RU2738122C1 - Method for plastic repair of marginal bone defects of tibial plateau - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to orthopedics, and can be used for plasty of proximal shin defects in knee joint replacement, for restoration of required support surface. Pre-operative planning is carried out: a pre-operative X-ray image is used to make a tibia axis, and perpendicular to it a condyle bonesaw-line is drawn, the height of the obtained bone fragment is determined. In the area of the bone bed defect, the bonesaw is made along the bottom of the defect at an acute angle to the transverse axis of the shin bone. Then, vertical bonesaw is made along the inner edge of the defect along the axis of the shin bone. Further, the bone fragment of the sawed condyle is placed in a bed formed along the bottom of the defect, the part projecting above the plane of the bonesaw is cut off along the level of the main bonesaw-line.

EFFECT: method provides stability of bone graft fixation without using additional structures, which reduces the risk of developing metallosis, reduces the risk of lateral shift of the graft by forming a bonesaw-line along the bottom of the defect at an acute angle, as well as reduces a risk of graft rejection by using its own bone tissue.

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Description

The invention relates to the field of medicine, namely to orthopedics, and can be used when performing knee arthroplasty (ECR) for plastic defects of the proximal tibia and restoration of the necessary bone support.

EKS is an effective surgical procedure that is performed when the articular surfaces are destroyed. In most cases, pacemaker can restore function and relieve pain.

EKS consists in removing the altered articular surfaces of the femur and tibia and placing the components on the formed sawdust. One of the important conditions for the long-term functioning of the endoprosthesis is the creation of a complete support for the implants. In some cases, extensive bone defects are formed in the proximal tibia, which greatly complicates the pacemaker. These changes are typical for a number of systemic diseases (rheumatoid arthritis, spondioarthritis and others), and can also develop after injuries of the knee joint.

In the presence of a pronounced deficiency of bone tissue, it becomes necessary to fill in the defects. For plastics, bone cement, own bone from another anatomical region, special metal blocks, etc. are used. [Kornilov N.N. Replacement of bone defects in primary knee arthroplasty / N.N. Kornilov, T.A. Kulyab, P.M. Tikhilov et al. // Traumatology and Orthopedics of Russia. - 2008. - No. 1 (47). - S. 76-81.].

There is a known method of plastics of bone defects in endoprosthetics of the hip and knee joints (Patent RU No. 2622608 C1, IPC А61В 17/56 - 06.16.2017, bull. No. 17). The method is based on the use of carbon composite augments. The selection of the shape and size of the augments is performed in the preoperative period, the installation of augments to eliminate the defect in the bone mass and to maximize the congruence of the receiving surface of the bone and the seating surface of the endoprosthesis components. In the course of surgery, taking into account the existing defect in the bone mass, the shape and size of the augment being installed is adjusted to the same characteristics of the residual bone defects.

The disadvantages of this method include:

- the need to make augments from carbon composite material;

- technical difficulties associated with the need for individual production of augments;

- the complexity of the use of augments for various types of endoprostheses, since the decision to choose a particular type of implant can be made during the pacemaker;

Closest to the claimed invention is a method of plastics of defects of the tibia (Patent RU No. 2200494 C2, IPC А61В 17/56, 20.03.2003, bull. No. 8). This method is based on the formation of a graft and a bed for it in the area of the tibial condyles. For this purpose, a line is drawn on the radiograph along the edge of the defect, a perpendicular is drawn through its middle and the height of the condyle defect is determined from the radiograph of the contralateral joint. Next, the epiphysis is intersected perpendicular to the axis of the lower leg so that the height of its medial part is equal to the depth of the defect. A flat bed is formed along the surface of the defect of the tibia, the cut-off bone fragment is placed on this bed and fixed with needles to the underlying bone. The protruding part of the fragment is cut off at the level of the section of the tibial condyles.

This invention is taken as a prototype.

The disadvantages of this method include:

- the impossibility of achieving stability of the bone graft without the use of additional structures;

- the presence of additional structures in the area of the components of the endoprosthesis increases the risk of metallosis and local inflammatory reactions;

- due to the flat surface of the bed under axial load, the risk of lateral displacement of the bone graft remains;

The objective of the claimed invention is to create a complete support surface for the tibial component of the knee joint endoprosthesis.

The utility of the claimed method is to reduce the risk of early loosening of the elements of the knee endoprosthesis

The technical result of the proposed method of plastics of bone defects of the tibia with pacemaker is stable fixation of the bone autograft without the use of additional structures and reducing the risk of graft rejection due to the use of own bone tissue.

The technical result of the claimed invention is achieved due to the fact that during preoperative planning, the height of the bone fragment obtained during the sawing of the tibial condyles is measured, the depth and filing of the bone defect is measured, the bone fragment and the tibial plateau of the endoprosthesis are laid, characterized in that the sawdust is performed in the area of the bone bed defect the bottom of the defect at an acute angle to the transverse axis of the tibia, vertical sawdust is performed along the inner edge of the defect along the axis of the tibia, the bone fragment of the sawn condyle is placed in a bed formed along the bottom of the defect, the part protruding above the plane of the sawdust is cut off at the level of the main sawdust.

