Journal of Limb Lengthening & Reconstruction

EDITORIAL
Year
: 2020  |  Volume : 6  |  Issue : 1  |  Page : 1--4

Shortening: The orthopedic theory of relativity


Dror Paley 
 Paley Orthopedic and Spine Institute, West Palm Beach, FL, USA

Correspondence Address:
Dror Paley
Paley Orthopedic and Spine Institute, 901 45th St., West Palm Beach, FL 33407
USA




How to cite this article:
Paley D. Shortening: The orthopedic theory of relativity.J Limb Lengthen Reconstr 2020;6:1-4


How to cite this URL:
Paley D. Shortening: The orthopedic theory of relativity. J Limb Lengthen Reconstr [serial online] 2020 [cited 2020 Aug 4 ];6:1-4
Available from: http://www.jlimblengthrecon.org/text.asp?2020/6/1/1/288573


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In 1985, I started my career path as a limb lengthening and deformity correction surgeon. I was privileged to introduce the Ilizarov techniques to Canada and the US and subsequently played an important role in their introduction to the rest of the world.[1] The idea of being able to gradually correct length and angular deformity was so much less invasive than extensile open surgery. As I applied external fixation distraction methods to every part of the upper and lower limbs for almost every indication, I not only learned the advantages but also experienced the disadvantages and limitations. These related both to the use of external fixation and to the effect of prolonged external fixation upon the muscles and joints. External fixation tethers muscles and fascia, while distraction stiffens muscles and joints and applies indirect pressure to the cartilage of joints and growth plates. The application of locking plates and nails for deformity correction reduced the problems related to tethering of muscles and stiffening of joints and made the rehabilitation easier and faster. Is it preferable to do only a single surgery to achieve limb lengthening with gradual deformity correction versus two independent procedures: deformity correction, first, followed by limb lengthening, second. The latter may offer the joints an advantage. The problem with acute deformity correction was entrapment of nerves and acute stretch of vessels. Therefore, to successfully correct angular deformities acutely, I incorporated nerve decompression to prevent entrapment[2],[3] and shortening of the bone to prevent neurovascular stretch injury.[4] The bigger the angular deformity, the greater the amount of shortening required to prevent the neurovascular stretch. A good way to think about this is to consider the axial length of the limb segment before correction. After correction with shortening, the axial length remains the same.

In the first 10 years of my practice, preserving length was a basic tenet of limb reconstruction and also of trauma reconstruction surgery. Since 1997, I started using shortening as a means to increase the magnitude and complexity of acute deformity correction. Shortening became one of the steps incorporated into the SUPERhip procedure [Figure 1],[5] SUPERankle procedure [Figure 2],[6] tibial hemimelia reconstruction,[7] ulnarization [Figure 3],[8] congenital pterygium, and knee flexion contracture correction [Figure 4]. We also used shortening to eliminate bone defects instead of bone transport.[9]{Figure 1}{Figure 2}{Figure 3}{Figure 4}

We have come full circle from deformity correction with lengthening, to, deformity correction with shortening. There are advantages to each of these methods and both are still useful and valid. Shortening like lengthening is but one more modality available for us use as part of the treatment algorithm. Hence, when is shortening indicated with deformity correction and what are the advantages and disadvantages? What are its consequences and limiting factors?

Acute deformity correction increases length and tension on the concave soft tissues and reduces length and tension on the convex soft tissues. Acute correction stretches muscles, nerves, vessels, and skin on the concave side. To avoid excessive tension on the nerves and vessels, the bone ends are allowed to shorten to maintain the neurovascular length unchanged. Consequently, the muscles on the convex side are not stretched because of the shortening. The muscles on the convex side may in fact be too lax due to the shortening. In most cases, they will readapt. The level of the shortening has a significant effect on this muscle readaptation (e.g., shortening of the distal femur for knee flexion contracture makes the quadriceps muscle length redundant leading to a quads lag. Shortening of the proximal femur has little effect on the quadriceps muscle length and tension since the bulk of the quads is attached distal to the osteotomy and remains anchored to the bone with no change in tension, thus avoiding a quads lag).

