Clinical experience with arthroscopic suture pull technique in isolated PCL avulsion injuries

Abstract

Objective

to assess twenty two cases of isolated PCL avulsion fractures from tibial insertion, arthroscopically treated with suture pull technique, and to evaluate achieved clinical outcomes in terms of radiographic laxometry (objective) and Lysholm scale (subjective).

Material and method

Study includes 22 cases operated between April 2014 and March 2017. Patients less than 18 years old, presentation after 3 weeks of injury, concomitant injury in the same limb, with open wounds or with comminuted avulsed fragment were excluded from the study. All cases were MRI proven. All arthroscopic suture fixation technique was used in all cases. Follow up was done at 3 weeks, 6 weeks, 3 months, 6 months and 12 months. Mean follow up was one year. Subjective complaints, Knee flexion, Lysholm score and stress radiographs were noted.

Results

Average Lysholm score was 96.3. Seventeen patients had excellent results and Five had good results based on Lysholm scores. In two patients, grade 2 laxity (5–10 mm) was present on stress radiographs but there were no clinical complaints. All patients achieved osseous union and had no functional limitation. Three Patients developed arthrofibrosis initially but gained functional range later.

Conclusion

Arthroscopic suture fixation method for PCL avulsion fracture from tibia is a good and safe method of choice for fixation.

1. Introduction

PCL (posterior cruciate ligament) is one of the primary restraint to posterior tibial translation and the secondary restraint to external rotation of the knee joint.¹ It is commonly a part of multiligamentous knee injuries owing to increased motor vehicle or road traffic accidents and sports injuries. Isolated PCL rupture is rare with reported incidence being around 1–44% of total knee ligament injuries.² PCL rupture can occur at its femoral attachment site, at mid substance or at tibial attachment site with or without bony avulsion.

Diagnosis of PCL injury can be made with proper history supplemented clinically by Posterior drawer test and tibial sag sign. Routine radiographs can show bony avulsion of PCL from tibia. Stress radiographs (radiographic laxometry) are helpful in making diagnosis in case of intra substance tear or avulsion from femoral attachment. Studies have reported that partial PCL tears results in less than 8 mm of increased posterior tibial translation, isolated complete PCL tears results in 8–12 mm, and combined complete PCL tears (usually with a PLC injury) results in greater than 12 mm^3,4. MRI is highly sensitive in confirming diagnosis and also provides information about site and grade of tear.⁵

Controversy persists in the management of isolated PCL tear. Isolated PCL tear is being managed conservatively traditionally^6,7,.⁸ But some authors have reported increased incidence of meniscal injury and arthritis in PCL deficient knees.^9,10 Consensus exists towards surgical treatment in case of PCL avulsion from its tibial insertion or combined multi ligamentous injury. Some authors add grade III tears (>10 mm posterior instability) to these indications.¹¹

Isolated PCL avulsion from its tibial insertion can be surgically managed either with open repair or arthroscopically using screw or suture pull through technique.¹² Arthroscopy favours minimal scaring, less tissue trauma and early rehabilitation.

This article aims to assess twenty two cases of isolated PCL avulsion fractures from tibial insertion, arthroscopically treated with suture pull technique, and to evaluate achieved clinical outcomes in terms of radiographic laxometry (objective) and Lysholm scale (subjective).

2. Material and method

This retrospective study includes 22 cases of isolated PCL avulsion from its tibial attachment operated between April 2014 and March 2017. Study includes isolated PCL avulsion fractures which were displaced from the fracture bed. Patients less than 18 years old, presentation after 3 weeks of injury, concomitant injury in the same limb, having undisplaced fracture fragment with open wounds or with comminuted avulsed fragment were excluded from the study. Informed consent was taken from all the patients.

All patients were clinically evaluated and routine radiographs (AP and Lateral) view of the affected knee joint were taken. Stress view was not taken for all patients due to complaint of pain during manoeuvre. For confirmation of diagnosis and to rule out associated injuries, MRI was done in all included cases [Fig. 1].

Fig. 1.

a- AP radiograph of knee joint showing avulsed fragment. b-lateral radiograph showing avulsed fragment from tibia. c- MRI showing PCL avulsion from Tibia. d- 3D CT showing avulsed fragment from tibia.

