Maj. Gen. Greg. Papadopoulos MD, Lt. Col Sp. Darmanis MD, D. Kiatos PHT Orthopedic and Trauma Department Athens Military Hospital and Iaso General Hospital Athens, Greece Iasimo Rehabilitation Centre, Athens, Greece

Treatment of unstable knee ACL deficiency using the new generation LARS artificial ligamentLong-term follow-up of 162 operated knees in 155 patients

Background Traditional ACL-R has achieved good-to-excellent results in only 60% of

patients Fu et al 2008

63% of ACLRs returned to their pre-injury activity level after 12 months 44% returned to competitive sport at 36.7 months post-op Ardern & Feller et al 2011

Mid (≤ 96months) to long -term (15 yrs) failure rates quoted at between 1 - 16% for autografts Pinczewski 2011, Magnusson 2011, Li 2010

Table 1: Sports Attempt at 12 Months for Most Commonly Played Sports (CI, confidence interval)

Seasonal Sports Year-round Sports

Overall Australian Rules Football Soccer Basketball Netball

n 503 197 102 85 119

Full competitionn (%)95% CI

168 (33.4)29.3-37.5

83 (42.1)35.2-49.0

30 (29.4)20.6-38.3

33 (38.8)28.5-49.2

22 (18.5)11.5-25.5

Training and/or modified competitionn (%)95% CI

169 (33.6)29.5-37.7

69 (35.0)28.4-41.7

34 (33.3)24.2-42.5

24 (28.2)18.7-37.8

36 (30.3)22.0-38.5

No attemptn (%)95% CI

166 (33.0)28.9-37.1

41 (20.8)15.1-26.5

37 (36.3)26.9-45.6

28 (32.9)23.0 -42.9

60 (50.4)41.4-59.4

Background Over 78% patients experience donor site pain with HT at up to 3 yrs post-op

Between 3-27% HT strength deficits compared with non-operated side Feller et al 2011

Incomplete graft ligamentisation at up to 2 years after ACLR Janssen 2011, Claes 2011

Autologous grafts approached only 50–60% of the intact ACL failure strength at up to 12 mnths in sheep studies Scheffler 2005, 2008

Table 2. Clinical Evaluation Data

Characteristic ST-G ST

IKDC subjective knee form score [mean ± SD (range)] 91.6 ± 8.1 (67 to 100) 94.4 ± 3.6 (85 to 100)

Side-to-side difference in knee laxity [mean ± SD (range)] (mm) 1.0 ± 2.8 (-7 to 5) 1.4 ± 2.9 (-5 to 5)

Postoperative hamstring pain (yes:no) 18:12 11:9

Side-to-side difference in active knee range of motion [mean ± SD (range)] (°) 2.3 ± 7.8 (-17 to 17) 24 ± 4.9 (-7 to 11)

Side-to-side difference in passive knee range of motion [mean ± SD (range)] (°) 1.9 ± 5.1 (-10 to 12) 3.0 ± 4.6 (-4 to 11)

Abbreviation: IKDC, International Knee Documentation Committee

Why LARS? Avoids donor site morbidity or any other iatrogenic injury

Provides the possibility of natural ligament healing and early proprioception Murray 2011, Ahn 2011

Permits early rehabilitation leading to a faster return to work and sport

What is LARS?

Soft tissue internal fixator – scaffold type PET (polyethylene terephthalate) with unique, pre-twisted ‘free fibre’ design

Human ACL: 1730 Nt LARS AC-100: 4700 Nt AC-120: 5000 Nt

Study objectives & design

Objective

To report long-term functional follow-up of LARS ligaments in patients with an unstable knee and ACL deficiency

Study design Monocenter prospective case-series Independant, blinded data analysis by AO foundation Follow-up examinations at upto 14 yrs (Average follow up 11 yrs)

− Lachman - Noulis test− Pivot shift test− IKDC subjective

Patients Eligibility criteria

Patient with mature skeleton Unstable knee with ACL deficiency Treated with LARS by same surgeon (Dr Papadopoulos) Standardized rehabilitation program (same Center) Consented to long term follow up Exclusion: complicated ligament injuries, dislocation or fractures,

non-compliant patients

8-year enrollment period: Jan 1996 to Dec 2003

155 patients (162 knees) Male:female = 123:32 Mean age = 38 years

(range 15-68) Side = 76 R, 72 L, 7 R+L

Causes Patients KneesSoccer 51 52Basketball 24 255X5 17 18Motorbike 15 17Downfall 14 15Tennis 8 8Skiing 7 7Other 19 20All 155 162

Injury characteristicsACL stump classification

 Grade I II III IVACL stump Plastic deformation Attached to PCL Degenerated or attached to PCL Complete degeneration

Anatomy Intact Torn Torn Torn

Length of the stump Normal Approx. 2/3 Approx. 1/2 Around ¼ or nothing (empty notch)

ACL ruptures

Total

Acute 17 41 4 69 43%

Anatomy 19 51 23 93 57%

Status of knee lesions

Chondral lesions

Chondral lesions Knees % of 162Patella 35 22%Trochlea 11 7%MFC 43 27%Tibial plateau 7 4%LFC 23 14%None (Total??) 72 44%

