Anterior cruciate ligament reconstruction: Difference between revisions

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{{short description|Surgical process}}

[[Image:ACLReconstruction.jpg|thumb|right|150px|Knees following ACL reconstruction surgery. A patellar tendon graft was used. Discoloration of the left leg is from swelling that drained from the knee to the shin.]]

{{redirect|Knee reconstruction|reconstructions on the Posterolateral corner of the knee|Posterolateral corner injuries#Operative treatment}}

{{Infobox interventions

| Name = Anterior cruciate ligament reconstruction

| Image = Anterior cruciate ligament repair 3 legend.jpg

| Caption = Arthroscopic anterior cruciate ligament (ACL) reconstruction (right knee). The tendon of the [[musculus semitendinosus|semitendinosus muscle]] was prelevated, folded and used as an [[autograft]] (1). It appears through the remnant of the injured original ACL (3). The autograft then courses upwardly and backwardly in front of the [[posterior cruciate ligament]] (2).

| ICD10 =

| ICD9 = {{ICD9proc|81.45}}

| MeshID =

| MedlinePlus = 007208

| OPS301 =

| OtherCodes =

| synonyms =ACL reconstruction

}}

'''Anterior cruciate ligament reconstruction''' ('''ACL reconstruction''') is a [[surgery|surgical]] [[medical grafting|tissue graft]] replacement of a tornthe [[anterior cruciate ligament]], located in the [[knee]]., to Becauserestore theits ACLfunction doesafter not[[anterior heal oncruciate its own,ligament injury|an ACLinjury]].<ref>{{cite reconstructionweb|title=Anterior requiresCruciate aLigament tissue(ACL) graftInjuries|url=http://www.webmd.com/a-to-z-guides/anterior-cruciate-ligament-acl-injuries-topic-overview|website=www.webmd.com|access-date=25 April 2016}}</ref> The torn [[ligament]] iscan either be removed from the knee before(most thecommon), graftor ispreserved inserted. The types of surgery differ mainly in(where the type of graft that is used.passed inside Inthe allpreserved cases,ruptured thenative surgeryligament) isbefore donereconstruction through an [[Arthroscopy|arthroscopic]]ally procedure.

==Types of graftsBackground==

The Anterior Cruciate Ligament is the ligament that keeps the knee stable.<ref name="The ACL Reconstruction Basics">{{cite web|title=Anterior Cruciate Ligament (ACL) Injuries {{ndash}} Topic Overview|url=http://www.webmd.com/a-to-z-guides/anterior-cruciate-ligament-acl-injuries-topic-overview|website=[[WebMD]]|access-date=22 April 2015}}</ref> Anterior Cruciate Ligament damage is a very common injury, especially among athletes. Anterior Cruciate Ligament Reconstruction (ACL) surgery is a common intervention. 1 in every 3,000 American ruptures their ACL and between 100,000 and 300,000 reconstruction surgeries will be performed each year in the United States.<ref name="pmid17920959">{{cite journal | vauthors = Baer GS, Harner CD | title = Clinical outcomes of allograft versus autograft in anterior cruciate ligament reconstruction | journal = Clinics in Sports Medicine | volume = 26 | issue = 4 | pages = 661–81 | date = October 2007 | pmid = 17920959 | doi = 10.1016/j.csm.2007.06.010 }}</ref><ref name="pmid19732639">{{cite journal | vauthors = Cohen SB, Yucha DT, Ciccotti MC, Goldstein DT, Ciccotti MA, Ciccotti MG | title = Factors affecting patient selection of graft type in anterior cruciate ligament reconstruction | journal = Arthroscopy | volume = 25 | issue = 9 | pages = 1006–10 | date = September 2009 | pmid = 19732639 | doi = 10.1016/j.arthro.2009.02.010 }}</ref> Around $500 million health care dollar will come from ACL injuries. ACL injuries can be categorized into groups- contact and non-contact based on the nature of the injury<ref>{{cite web | url = http://www.livestrong.com/article/548782-statistics-on-acl-injuries-in-athletes/ | title = Stats on ACL injuries }}</ref> Contact injuries occur when a person or object come into contact with the knee causing the ligament to tear. However, non-contact tears typically occur during the following movements: decelerating, cutting, or landing from a jump. ACL injury is 4-6 times higher in females than in males. ACL injuries account for a quarter of all knee injuries in the high school population.<ref name="pmid31393290">{{cite journal | vauthors = Wong SE, Feeley BT, Pandya NK | title = Complications After Pediatric ACL Reconstruction: A Meta-analysis | journal = Journal of Pediatric Orthopedics | volume = 39 | issue = 8 | pages = e566–e571 | date = September 2019 | pmid = 31393290 | doi = 10.1097/BPO.0000000000001075 | s2cid = 199503697 }}</ref> An increased Q angle and hormonal differences are a few causes of the gender disparity in ACL tear rates.<ref>{{cite web | url = http://maxpotentialsports.com/2013/06/07/anatomy-and-gender-disparity-of-acl-injuries/ | title = Anatomy and Gender Disparity of ACL injuries | archive-url = https://web.archive.org/web/20150402163452/http://maxpotentialsports.com/2013/06/07/anatomy-and-gender-disparity-of-acl-injuries/ | archive-date = 2 April 2015 }}</ref>

===Patellar tendon===

== Types of grafts ==

The [[patella]]r [[tendon]] connects the patella (kneecap) to the [[tibia]] (shin). Generally the graft is taken from the injured knee, but in some circumstances (such as a second operation) the other knee may be used. The middle third of the tendon is used, with bone fragments on each end removed. The graft is then threaded through holes drilled in the tibia and [[femur]], and finally screwed into place.

[[File:LCA-RX2.jpg|right|thumb|Grafts are inserted through a tunnel that is drilled through the shin bone (tibia) and thigh bone (femur). The graft is then pulled through the tunnel and fixated with screws. The two bright objects in this X-ray are screws in the thigh bone (above) and shin bone (below).]]

Graft options for ACL reconstruction include:

*[[Autograft]]s (employing bone or tissue harvested from the patient's body).

The graft is slightly larger than a hamstring graft, however graft size is not a determinant of outcome. The most important factor in determining the outcome is correct graft placement.

*[[Allograft]]s (using bone or tissue from another body, either a [[cadaver]] or a live donor).

*Bridge-enhanced ACL repair (using a bio-engineered bridging scaffold injected with the patient's own blood).

*Synthetic tissue for ACL reconstruction has also been developed, but little data exists on its strength and reliability.{{citation needed|date=April 2012}}

=== Autograft ===

The disadvantage is that the use of the patellar tendon is more painful than the other options. Strong [[painkillers]] may be prescribed for several weeks following the surgery. The patellar tendon also takes about one year to fully recover; until then there is an increased risk of [[tendonitis]].