After taking informed consent, routine blood investigations were done and pre anaesthetic check up was performed. Antibiotic injection cefuroxime 500 mg i.v. was given pre operatively. All patients were operated under spinal anaesthesia. Tourniquet was used in all cases. With all aseptic precaution painting – draping was done in supine position. All clinical findings were confirmed on table after giving anaesthesia.

2.1. Surgical technique

Standard anterolateral port was used as viewing portal. After giving thorough wash, diagnostic arthroscopy was done to confirm diagnosis and to rule out any other associated lesions. Standard anteromedial portal was used for shaver. Synovium debrided and working space was created between PCL and medial femoral condyle and between PCL and ACL. Once posteromedial compartment is visualised, a posteromedial portal was created under direct visualisation using a needle as reference. Again a working space was created between posterior tibial margin and posterior capsule using shaver through postero medial portal. Now posteromedial portal was used as viewing portal and fracture bed was prepared using curette and rasp through anteromedial portal. Under direct visualisation, PCL tibial guide was placed at the centre of fracture bed using anteromedial portal and through the space between PCL and medial condyle of femur. A beath pin was passed after giving a small 3 cm incision over medial aspect of proximal tibia just 2 cm medial to tibial tuberosity. 4 mm reamer was drilled over this beath pin. Using beath pin, a looped thread was passed through this tunnel and retrieved through posteromedial portal and parked there. Now using anterimedial portal, a Lasso was used to pass suture through and around PCL at bone ligament junction. One end of this suture was retrieved through posteromedial portal and tied to looped thread. Now a Fibre tape was loaded on suture end outside anteromedial portal. Looped thread was pulled in such a way that this fibre tape passes through the PCL bone ligament junction (where Lasso was passed) and encircles it. The free ends were pulled out through the tunnel and they are tied over a suture disc after maximum pulling and giving anterior drawer at the same time. Knee is checked for any posterior sag and made sure anterior tibial step is maintained now [Fig. 2, Fig. 3, Fig. 4, Fig. 5].

Fig. 2.

A- Black arrow shows avulsed fragment from its bed Blue arrow points towards the fracture bed. B- curettage and preparation of the fracture bed. C- beath pin passed through the fracture bed using PCL zig.

Fig. 3.

Immediate post op radiograph showing fixation of avulsed fragment on its bed and tied anteriorly on tibia using suture disc.

Fig. 4.

Line diagram depicting suture pull technique – posterior view.

Fig. 5.

Line diagram depicting suture pull technique – Lateral view.

2.2. Post op protocol

Limb was immobilised for 3 weeks with a posterior pad applied to tibia. Suture removal was done at 3 weeks. Closed chain exercises were started at 3 weeks and full knee bending achieved around 6 weeks. Partial weight bearing was allowed at 6 weeks and gradually progressed to full weight bearing as tolerated. Follow up was done at 3 weeks, 6 weeks, 3 months, 6 months and 12 months. Subjective complaints, Knee flexion, Lysholm score and stress radiographs were noted. Stress radiographs were taken by applying posterior drawer force at 80–90° of knee flexion and taking lateral view of knee joint. Osseous union was assessed using plain radiographs AP and lateral view at 3 months of follow up (Fig. 6).

Fig. 6.

Osseous union at 3 months follow up. a – lateral view. b – AP view.

3. Results

A total of 22 patients were operated including 20 males and 2 females. Mean age of the patients was 26.45 ± 6.65 years (range = 18–42 years). Right knee was injured in 14 patients and left in 8. Road traffic accident (motor vehicle) was the most common mode of injury (17 patients). The other cause was sports injury (5 patients). All patients who suffered sports injury were male (Table 1).

Table 1.

Age, sex, mode of injury and Lysholm score at 1 year follow up along with knee flexion and laxity on stress testing.

