Patient Information -Knee

The knee is the largest joint in the body and is vital to movement. Two sets of ligaments in the knee give it stability: the cruciate and the collateral ligaments. 

The cruciate ligaments are located inside the knee joint and connect the thigh bone (femur) to the shin bone (tibia). They are made of many strands and function like short ropes that hold the knee joint tightly in place when the leg is bent or straight. This stability is needed for proper knee joint movement.

The name, cruciate, derives from the word crux, meaning cross, and crucial. The cruciate ligaments not only lie inside the knee joint, they criss-cross each other to form an "x". The ACL is a ligament in the center of your knee that can become damaged when twisted too far, such as in a skiing injury. ACL Reconstruction is performed using a combination of open surgery and arthroscopy. The cruciate ligament located toward the front of the knee is the anterior cruciate ligament (ACL), and the one located toward the rear of the knee is called the posterior cruciate ligament (PCL).

The ACL prevents the shinbone from sliding forwards beneath the thighbone. The ACL can be injured in several ways:

• Changing direction rapidly

• Slowing down when running

• Landing from a jump

• Direct contact, such as in a football maneuver

If you injure your ACL, you may not feel any pain immediately. However, you might hear a slight popping noise and feel your knee give out from under you. Within 2 to 12 hours, the knee will swell, and you will feel pain when you try to stand. RICE- Rest, Ice, Compression, Elevation can help greatly until you can see an orthopaedic surgeon.

A diagnosis of ACL injury is based on a thorough physical examination of the knee. The exam may include several tests to see if the knee stays in the proper position when pressure is applied from different directions. Your orthopaedist may order an X-ray and MRI (magnetic resonance imaging) or, in some cases, inspection under arthroscopy.  

A partial tear of the ACL may or may not require surgical treatment. A complete tear is more serious. Complete tears, especially in younger patients, may require reconstruction.

Both operative and non-operative treatment choices are available depending on the severity of the injury and the surgeon’s opinion.

Before the ACL reconstruction process begins, the orthopaedic surgeon will examine your knee arthroscopically, and repair any additional damage to the knee, such as a torn meniscus, or worn articular cartilage if necessary.

Operative treatment (either arthroscopic, mini open or open surgery) uses a strip of tendon, usually taken from the patient’s knee (patellar tendon) or hamstring muscle, that is passed through the inside of the joint and secured to the thighbone and shinbone. Refer to the diagrams.

The surgery is followed by an exercise and rehabilitation program to strengthen the muscles and restore full joint mobility.

There are several materials used to manufacture orthopaedic implants, however the use of biodegradable materials is becoming increasingly more popular as well as accepted due to the significant clinical advantages they provide.

Inion Hexalon™ ACL/PCL screw is a  biodegradable ACL/PCL interference screw. The design of Inion Hexalon™ gives superior torsional strength to conventional screws which significantly reduces the possibility of screw breakage. The innovative design of the taper of the screw and optimized screw thread design provides for stability during insertion and grip once in place. The Inion Hexalon™ screw is self tapping therefore no starter screw driver is required.

The Inion Hexalon™ screw is used in ACL or PCL reconstruction cases were either the anterior cruciate or posterior cruciate ligaments have been torn.

The Inion Hexalon™ Biodegradable ACL/PCL Screws gradually lose their strength during 18-36 weeks. This coincides with the average healing time of this type of injury. Complete biodegradation takes place within two to four years.

Inion Hexalon™ is the first coloured ACL-screw launched to the orthopaedic market, giving maximum visibility during the screw insertion and clear arthroscopic views. The pigment is a pigment approve by regulatory authorities like the US FDA.

One of the big advantages of using biodegradable products is that if revision surgery is required the implant, depending on time since insertion, is either absorbed, semi absorbed or can be easily drilled over without compromising the bone tunnel.

The posterior cruciate ligament, or PCL, is not injured as frequently as the ACL. PCL sprains usually occur because the ligament was pulled or stretched too far, or as a result of a blow to the front of the knee.

PCL injuries disrupt knee joint stability because the shinbone can sag backwards. The ends of the thighbone and shinbone rub directly against each other, causing wear and tear to the thin, smooth articular cartilage. This abrasion may eventually lead to arthritis in the knee.

Patients with PCL tears often do not have symptoms of instability in their knees, so surgery is not always needed. Many patients return to their normally daily activity without significant impairment after completing a recommended rehabilitation or physical therapy program. If the PCL injury pulls a piece of bone out of the top of the shinbone, surgery is needed to reattach the ligament. The knee function after this surgery is normally good.