An accessory [[hamstring]] or part of the [[patellar ligament]] are the most common donor tissues used in autografts. While originally less commonly utilized, the [[quadriceps tendon]] has become a more popular graft.<ref>{{cite journal | vauthors = Ouabo EC, Gillain L, Saithna A, Blanchard J, Siegrist O, Sonnery-Cottet B | title = Combined Anatomic Anterior Cruciate and Anterolateral Ligament Reconstruction With Quadriceps Tendon Autograft and Gracilis Allograft Through a Single Femoral Tunnel | journal = Arthroscopy Techniques | volume = 8 | issue = 8 | pages = e827–e834 | date = August 2019 | pmid = 31700778 | pmc = 6823836 | doi = 10.1016/j.eats.2019.03.021 }}</ref>

Because the tissue used in an autograft is the patient's own, the risk of [[Transplant rejection|rejection]] is minimal. The retear rate in young, active individuals has been shown to be lower when using autograft as compared to allograft.

===Hamstring tendon===

No fully ideal autograft site for ACL reconstruction exists. Surgeons have historically regarded patellar tendon grafts as the "gold standard" for knee stability.<ref name=Kraeutler />

For this procedure, the gracilis and semitendinosus tendons from the [[hamstring]] of the injured knee are the source of the graft. A long piece (about 25 cm) is removed from each of two tendons. The tendon segments are folded and braided together to form a quadruple thickness strand for the replacement graft. The braided segment is threaded through the heads of tibia and femur and its ends fixated with screws on the opposite sides of the two bones.

Hamstring autografts have failed at a higher rate than bone-tendon-bone autografts (2017 meta-analysis), after short- to mid-term followup of primary ACL reconstruction. However, the observed difference in failure rates is small enough that both are still regarded as viable options for primary ACL reconstruction.<ref>{{cite journal | vauthors = Samuelsen BT, Webster KE, Johnson NR, Hewett TE, Krych AJ | title = Hamstring Autograft versus Patellar Tendon Autograft for ACL Reconstruction: Is There a Difference in Graft Failure Rate? A Meta-analysis of 47,613 Patients | journal = Clinical Orthopaedics and Related Research | volume = 475 | issue = 10 | pages = 2459–2468 | date = October 2017 | pmid = 28205075 | pmc = 5599382 | doi = 10.1007/s11999-017-5278-9 | url = }}</ref>

Unlike the patellar tendon, the hamstring tendon's fixation to the bone can be affected by motion in the post-operative phase. Therefore, following surgery, a brace is often used to immobilize the knee for one to two weeks while the most critical healing takes place. Evidence suggests that the hamstring tendon graft does just as well, or nearly as well, as the patellar tendon graft in the long-term{{citeneeded}}.

Hamstring grafts historically had problems with fixation slippage and stretching out over time. Modern fixation methods avoid graft slippage and produce similarly stable outcomes with easier rehabilitation, less anterior knee pain and less joint stiffness.

This procedure is less painful than the patellar tendon graft, and rehabilitation is typically easier.

The quadriceps tendon, while historically reserved for revision reconstructions, has enjoyed a renewed focus as a versatile and durable graft for primary reconstructions. Use of the quadriceps tendon usually does not result in the same degree of anterior knee pain postoperatively, and quadriceps tendon harvest produces a reliably thick, robust graft. The quadriceps tendon has approximately 20% greater collagen per cross-sectional area than the patellar tendon, and a greater diameter of usable soft tissue is available.{{medcn|date=May 2017}}

===Allograft===

==== Hamstring tendon ====

An ACL, patellar tendon, or [[achilles tendon]] may be harvested from a [[cadaver]] and used as an [[allograft]] in reconstruction. The achilles tendon is so large it needs to be shaved to fit within the cavity inside the knee. This method has the benefit that the most painful part of the surgery, the harvesting of tendon tissue, is avoided. However, there is a slight chance of rejection which would lead to another surgery to remove the graft and replace it again. Allografts are often [[irradiation|irradiated]] to remove infectious agents. There is a risk of weakening the selected tendon, although for ACL surgery the weakened tendon is still as strong or about as strong as the ligament being replaced. [http://www.orthoassociates.com/ACL_grafts.htm] Even with the extensive and redundant screening process for donor grafts, there is still a risk of infection, which would be grounds to remove the graft. Therefore, this option runs the largest health risk.

[[File:ACL reconstruction hamstring autograft.jpg|thumb|right|Left knee following hamstring autograft ACL reconstruction, partial [[meniscectomy]] and [[medial meniscus]] repair. "Socks" are actually post-op pressure stockings.]]

Hamstring autografts are made with the [[semitendinosus|semitendinosus tendon]], either alone or accompanied by the [[Gracilis muscle|gracilis tendon]] for a stronger graft. The semitendinosus is an accessory hamstring (the primary hamstrings are left intact), and the gracilis is not a hamstring, but an accessory adductor (the primary adductors are left intact as well). The two tendons are commonly combined and referred to as a four-strand hamstring graft, made by a long piece (about 25&nbsp;cm) removed from each tendon. The tendon segments are folded and braided together to form a tendon of quadruple thickness for the graft. The braided segment is threaded through the heads of the [[tibia]] and [[femur]], and its ends are fixed with screws on the opposite sides of the two bones.{{citation needed|date=January 2022}}

Unlike the patellar ligament, the hamstring tendon's fixation to the bone can be affected by motion after surgery. Therefore, a brace is often used to immobilize the knee for one to two weeks. Evidence suggests that the hamstring tendon graft does as well, or nearly as well, as the patellar ligament graft in the long term.<ref name="pmid17261567">{{cite journal | vauthors = Pinczewski LA, Lyman J, Salmon LJ, Russell VJ, Roe J, Linklater J | title = A 10-year comparison of anterior cruciate ligament reconstructions with hamstring tendon and patellar tendon autograft: a controlled, prospective trial | journal = The American Journal of Sports Medicine | volume = 35 | issue = 4 | pages = 564–574 | date = April 2007 | pmid = 17261567 | doi = 10.1177/0363546506296042 | s2cid = 73233440 }}</ref> A Cochrane review in 2011 found insufficient evidence to suggest whether a hamstring versus patellar ligament graft was superior.<ref name="Mohtadi_2011">{{cite journal | vauthors = Mohtadi NG, Chan DS, Dainty KN, Whelan DB | title = Patellar tendon versus hamstring tendon autograft for anterior cruciate ligament rupture in adults | journal = The Cochrane Database of Systematic Reviews | volume = 2011 | issue = 9 | pages = CD005960 | date = September 2011 | pmid = 21901700 | pmc = 6465162 | doi = 10.1002/14651858.CD005960.pub2 | editor-last = Cochrane Bone, Joint and Muscle Trauma Group }}</ref> It found that individuals receiving hamstring autografts had reduced flexion (bending knee) range of motion and strength.<ref name="Mohtadi_2011" /> Common problems during recovery include strengthening of the [[Quadriceps femoris muscle|quadriceps]], [[Iliotibial tract|IT-band]], and [[Triceps surae muscle|calf muscles]].{{citation needed|date=January 2022}}

