional exercise was started as soon as the patient could tolerate such movements (after the plaster was removed in the APS group), and the intensity of exercise and the weight-bearing time were determined according to fracture healing and ankle functional recovery. X-ray films were reexamined 2 weeks, 4 weeks and 3 months after the operation and then every 3 months from 3 to 12 months after surgery to observe bone healing and record complications.
At the last follow-up, ankle joint function was assessed using the American Orthopedic Foot and Ankle Society (AOFAS) score[17]. The visual analog scale (VAS)[18] was used to assess ankle joint pain during rest and exercise, where the score gradually increased from 0 to 10 with an increasing pain level. The Burwell-Charnley scoring system[19] was used to assess fracture reduction in imaging evaluations.
Statistical analysis
SPSS 22.0 (SPSS, Chicago, IL, USA) software was used for statistical analysis. The measurement data were expressed as the mean±standard deviation (𝑥̅±s). The follow-up time, bone healing time, VAS scores during rest and exercise, and AOFAS scores were compared by an independent samples t test. The enumeration data were expressed as rates. P values < 0.05 were considered significant (bilateral test).