Surgical Lengthening Of The Very Short Humeral Amputation Stump
James M. Hunter, M.D. Mohaveer P. Prabhakar, M.D. Alfons R. Glaubitz, C.P.O.
In recent years, advances in engineering design and the development of sophisticated external power systems have been stimulated by the thalidomide tragedy. The goal has been to provide improved prosthetics functions for the severely disabled upper-extremity amputee. Recent reports1, 2,3 indicate that the use of externally-powered prostheses is yielding encouraging results especially for adults, traumatic amputees and patients with bilateral amelia where conventional shoulder-disarticulâtion prostheses have proved ineffective.
The child who sustains a traumatic amputation will usually retain the potential for prosthetics functions through the use of muscles and joints that were normal in development and function prior to injury. Under these circumstances, the typical above-elbow amputee will usually obtain satisfactory function through a conventional body-powered cable system. As the amputation site approaches the level of the humeral neck, however, instability of the prosthesis may limit terminal-device function to such a degree that the prosthesis is either discarded or worn only as a filler for the Sunday suit.
Arthrodesis of the shoulder to harness scapulohumeral motion has been shown to be effective for the flail above-elbow amputation stump4. Swanson has been encouraged by the functional results of creating an above-elbow stump in a selected case of amelia by using scapular motion with length augmented by a tube pedicle skin and a fibular graft supported by an internal fixation pin(5). For the patient who has the potential for conventional fitting as an above-elbow amputee by reason of a glenohumeral joint and good muscle control, but who lacks sufficient length, a surgical program to increase humeral length warrants consideration.
This paper will describe the case of a boy, now twelve years old, who had a very short, traumatic, above-elbow amputation stump which could not be fitted satisfactorily with a prosthesis. As the boy grew older and the stump proportionately shorter, the problem was approached by surgically augmenting the length of the bone and by using bone and pedicle tube grafting to alter the shape of the humeral stump. Prosthetic fitting, training programs and final results will be discussed.
B.K. was first seen in the child amputee clinic, State Hospital for Crippled Children, with a history of having fallen into the power take-off of a farm tractor in December 1959, at the age of 5 1/2 years. Initial examination revealed a short, right above-elbow amputation with a well-healed stump approximately four inches in length (Fig. 1 ) and good muscle control of the shoulder girdle.
He was fitted with a double-walled humeral-neck prosthesis, positive-locking elbow, and a shoulder saddle and chest-strap harness in November 1961 (Fig. 2 ).
During the initial patient-training period, considerable difficulty was encountered because of socket instability. The check-out findings are indicated in Table 1 , but these findings were inconsistent and varied with adjustments made in the harness. Actually, very little useful function was obtained until the prosthetic fitting was improved and the training program extended one year later.
The patient outgrew his prosthesis and was refitted in 1965 with an elbow-lift assist added to the prescription. Despite improved elbow function, terminal-device opening remained fair to poor at 90 degrees of elbow flexion and shoulder-socket instability seemed to be an increasing problem as the patient grew older.
In 1967 reevaluation of the case by the amputee clinic team revealed a prosthesis that showed little wear. Terminal-device opening could be achieved only on full extension of the elbow, and considerable shoulder-socket instability was apparent (Fig. 3 ). X-rays revealed loss of practically all humeral length (Fig. 4 ). Palpation of the humeral head in the soft stump showed joint laxity but abduction and forward flexion of the stump could be achieved in a useful range and with good muscle power (Fig. 5 and 6 ).
The possibility that this boy could be provided with improved function through surgical lengthening of the humeral stump seemed to offer the only alternative to a shoulder-disarticulation prosthesis. The amputee clinic team was in agreement that this bright, well-motivated, twelve-year-old boy, on the threshold of adolescence, deserved a special-treatment effort. The patient and his parents agreed to a plan of staged surgical reconstruction that offered hope for improvement with reasonable assurance that he would be no worse off if surgical reconstruction failed.
On August 4, 1967, the first stage of the total reconstruction program was carried out. The skin incision was placed so as to develop two elongated sensory-innervated, full-thickness skin flaps laterally and medially. A full-thickness pedicle flap measuring 5 in. x 6 in. was elevated on the lateral thorax beneath the axilla. The flap was based posteriorly for supportive blood supply during the transfer period. The anterior edges of the skin flap were sutured to the free borders of the open stump. The remainder of the open flap was closed with sutures, forming a tube. A split-thickness skin graft was removed from the right thigh and secured over the skin defect on the thoracic wall with stint pressure dressings. Healing progressed uneventfully (Fig. 7 ).
On September 8, 1967, the base of the pedicle was divided and the sutured surface of the tubed portion of the skin was opened (Fig. 8 ). A 4-inch bone graft was removed from the left fibula, transferred to a large drill hole in the neck of the humerus, and secured with crossed metal pins (Fig. 9 ). The pedicle skin was closed around the bone graft and the skin edges of the donor sites for skin (Fig. 10 ) and bone were approximated.