S no.	Age in yr	Sex	Mode of injury	Days from injury to operation	Profession	Lysholm score	Radiographic laxometry	Knee flexion
1.	18	M	SPORTS	3	Student	100	< 5 mm	130
2.	18	M	SPORTS	4	Student	100	< 5 mm	125
3.	32	M	RTA	17	Farmer	90	5–10 mm	120
4.	27	M	RTA	12	Salesman	99	< 5 mm	130
5.	24	M	RTA	4	Engineer	95	< 5 mm	125
6.	19	M	SPORTS	5	Student	100	< 5 mm	130
7.	42	M	RTA	10	Farmer	95	< 5 mm	125
8.	27	M	RTA	8	Engineer	86	5–10 mm	110
9.	28	M	RTA	12	Daily wage worker	95	< 5 mm	130
10.	29	M	RTA	15	Waiter	90	< 5 mm	125
11.	36	M	RTA	18	Farmer	95	< 5 mm	125
12.	20	M	RTA	5	Student	100	< 5 mm	125
13.	22	M	RTA	11	Student	100	< 5 mm	130
14.	29	F	RTA	7	Teacher	90	< 5 mm	120
15.	32	M	RTA	16	Farmer	95	< 5 mm	130
16.	19	M	SPORTS	15	Student	99	< 5 mm	130
17.	25	M	RTA	20	Student	95	< 5 mm	130
18.	30	M	RTA	5	Salesman	100	< 5 mm	130
19.	21	M	SPORTS	7	Student	95	< 5 mm	125
20	26	F	RTA	14	Housewife	100	< 5 mm	125
21.	20	M	RTA	6	Student	100	< 5 mm	130
22.	28	M	RTA	8	Banker	100	< 5 mm	125

All cases were examined and operated by same senior surgeon. Mean follow up was one year. At one year follow up for all patients knee flexion was noted and stress radiograph was taken. Lysholm score was also calculated. All patients had full range of flexion at 3 months follow up except three cases who developed arthrofibrosis. One of these patients eventually ended up with 110° of flexion and other two with 120° of flexion at final follow up. Due to the same reason they had difficulty in squatting also. Average Lysholm score was 96.3 ± 4.22 (range being 86–100) (Table 1). 17 patients had excellent results and 5 had good based on Lysholm score (>90 excellent, 84–90 good, 65–83 fair, <65 poor). In two patients, grade 2 laxity (5–10 mm) was present on stress radiographs but there were no clinical complaints. All patients achieved osseous union and had no functional limitation. We did not face any complications like neuro vascular injury, infection or non union.

4. Discussion

Though PCL avulsion injury from tibia is rare, it requires precise diagnosis and early treatment. We excluded patients who presented after 3 weeks of injury as earlier studies show poorer outcome with delayed intervention. In a study conducted by Torisu¹³ he reported that results were better when operated within 7 weeks after injury and were less satisfactory if delayed more than 11 weeks. Meyers¹⁴ also reported that patients who had late intervention showed slight positive posterior drawer sign at the time of follow up.

Most common mode for this type of injury stated in literature is road traffic accidents with cars. In this kind of injury flexed knee strikes against the dashboard transmitting force anterior to posterior on proximal tibia. In our study, we found most common mode of injury was road traffic accidents (77%). These are mainly associated with two wheelers as these are more common mode of transport in India. Second most common mode of injury in our study was sports injury (23%) similar to previous studies.¹⁵

Out of total cases, majority (90%) were males. Males are more involved in contact sports and more associated with motorcycle driving. Average age in our study is 26.5 ± 6.65. It is similar to age stated in previous epidemiological studies^15,16 and is due to the fact that young individuals are more involved in sports and motor cycle driving.

PCL injuries were treated traditionally by conservative methods. Some authors have got good results with it. J S Torg while studying natural history of PCL deficient knee stated that those knees with PCL disruption without associated ligamentous laxity will probably remain symptom-free.⁶ K Shino managed 15 isolated PCL patients conservatively and 14 of them did not develop any kind of arthritis at 51 months follow up. He concluded “Knees with an isolated injury to the PCL without concomitant articular damage may be successfully managed by conservative treatment”.⁷ Donald Shelbourne published long-term results (10 years) after an isolated PCL injury states that patients remain active, have good strength and full knee range of motion, and report good subjective scores. The prevalence of moderate to severe osteoarthritis was 11%.⁸ But these authors don't mention the kind of PCL injury whether bony avulsion or not and whether displaced or undisplaced.

On the other hand some authors totally deny the concept of conservative management. Meyers reported poor outcome with all five PCL avulsion fractures managed non operatively and suggests that even minimally displaced PCL avulsion fractures should be surgically treated.¹⁴ Boynton followed up 38 patients with isolated PCL injury for a mean follow up of 13.4 years and he suggested “the prognosis for the isolated posterior cruciate ligament-deficient knee varies. Some patients experience significant symptoms and articular deterioration, while others are essentially asymptomatic and maintain their usual knee function.⁹” Okazaki used T1ƿ MRI mapping and reported that subclinical cartilage damage is present even in asymptomatic patients following isolated PCL injury.¹⁰ We support operative treatment for PCL avulsion fractures from tibia.

