Incidence of Bone Overgrowth in the Juvenile Amputee Population

Raymond J. Pellicore, M.D. Jean Sciora, R.N., B.S.P.H.N., R.P.T. Claude N. Lambert, M.D. Robert C. Hamilton, M.D.


Introduction

A juvenile amputee is an individual who is skeletally immature and has either an acquired amputation or a congenital deficiency of one or more of his limbs. Once skeletal maturity is achieved, the treatment problems of the erstwhile juvenile are the same as those of an adult. The stump of an adult amputee will remain essentially as fashioned at the time of surgery except for general weight gain or loss, or stump shrinkage. Surgical considerations of the juvenile amputee are different from those of the adult. The surgeon must lake into consideration anticipated body and slump growth so that the child has a useful, healthy slump that will continue to be satisfactory until growth potential has been realized. To attain this goal it is necessary to save all length possible and disarticulate wherever possible to preserve distal epiphyses. Disarticulation not only allows longitudinal growth of the stump to continue at a normal rate but also negates the possibility of bone overgrowth. Bone overgrowth per se, however, must not be considered a contradiction to elective amputation surgery if, of necessity, it must be done at a supraepiphyscal level.

The complication of bone overgrowth in juvenile amputees has been recognized for a number of years. This phenomenon has been demonstrated to be due to appositional bone growth from the end of the stump and not related to the growth at the proximal epiphysis. Why one patient will develop this complication (and often if overgrowth has developed once, it tends to recur) and another will not is not known. It has been shown that any attempt at arresting epiphyseal growth, either permanently or temporarily, has no effect on bone overgrowth. Several procedures directed at the point of overgrowth of the residual limb such as cross-synostosis, capping the bone end with various materials, including a Silastic plug, have, in our hands, been uniformly unsuccessful. Seven cases in which these Silastic plugs have been used, either on the first or a subsequent revision, have resulted in rejection of the plug in from one month to three years, probably due to our surgical techniques.

This paper will discuss our experience at the University of Illinois Amputee Clinic with 938 juvenile amputees: 576 male and 362 female-479 (249 male and 230 female) congenital deficiencies and/or anomalies; and 459 acquired (327 male and 132 female).

Anomalous Limbs: Lower

One hundred and thirty-seven juvenile amputees had anomalous lower limbs, i.e., the deficiencies would fall into the categories of terminal longitudinal, intercalary transverse and intercalary longitudinal in the Frantz-O'Rahilly system. Of this group, 68 had conversion amputations: 39 were ankle disarticulations, 12 knee disarticulations, 2 above-knee amputations, and 15 below-knee amputations. Thirteen of this group needed revisions for bone overgrowth-all in the below-knee-amputation category. (Two have proximal focal femoral deficiencies and, although amputated below the knee, have above-knee prosthetic fittings.) Twelve had tibial overgrowth, one had tibial and fibular overgrowth. Six had one revision, two had two revisions, one had three revisions, one had four revisions, two had five revisions, and one had eight revisions. Of these 68 patients all but three had their conversion amputations before they were 5 years of age, one had hers at 4 days of age while in the nursery. The three exceptions had their conversion amputations at 7, 10, and 17 years of age, respectively.

Case Presentations

  • D.A. had her conversion amputation at 4 days of age and was lined with her first prosthesis at 9 months of age. She had revisions for bone overgrowth at 3 1/2 and 7 1/2 years of age, and may need more as she is now only 10 years of age.
  • C.J. had her amputation at 5 years of age with revisions at 7 and 11 years of age.
  • S.M. had her amputation at 2 years of age with revisions at 8, 9, 10, and 12 years of age.
  • R.S. had her amputation at 7 years of age and a revision at 10 years of age.
  • K.W. had his amputation at 1 year of age and revisions at 5. 7. 8, 12, and 14 years of age.
  • H.P.P. had her amputation at 10 years of age and a revision at 13 years of age.
  • M.L.C. had her amputation at 5 years of age with a revision at 9 years of age.
  • E.S. had hi.s amputation at 2 years of age and a revision at 5 years of age.
  • A.L. had his amputation at 2 1/2 years of age with revisions at 7, 10, 12, 14 (with Silastic plug which fell out in six months), and 14 1/2 years of age.
  • T.G. had his amputation at 2 1/2 years with a revision at 5 years of age.
  • B.M.C. had her amputation at 13 months of age with revisions at 4. 10, and 14 years of age.
  • R.H. had her amputation at 2 years of age and had a revision at 14 years of age.

