Barriers To In Vitro Organ Recreation For Scientific Experiments: A Focus On A Specific Organ

what are the barriers to re-creating organs in vitro for scientific experiments? Use a specific organ we have studied as an example system.

The anterior cruciate ligament (ACL) is a significant, internal, stabiliser of the joint of the knee, restraining hyperextension. The knee joint’s bone structure is made up of the tibia, the femur and the patella. One out of the four important ligaments found in the knee is the ACL present between the the tibia and the femur and connecting them. The knee is held along together by the medical collateral ligament (MCL), anterior cruciate ligament (ACL), posterior cruciate (PCL) ligaments and the lateral collateral ligament (LCL). The ACL is found in the middle of the knee, and it prevents the tibia from coming out in front of the femur. It is also responsible for giving rotational stability in addition. The knee’s surface that is weight bearing has a covering of the layer of articular cartilage (Oiestad et al. 2009). The anterior cruciate ligament (ACL) is a frquently injured ligament of the knee. In many patients, the knee injury to the knee means that the ACL is injured to a great extent. The prevalence of ACL injury is thought to be at roughly 200,000 annually. Around hundred thousand ACL reconstructions undertaken every year. When spoken on a general basis, the occurrence of ACL injury is found to be more in people who take part in sports that have high risk, like football, basketball, soccer and skiing. On an average, around fifty percent of the ACL injuries take place along with damage done to articular cartilage, meniscus, and other ligaments. In addition, patients can have bruises of the bone below the surface of the cartilage. This scan is diagnosed by magnetic resonance imaging (MRI) scan. It may determine injury done to the articular cartilage that is overlying (Kiapour and Murray, 2014).

2.1 An estimation is done that around seventy percent of the occurring ACL injuries take place by mechanisms that do not associate with contacts with other substances and thirty percent take place when direct contact occurs with some other object. Suchprocesses of the injury occurring to the ACL is associated with deceleration along with awkward landings, pivoting, cutting and sidestepping maneuvers, or play that is out of control (Oiestad et al. 2009).

2.2 Many studies have indicated that female athletes may be having more chances of having an ACL injury during sports when compared to male athletes. It is proposed that the reason is the difference in muscular strength, physical conditioning and neuromuscular control. Another hypothesis is that the difference in injury in ACL is pelvis and the lower extremity alignment of the leg, influence the hormone estrogen has on the properties of the ligament and the ligamentous laxity. Moreover, women have a wider pelvis that requires the femur to make an angle towards the knee. This angle is known as the Q angle. The average Q angle for women is 17 degrees and for men it is 14 degrees. The enhanced risk of ACL injury taking place among females is predicted by their undertaken motion and the laoding as observed in the knee during particular situations (Hewett, Torg and Boden, 2009).

Current treatment

2.3 The ligament dominance theory states that females undertake athletic movements with valgus angles of the knee that is greater. A large amount of the stress is put on the ACL. This is due to the high activation of the quadriceps muscles in spite of the fact that the knee flexion is limited as well as hip flexion is limited, hip adduction is greater and the knee adductor moment is large. Ligament dominance is seen when cases are with more movement in the frontal plane for accommodating limited movement n the saggital plane. This is due to weak hamstring muscles (Myer et al. 2009).

2.4 The quadriceps dominance theory is able to identify when the hamstring muscles are weaker than the quadriceps muscle. After the injury takes place, patients have much pain and the area of the injury gets a swelling and the area of the injury feels unstable. In the next hours of the ACL injury, patients have more swelling of the knee, and there is a considerable loss of motion to the full range. There are tenderness and pain along the line of the joint, and the person feels distress while walking. The natural past of an injury occurring to the ACL without surgical intervention is found to be varying from one patient to another, and it depends on activity level shown by the patient, the limit of the injury and the symptoms of instability. Complete ruptures of the ACL has an outcome that is less favourable. After an ACL tear, some patients are not able to take part in physical activity (Wilk et al. 2012).

The treatment for such tear and rupture of the ACL has been advanced in the medical field. Treatments include a non surgical method and surgical process (Kiapour and Murray, 2014).

3.1 In  the non-surgical method of treatment, physical therapy and rehabilitation are the best options for restoring the knee to particular suitable condition like the pre-injury condition. It is very much needed to educate the patients on the methods of preventing instability. A hinged knee brace can be used as a supplement. Surgical treatment is needed in cases where combined injuries take place. The choice between surgical and non-surgical treatment varies from patient to patient (Ardern et al. 2011).

3.2 Tears in the ACL is not repaired by using suture for sewing it together. Thus, the torn and ruptured ACL is replaced by the use of a substitute graft that is made up of a tendon. Such grafts usually used for replacing the ACL include Quadriceps tendon autograft, Patellar tendon autograft, Allograft patellar tendon, Hamstring tendon autograft, Achilles tendon, gracilis, semitendinosus, or posterior tibialis tendon. Patients who undergo surgical reconstruction achieve success, and the rate is around ninety percent. The main aim of the ACL reconstruction is the prevention of the instability and restoration of the function of the ligament that is already torn. The result is that a stable knee is created. The patient can therefore take up sports again. Some complications are associated with the surgical procedure. These include infection, viral transmission, numbness and bleeding,  blood clot, stiffness, instability, pain in the knee cap and injury in the growth plate. All these depend on the health condition of the patient (Meisterling, Schoderbek and Andrews, 2009).

