In young amputees a strong stump allowing full end bearing seems to be desirable. During the last 50 years, surgical techniques have evolved in an effort to improve prosthetic fitting and off-load body weight from the end of the stump. 1
Although the current trend is to fit transtibial amputees with a total surface bearing prosthesis, many amputees in our experience have difficulty in tolerating weight bearing on the distal end of the stump because of pain or discomfort. The ability to tolerate good load or “end bearing” on the distal stump end is biomechanically sound for the prosthesis socket. This provides good proprioception transmitted through the remnants of the tibia and the fibula, thus allowing improved balance and feedback for the amputee.
Because of good results, surgical attempts to create end bearing have emerged.
We present a case of congenital pseudarthrosis of the tibia (CPT) that required transtibial amputation. Based on the pathology, we decided to use the osteomyoplastic technique, which has been reported rarely in the literature.
MATERIALS AND METHODS
The technique of osteomyoplasty was described by Ertl 2 in 1949. Based on the work of Bier 3 and his own observation, that nature itself tries to connect the transected surfaces of the tibia and fibula together, Ertl created a new method to gain end bearing (Figure 1). He reported excellent results, especially for reamputation. Most patients regained full end-bearing stumps within a short period. Bilateral amputees were able to walk a short distance directly on their stumps.
This technique is also recommended for primary amputation in young patients without ischemia. 1,4–9 The advised level is just above the musculotendinous junction of the calf. 6
Loon 1 as well as Murdoch 5,6 and Dederich 4 recommend fixing the various muscle groups to the periosteal flap to improve function and circulation. Mondry 10 positioned the ends of the nerves just distal to the bony bridge to minimize mechanical irritation. Maurer 11 used a short section of the fibula to build the osseous handle and fixed it by an intramedullary screw.
We used a modification of Ertl’s technique in our 16-year-old patient. Apart from his CPT, he was otherwise fit and well. The patient’s history started at the age of 12 months, when he sustained a spontaneous fracture of his left tibia. After a period of more than 10 years in plaster and two failed surgical procedures with intramedullary rods, he was referred to our department, where an excision of the pseudarthrosis, proximal osteotomy for lengthening, and application of a circular external fixation frame were performed. The history and the histologic report confirmed that we were dealing with a CPT Type II, 12 which has the poorest prognosis of all CPTs. Equal leg length and good alignment were achieved. But several problems with pin site infection caused by the very porotic bone, together with the patient’s desire for rapid independent mobility, led to early frame removal and amputation.
The poor nature of the tibia and periosteal soft tissues prevented us from using the osteoperiosteal tibial flap described by Ertl. 2 The tibia was transected at the determined amputation level (16 cm below the knee joint). The lateral compartment muscles were left four centimeters longer than the division of the tibia to perform the myodesis. The fibula was cut five centimeters distal to the tibial end, nibbled at its lateral cortex at the level of the tibia, then bent over green-stick fashion into a notch made into the tibia and sutured through periosteal drill holes with its overlying peroneal musculature. Figure 2 shows the radiograph 1 month after surgery.
The patient recovered well, walked independently for the first time in his life, and described the amputation as “the best thing I ever did.”
He was able to wear his prosthesis all day without any problems and started working as a bricklayer, which included climbing ladders with a load of 25 bricks. In the 13-year follow-up period, three episodes of pain stopped him from working for brief periods. The first occurrence was caused by a large elongated bony spur pointing medially from the tip of the tibial stump, which was successfully treated by trimming in a minimal surgical procedure. An asymptomatic fracture of the bony bridge was also noted (Figure 3A). The second and third instances were related to two episodes of neuromas on the fibula side. The patient has had no symptoms for the last 5 years. Assessment of the stump at other times did not reveal any evidence of overloading and final radiographs showed hypertrophy of the bridge (Figure 3B), implying that effective end bearing was achieved.
Despite all the advances in limb reconstruction techniques, there are still a number of patients who require amputation. The loss of an extremity or a part of it is accompanied by both medical and social problems, especially in young people. Using the proper indication and technique, amputation does not have to be a step backward. In cases of tibial hypoplasia, such as CPT, potential for end bearing after amputation may be significantly reduced. Our case shows the value of creating an end-bearing stump to facilitate the patient’s work and social life. Osteomyoplasty can achieve this goal. The advantages of this technique are:
- A wide stable surface, perhaps comparable to a Syme’s amputation stump, providing excellent conditions for end bearing.
- Even in very short stumps the bony fixation to the tibia stabilizes the fibula against the lateral force of the strong biceps femoris.
- Occlusion of the medullary cavities, thus restoring normal intramedullary pressure and normal deep venous return.
- Protection of the cut ends of nerves and vessels by a bony wall.
- Excellent conditions for soft tissue coverage.
- Increased thickness 1,4 of the fibula.
In cases with poor tibial bone quality, we recommend our described modification, which is similar to that of Maurer. 11
The literature provides little information about complications. Only Loon 1 mentioned two cases of asymptomatic fractures incidentally diagnosed on a radiograph, similar to that seen in our case. Bony spurs, as appeared in our case, are common in young amputees.
We believe that this technique is important because in this case it has permitted end bearing in a young, active manual laborer.
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