===Choice of Graft===

The main surgical wound is over the upper [[Anatomical terms of ___location#Proximal and distal|proximal]] tibia, which prevents the typical pain experienced when kneeling after surgery. The wound is typically smaller than that of a patellar ligament graft, and so causes less post-operative pain. Another option first described by Kodkani et al in 2004, a minimally invasive technique for harvesting from the back of the knee (Posterior Mini-incision), is faster, produces a significantly smaller wound, avoids the complications of graft harvesting from the anterior incision, and decreases the risk of nerve injury.<ref name="pmid15483531">{{cite journal | vauthors = Kodkani PS, Govekar DP, Patankar HS | title = A new technique of graft harvest for anterior cruciate ligament reconstruction with quadruple semitendinosus tendon autograft | journal = Arthroscopy | volume = 20 | issue = 8 | pages = e101-4 | date = October 2004 | pmid = 15483531 | doi = 10.1016/j.arthro.2004.07.016 }}</ref>

No ideal graft for ACL reconstruction exists. All graft choices have advantages and disadvantages. Patella tendon grafts are still considered the historical "gold standard" for knee stability by surgeons, however they suffer a slightly higher complication rate. Hamstring grafts had initial problems with fixation slippage. Modern fixation methods of hamstrings avoid graft slippage, producing outcomes that are the same in terms of knee stability with easier rehabilitation, less anterior knee pain and less joint stiffness. The main factors in knee stability are correct graft placement by the surgeon and treatment of other menisco-ligament injuries in the knee, rather than choice of graft.

There is some controversy as to how well a hamstring tendon regenerates after the harvesting. Most studies suggest that the tendon can be regenerated at least partially, though it will still be weaker than the original tendon.<ref name="pmid16525795">{{cite journal | vauthors = Okahashi K, Sugimoto K, Iwai M, Oshima M, Samma M, Fujisawa Y, Takakura Y | title = Regeneration of the hamstring tendons after harvesting for arthroscopic anterior cruciate ligament reconstruction: a histological study in 11 patients | journal = Knee Surgery, Sports Traumatology, Arthroscopy | volume = 14 | issue = 6 | pages = 542–5 | date = June 2006 | pmid = 16525795 | doi = 10.1007/s00167-006-0068-z | s2cid = 7147812 }}</ref><ref>{{cite journal | vauthors = Gill SS, Turner MA, Battaglia TC, Leis HT, Balian G, Miller MD | title = Semitendinosus regrowth: biochemical, ultrastructural, and physiological characterization of the regenerate tendon | journal = The American Journal of Sports Medicine | volume = 32 | issue = 5 | pages = 1173–81 | date = July 2004 | pmid = 15262639 | doi = 10.1177/0363546503262159 | publisher = The American Orthopedic Society for Sports Medicine | s2cid = 28512769 }}

==Recovery==

</ref>

Advantages of hamstring grafts include their high "load to failure" strength, the stiffness of the graft, and the low postoperative morbidity. The natural ACL can withstand a load of up to 2,160 [[Newton (unit)|newtons]]. With a hamstring graft, this number doubles, decreasing the risk of re-injury. The stiffness of a hamstring graft—quadruple that of the natural ACL (Bartlett, Clatworthy and Ngugen, 2001)—also reduces the risk of re-injury.{{citation needed|date=January 2022}}

All surgeries have a similar long-term recovery time frame. After surgery, motion of the knee joint recovers fairly quickly. Initial therapy consists of range of motion exercises, often with the guidance of a physical therapist, to regain the flexibility and prevent scar tissue from forming, and simple exercises to reduce loss of muscle (for example, quadriceps contractions, and straight leg raises). Often a [[continuous passive motion machine]] is used immediately after surgery to help with flexibility; and the preferred method of preventing muscle loss is isometric exercises that put no strain on the knee.

==== Patellar tendon ====

About six weeks are required for the bone to attach to the graft. However, the patient can typically walk on their own and perform simple physical tasks prior to this with caution, relying on the surgical fixation of the graft until true healing (graft attachment to bone) has taken place. At this stage the first round of physical therapy can begin. This usually consists of careful exercises to regain flexibility, and small amounts of strength back.

[[File:ACLReconstruction.jpg|thumb|left|Knees following ACL reconstruction surgery. A patellar tendon graft was used. Discoloration of the left leg is from swelling that drained from the knee to the shin.]]

The patellar tendon connects the [[patella]] (kneecap) to the tibia (shin). The graft is normally taken from the injured knee, but in some circumstances, such as a second operation, the other knee may be used. The middle third of the tendon is used, with bone fragments removed on each end. The graft is then threaded through holes drilled in the tibia and femur, and screwed into place. It is slightly larger than a hamstring graft.{{citation needed|date=January 2022}}

A 2011 Cochrane review, found no significant difference in long term outcome between patellar and hamstring autografts.<ref name="Mohtadi_2011" /> Those receiving patellar autografts had improved static stability but a loss of extension (straightening knee) range of motion and strength.<ref name="Mohtadi_2011" />

One of the more important benchmarks in recovery is the 12 weeks period. After this the patient can typically begin a more aggressive regimine of exercises involving stress on the knee, and increasing resistance. Jogging is often incorporated at or around this time.

Disadvantages compared with a hamstring graft include:

After four months, more intense activities such as running are possible without risk. After six months, the reconstructed ACL is generally at full strength ([[ligament]] tissue has fully regrown), and the patient may return to activities involving cutting and twisting. Recovery varies highly from case to case, and sometimes resumption of stressful activities may take a year or longer.

* Increased wound pain

* Increased scar formation

* Risk of fracturing the patella during harvesting of the graft

* Increased risk of [[tendinitis]].

* Increased pain levels, even years after surgery, with activities that require kneeling.<ref name="Kraeutler">{{cite journal | vauthors = Kraeutler MJ, Bravman JT, McCarty EC | title = Bone-patellar tendon-bone autograft versus allograft in outcomes of anterior cruciate ligament reconstruction: a meta-analysis of 5182 patients | journal = The American Journal of Sports Medicine | volume = 41 | issue = 10 | pages = 2439–48 | date = October 2013 | pmid = 23585484 | doi = 10.1177/0363546513484127 | s2cid = 7445341 }}</ref>

Some or all of these disadvantages may be attributable to post-operative patellar tendon shortening.<ref name="pmid17429611">{{cite journal | vauthors = Marrale J, Morrissey MC, Haddad FS | title = A literature review of autograft and allograft anterior cruciate ligament reconstruction | journal = Knee Surgery, Sports Traumatology, Arthroscopy | volume = 15 | issue = 6 | pages = 690–704 | date = June 2007 | pmid = 17429611 | doi = 10.1007/s00167-006-0236-1 | s2cid = 12469855 }}</ref>

{{anchor|Anterior cruciate ligament reconstruction with contralateral autogenous patellar tendon graft}}

The reconstructed ACL has a high success rate. Studies show that cases in which the ACL retears are generally caused by a traumatic impact. Statistically, it does not appear to matter if the patient uses a brace after recovery. A sufficiently traumatic impact to retear the ACL is unlikely to be mitigated by the use of a brace.