During the later phase of healing, the patient was encouraged to move his stump to tolerance. With healing of the incisions, he was placed on active and light passive-resistant exercises to enhance the return of muscle tone and, hopefully, to secure earlier nutrition of the bone graft.
Prosthetic Fitting and Training
Approximately four months after surgery, X-rays revealed the fibular bone graft to be fully incorporated. The skin was well healed and offered good coverage of the bone graft. The right upper extremity measured 5 inches from acromion to the tip of the newly formed stump (Fig. 11 ). The stump was noted to be in a slightly hyperextended position. Forward flexion measured 30 degrees (Fig. 12 and 13 ), abduction 30 degrees, and extension 45 degrees (Fig. 12 and 13 ). The patient was considered a good candidate for a standard above-elbow prosthesis.
During fabrication of the prosthesis, the distal cap of the check socket was removed for better inspection of the new stump. The stump socket was held in 5 degrees of shoulder extension to improve the range of shoulder flexion. The boy was fitted with a standard above-elbow prosthesis and a Northwestern University ring harness.
The patient adapted to his new prosthesis rapidly and the preliminary check-out showed useful terminal-device function at 135 degrees of elbow flexion. He was discharged from the hospital to be followed in the child amputee clinic.
Approximately six weeks following discharge, he reported to clinic with a tender, swollen stump. X-rays revealed that the patient had sustained a fracture at the level of the distal one-half inch of the bone graft. He stated that he had been wrestling and was thrown to the floor, bearing his full weight on the prosthesis. He was placed on a program of limited activity for ten days, the swelling and tenderness decreased, and he was returned to his schedule of full prosthetic activity without loss of functional gain.
For purposes of comparison pertinent data at the six-month post-fitting check-out (August 1968) are included in the chart with the check-out findings of 1961. At this six-month follow-up an X-ray was taken with the prosthesis in place (Fig. 14 ). The X-ray shows the length of the bone graft and the fitting of the soft tissues within the contours of the new socket. The irregularity of the bone in the distal 10 to 15 percent represents the site of the earlier fracture. No evidence of further injury to the bone graft was apparent at this recent check-out and the stump was in good condition with no sign of deterioration or breakdown.
The patient was questioned on specific points related to advantages of the current prosthetic fitting after surgery, compared to the fitting prior to surgery. He reported that the socket stays on his stump which makes it easier to perform such activities as reaching for his shoes and taking his shirt and coat off and putting them on. Prior to this revision the prosthesis would fall off as his clothing became entangled in the straps, due to shoulder instability. He finds that riding his bicycle is easier now as he can hold the handlebars more securely. Prior to surgery, he had stopped using the prosthesis for bike riding as the socket would slip from his stump. The patient further indicated that the strain on his good shoulder was now less and that in pulling to open the hook, the socket stayed securely in place. On questioning he stated that he had feeling in the proximal half of the new stump and enjoyed an improvement in balance and a feeling of security while wearing the prosthesis in baseball games (Fig. 15 ).
The patient and his parents are pleased with the final result (Fig. 16-18 ).
The problems of a young male with a very short, right, humeral traumatic amputation have been discussed. The program of staged lengthening of the humerus by a pedicle skin graft and a fibular bone graft has produced satisfactory stump-socket stability. This stability has contributed to improved terminal-device function during elbow extension and at all angles of elbow flexion.
The staged stump-lengthening program used with this patient is considered to have had worthwhile results by the Elizabethtown Child Amputee Clinic team. Based on our experience with this case, we would not hesitate to recommend consideration of this program for a similar problem in the future.
The suggestions and assistance of James Sweigert, CO., Chief of the Orthotic-Prosthetic Facility, Ron Masitis, R.P.T., and Rusty Gilmore, X-rays and photography, in the treatment of this patient are gratefully acknowledged.
James M. Hunter, M.D., Clinic Chief, Mohaveer P. Prabhakar, M.D., Alfons R. Glaubitz, C.P.O. and Adaline J. Plank, O.T.R. are associated with the Child Amputee Clinic State Hospital for Crippled Children Elizabethtown, Pennsylvania
1. Mongeau, Maurice, "New Hope for the Patient With Severe Upper-Extremity Deficiencies: Externally Powered Prostheses," ICIB, Vol. VII, No. 5, February 1968.
2. Lippay, Andrew, "External Power and the Amputee: An Engineer's View," ICIB, Vol. VII, No. 5, February 1968.
3. Corriveau, Camille, "Prosthesis Powered by Carbon Dioxide," ICIB, Vol. VII, No. 5, February 1968.
4. Yelton, Chestley, "The Flail Above-Elbow Stump," ICIB, Vol. VII, No. 6, March 1968.
5. Swanson, Alfred B., "Phocomelia and Congenital Limb Malfunctions, Reconstruction and Prosthetic Replacement," The American Journal of Surgery, Vol. 109, p. 294, March 1965.