Injuries to the MCL are usually caused by contact on the outside of the knee and are accompanied by sharp pain on the inside of the knee. Normally whilst playing a contact sport such as football. The lateral collateral ligament is rarely injured.

You should also consult your doctor about a course of rehabilitation exercises for good healing.

If the collateral ligament is completely torn or torn in such a way that ligament fibers cannot heal, you may need surgery. Repair may bring good results, with a return to good knee stability. After satisfactory rehabilitation, many people resume their previous levels of activity.

The meniscus is a “C-shaped” cushion pad in the knee between the thigh bone (femur) and the lower leg bone (tibia). It acts as a shock absorber and makes the motion of the knee smooth.

The medial and lateral menisci are fixed between the two weight-bearing surfaces within the knee, and as such can become “pinched” by the other structures of the knee between the joint when an injury occurs. Typically, the injury involves twisting on a bent knee. When this happens the menisci can become torn (“torn cartilage”).It may be torn by twisting or bending in sports or daily activities. 

 The classic symptom of a torn meniscus is pain, often felt as a sharp, almost “knife-like” stabbing sensation on the inside (medial tear) or outside (lateral tear) of the knee. This pain is often felt in waves, with bouts of severe discomfort, followed by no pain, felt over the course of several days or weeks.

A meniscal tear results in knee swelling, locking and giving way. It may cause pain with bending, squatting, twisting, stair climbing or getting up from a seated position. A meniscal tear is best diagnosed by a physical examination by the orthopedist. An MRI (magnetic resonance imaging) may be obtained to confirm a meniscal tear.

Most surgeons these days will try to repair a torn meniscus where practical. Usually the repair is done with a biodegradable material, which holds its strength just long enough for healing to occur, before getting absorbed by the body, leaving no repair material.

A small percentage of meniscal tears may heal on their own within about 6 weeks. If symptoms continue, then it is unlikely that the meniscal injury will heal and arthroscopy is necessary. The arthroscope shows a picture of the location and anatomy of the tear. These factors help determine if a tear is repairable (meniscal repair) or removable (partial meniscectomy).

The Inion Trinion™ Meniscus Screw is indicated for use in the fixation of bucket handle repairs which are longitudinal tears that may take the shape of a bucket-handle if part of the tear is floating free. These tears are normally found in the area of the meniscus which has blood supply.

Easy insertion through the cannula with needle-tipped flexible screw driver allows your surgeon to achieve good contact with tissue, compared to other systems such as arrows and darts. the design of the implant helps to bring together the sides of the repair. Because the Inion Trinion™ meniscal screw is coloured green good visibiltiy is achieved allowing the surgeon to position the implant well and to ensure that the implant if completely inserted into the soft tissue.

• implant size

• how the material is processed

• where the device is implanted in the body area, e.g. shoulder area is more vascular than the knee area

Because the Inion Trinion™ meniscal screw is coloured green good visibility is achieved allowing the surgeon to position the implant well and to ensure that the implant if completely inserted into the soft tissue helping to eliminate the risk of damage to the knee joint.

If the tear is in the outer third of the meniscus and is smooth and straight, then there is usually an adequate blood supply to allow repair of the tear with small stitches. If however, the meniscal tear is in the inner two-thirds or is shredded, then minimal blood supply is present. These tears require removal. The removed portion of the meniscus does not grow back, but if the damaged portion is left in the knee joint, it can cause further joint destruction. In the past, the entire meniscus was removed for tears and patients had good knee function for many years. The arthroscope allows the orthopaedic surgeon to minimize the amount of meniscal tissue removed resulting in normal knee function for even longer. This surgery takes about 20-40 minutes to perform and is done on an outpatient basis (without spending the night in the hospital.)

The surgery is followed by an exercise and rehabilitation program. Patients return for follow-up visit generally in 7-10 days; stitches are removed at that time and an exercise program is started. Patients may do exercises by themselves or with a physical therapist, depending upon the seriousness of the injury and whether the meniscus was repaired or removed.

Patients return to work within several days. If however, their job requires heavy lifting or climbing, then return may be delayed several weeks. Full recovery and return to pre-injury athletic activities occurs in 3-6 weeks for a partial meniscectomy and 8-12 weeks for a meniscal repair.