3.1 Non-surgical method

3.2.1 In Patellar tendon autograft, the middle section of the patient’s patellar tendon together with a bone plug from the kneecap and the shin is used. This procedure is used for patients whose activities does not require a great amount of kneeling. The  semitendinosus hamstring tendon is under use for creating the hamstring tendon autograft forreconstructing the ACL. Such grafts have few problems related to the graft harvesting when compared to the patellar tendon autograft., including fast recovery, a smaller incision and fewer problems of stiffness. Uses of quadriceps tendon autograft are in cases where patientspreviously have experienced let-down with a reconstruction of ACL. The middle third of the patient's quadriceps tendon together with a bone plug originating from the upper end of the knee cap are considered (Kline et al. 2015).

3.2.2 Allografts are those grafts that are taken from cadavers. This method of grafting is under development. This therapy is being researched into to a great extent and is becoming popular in an increasing manner. These grafts are used for those patients who have not achieved success with ACL reconstruction in the past. Such procedure is used in those surgeries also where the need is to repair and undertake reconstruction of more than one ligament of the knee. The advantages of the allograft are that pain is eliminated by taking the graft from the patient, smaller incision and decreased the time for surgery. The allograft allows proper bony fixation to occur in the femoral and tibial bone tunnels with the help of screws (Kline et al. 2015).

Advancements in the knowledge of kinematics, anatomy and physiology promise to improve future treatment processes for anterior cruciate ligament tear and rupture. The ultimate objective of complete restoration of ACL injury to the status before an injury is possible in future by genetic manipulation inducing tissue regeneration. In future, resorbabale stents with bioactive growth factors incorporated in them have immense prospective of inducing normal anatomy of anterior cruciate ligament. This process would not need detrimental harvesting of the tissues of the patient. The risk of microbial transmission is also less with the use of such allograft (Hu et al. 2013). In the future, the advancement of benign allografts and autografts may be possible with resorbable fixation of the graft with the bone. Future advancement of robotic surgical techniques may be of great help in the process of treatment of ACL tear and rupture. It holds potential for improvement in a placement of the graft. Advancements in non-surgical procedures may also take place. These would include control of muscle atrophy, better techniques for bracing, enhanced  cerebellar- proprioceptive rehabilitation. The fundamental principle of such therapies would be to maximise the transference capacity and load acceptance with reduced degree of potential risks for the patient (Dunn et al. 2015).

3.2 Surgical method

My personal opinion is that these techniques would be realy useful in different situations and patients would be highly benefitted from them. In clinical situations, they would be realistic and beneficial. The non-surgical procedures would be of more prominence. This is in particular to situations where the repairing of the torn ligament does not work properly. Processes that are costly and challenging from the recovery standpoint can be resolved by such methods.

5. References

Ardern, C.L., Webster, K.E., Taylor, N.F. and Feller, J.A., 2011. Return to sport following anterior cruciate ligament reconstruction surgery: a systematic review and meta-analysis of the state of play. British journal of sports medicine, p.bjsports76364.

Dunn, W.R., Wolf, B.R., Harrell, F.E., Reinke, E.K., Huston, L.J. and Spindler, K.P., 2015. Baseline Predictors of Health-Related Quality of Life After Anterior Cruciate Ligament Reconstruction. The Journal of Bone & Joint Surgery, 97(7), pp.551-557.

Eorthopod.com,. (2016). Hamstring Tendon Graft Reconstruction of the ACL | eOrthopod.com. Retrieved 7 January 2016, from https://www.eorthopod.com/hamstring-tendon-graft-reconstruction-of-the-acl/topic/166

Hewett, T.E., Torg, J.S. and Boden, B.P., 2009. Video analysis of trunk and knee motion during non-contact anterior cruciate ligament injury in female athletes: lateral trunk and knee abduction motion are combined components of the injury mechanism. British journal of sports medicine, 43(6), pp.417-422.

Hu, J., Qu, J., Xu, D., Zhou, J. and Lu, H., 2013. Allograft versus autograft for anterior cruciate ligament reconstruction: an up-to-date meta-analysis of prospective studies. International orthopaedics, 37(2), pp.311-320.

Kiapour, A. and Murray, M. (2014). Basic science of anterior cruciate ligament injury and repair.Bone and Joint Research, 3(2), pp.20-31.

Kline, P.W., Morgan, K.D., Johnson, D.L., Ireland, M.L. and Noehren, B., 2015. Impaired quadriceps rate of torque development and knee mechanics after anterior cruciate ligament reconstruction with patellar tendon autograft.The American journal of sports medicine, 43(10), pp.2553-2558.

Meisterling, S.W., Schoderbek, R.J. and Andrews, J.R., 2009. Anterior cruciate ligament reconstruction. Operative techniques in sports medicine,17(1), pp.2-10.

Myer, G.D., Ford, K.R., Foss, K.D.B., Liu, C., Nick, T.G. and Hewett, T.E., 2009. The relationship of hamstrings and quadriceps strength to anterior cruciate ligament injury in female athletes. Clinical journal of sport medicine,19(1), pp.3-8.

Øiestad, B. E., Engebretsen, L., Storheim, K., & Risberg, M. A. (2009). Knee osteoarthritis after anterior cruciate ligament injury a systematic review. The American journal of sports medicine, 37(7), 1434-1443.

Orthoinfo.aaos.org,. (2016). Anterior Cruciate Ligament (ACL) Injuries-OrthoInfo - AAOS. Retrieved 7 January 2016, from https://orthoinfo.aaos.org/topic.cfm?topic=a00549

Wilk, K.E., Macrina, L.C., Cain, E.L., Dugas, J.R. and Andrews, J.R., 2012. Recent advances in the rehabilitation of anterior cruciate ligament injuries.journal of orthopaedic & sports physical therapy, 42(3), pp.153-171.