[[File:ACL Recon - A Lanpher.webm|thumb|Contralateral patellar tendon ACL revision]]

The [[Physical medicine and rehabilitation|rehabilitation]] after the surgery is different for each knee. The beginning rehab for the ACL graft knee is focused on reducing [[swelling (medical)|swelling]], gaining full [[range of motion]], and stimulating the leg muscles. The goal for the [[Graft (surgery)|graft donor]] need is to immediately start [[Strength training|high repetition strength training]] exercises.<ref name="pmid17920952">{{cite journal | vauthors = Shelbourne KD, Vanadurongwan B, Gray T | title = Primary anterior cruciate ligament reconstruction using contralateral patellar tendon autograft | journal = Clinics in Sports Medicine | volume = 26 | issue = 4 | pages = 549–65 | date = October 2007 | pmid = 17920952 | doi = 10.1016/j.csm.2007.06.008 }}</ref>

==References==

* Dawn Hastreiter, ''[http://uwmsk.org/residentprojects/aclreconstruction.html ACL Reconstruction]'', University of Washington, UWMC Roosevelt Clinic, Musculoskeletal Radiology.

=== Allograft ===

* [http://www.orthopaedics.com/knees.html#acl ACL Reconstruction video]

The patellar ligament, [[Tibialis anterior muscle#Origin and insertion|tibialis anterior tendon]], or [[Achilles tendon]] may be recovered from a cadaver and used in ACL reconstruction. The Achilles tendon, because of its large size, must be shaved to fit within the joint cavity.

Although there is less experience with the use of [[tibialis anterior]] grafts, preliminary data has shown no difference in short-term subjective outcomes between tibialis anterior allografts and patellar tendon allografts.<ref>{{cite journal | vauthors = O'Brien DF, Kraeutler MJ, Koyonos L, Flato RR, Ciccotti MG, Cohen SB | title = Allograft anterior cruciate ligament reconstruction in patients younger than 30 years: a matched-pair comparison of bone-patellar tendon-bone and tibialis anterior | journal = American Journal of Orthopedics | volume = 43 | issue = 3 | pages = 132–6 | date = March 2014 | pmid = 24660179 }}</ref>

==External links==

* [http://www.thedoctorslounge.net/orthopedics/articles/acl_healing/index.htm Orthopedic surgeon Martha Murray at Children's Hospital Boston may have found a better way to repair tears to the ACL tears -- a collagen gel, enriched with blood platelets, can stimulate natural healing of a partial ACL tear, encouraging the body's cells to fill in the defect and restore mechanical strength to the ligament]

* [http://www.knee1.com/forum/ ACL injury/reconstruction surgery discussion forum.]

* [http://health.groups.yahoo.com/group/kneesurgeryforum/ Knee surgery discussion group.]

* [http://www.mrsampath.com/video3.html ACL and Computer Aided ACL Reconstruction Presentation]

* [http://www.kneeclinic.com.au/pdfdoc/ACLGraft.pdf Rough paper comparing Hamstring and Patellar grafts]

* [http://www.orthoassociates.com/ACL_grafts.htm Anterior Cruciate Ligament (ACL) Graft Options]

* [http://video.google.com/videoplay?docid=4784825947320070673&sourceid=searchfeed Arthrosopic Surgery ACL Reconstruction Video]

=== Bridge Enhanced ACL Restoration (BEAR Implant) ===

A new approach to treating ACL tears was developed at [[Boston Children's Hospital]] and is currently in clinical trials.<ref>{{cite web|url=http://www.childrenshospital.org/centers-and-services/anterior-cruciate-ligament-program/bridge-enhanced-acl-repair-trial|title=ACL Program - Bridge-Enhanced ACL Repair (BEAR) Clinical Trial|website=www.childrenshospital.org|url-status=dead|archive-url=https://web.archive.org/web/20170520082510/http://www.childrenshospital.org/centers-and-services/anterior-cruciate-ligament-program/bridge-enhanced-acl-repair-trial|archive-date=20 May 2017|access-date=25 April 2016}}</ref> The Bridge Enhanced ACL Restoration (BEAR) implant is a bio-engineered bridging implant made from cow [[extracellular matrix]] scaffold (containing mostly [[collagen]]). It is injected with a small amount of patient's own blood, which turns the scaffold into a flexible material. The combination of blood and collagen is able to stimulate healing and reconnection of the ACL.<ref name=BEAR19/>

To install the scaffold, tunnels are drilled into the tibia and femur. The scaffold is placed at the femur end of the ligament. A few nonadsorbable sutures go through the femoral tunnel and then the scaffold to end up anchored the tibial tunnel. A few adsorbable sutures goes through the same femoral tunnel and then the scaffold to become attached to the tibial stump of the broken ACL. Blood is then added to the scaffold to make it flexible. The adsorbable wires are then pulled up, so that the stump comes into tight contact with the scaffold. This will allow the stump to regrow into a full ACL.<ref name=BEAR19/>

[[Category:Surgical specialties]]

[[Category: Surgical procedures]]

Results from the first-in-human study published in March 2019 in the ''Orthopedic Journal of Sports Medicine'' showed the 10 patients who received the BEAR implant had similar clinical, functional and patient-reported outcomes as the 10 patients undergoing autograft ACL reconstruction.<ref name=BEAR19>{{cite journal | vauthors = Murray MM, Kalish LA, Fleming BC, Flutie B, Freiberger C, Henderson RN, Perrone GS, Thurber LG, Proffen BL, Ecklund K, Kramer DE, Yen YM, Micheli LJ | display-authors = 6 | title = Bridge-Enhanced Anterior Cruciate Ligament Repair: Two-Year Results of a First-in-Human Study | journal = Orthopaedic Journal of Sports Medicine | volume = 7 | issue = 3 | pages = 2325967118824356 | date = March 2019 | pmid = 30923725 | pmc = 6431773 | doi = 10.1177/2325967118824356 }}</ref> Additional clinical studies are underway.<ref>{{Cite web|url=https://clinicaltrials.gov/ct2/show/NCT03776162|title=A Comparison of ACL Repair With BEAR Device vs. Autograft Patellar Tendon ACL Reconstruction - Full Text View - ClinicalTrials.gov|website=clinicaltrials.gov|language=en|access-date=2019-10-22}}</ref> In a study by the American Journal of Sports Medicine, they looked at a young and active population two years post surgery using the BEAR technique. The results showed that the BEAR technique was non-inferior to the autograft ACLR, and that it can also show an improvement in hamstring muscle strength at a two year follow up.<ref>{{cite journal | vauthors = Murray MM, Fleming BC, Badger GJ, Freiberger C, Henderson R, Barnett S, Kiapour A, Ecklund K, Proffen B, Sant N, Kramer DE, Micheli LJ, Yen YM | display-authors = 6 | title = Bridge-Enhanced Anterior Cruciate Ligament Repair Is Not Inferior to Autograft Anterior Cruciate Ligament Reconstruction at 2 Years: Results of a Prospective Randomized Clinical Trial | journal = The American Journal of Sports Medicine | volume = 48 | issue = 6 | pages = 1305–1315 | date = May 2020 | pmid = 32298131 | pmc = 7227128 | doi = 10.1177/0363546520913532 }}</ref>