K.O. has a partial adactylia of the right hand, transverse hemimelia of the right lower limb, and a left longitudinal paraxial fibular hemimelia complete, which was convened to a left helow-k?ee amputation at another facility when he was 21 months of age. He has had eight revisions for tibial overgrowth at ages 3, 4, 6, 7, 10, 11 (with Silastic implant which was rejected in a short time), 13, and 14 years of age. He is now l7yearsold.

The story of L.D.. who did not have his conversion amputation until he was 17 years of age, is presented to show that a child and/or his parents may take a considerable time to accept a recommendation for surgical conversion. He and his parents consistently refused amputation. Initially he was fitted with an extension orthosis. His leg-length discrepancy increased and he had problems with trouser fittings because his natural fool on the anomalous side (right) was about level with the middle of the left shin. He also had a rather awkward gait. With the increase in leg-length discrepancy he was filled with a platform orthosis/prosthesis which included a thigh corset, a hinged knee, a molded leather corset below the knee to include his natural foot for weight-bearing, and an extension with a SACH foot attached for leg-length equality. In 1968. when he was 13 years of age. the leather corset was changed to a plastic socket encasing his natural fool. When he was 14 years old, he and his father were in agreement to accept surgery but the mother still resisted. Finally, at 17 years of age. he agreed to ankle-disarticulalio? surgery and has been filled with a PTB prosthesis since that time. He has been very pleased because of the cosmetic improvement- he is now able to wear fashionahle trousers-and because he walks (and runs) more smoothly and efficiently (Fig. 1 , Fig. 2 , and Fig. 3 ).

Four of these 137 patients had the Van Nes procedure, four had Brown's procedure in addition to an ankle disarticulation, one had a bifid femur-the lateral condyle of the femur was excised in addition to ankle disarticulation, one knee disarticulation needed resection of a sciatic neuroma, three needed hip-flexion contracture releases, three needed osteotomies to correct valgus deformities, three needed surgery to correct chronic dislocating knees, four of the PFFDs had knee fusions, and six had excision of constriction bands.

Percentage-wise, if the complete group with anomalous limbs (137) is considered, 9 percent needed stump revision for bone overgrowth. If only those who had conversion amputations through the metaphysis of the tibia and fibula (17) are considered, the percentage is considerably higher-76 percent (Table 1 ).

Anomalous Limbs: Upper

One hundred and thirty-five juvenile amputees had anomalous upper limbs. Three were converted to elbow disarticulations. Thirty-one had reconstruction surgery as osteotomies, fixation, repair of syndactyly, removal of anomalous bone between metacarpals, deepening of webs, excision of constriction bands, bone grafts, removal of useless rudimentary nubbins which, due to torsion or infection, became gangrenous or painful. With upper-limb anomalies, preservation of anomalous parts is recommended as prosthetics fitting can usually be done about such parts and they may also be useful eventually in operating externally powered prostheses.

Terminal Transverse Deficiencies

Two hundred and seventy-six children had terminal transverse deficiencies: 234, upper-limb and 42, lower-limb involvement. Of the 42 with lower-limb involvement, 5 (or 11.9 percent) had revisions. Four children with terminal transverse partial hemimelia of the lower limb needed revision for tibial overgrowth and one for fibular overgrowth. Two had one revision, two had two revisions, and one had five revisions.

Of the 234 with upper-limb terminal transverse hemimelia, 3 (or 1.2 percent) needed revision for humeral overgrowth: one had one revision and two had two revisions. One child who had never been fitted with a prosthesis presented at clinic with a humeral overgrowth which had to be revised prior to prosthetics fitting.