The advantage provided by the above set of features is the minimization of the use of fixation structures during joint replacement.

The essence of the invention is illustrated by drawings, where:

fig. 1 - diagram of the knee joint, preoperative planning of the pacemaker;

fig. 2 is a diagram of the knee joint after preparation of the formation of the bone bed in the area of the defect;

fig. 3 is a diagram of the knee joint after the placement of the bone graft in the defect area.

In the figures the following positions are indicated by numbers:

1 - the axis of the tibia, 2 - the line of the saw cut of the tibial condyles.

To solve the problem posed, the method of tibial bone defects plasty is carried out as follows:

Preoperative planning is performed. To do this, on the preoperative X-ray, the axis of the tibia is drawn (1), and the condyles sawdust line (2) is drawn perpendicular to it, the height of the resulting bone fragment (ED) is determined, to prepare the bone bed, sawdust lines are drawn in the defect area, sawdust along the bottom of the defect under an acute angle to the axis of the tibia (A-B), sawdust on the border of the defect along the axis of the tibia (C-B). Measure the depth of the resulting defect (B-F). For complete defect repair, the height of the bone fragment (E-D) should be equal to or greater than the depth of the defect (B-F). The formed bony protrusion (B-F) prevents lateral displacement of the graft towards the contralateral condyle, and the inclination of the sawdust plane (AB) along the bottom at an acute angle to the tibial axis limits the displacement beyond the tibial plateau.

EKS is performed under anesthesia. Arthrotomy is performed from the anteromedial approach. Produce sawdust of the femur according to the standard technique. After sawing the tibial condyles in the presence of a defect, a bone bed is formed, according to preoperative planning. The sawdust is carried out along the bottom of the defect. The bone fragment of the sawed condyle is placed in a bed formed along the bottom of the defect (F-B-A), the part protruding above the sawdust plane is cut off at the level of the main sawdust (2). Due to the shape of the sawdust bed in the area of the defect under axial load, the bone graft retains its stability and position without additional fixation with metal structures. The tibial and femoral components of the endoprosthesis and an insert are installed on the bone cement. The wound is sutured in layers. In the postoperative period, walking is allowed with the help of additional means of support with limited load on the operated limb for 8 weeks.

The method is illustrated by specific clinical examples.

Example 1.

Patient F., born in 1955, was admitted with a diagnosis of Left-sided gonarthrosis, grade IV. FTS 2 Art. Varus deformity, mixed contracture of the left knee joint. Considers himself sick for about 15 years. On admission: Limb length D = S, severe lameness. Varus deformity of the knee joint 30 degrees. Painful movements in the left knee joint. The range of motion in the left knee joint is significantly limited - extension / flexion 0-5-90. Sensitivity movements of the left toes are preserved. The pulsation of the a.dorsalis pedis is preserved on both feet.

The patient was prepared for surgical treatment, under spinoepidural anesthesia, from the anteromedial approach, arthrotomy of the knee joint was performed, the femur was filed according to the standard technique, after the tibia was filed in the medial condyle, a bone defect was revealed. The sawdust was made along the bottom of the defect, additional at the border with the normal condyle in order to form a persistent platform. The sawn-off fragment of the lateral condyle is laid in the formed bone bed, the part protruding above the level of the sawdust is cut off with a saw. Further preparation of the tibia was carried out according to the standard technique. The tibial and femoral components of the endoprosthesis were installed on the bone cement, and an insert was installed. The postoperative wound was sutured in layers. The postoperative period was without complications, the wound healed by primary intention. The patient was activated on the 1st day after the operation, walking with additional support means, with partial load on the left lower limb, was allowed. On control radiographs of the knee joint, the position of the components of the endoprosthesis is correct.

At the control examination after 3 years. The patient has been rehabilitated, can move without additional support. Postoperative scar without signs of inflammation. Movement in the left knee joint is painless. Range of motion in the left knee joint extension / flexion 0-0-95. The control X-ray showed no signs of instability of the components of the endoprosthesis, the bone autograft is sound, consolidated to the bed.

Claims (1)

A method of plasty of marginal bone defects of the tibial plateau during knee arthroplasty, including preoperative planning with measuring the height of the bone fragment obtained by sawing the tibial condyles, measuring the depth and filing of the bone defect, placing the bone fragment and the tibial plateau of the endoprosthesis, characterized in that in the defect area of the bone bed, sawdust is performed along the bottom of the defect at an acute angle to the transverse axis of the tibia, vertical sawdust is performed along the inner edge of the defect along the axis of the tibia, the bone fragment of the sawn condyle is placed in the bed formed along the bottom of the defect, protruding above the plane of the sawdust, the part is cut off at the level of the main sawdust.

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