[[Category: Orthopedic surgery]]

=== Synthetic tissue: Ligament Advanced Reinforcement System (LARS) ===

The anterior cruciate ligament (ACL) of the knee is commonly injured. There is insufficient re-vascularization of the ligament after complete rupture, which limits its ability to heal and necessitates reconstruction surgery. Within the last 20 years, new types of synthetic ligaments have been developed. The Ligament Advanced Reinforcement System (LARS), is one of these new synthetic ligaments that has recently gained popularity. There is evidence that supports LARS as a viable option for reconstruction surgery in regards to complication rates and high patient satisfaction scores, when compared to traditional surgical techniques. However, systematic reviews of the LARS in regarding graft stability and long term functional outcomes, have highlighted several important gaps in existing literature that requires future investigation. The necessity of rehabilitation following LARS is well recognized, but there is limited evidence available that guide rehabilitation protocols.<ref>{{cite journal | vauthors = Machotka Z, Scarborough I, Duncan W, Kumar S, Perraton L | title = Anterior cruciate ligament repair with LARS (ligament advanced reinforcement system): a systematic review | journal = Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology | volume = 2 | issue = 1 | article-number = 29 | date = December 2010 | pmid = 21138589 | pmc = 3016369 | doi = 10.1186/1758-2555-2-29 | url = | doi-access = free }} [[File:CC-BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/2.0/ Creative Commons Attribution 2.0 (CC BY 2.0)] license.</ref>

===Choice of graft type===

Typically, age and lifestyle help determine the type of graft used for ACL reconstruction.<ref name=Kraeutler /> The biggest factors in knee stability are correct graft placement by the surgeon and treatment of other menisco-ligament injuries in the knee, rather than type of graft. However, with the current literature, only KT-1000 arthrometer assessment demonstrated more laxity with allograft reconstruction.<ref>{{cite journal | vauthors = Tibor LM, Long JL, Schilling PL, Lilly RJ, Carpenter JE, Miller BS | title = Clinical outcomes after anterior cruciate ligament reconstruction: a meta-analysis of autograft versus allograft tissue | journal = Sports Health | volume = 2 | issue = 1 | pages = 56–72 | date = January 2010 | pmid = 23015924 | pmc = 3438864 | doi = 10.1177/1941738109347984 }}</ref> Bone-patellar tendon-bone grafts have resulted fewer failures and more stability on KT-1000 arthrometer testing.<ref name="pmid21084660">{{cite journal | vauthors = Spindler KP, Huston LJ, Wright RW, Kaeding CC, Marx RG, Amendola A, Parker RD, Andrish JT, Reinke EK, Harrell FE, Dunn WR | title = The prognosis and predictors of sports function and activity at minimum 6 years after anterior cruciate ligament reconstruction: a population cohort study | journal = The American Journal of Sports Medicine | volume = 39 | issue = 2 | pages = 348–59 | date = February 2011 | pmid = 21084660 | pmc = 3692351 | doi = 10.1177/0363546510383481 }}</ref><ref>{{cite journal | vauthors = Li X, Orvets N | title = Arthroscopic ACL Reconstruction with Bone Patellar Bone Graft using Anteromedial Technique. | journal = Journal of Medical Insight | date = February 2016 | volume = 2016 | number = 45 | doi = 10.24296/jomi/45 }}</ref>

== Surgical technique ==

=== All-inside ACL reconstruction technique ===

The all-inside anterior cruciate ligament reconstruction (ACLR) technique is considered state-of-the-art in many elite sports medicine practices. This minimally invasive technique, compatible with various grafts (e.g., hamstring autograft, quadriceps tendon), uses sockets rather than full tunnels on both the tibia and femur to preserve bone and reduce postoperative pain. Originally described by Morgan et al., the procedure was later modified by Dr. [[James H. Lubowitz]] who introduced a nonincisional variation in 2006. Initially, this method faced anatomical and biomechanical shortcomings, including risks associated with tunnel placement and graft fixation. Lubowitz and colleagues introduced a second-generation technique in 2011 using an outside-in technique for the creation of femoral sockets, flip-cutter for drilling tibial sockets, and adjustable loop cortical suspensory fixation. These refinements overcame previous complications and have subsequently contributed to broader adoption of the all-inside method in ACL reconstruction. <ref>{{Cite journal |last1=Yang |first1=Yun-tao |last2=Cai |first2=Zi-jun |last3=He |first3=Miao |last4=Liu |first4=Di |last5=Xie |first5=Wen-qing |last6=Li |first6=Yu-sheng |last7=Xiao |first7=Wen-feng |date=2022 |title=All-Inside Anterior Cruciate Ligament Reconstruction: A Review of Advance and Trends |url=https://doi.org/10.31083/j.fbl2703091 |journal=[Frontiers_in_Bioscience] (Landmark Ed) |volume=27 |issue=3 |pages=91 |doi=10.31083/j.fbl2703091 |via=IMPRESS|doi-access=free }}</ref>

== Stem cell treatment ==

[[Autologous stem-cell transplantation]] using [[mesenchymal stem cell]]s (MSCs) has been used to improve recovery time from ACL surgery, especially for athletes. MSCs are multipotent stem cells, meaning they can differentiate into multiple cell types. In the case of mesenchymal stem cells, these cell types include [[osteoblast]]s (bone cells), [[adipocyte]]s (fat cells), and [[chondrocyte]]s (cartilage cells). Ligament tissue mainly consists of [[fibroblast]]s and [[extracellular matrix]]. Ligament cells differ in size, respond to different cues in the cell environment, and express different cell surface markers, limiting the number of clinical treatments for accelerated repair of ACL tissue to MSCs and primary fibroblasts obtained from other ACL tissue. Therefore, most modern stem cell injections use MSCs to promote faster repair of the ACL and allow people such as athletes to return to their previous form faster.{{citation needed|date=January 2022}}