Acquired Amputations

Of 459 patients with acquired amputations (Table 2 ), 350 had metaphyseal amputations: 118 were below-knee, 108 above-knee; 66 below-elbow and 58 above-elbow. The remainder had disarticulations at various levels including hemipelvectomy, hip, knee, ankle, and Syme's; transmetatarsal and partial foot amputations; forequarter, shoulder, elbow, and wrist disarticulations; and partial hand amputations. Of these, 317 were under 16 years of age-usually long bones have reached most of their growth potential by that age. Of this group (all etiologies), 33 needed revisions (Table 3 ). Neither sex nor etiology was a significant factor. However, age at time of amputation and level of amputation seemed to be major considerations. The number of revisions ranged from one to seven. Initial amputations for these 33 patients were done from 8 months of age to 11 years of age. One child with an above-elbow amputation done at 9 years, 6 months of age, was presented at clinic at 10 years, 3 months of age. He had never been fitted with a prosthesis and needed revision for humeral overgrowth before he could be fitted. Other types of stump revisions were done such as excision of adherent or hypertrophied scar (6), resection of median and ulnar nerve neuroma (1), skin grafts and release of contractures (4), resection of sinus tract and scar (1), section of tendo Achillis and ankle fusion with Steinmann pin fixation to correct relationships of talus and calcaneus to tibiofibular joint (1) in a right transtarsal amputation.

If this entire group (459) is considered, 7 percent needed revision. If only those who had their initial amputation before 16 years of age (317) are considered, the percentage needing revision would be 10.4. Since any child having the initial amputation after 12 years of age did not develop bone overgrowth, a bone-overgrowth rate of about 15 percent would be expected in those children (212) who had th eir amputations before 12 years of age.

If the total juvenile amputee population (938) is considered, 54 (or 5.7 percent) needed revision (Table 4 ). Classifying this number by sex, there were 6 males and 2 females with terminal transverse deficiencies; 8 females and 5 males with conversions of anomalous limbs; and 26 males and 7 females with acquired amputations. Of the total 54 needing revisions, 37 were males and 17 were females.

Thirteen of these 54 children who had had their primary amputations before they were 12 years old had fourteen revisions after they were 12 years of age, as follows:

  • S.M., sixth and seventh revisions at 14 and 15 years of age.
  • J.C., fifth at 13 years of age.
  • J.N., second at 13 years of age.
  • A.P., first and only at 12 years, 10 months of age.
  • F.B., first and only at 14 years of age.
  • J.D., second at 14 years, 7 months of age.
  • J.F., second at 13 years of age.
  • J.P., first and only at 13 years of age.
  • K.B., first and only at 13 years of age.
  • K.O., eighth at 14 years of age.
  • K.W., fourth at 14 years, 5 months of age.
  • A.L., fifth at 15 years of age.

In all, the 54 children had 109 revisions.

Conclusions

  • Bone overgrowth is the most common complication in the juvenile amputee.
  • Bone overgrowth, while occurring chiefly in the patient with an acquired amputation or in those with anomalies which have been converted to a metaphyseal amputation level, may occur infrequently in the terminal-transverse-arrest type of congenital deficiency. Sex was not a significant factor in relation to overgrowth. Age at time of amputation and level of amputation was significant.
  • In this series, if the primary amputation occurred after the age of 12 years, bone overgrowth did not occur. However, if the primary amputation does take place before 12 years, revision for overgrowth may be necessary after that milestone.
  • The need for revision for bone overgrowth apparently decreases sharply after age 12 no matter what the etiology, sex, or age at time of original amputation.
  • Bone overgrowth may occur prior to prosthetics fitting.
  • In this series, overgrowth occurred most frequently in the tibia, humerus, fibula, femur, tibia/fibula, and in that order.
  • The best way to prevent bone overgrowth is to do joint disarticulations rather than metaphyseal amputations, if at all possible.

We hope that this presentation will provide a framework for further investigation of this phenomenon.

University of Illinois Amputee Clinic, Chicago, Illinois

References:

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