Joints like reduced muscle tension. It improves their passive arc of motion by eliminating an extra-articular contracture component. When intra-articular contracture is present, capsular release is also required. When inter-articular adhesions are present, arthrolysis is also added.

What are the limitations of shortening? There are bony limitations and soft tissue limitations. The bony limitations relate to the existing length of the bone. The total length of the bone that needs to be shortened can be too short to allow enough resection needed for full angular correction. We see this in the most severe cases of congenital femoral deficiency (CFD) in which there is >90° angular deformity of the proximal femur combined with a 90° flexion contracture at the knee. The total amount of shortening to fully correct the upper femur and knee deformities can be greater than the length available in the already congenitally short femur. In such cases, the SUPERhip and SUPERknee procedures need to wait until an older age when the bone is longer. The same is true for such severe deformities as congenital pterygium where the bone resection can range from 5 cm to 8 cm.

Soft tissue limitation is not just the length of nerves and vessels. The branches off of the vessels may still tether the vessels and limit the total shortening efficacy. For example, in the distal femur in a young child, one has to be careful to preserve the epiphyseal vessels coming off of the femoral artery and vein before it crosses the knee joint. Therefore, there is a risk of avascular necrosis of the distal femoral epiphysis at the time of posterior capsulotomy and femoral shortening for knee contracture. The second soft tissue limitations are the skin and subcutaneous tissues on the convex side. These tend to bunch up and kink. If the incision is placed on the convex side, it is better to be transverse. Shortening causes a convex side longitudinal incision to pucker open and can even make it impossible to close. The solution sometimes is to combine a transverse and longitudinal incision together. Therefore, L-, Z-, and S-shaped incisions are preferred. One particular incision that was taught to me by our plastic surgeon Dr. Mark Pinsky, is to use a Z-plasty concept in reverse [Figure 5]. A Z-plasty is usually used to lengthen an incision line. The axis of the Z perpendicular to the lengthening shortens. Therefore, a Z placed with its middle line transverse and its other two lines at 60° to the transverse with arms all of equal length will shorten. This concept has been used in the SUPERankle procedure with the middle line of the Z along the ankle joint crease anteriorly.{Figure 5}

Shortening has been particularly instrumental for reconstruction of congenital limb deficiencies since these deformities have neurovascular bundles of restricted length and bones with very severe periarticular deformities. It has allowed us to acutely correct the hip deformity of CFD (SUPERhip), the knee deformity of congenital pterygium of the knee and arthrogryposis, the ankle deformity of fibular hemimelia, the tibial deformity of congenital pseudarthrosis of the tibia, the wrist deformity of radial club hand, and the elbow deformity of congenital pterygium of the elbow and arthrogryposis. This concept is used in the spine for severe kyphosis and scoliosis by performing a vertebrectomy.[10] In trauma, acute shortening allows for immediate closure of soft tissues and less need for flaps.[11]

Shortening is not a new concept for deformity correction. It is a standard part of treated developmental dislocation of the hip (DDH) by doing a femoral shortening in order to reduce the hip into place. Talectomy is another example of shortening to treat clubfoot deformity. What is different is that we are doing it systematically as part of the procedure to allow us to acutely correct deformities without neurovascular injury or embarrassment. Shortening conceptually is not appealing to patients or surgeons. This is because the bone length present is visible physically and on the radiographs, while the soft tissue length is invisible. What is needed is a different way to look at the problem. Instead of thinking of the soft tissues as short, think of the bone as relatively long to the soft tissues. When one looks at it this way, the obvious solution is to shorten the bone so that it matches the length of the soft tissues. This has many benefits including not weakening the muscles. If instead of shortening, the tendons are lengthened, the muscle tendon length ratio is altered, and the muscle strength is reduced. The best example of this is Achilles tendon lengthening. If instead, the bone is shortened and adjusted to the length of the muscle, there is no weakening since the muscle tendon length ratio is preserved.