In order for MSCs to differentiate into an ACL, they must be placed in a proper [[Tissue engineering#Scaffolds|scaffold]] on which to grow, and must be in a [[bioreactor]] that maintains a normal physiological environment for the cells to reproduce and proliferate effectively.<ref name="Coutu, DL et al"><!--pmid/pmc/doi/ref error doesn't agree with author or title-->{{cite journal | vauthors = King JA, Miller WM | title = Bioreactor development for stem cell expansion and controlled differentiation | journal = Current Opinion in Chemical Biology | volume = 11 | issue = 4 | pages = 394–8 | date = August 2007 | pmid = 17656148 | pmc = 2038982 | doi = 10.1016/j.cbpa.2007.05.034 }}</ref> The scaffold must have the mechanical properties of a healthy ACL to sustain the ligament while it is in its primary form and maintain normal knee movement. Scaffolds that are used for ACL growth include [[collagen]], silk, gelatin, [[polylactic acid]], and [[glycosaminoglycan]]s.<ref name="Farrell, E et al">{{cite journal | vauthors = Farrell E, O'Brien FJ, Doyle P, Fischer J, Yannas I, Harley BA, O'Connell B, Prendergast PJ, Campbell VA | display-authors = 6 |author5-link=Ioannis Yannas | title = A collagen-glycosaminoglycan scaffold supports adult rat mesenchymal stem cell differentiation along osteogenic and chondrogenic routes | journal = Tissue Engineering | volume = 12 | issue = 3 | pages = 459–68 | date = March 2006 | pmid = 16579679 | doi = 10.1089/ten.2006.12.459 }}</ref> Mechanical properties of the scaffolds are further enhanced through braiding and twisting of the scaffold materials.

The bioreactor must have similar properties to a knee joint so that when the ACL is inserted into the body, it is not rejected as foreign, which could cause infection. Therefore, it has to have compatible [[PH|pH levels]], oxygen concentration levels, [[metabolite]] levels and temperature, in addition to being sterile.<ref>{{cite journal | vauthors = Yates EW, Rupani A, Foley GT, Khan WS, Cartmell S, Anand SJ | title = Ligament tissue engineering and its potential role in anterior cruciate ligament reconstruction | journal = Stem Cells International | volume = 2012 | pages = 438125 | year = 2012 | pmid = 22253633 | pmc = 3255293 | doi = 10.1155/2012/438125 | doi-access = free }}</ref>

== Recovery ==

Initial [[physical therapy]] consists of [[range of motion]] (ROM) exercises, often with the guidance of a physical therapist. Range of motion exercises are used to regain the flexibility of the ligament, prevent or break down [[Granulation tissue|scar tissue]] from forming and reduce loss of [[muscle]] tone. Range of motion exercise examples include: quadriceps contractions and straight leg raises. In some cases, a [[continuous passive motion]] (CPM) device is used immediately after surgery to help with flexibility. The preferred method of preventing muscle loss is [[isometric exercise]]s that put zero strain on the knee. Knee extension within two weeks is important with many rehab guidelines.

Perturbation training can help improve gait asymmetries of the knee joint.<ref name="pmid28224443">{{cite journal | vauthors = Arundale AJ, Cummer K, Capin JJ, Zarzycki R, Snyder-Mackler L | title = Report of the Clinical and Functional Primary Outcomes in Men of the ACL-SPORTS Trial: Similar Outcomes in Men Receiving Secondary Prevention With and Without Perturbation Training 1 and 2 Years After ACL Reconstruction | journal = Clinical Orthopaedics and Related Research | volume = 475 | issue = 10 | pages = 2523–2534 | date = October 2017 | pmid = 28224443 | pmc = 5599384 | doi = 10.1007/s11999-017-5280-2 }}</ref><ref name="pmid28224442">{{cite journal | vauthors = Capin JJ, Zarzycki R, Arundale A, Cummer K, Snyder-Mackler L | title = Report of the Primary Outcomes for Gait Mechanics in Men of the ACL-SPORTS Trial: Secondary Prevention With and Without Perturbation Training Does Not Restore Gait Symmetry in Men 1 or 2 Years After ACL Reconstruction | journal = Clinical Orthopaedics and Related Research | volume = 475 | issue = 10 | pages = 2513–2522 | date = October 2017 | pmid = 28224442 | pmc = 5599383 | doi = 10.1007/s11999-017-5279-8 }}</ref>

Approximately six weeks is required for the bone to attach to the graft. However, the patient can typically walk on their own and perform simple physical tasks prior to this with caution, relying on the surgical fixation of the graft until true healing (graft attachment to bone) has taken place. At this stage, the first round of physical therapy can begin. This usually consists of careful exercises to regain flexibility and small amounts of strength. One of the more important benchmarks in recovery is the twelve weeks post-surgery period. After this, the patient can typically begin a more aggressive regimen of exercises involving stress on the knee, and increasing resistance. [[Jogging]] may be incorporated as well.

After four months, more intense activities such as [[running]] are possible without risk. After five months, light ball work may commence as the ligament is nearly regenerated. After six months, the reconstructed ACL is generally at full strength (ligament tissue has fully regrown), and the patient may return to activities involving cutting and twisting if a brace is worn. Recovery varies highly from case to case, and sometimes resumption of stressful activities may take a year or longer.

===Risks===

If the proper rehabilitation procedure is not followed out post surgery, the ACL becomes less mobile and the bones begin to rub against each other. The abnormal bone movement can also damage the tissue, this damage can lead to osteoarthritis. If the proper rehabilitation regiment is not followed, chances of reinjury increase. Correlational analysis studies show that greater attendance at rehab sessions correspond with fewer reported symptoms in the surgical knee. However, this does also depend on the quality of the physical therapist or athletic trainer. Fear is a known factor in recovery and return to sport as well, with studies showing that greater self-reported levels of fear in an athlete while rehabbing had lower scores on hop tests and quadriceps strength symmetry, increasing the risk of reinjury. <ref>BW Brewer, AE Cornelius, JL Van Raalte, JC Brickner, JH Sklar, JR Corsetti, MH Pohlman, TD Ditmar & K Emery (2004). Rehabilitation adherence and anterior cruciate ligament reconstruction outcome, Psychology, Health & Medicine, 9:2, 163-175, DOI: 10.1080/13548500410001670690</ref><ref>Paterno MV, Flynn K, Thomas S, Schmitt LC. Self-Reported Fear Predicts Functional Performance and Second ACL Injury After ACL Reconstruction and Return to Sport: A Pilot Study. Sports Health. 2018;10(3):228-233. doi:10.1177/1941738117745806</ref><ref>{{cite web|url=http://www.webmd.com/a-to-z-guides/anterior-cruciate-ligament-acl-injuries-topic-overview|title=Anterior Cruciate Ligament (ACL) Injuries - Topic Overview|website=www.webmd.com|access-date=25 April 2016}}</ref>

== Rehabilitation ==

The recovery process for the ACL is usually broken down into different phases of rehabilitation. Each phase has its own objectives, however is intertwined with other phases since the goals are as progressive as the recovery itself. The rehabilitation process is at the pace of the patient. It is also important to take the patients mental health into account. The rehab and recovery is very demanding. With this being said, it can often lead to depressive disorders, mood changes, and low self-esteem.<ref>{{cite web |title=ACL Surgery Can Affect Emotional Health |url=https://powerplay.us/emotional-health-affects-recovery-acl-surgery/#:~:text=Mood%20changes%20are%20also%20common,into%20depression%20as%20workouts%20end. |website=Powerplay | date=7 August 2023 |access-date=September 12, 2023}}</ref> Timelines are sometimes given to help give an idea of where one can be during rehabilitation. Timelines are not used to discourage or encourage those who are not ready to advance their recovery process. Such acts may cause serious injury or re-injury of the ACL.