Open as well as arthroscopic reduction and fixation of PCL avulsion fractures, both of them are well known and established techniques. Standard posterior approach described by Abbott¹⁷ was time consuming as it required handling of popliteal vessels. Trickey's¹⁸ modification reduced the operative time but increased the rehabilitation time as splitting of medial head of gastrocnemius was required. Burks and Schaffer¹⁹ modified the approach by using interval between the medial head of gastrocnemius and semimembranosus. It does not require the handling of vessels and improves rehabilitation time but visualisation of fracture fragment and placement of screw perpendicular to the fracture plane is difficult.²⁰ Besides these, prone position and simultaneous treatment of concomitant injuries through same incision are other difficulties. Joshi et al.²¹ and Khatri et²² al have reported good results with open approach.

Martinez-Moreno and Blanco-Blanco²³ first performed arthroscopy assisted percutaneous fixation of PCL in cadavers. Littlejohn and Geissler²⁴ first reported PCL fixation under arthroscopic control in a clinical setting. Though arthroscope assisted technique requires advance instrumentation and has long learning curve but it gives the benefit of diagnosis and treatment of concomitant injuries, smaller scar and early rehabilitation.

Sabat et al.²⁵ retrospectively compared arthroscopic suture fixation and open screw fixation in patients with PCL avulsion fractures, laxity measurements favoured arthroscopic management while Lysholm, Tegner activity, IKDC scores and one-leg hop test were similar between the two groups at 1 year of follow up. Pardiwala et al.²⁶ reported requirement of second stage arthroscopy surgery between 6 and 19 months for concomitant pre operative injuries in 50% of the patients whose PCL avulsion injuries were treated via open approach. In a recent systematic review by Hooper et al.²⁷ in 28 studies with a total of 637 patients, arthroscopic group had better IKDC grade A scores and higher return to pre-injury activity. However, Lysholm scores were comparable between the arthroscopic (95) and open (92.8) groups.

Zhu et al.²⁸ in their series of 18 cases reported good outcome with all arthroscopic high strength suture technique. This also avoided second surgery for hardware removal. He used this technique irrespective of size of avulsed fragment. He stated that high strength suture fixation has high tensile strength and is on principles of bio fixation. Incisions are small so recovery is fast and using arthroscope avoids injury to vital structures and concomitant injuries can be treated. They reported post operative Lysholm score of 95.2 ± 3.8. In our study we obtained post operative Lysholm score of 96.3 ± 4.2. Lysholm score being more specific towards pain and instability many authors have reported their studies using it. Mazda et al.²⁹ had shown that IKDC is more sensitive compared to Lysholm scoring while evaluating knee ligament injuries. But their study was not specific for PCL injuries. IKDC scoring gives equal importance to all parameters but Lysholm gives more points to pain and instability. Zhu et al. have used KT3000 to measure post op laxity. We relied upon post op stress radiographs with posterior drawer test. Hewett et al.³⁰ in their study have claimed superiority of stress radiographs.

Kim et al.³¹ used arthroscopic technique for fixation of PCL avulsion, but they used hardware depending upon the size of the fragment. We have used suture fixation method irrespective of the size of the fragment and have obtained good results with this technique.

Similar studies done on arthroscopic suture fixation for PCL avulsions have claimed good results. They have reported well documented osseous healing, joint stability and good clinical outcome with low complication rate with this technique^32,33,.³⁴

Most common complication stated in studies whether open or arthroscopic, is knee arthrofibrosis.²⁷ In our study also three patients developed knee arthrofibrosis which were treated by manipulation under general anaesthesia and all of them achieved good functional range. We did not face complications like infection, neurovascular injury or loss of reduction.

Our study has certain limitations like small sample size and short follow up. We reported results of only isolated PCL injuries which were not older than 3 weeks and used Fibre Tape for fixation. Future studies could be done with PCL avulsion with concomitant injuries or injuries presenting late and use of different fixation material with larger sample size and longer follow up.

5. Conclusion

Arthroscopic suture fixation method for PCL avulsion fracture from tibia is a good and safe method of choice for fixation irrespective of fragment size.

Conflicts of interest

None.

Appendix A. Supplementary data

The following is the Supplementary data to this article: