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Leg Axis Correction

The painful knock-knees and bow-legs: Surgical leg axis correction by means of stable-angle plates
The term leg-axis-misalignment is used to describe the leg axis and articulation plane angle deviation from the standart dimensions. The angle between the femoral and tibial anatomical axis line usally measures 7° valgus (Knock-kneeded) and the mechanical axis line (Miculicz-line) shall be 180°.
Both, an excessive genu varum (Bow-leg) as well as a profuse genu valgum (knock-knee) can lead to overload phenomena, wear and tear and to painful osteoarthrosis. Therefore timely examination and treatment is important in order to avoid premature damages. With correct indication a leg axis correction can be used to slow down the arhrosis progession and relieve symptoms considerably.

Etiology
You differ congential such as highly overstretched joints (genu recurvatum) and acquired leg axis misalignments. But also excessive bow-legs and knock-knees at both legs are often inherited (Fig. 1a, b). Acquired leg axis misalignments can be a resulst of f.e. accidents. Different fractures, growth plate injuries as children or adolescents as well as profuse osteoarthrosis which can lead to bone deformities and leg axis mutations in the hip and foot area. Rare causes for misalignments are inflammations, metabolic disorders of the bone and systemic diseases.


Figure 1: (a): Genu valgum (Knocked-Knee ), (b): Genu varum (Bow-Leg)

Symptoms
Leg axis misalignments have a negative impact on the pressure distribution inside the knee joint. The consequence is one-sided load and and a uneven abrasion on the inside and outside of the joint. Thus overload phenomens already appear at the age of 30. till 40. increasing load and rest pain.
Morphological correlates are painful edema, degenerative meniscus lesions, cartilage abrasions, joint line thinning and a one-sided arthrosis. This frequently involves an increasing functional impairment in the knee joint. With congential misalignments the symptoms develop mostly insidously. A positive family history including similar tale of woes are often found. Usually there was no accident. However , external influences f.e. sport accidents may accelerate the natural disease process. Therefore in case of the treatment of acute and chronical joint disorders it is neccessary to take the misalignment into count. Under circumstances a combination of an arthroscopy and a leg axis correction make sense in order to ensure the success of the treatment.


Figure 2: X-ray, standing : Medial joint line thinned due to an meniscus and/or cartilage abrasion

The painful knock-knees and bow-legs: Surgical leg axis correction by means of stable-angle plates
The term leg-axis-misalignment is used to describe the leg axis and articulation plane angle deviation from the standart dimensions. The angle between the femoral and tibial anatomical axis line usally measures 7° valgus (Knock-kneeded) and the mechanical axis line (Miculicz-line) shall be 180°.
Both, an excessive genu varum (Bow-leg) as well as a profuse genu valgum (knock-knee) can lead to overload phenomena, wear and tear and to painful osteoarthrosis. Therefore timely examination and treatment is important in order to avoid premature damages. With correct indication a leg axis correction can be used to slow down the arhrosis progession and relieve symptoms considerably.

Etiology
You differ congential such as highly overstretched joints (genu recurvatum) and acquired leg axis misalignments. But also excessive bow-legs and knock-knees at both legs are often inherited (Fig. 1a, b). Acquired leg axis misalignments can be a resulst of f.e. accidents. Different fractures, growth plate injuries as children or adolescents as well as profuse osteoarthrosis which can lead to bone deformities and leg axis mutations in the hip and foot area. Rare causes for misalignments are inflammations, metabolic disorders of the bone and systemic diseases.


Figure 1: (a): Genu valgum (Knocked-Knee ), (b): Genu varum (Bow-Leg)

Symptoms
Leg axis misalignments have a negative impact on the pressure distribution inside the knee joint. The consequence is one-sided load and and a uneven abrasion on the inside and outside of the joint. Thus overload phenomens already appear at the age of 30. till 40. increasing load and rest pain.
Morphological correlates are painful edema, degenerative meniscus lesions, cartilage abrasions, joint line thinning and a one-sided arthrosis. This frequently involves an increasing functional impairment in the knee joint. With congential misalignments the symptoms develop mostly insidously. A positive family history including similar tale of woes are often found. Usually there was no accident. However , external influences f.e. sport accidents may accelerate the natural disease process. Therefore in case of the treatment of acute and chronical joint disorders it is neccessary to take the misalignment into count. Under circumstances a combination of an arthroscopy and a leg axis correction makes sense in order to ensure the success of the treatment.


