Wedge Osteotomy
General Information
RELEVANT LINKS:
Wedge Osteotomy - Surgical Technique
Wedge Osteotomy - Rehabilitation Protocol
Patient Experience - L.H. (Graphic Images)
Patient Experience - E.P. (Graphic Images)
Minimally Invasive Biologic Joint Replacement
A "Wedge" is a resorbable implant that can be inserted in the upper tibia to correct malalignment of the knee (i.e. bow leg). This bow leg correction wedge is designed to hold the bones apart until healing can occur and to replace the current procedure of surgical placement of metal plates and screws that are normally used to surgically treat this condition. The overall objective of this study was to assess the safety and effectiveness of this device. The study was conducted in ten consecutive patients who we have assessed for implant stability and bone healing by x-ray.
The material used to make the wedge was a polymer called PLLA (polylactide) that was synthesized under conditions for medical device use. This material has been in human use for the past 15 years. Current clinical uses include; placement in the knee to repair meniscus tissue, fracture fixation, and bone-tendon-bone repairs. The osteotomy wedge technique is a new use for this material.
(We currently are evaluating a screw version of this wedge.)
Background/Significance
Bow leg malalignment of the lower extremity can occur from multiple causes. Most commonly, post traumatic arthritis from loss of the medial meniscus leads to progressive varus deformity of the tibia. Most bow leg patients present with medial knee pain and a bowed leg(s), and may have lost their cartilage from previous trauma or surgery. To relieve the pain for bow leg there are various cartilage procedures currently performed. However, malalignment, and subsequent detrimental biomechanical forces through the knee joint destroy most efforts at cartilage replacement. Therefore, correction of the bow leg malalignment becomes crucial for success of the cartilage procedure and for the relief of pain. To correct bow leg malalignment, the surgeon usually cuts a wedge out of the top of the tibia and closes the gap with a plate and screws. Alternately, the surgeon can perform a cut in the bone and wedge the bone open with bone graft, and then fix the newly aligned bone with a plate and screws. The standard procedures suffer from the large surgical incision and tissue exposure required to fit the plate and screws, the frequent loss of fixation of the devices, and the requirement to remove the devices at a later surgery. To relieve some of these concerns, the resorbable wedge was designed. Based on previous clinical experience, we believe that if this wedge lasts long enough to support the bone in the new position, this technique will become clinically useful for correcting malalignment.
Polylactides (PLA) are produced by the polymerization of lactide, the cyclic dimer of lactic acid. There are two possible polymers that can be manufacturered from PLA - PLLA and PDLA. PDLA is the polymer obtained from an equivalent mixture of D- and L-lactic acid. PLLA and PDLA are semicrystalline materials and have similar mechanical properties however, PLLA is more frequently used as, in its semicrystalline form, it is one of the strongest medical polymers currently available. It is preferred for high-strength applications as required in orthopaedic implants.
Indication and Patient Selection
The Wedge is indicated for the correction of varus deformity (bow legs) of up to 15 degrees in the medial to lateral plane. Flexion and extension deformities can also theoretically be corrected by using Wedges of differing thicknesses. Most commonly, patients will present with varus knees having medial arthritic changes and well preserved lateral compartments. The surgical goal is to use an opening wedge osteotomy and Stone Wedge fixation to decrease force transference in the medial compartment of the knee. The determination of the amount of weight transference to the lateral side is left to the surgeon's judgement.
Wedge Osteotomy - Surgical Technique
Wedge Osteotomy - Rehabilitation Protocol
Patient Experience - L.H. (Graphic Images)
Patient Experience - E.P. (Graphic Images)
Minimally Invasive Biologic Joint Replacement
A "Wedge" is a resorbable implant that can be inserted in the upper tibia to correct malalignment of the knee (i.e. bow leg). This bow leg correction wedge is designed to hold the bones apart until healing can occur and to replace the current procedure of surgical placement of metal plates and screws that are normally used to surgically treat this condition. The overall objective of this study was to assess the safety and effectiveness of this device. The study was conducted in ten consecutive patients who we have assessed for implant stability and bone healing by x-ray.
The material used to make the wedge was a polymer called PLLA (polylactide) that was synthesized under conditions for medical device use. This material has been in human use for the past 15 years. Current clinical uses include; placement in the knee to repair meniscus tissue, fracture fixation, and bone-tendon-bone repairs. The osteotomy wedge technique is a new use for this material.
(We currently are evaluating a screw version of this wedge.)
Background/Significance
Bow leg malalignment of the lower extremity can occur from multiple causes. Most commonly, post traumatic arthritis from loss of the medial meniscus leads to progressive varus deformity of the tibia. Most bow leg patients present with medial knee pain and a bowed leg(s), and may have lost their cartilage from previous trauma or surgery. To relieve the pain for bow leg there are various cartilage procedures currently performed. However, malalignment, and subsequent detrimental biomechanical forces through the knee joint destroy most efforts at cartilage replacement. Therefore, correction of the bow leg malalignment becomes crucial for success of the cartilage procedure and for the relief of pain. To correct bow leg malalignment, the surgeon usually cuts a wedge out of the top of the tibia and closes the gap with a plate and screws. Alternately, the surgeon can perform a cut in the bone and wedge the bone open with bone graft, and then fix the newly aligned bone with a plate and screws. The standard procedures suffer from the large surgical incision and tissue exposure required to fit the plate and screws, the frequent loss of fixation of the devices, and the requirement to remove the devices at a later surgery. To relieve some of these concerns, the resorbable wedge was designed. Based on previous clinical experience, we believe that if this wedge lasts long enough to support the bone in the new position, this technique will become clinically useful for correcting malalignment.
Polylactides (PLA) are produced by the polymerization of lactide, the cyclic dimer of lactic acid. There are two possible polymers that can be manufacturered from PLA - PLLA and PDLA. PDLA is the polymer obtained from an equivalent mixture of D- and L-lactic acid. PLLA and PDLA are semicrystalline materials and have similar mechanical properties however, PLLA is more frequently used as, in its semicrystalline form, it is one of the strongest medical polymers currently available. It is preferred for high-strength applications as required in orthopaedic implants.
Indication and Patient Selection
The Wedge is indicated for the correction of varus deformity (bow legs) of up to 15 degrees in the medial to lateral plane. Flexion and extension deformities can also theoretically be corrected by using Wedges of differing thicknesses. Most commonly, patients will present with varus knees having medial arthritic changes and well preserved lateral compartments. The surgical goal is to use an opening wedge osteotomy and Stone Wedge fixation to decrease force transference in the medial compartment of the knee. The determination of the amount of weight transference to the lateral side is left to the surgeon's judgement.