Hence, what do we do with the leg length discrepancy created by the shortening? This will require limb lengthening in most cases with the short leg. It is much easier to lengthen a bone without complications when the bone and its adjacent joints are straight and stable. We are very good at making more bone by lengthening. We are not good at making a new joint that is damaged by lengthening. Joints and soft tissues heal with scar In contrast bones heal without scar. Therefore, the primary indication for shortening is to prioritize and preserve the joints and soft tissues over the bones. As lengthening techniques become less arduous with lengthening plates and nails it becomes more attractive to consider shortening combined with deformity correction followed by implantable limb lengthening at a later date.

We are only touching the surface with the indications for shortening. We started with the most difficult congenital indications. Other more common indications include spastic patients for both children and adults. Normally, spastic muscles are considered short and are treated by lengthening tendons. What if instead we considered the muscles with normal length, and the bones as being relatively long. I have been using shortening as a method to treat spastic patients instead of tendon lengthenings. For example, combining shortening with bilateral varus derotation osteotomies of the femurs relaxes the hamstrings and adductors helping to treat the knee flexion contracture and hip adduction contracture at the same time without muscle releases. Similarly, shortening the distal tibia treats the equinus contracture without gastrosoleus or Achilles lengthening. If the problem is bilateral, there is no resultant leg length discrepancy. Talectomy for example should be replaced with distal tibial shortening to achieve the same effect.

How much shortening is needed? This is determined by a very simple intraoperative test. The first of the two osteotomies for shortening is performed. The bone ends are disengaged and overlapped in a bayonet position [Figure 1], [Figure 2], [Figure 3]. The amount of overlap with the dislocated joint reduced, the contracted flexed joint extended, and the deformed bone straightened is the amount of shortening required.

From now on as you evaluate deformities, ask yourself whether the soft tissues are short relative to the bone, or is the bone long relative to the soft tissues. This is the orthopedic theory of relativity.

References

1Paley D. The ilizarov technology revolution: History of the discovery, dissemination and technology transfer of the Ilizarov method. J Limb Length Recon 2018;4:115-28.
2Nogueira M, Paley D. Prophylactic and therapeutic peroneal nerve decompression for deformity correction and lengthening. Oper Tech Orthop 2011;21:180.
3Lamm BM, Paley D, Testani M, Herzenberg JE. Tarsal tunnel decompression in leg lengthening and deformity correction of the foot and ankle. J Foot Ankle Surg 2007;46:201-6.
4Paley D, Chong DY, Prince D. Congenital Femoral Deficiency Reconstruction and Lengthening Surgery, Pediatric Lower Limb Deformities. Principles and Techniques of Management. Ch. 22. Heidelberg New York, Dordrecht London: Springer, Cham; 2016. p. 361-427.
5Paley D, SUPERhip and SUPERhip 2 procedures for congenital femoral deficiency. In: Hamdy R, editor. Pediatric Pelvic and Proximal Femoral Osteotomies. Ch. 35. Switzerland: Springer; 2018. p. 287-35.
6Paley D. Surgical reconstruction for fibular hemimelia. J Child Orthop 2016;10:557-83.
7Paley D. Tibial hemimelia: New classification and reconstructive options. J Child Orthop 2016;10:529-55.
8Paley D. The Paley ulnarization of the carpus with ulnar shortening osteotomy for treatment of radial club hand. SICOT J 2017;3:5.
9Tetsworth K, Paley D, Sen C, Jaffe M, Maar DC, Glatt V, et al. Bone transport versus acute shortening for the management of infected tibial non-unions with bone defects. Injury 2017;48:2276-84.
10Aydogan M, Ozturk C, Tezer M, Mirzanli C, Karatoprak O, Hamzaoglu A. Posterior vertebrectomy in kyphosis, scoliosis and kyphoscoliosis due to hemivertebra. J Pediatric Orthopaedics B 2008;17:33-7.
11Zarka S, Lerner A. Complicated War Trauma and Care of the Wounded. Berlin: Springer, Berlin; 2017.