Figure 2: X-ray, standing : Medial joint line thinned due to an meniscus and/or cartilage abrasion

Diagnosis
At first the leg axis is assessed while extension. Thus the precise geometric measurement must be pursued with the help of an radiological still picture of the complete leg. Nowadays, the anatomic leg axis is measured digitally. Additionally, a x-ray while standing (Rosenberg view) should be implemented in order to capture the remainded joint line width. Only then therapy planning makes sense (Fig. 3a,b).


Fig. 3: Still picture of the complete leg. (a): Knock-Knee-Axis, (b): Bow-Leg-Axis

Leg Axis Correction: conservative

The aim of the treatment with the leg axis misalingments is to relieve pain, improve the patients quality of life and to normalize the movement as much as possible. The development of premature wear and tear should be prevented and progession of arthrosis should be stalled.
In arising peroids of pain we advise you to avoid a knee joint overloading through heavy sports activities f.e. stop and go sports. Weight reduction is also useful. Weight and load must be adjusted in order to improve the symptoms. Precise physiotherapy, pain medication and orthropaedic shoes as well as hyluronic preparations can bring relief.
However, in cases of heavy misalignmets and younger patients and at the latest with the beginning of complaints surgical treatments should be considered as an option.
This is neccessary in order to normalize the load axis and to prevent premature cartilage and meniscus tear.

Leg Axis Correction: surgical

In case of severe symptoms in everyday life, sports and profession surgical therapy becomes inevitably. This is based on the prerequisite that the pain is clinical traceable and that there is a change of improvement. The correct indication matters in order to achieve a high success surgery. Age, weight, Knee joint movement, ligamnet stability, extent of the misalingment, further damages, the dregree of activity of the patient and their profession are important factors. Furthermore the patients compliance must be considered because the follow-up treatment requires patience.
The leg axis correction can not heal the arthrosis but it reduces the symptoms for as long as possible. Another aim of this treatment is to delay total knee replacements.

Surgical Treatment: Bow-Leg

In case of a bow-leg (genu varum) a leg axis correction can be proceeded due two surgical treatments. Nowadays most commonly, a wedge-shaped varus correction with opening of the medial tibia plateau and a fixation with stable-angle plates beneith the knee joint is performed. This is the so-called „open wedge osteotomy“ (Fig. 4a,b). Depending on the extent of correction bone from the iliac crest is needed to refill the resulting gap. Less frequently a so-called „closed wedge osteotomy is implemented. Therefore a wedge of bone is removed from the exterior tibia plateau beneith the knee joint. When the gap has been closed and it is fixated with a stable-angle plate the genu valgum results.


Fig. 4: Open wedge-Osteotomy by stable-angle TomoFix-Plate (Fa. Synthes). (4a): Surgery, (4b): 6 months post-op: Osteotomy gap is ossified

Surgical Treatment: Knock-Knee
Excessive genu valgums are less common and are treatened a similar way. Usually this bony deformity is located in the tight near the knee joint. On these grounds the varus leg axis correction is performed at the tight above the joint. The surgery is way more complicated and the healing process slower because of the slow bone healing in the osteotomy area. Although rarely, within smaller corrections a bone wadge can be removed from the medial tibia plateau and refixated with a stable-angle plate.

Continous X-Ray during Surgery
During surgery the individual steps get controlled and documented via intraoperative x-ray images. But also the extent of the osteotomy is checked. Post-op (4-6 weeks) images can show the healing process and the osteotomy gap conslidation. After 6 -12 months the plates should get removed.

Post-Op Therapy
Nowadays we prefer to use a modern and particular stable-angle plate system (TomoFix). This system enables that the patient can go on full load after 2 -3 weeks. After this type of surgery the sojourn in the hosptial is 4 to 5 days. Early functional physiotherapeutic treatment ( physiotherapie, manual therapy, lymphatic drainage, cryotherapy etc.) accelerate the healing process and should be performed 2 to 3 times a week. Water gymnasticts and ergometer can be useful after wound healing.