=== Pre-rehabilitation ===

Pre-rehabilitation before ACL reconstruction surgery has been shown to help with recovery post operation. Increased knee extensor strength and range of motion for those who participated in a pre-rehabilitation program in the first 3 to 6 weeks, but no significant change at 3 to 6 months.<ref>{{cite journal | vauthors = Cunha J, Solomon DJ | title = ACL Prehabilitation Improves Postoperative Strength and Motion and Return to Sport in Athletes | journal = Arthroscopy, Sports Medicine, and Rehabilitation | volume = 4 | issue = 1 | pages = e65–e69 | date = January 2022 | pmid = 35141537 | pmc = 8811524 | doi = 10.1016/j.asmr.2021.11.001 }}</ref>

===Phase 1 ===

This phase begins immediately post surgery while the patient is still on crutches and in a removable knee brace, which they're projected to be using for seven to ten days. During this phase the patient will begin seeing a physical therapist that will discuss the main goals of rehabilitation. Some of these goals include: reducing pain and inflammation, increasing range of motion, strengthening surrounding muscles, and beginning weight bearing exercises. Generally, in Phase 1 strengthening consists of isometric exercises.<ref name="Acl Rehab">{{cite journal | vauthors = Andrade R, Pereira R, van Cingel R, Staal JB, Espregueira-Mendes J | title = How should clinicians rehabilitate patients after ACL reconstruction? A systematic review of clinical practice guidelines (CPGs) with a focus on quality appraisal (AGREE II) | journal = British Journal of Sports Medicine | volume = 54 | issue = 9 | pages = 512–519 | date = May 2020 | pmid = 31175108 | doi = 10.1136/bjsports-2018-100310 | doi-access = free }}</ref> Extension deficit is a frequent issue after surgery and is often related to arthrogenic muscle inhibition.<ref>{{cite journal | vauthors = Sonnery-Cottet B, Saithna A, Quelard B, Daggett M, Borade A, Ouanezar H, Thaunat M, Blakeney WG | display-authors = 6 | title = Arthrogenic muscle inhibition after ACL reconstruction: a scoping review of the efficacy of interventions | journal = British Journal of Sports Medicine | volume = 53 | issue = 5 | pages = 289–298 | date = March 2019 | pmid = 30194224 | pmc = 6579490 | doi = 10.1136/bjsports-2017-098401 }}</ref> Specific exercises and cryotherapy are proven to be effective in addressing arthrogenic muscle inhibition.<ref>{{cite journal | vauthors = Delaloye JR, Murar J, Sánchez MG, Saithna A, Ouanezar H, Thaunat M, Vieira TD, Sonnery-Cottet B | display-authors = 6 | title = How to Rapidly Abolish Knee Extension Deficit After Injury or Surgery: A Practice-Changing Video Pearl From the Scientific Anterior Cruciate Ligament Network International (SANTI) Study Group | journal = Arthroscopy Techniques | volume = 7 | issue = 6 | pages = e601–e605 | date = June 2018 | pmid = 30013901 | pmc = 6019855 | doi = 10.1016/j.eats.2018.02.006 }}</ref> If the patient used a patellar tendon graft for their reconstructed ACL, therapist will also work on mobilizing the patellar tendon to keep it from shortening.{{medcn|date=May 2017}}

''Some equipment that can be used and exercises that can be performed are:''

** Use of cryo-cuff

*** provides cold compression

** Isometric contraction of wuads

** Quad sets

*** stand against wall, push extended knee against rolled towel

*** progress to straight leg raised to 30deg.

** Wall slides

*** To increase knee flexion

** Assisted knee flexion

** Towel squeeze

*** Sit in chair, squeeze rolled towel between knees for 5 seconds. Relax & repeat.

** VMO strengthening exercise

** Supported bilateral calf-raises

** Walk without crutches

** Swimming (freestyle front crawl)

This particular swimming technique encompasses all the muscles in the knee and will increase not only mobility but also the strength of the surrounding muscles, which include the quadriceps, hamstrings, gastrocnemius, tibialis anterior (shin muscle), abductor hallucis, abductor digiti minimi, and flexor digitorum brevis (foot muscles).

===Phase 2 ===

Many of the goals from phase I will be continued to the following phases until they have been reached. Some of these goals are reducing pain, swelling, and increasing the knee's range of motion is still crucial during this phase. Physical therapist may begin to incorporate core exercises as well as light weight exercises to strengthen the surrounding muscles and hips. Some examples of these exercises include the usage of resistance/stretch bands, stationary biking, and elliptical. During this phase the patient may begin performing more strenuous exercises such as half-squatting and partial lunges.{{medcn|date=May 2017}}

''Some exercises that can be performed are:''

** Mini squats

*** Progress to full squats → single-leg half squat

** Mini lunges

*** Progress to full lunges

** Leg press

*** Double-leg → single

** Step-ups

** Bridges

*** Double-leg → single

*** Floor → Swiss ball

** Hip abduction w/ Theraband

** Hip extension w/ Theraband

** Wobble board

*** Assisted → un-assisted → eyes closed (assisted → unassisted)

** Stork stand

*** Assisted → un-assisted → eyes closed (assisted → unassisted) → unstable surface

** Static proprioceptive hold/ball throwing

** Functional exercises that can be performed at this time include:

*** Walking

*** Bike

*** Roman chair

===Phase 3 ===

Patients will continue to work on decreasing pain/swelling and building up their strength. Lateral movement, jogging in a straight line, single-leg squats and exercises will start to be incorporated as patient begins to regain confidence in the knee. Building strength in the hips with lateral stepping as well as step-ups and step-downs will still be a strong focus in this phase.{{medcn|date=May 2017}}

''Some exercises that can be performed are''

** Continue exercises from Phase 2, progress as necessary

** Jump & land drills

*** Jump from block & stick landing

*** Double-leg landing → single-leg

** Plyometric drills

*** Jumping over blocks, sideways & forward

*** Hopping up & down steps/stairs

''Return to running can begin when certain criteria are met including:''<ref name=":0">{{Cite journal |last1=Kotsifaki |first1=Roula |last2=Korakakis |first2=Vasileios |last3=King |first3=Enda |last4=Barbosa |first4=Olivia |last5=Maree |first5=Dustin |last6=Pantouveris |first6=Michail |last7=Bjerregaard |first7=Andreas |last8=Luomajoki |first8=Julius |last9=Wilhelmsen |first9=Jan |last10=Whiteley |first10=Rodney |date=May 2023 |title=Aspetar clinical practice guideline on rehabilitation after anterior cruciate ligament reconstruction |journal=British Journal of Sports Medicine |volume=57 |issue=9 |pages=500–514 |doi=10.1136/bjsports-2022-106158 |issn=1473-0480 |pmc=11785408 |pmid=36731908}}</ref>

* Knee flexion range of motion (ROM) to 95% of full range.