Associated meniscus and ligamentous lesions

Associated lesions Patients KneesIsolated ACL 38 38Medial meniscus tear (MM) 47Lateral meniscus tear (LM) 36MM + LM 22MCL 12LCL 3PCL 3PL-Corner 1All 162

Operation technique Notchplasty = 18% Recommended LARS technique followed Preservation of stump where possible No tension philosophy

Rehabilitation program No brace post-operative (OP) Immediate active quadriceps exercises Immediate full weight bearing CPM started on 2nd–3rd post-OP day Normal walking 1.5-2.5 weeks post-OP Jogging

progressive training from 4-6 weeks post-OP Return to vigorous activities

sports practiced 8-12 weeks post-OP

Results: Lachman-Noulis

No change in Lachman- Noulis test results over time, with up to 14 years FU

Each of the 162 knees were evaluated twice 2 years apart

Results: Pivot Shift

No change in Pivot Shift test results over time, with up to 14 years FU

Each of the 162 knees were evaluated twice 2 years apart

Results: IKDC

No overall significant change in IKDC score over time, with up to 14 years FUEach of the 162 knees were evaluated twice 2 years apart (mixed model with repeated measure)

Results: IKDC adjusted for age

<=30 >30-40 >40

There is a significant age effect :• Patients in the older group have lower mean IKDC than younger

patients by -2.5 pointsThere is some time-related decrease in IKDC, however the change is not significant

Results*: Knee pain during daily activity

5 - I have no pain in my knee.4 - I have some pain in my knee but this does not affect my daily activities.3 - The pain affects my daily activities a little.2 - The pain affects my daily activities moderately.1 - The pain affects my daily activities a lot.0 - The pain in my knee is severe. I can’t do my daily activities.

*at final follow up time point

Results*: Knee stiffness during daily activity

5 - I have no stiffness in my knee.4 - I have some stiffness in my knee but this does not affect my daily activities.3 - The stiffness in my knee affects my daily activities a little.2 - The stiffness in my knee affects my daily activities moderately.1 - The stiffness in my knee affects my daily activities a lot.0 - The stiffness in my knee does not allow me to do my daily activities.

*at final follow up time point

Results*: Knee stabilityNoyes Personal Questionaire

20 - I have no giving way sign.16 - I feel my knee unstable when I participate in contact sports or do heavy work.12 - I feel my knee unstable when I go jogging, which restricts my sports activities or heavy work. 8 - I feel my knee unstable and I cannot participate in sports.4 - I often have giving way sign even when I walk.0 - I have a big problem of stability when I must turn or suddenly change direction.

*at final follow up time point

Results*: Knee activity levelNoyes Personal Questionaire

20 - I have no restrictions. I have a normal knee. I can participate in contact sports.16 - I participate in sports but with lower demands.12 - I can do weekend sports with some symptoms.8 - I cannot participate in sports at all. Only jogging with symptoms.4 - I have problems in my daily activities.0 - I have severe problems in my daily activities.

*at final follow up time point

Results*: EdemaNoyes Personal Questionaire

10 - I have no edema in my knee.

8 - My knee is edematous from time to time when

I participate in competitive sports or do

heavy work.

6 - My knee is edematous after sports or moderate work.

4 - The edema limits my sports activities more than

4 times a year.

2 - My knee is edematous after running and the edema

disappears after relaxing.

0 - My knee is edematous even when I walk and this

remains after relaxing

*at final follow up time point

Revisions• Overall failure rate: 5.5% (9 Knees)

− 2 knees, 1.2% due to graft rupture (technical error)− 3 knees, 1.8% due to persisting joint instability following trauma (re-tightening )− 4 knees, 2.5% due to new trauma to the knee

Revised to: – Autogenous (3)– LARS (2)– Stand by (1)– Mini revision (3)

Minor complications– Superficial infection in the tibial portal – 3 knees, 1.8% – Lack of extension – 2 knees, 1.2%– Staple removal – 2 knees, 1.2%

0% synovitis

Revisions

Analysis of a failure case

We found revision of a LARS to be a simple procedure1. Remove all fixation

2. Apply a very strong clamp applying mild traction

3. If the ligament wont strip out, pass a blunt K wire into tunnel, drill over with 4.5mm drill at low speed

Discussion In our centre, LARS ACL has demonstrated excellent patient outcomes at

an average follow up of 11 yrs

These failure rates are comparable to published HT and PT results at the same average follow up interval Pinczewski 2007 Wipfler 2011

Acute cases of ACL injury and those of chronic laxities with well-vascularised ACL-stump are the best indications to use the LARS ligament

Weaknesses: No radiographic follow up, further objective/subjective testing could have been included in this study

Conclusions LARS has not exhibited high rates of complications associated with previous

synthetics

LARS avoids donor site complications associated with autografts

Does not “burn any bridges” for possible revision surgery

Provides the possibility of natural ligament healing and early proprioception Murray 2011, Ahn 2011

Permits early rehabilitation leading to a faster return to work and sport

Thank you for your attention