LARS Ligament ACL Reconstruction

Anterior Cruciate Ligament Reconstruction

The anterior Cruciate Ligament (ACL) is the main support structure of the knee that prevents:

• The tibia from translating forward on the femur.
• Valgus, varus and hyperextension.
• Rotation of the thigh bone (femur) on the shin bone (tibia).

Epidemiology

An ACL rupture is one of the most common sports injuries and it is recommend to reconstruct a torn ACL to prevent future osteoarthritis. ACL rupture in females is three times than males the reasons are:

• Oestrogen hormone lead to weaker collagen.
• Anatomical tight notch.
• Wider pelvis lead to altered mechanics, which increase valgus stress on landing from a jump. Usually 70% are non contact injury since contact injuries are more likely to have an associated other ligament injuries such as PCL and collaterals (MCL, LCL).

Signs and Symptoms

Twisting injury to the knee or a forceful jump with the knee in flexion may lead to ACL injury.
Pain, feeling a 'pop' in 30%-50%, instability and rapid effusion (swelling) are the main symptoms and signs that one could notice in case of ACL rupture.

Diagnosis

Best current method of identifying the pathology is by using MRI scan which has a high sensitivity and specificity in diagnosing ACL injury and any associated meniscal injury.

Treatment options

Currently it is recommended that ACL rupture in young active patients is best treated by reconstruction operatively since it is menisci-protective. Conservative management is ideal in older non active patients. In other words surgery is indicated if the patient in unable to live within the envelope of stability of the knee.

Different surgical modalities are used to reconstruct the ACL ligament such as the use of autologus hamstring or patellar tendon graft, cadaveric donor grafts and synthetic graft (LARS). From the literature there is no significant difference between any of the modalities; but each method has its own advantages and disadvantages.

 LARS ligaments are designed to mimic the normal anatomic ligament fibre. Using LARS ligaments can reduce surgery time considerably, because no additional harvesting of grafts is needed.
The patient can expect a faster return to full function than after ACL reconstruction using hamstrings or patella tendon grafts.

Surgical Procedure

With LARS ligament technique the operation can be performed using minimally invasive surgery a smaller incision than the conventional ACL surgery. There are no donor site complications since there is no need to harvest hamstring tendons or patella tendons.

To place the graft in place, tunnels will be drilled minimal invasively and precisely through the remnants of the native ACL using an arthroscopic technique.

The ligament is pulled into the bony tunnels whilst observing it through an endoscope. The LARS ligament should pass through the centre of the native ACL. Once in place the LARS ligament is nearly fully covered by native tissue.

Photos:

ACL Reconstruction Surgery

The LARS ligament is fixed by using two titanium screws.
The surgery will take between one and two hours.
Intravenous antibiotics given intra-operatively and DVT prophylaxis.

Post Operative

Postoperatively, on discharge the large outer dressing is removed leaving the water proof dressing in place.
Tube-grip bandage may be applied.
No brace or immobilisation will be needed.
Regular ice pack or Cryocuff until swelling subsides.
Usually, there will be a wound check after 14 days performed in the rooms by your specialist.

Rehabilitation

Physiotherapy should start at 2-5 days after surgery. Major goals are a quick return to a full range of motion and the strengthening of both quadriceps muscles and hamstrings muscles.

Recovery Photos:

Range of motion

Passive and active ROM exercises ensuring that full extension is achieved and maintained within 1 week.
Aim for 90? of flexion by week 2.
Progress to full flexion as tolerated.

Weight bearing status and driving

Weight bear as tolerated, initially with crutches. Discontinue crutches when patient has full extension, without an extensor lag and is able to walk without a flexed knee gait pattern. you can drive between one and two weeks after the surgery.

Muscle rehabilitation

Static quadriceps and co-contraction to commence immediately post operatively.
Closed kinetic chain exercises for first 2-3 months. Exercise bike, swimming and leg presses may commence after 2 weeks.
Proprioception training at 4 weeks.

Sports

Initiate stationary exercise bike as the knee swelling settles. Commence low impact exercises such as swimming at 2 weeks.
Jogging can be commenced at 6 weeks.
Return to sport specific training at 12-16 weeks and when quadriceps strength is at least 80%.
Return to sport when quadriceps is at least 90% and tolerating sport specific skills without symptoms.

Advantages of LARS:

Earlier return to work (depending on particular activity level and individual recovery time)
Earlier return to competitive training
Earlier return to full contact sports once the sense of motion and muscle strength has completely returned.

Meniscal Repair

In acute injury it is usually the lateral meniscus to be torn. Chronic ACL rupture lead to medial meniscus injury.
Meniscal repair surgery delicate surgery to the meniscus so it should be perfected until healing is achieved.

Postoperatively (ACL reconstruction with meniscal repair)

ACL rehabilitation must be adjusted to protect the meniscal repair.
Mobilising weight bearing as tolerated with crutches for the first 6 weeks.
Avoid knee flexion beyond 90 degrees for the first  6 week, ensure the knee is extended during stance phase of gait.
No resisted quadriceps exercises until 6 weeks post operatively.
Avoid deep knee squats and leg presses beyond 90? knee flexion for 3 months.
All other instructions are similar to standard ACL protocol (see above).