* Knee extension ROM to full range.

* No effusion or trace of effusion.

* Quadriceps strength is greater than 80% on the limb symmetry index (LSI).

* Eccentric impulse is greater than 80% on LSI during countermovement jump.

* Pain-free running in an anti-gravity treadmill and pain-free aqua jogging.

* Repeating single-leg hops pain-free.

=== Phase 4 ===

By this time the range of motion should be greater than 110 degrees flexed and the patient's bodily mechanics like walking and light jogging should be back to normal (before operation). Single leg exercises will be continued as well as balancing activities to strengthen the core and lower body. Stamina and endurance should be improved for exercises such as biking, jogging, and step-ups/downs. If by this time the patient does not have 110 degrees of flexion in the knee, they are advised to see their therapist or surgeon. There is a chance that the knee could need another operation to increase the elasticity of the ligament. {{medcn|date=May 2017}}

The goal of this phase is a return to activity, however it requires an ability to perform some functional performance tests such as:

* Agility tests

**[[Illinois Agility Test]]

**Zig zag agility test

These tests are used to test the ability of the knee to withstand cutting and planting maneuvers.

* Single leg step-down tests: These tests can be used to identify any hip and core musculature weaknesses before cleared for return-to-play.

** Standing vertical jump:The patient jumps straight in the air from a standing start and lands on two feet as stable as possible.

** Heiden hop test: The patient jumps as far as possible with the uninjured leg and lands on the injured leg. A patient's ability to stick the landing is indicative of good knee function.

* Isokinetic testing

**This is used to evaluate muscle strength.

**The individual should have at least 90% quadricep strength of the uninjured leg.

**They should also have equal hamstring strength to their uninjured leg as well.

=== Phase 5 ===

This is the last phase of the recovery rehabilitation. Phase V includes returning to sports after being cleared by therapist or surgeon. In order for this to happen the patient must have full range of motion, continue maintaining strength and endurance, and be able to increase [[proprioception]] with agility drills. The patient is still to be aware that going down hill or down stairs while the knee is aggravated may cause further injury like a meniscus tear.{{medcn|date=May 2017}}

''The patient can be cleared for return to sport when they meet the following criteria:''<ref name=":0" />

* No pain or swelling in the knee.

* Full ROM of the knee.

* The knee is stable.

* Reports of normal knee function and psychological readiness from the patient.

* Isokinetic hamstring and quadriceps strength should be 100% symmetrical at peak torque at 60°/s.

* When jumping, values should be absolute and symmetric for vertical and horizontal jumps at the hip, knee, and ankle.

* When running, greater than 90% symmetry should be restored of vertical ground reaction forces as well as knee biomechanics during direction changes and high speed running.

* Completion of a sports specific training program.

== Cost of procedure ==

The cost of an ACL reconstruction surgery will vary due to a few different reasons such as where a patient lives, which graft is used, if the meniscus is also torn, and the coverage of the patient's insurance. A study has shown in 2016 that metropolitan areas, of at least one million residents, located on the western coast of the United States of America and areas like Minnesota, Indiana, and Michigan were more expensive than the East and South East coast of the United States.<ref>{{Cite news|url=https://amino.com/blog/acl-surgery-cost/|title=How much does ACL surgery cost?| vauthors = Vanvuren C |date=2016-11-29|work=Amino Blog: Telling Health Care Stories with Data|access-date=2017-05-15}}</ref> Another study, conducted by Baylor University, found that ACL reconstruction procedures using the bone-patella tendon-bone technique took 2.5 hours longer than using a hamstring graft. The operation room costs and hospital charges for that amount of extra time came to about $1,580 more expensive.<ref>{{cite journal | vauthors = Bonsell S | title = Financial analysis of anterior cruciate ligament reconstruction at Baylor University Medical Center | journal = Proceedings | volume = 13 | issue = 4 | pages = 327–30 | date = October 2000 | pmid = 16389334 | pmc = 1312224 | doi = 10.1080/08998280.2000.11927697 }}</ref> This also applies to having a torn meniscus during the procedure. Fixing the torn cartilage will increase the procedure time, increasing cost. Insurance plays the biggest role in cost for an ACL reconstruction since that it will be covering majority of the costs. The coverage of a patient's plan, deductibles, and insurance company will determine how much the patient will pay in copays.<ref>{{Cite news|url=https://www.healthgrades.com/procedures/how-much-does-acl-surgery-cost|title=How Much Does ACL Surgery Cost?| vauthors = Lewis S |date=2016-10-17|work=Healthgrades Operating Company, Inc.|access-date=2017-05-15}}</ref>

Despite the complexity of the procedure and numerous doctor's visits involved, 80–90% of patients who have had the surgery said they had favorable results.<ref>{{cite web|url=http://www.webmd.com/a-to-z-guides/anterior-cruciate-ligament-acl-surgery|title=Anterior Cruciate Ligament (ACL) Surgery|work=WebMD|access-date=25 April 2016}}</ref>

== ACL repair ==

'''ACL repair''' is also a surgical option. This involves repairing the ACL by re-attaching it using sutures, instead of performing a reconstruction using new material. ACL repair as a technique is older than ACL reconstruction.<ref name=HSS>{{cite web |title=ACL Reconstruction Surgery: Procedure and Recovery {{!}} HSS |url=https://www.hss.edu/condition-list_acl-surgery.asp |website=Hospital for Special Surgery |language=en}}</ref>

With the modernized form of ACL repair (still using sutures), theoretical advantages of repair include faster recovery and a lack of donor site morbidity, but randomised controlled trials and long-term data regarding re-rupture rates using contemporary surgical techniques are lacking.<ref>{{cite journal | vauthors = Praz C, Kandhari VK, Saithna A, Sonnery-Cottet B | title = ACL rupture in the immediate build-up to the Olympic Games: return to elite alpine ski competition 5 months after injury and ACL repair | journal = BMJ Case Reports | volume = 12 | issue = 3 | pages = e227735 | date = March 2019 | pmid = 30878956 | pmc = 6424301 | doi = 10.1136/bcr-2018-227735 }}</ref> "Failure rates for ACL repair appear to be between 5 and 10 times higher than those for ACL reconstruction in people of all ages. This results in graft failure rates as high as 50% in adolescent patients."<ref name=HSS/>

The {{section link||Bridge Enhanced ACL Restoration (BEAR Implant)}} mentioned above is also a type of repair, though with added "bridging" material.

== References ==

{{reflist}}

{{Bone, cartilage, and joint procedures}}

[[Category:Orthopedic surgical procedures]]

[[Category:Knee treatments]]

[[Category:Knee ligaments]]