Medial Patellofemoral Ligament Ruptures
Location/anatomy of the medial patellofemoral ligament (MPFL)
The medial patellofemoral ligament is a band of tissue which is connected to the medial (inside) edge of the patella (kneecap) and a bony protrusion on the inner edge of the lower end of the femur (thigh bone), known as the femoral medial epicondyle.
- Medial patellofemoral ligament (MPFL)
- Femoral medial epicondyle
What is the function of the MPFL?
The medial patellofemoral ligament prevents the kneecap from being dislocated. It stabilizes, or keeps the kneecap in place, and stops it from moving/sliding outwards, which is known as lateral translation.
What is the main cause of MPFL ruptures?
The main cause of MPFL ruptures is dislocation of the kneecap. A dislocated kneecap can cause the MPFL to be weakened or damaged, which in turn makes further dislocations more likely in the future.
Dislocation can be caused by a direct trauma or blow to the kneecap, or by excessively turning or twisting the leg, with the foot flat on the floor.
Typical treatment options for MPFL ruptures
The first step of conservative, or non-surgical treatment for a dislocated kneecap is usually a procedure known as reduction, which is essentially moving the kneecap back into its proper place. In some cases this can happen spontaneously, however a doctor may need to physically manipulate the kneecap back into place. Once the kneecap has been moved back into place, the knee is strapped or put in a brace to keep it in the correct position while healing occurs.
Physiotherapy may also be recommended as part of conservative treatment.
However, if the kneecap continues to dislocate after conservative treatment, surgery may be necessary in order to reconstruct or strengthen the MPFL, and in doing so, stabilize the kneecap.
Surgical treatment is usually necessary in cases of recurrent patellar dislocation, where the kneecap continues to dislocate despite having been treated conservatively. In cases of recurrent patellar dislocation, the tissue which keeps the kneecap in place is usually found to be of poor quality, torn, or otherwise damaged, and needs surgical reconstruction in order to function properly.
For more information about some typical surgical treatments for reconstruction of the medial patellar femoral ligament, please click the buttons above.
In an autograft procedure tissue is taken, or “harvested” from another part of the patient’s body and implanted at the site of injury to strengthen and repair the damaged tissue. In the case of MPFL reconstruction, common autograft tissues include hamstring tendons such as the semitendinosus tendon or the gracilis tendon.
Disadvantages of autografts can include weakness in the area from which the harvested tissue is extracted. This is known as donor site morbidity. Autograft tissue also tends to debilitate (lose strength) when it is harvested, as the tissue suffers necrosis (tissue death). Some strength is gradually regained after implantation, but this can mean a longer recovery period.
Alternatively, allografts may be used for MPFL reconstruction. These are similar to autografts in that harvested tissue is implanted at the injury site. However, unlike autografts, which come from the patient’s own living body, allograft tissue is cadaveric and comes from a donor.
Like autografts, disadvantages of allografts can include a longer recovery period due to the initial loss of strength in the harvested tissue. Weakness in the area from which the tissue is harvested is eliminated with allografts, as the tissue comes from a donor rather than the patient’s own body, however there may be some risk of disease or infection transmission from the donor tissue.
Repairing a ruptured MPFL with Neoligaments’ MPFL System
The Neoligaments 10 mm x 500 mm Poly-Tape implant, in conjunction with the 6 mm Fastlok fixation device (MPFL System) is indicated for reconstruction of the medial patellofemoral ligament in cases of recurrent patellar dislocation.
The Poly-Tape is a textile implant made from polyethylene terephthalate (polyester), which has been in use for the reconstruction of ligaments and tendons for more than 25 years.
The Fastlok consists of a titanium alloy staple and buckle, and is designed to securely fix polyester tapes directly to the bone.
- The open weave structure of the Poly-Tape acts as a scaffold that encourages tissue ingrowth to speed up healing of the reconstruction.
- The continuous longitudinal yarns of the Poly-Tape provide it with sufficient strength to allow early mobilization postoperatively.
- The unique triple clamping action of the Fastlok fixation device holds the Poly-Tape and the repair firmly in place.
- Autografts and allografts are unnecessary, which results in a quick and easy surgical technique with no donor site morbidity, reduced risk of infection, and fewer incisions.
- The implant only requires a small bone tunnel in the patella, so the potential of patella fracture is reduced.
- Postoperative immobilization in a cast is unnecessary.
- A small (4-6 cm long) incision is made next to the patella (kneecap), on the medial (inside) side.
- A section of soft tissue known as the medial patellofemoral retinaculum is dissected and lifted to form a flap just above the MPFL. This will later be stitched back down over the repair.
- A bone tunnel is drilled through the patella from medial (inside) to lateral (outside) and the Poly-Tape is passed through. The Poly-Tape is then passed back across the surface of the patella from lateral to medial, so that it is essentially looped around the patella.
- The Poly-Tape is then secured to the lower end of the femur (thigh bone) at the medial (inside) side, using the Fastlok fixation device, which is impacted into the bone.
- The medial patellofemoral retinaculum is stitched back down over the repair, and the incision is closed using sutures (stitches).
- Ruptured MPFL
- Femoral medial epicondyle
Postoperative care and rehabilitation
All of our rehabilitation regimes have been developed in conjunction with Ian Horsley MSc, MCSP, Clinical Lead Physiotherapist, English Institute of Sport (EIS) North West, of BackinAction Physiotherapy and Sports Injury Clinic, Wakefield.
Below is a brief outline of the prescribed programme following surgery with the MPFL System. If you would like to see the full rehabilitation programme, please click the link below.
Rehabilitation programmes should always be supervised by a specialist physiotherapist, and prescribed activity levels should not be exceeded before complete healing has occurred.
- A cricket pad splint is applied in theatre and the patient usually stays in hospital overnight, followed by consultation with a physiotherapist prior to discharge the following morning.
- The patient may fully weight bear, with crutches initially, and is instructed to perform isometric exercises.
- The patient is seen in clinic at two weeks to discard the splint, inspect the wound and remove the stitches.
- Physiotherapy continues with knee flexion exercises and glute medius exercises. Heel walking and toe walking are commenced.
- Light exercise may be undertaken such as walking, running on a treadmill and cycling.
Week 12 onwards:
- On agreement with the physiotherapist the patient can commence functional training and return to competitive sport.
The technique for reconstruction of the MPFL using the Neoligaments 10 mm x 500 mm Poly-Tape in conjunction with the 6 mm Fastlok was developed in conjunction with Mr. C. A. Bailey of Royal Hampshire County Hospital, and Mr. S. H. White of Robert Jones and Agnes Hunt Orthopaedic Hospital, from the original technique of Dr. E. Nomura, of Saitama Municipal Hospital in Japan.