Results and Discussion

Our personal experience with epiphyseal plate transplantation in upper limb skeletal reconstruction refers to a population of 20 patients ranging in age between 3 and 11 years.22 All of them were affected by malignant bone sarcomas located in the meta-ephyphisis of a long bone of the upper extremity. The described reconstructive procedure was used to replace the proximal humerus in 15 cases and the distal radius in five. The follow up period ranges between nine months and eight years.

The analysis of the results should take into account such variables as graft survival and bone fusion, quality and quantity of growth, remodeling of the transplanted bone, functional outcome and morbidity at the level of donor site.

As far as the viability of the grafts and their fusion with the host bone is concerned, we observed a rapid bone union in all cases and the reliability of the diaphy-seal blood supply was further on confirmed in those patients who were investigated

Fig. 10D.5. The distance lain between a fixed landmark ( the plate ) and the tip of the epiphysis is periodically evaluated in order to assess the axial growth of the transferred fibula.

Fig. 10D.6. Distal radius reconstruction after resection of osteogenic sarcoma. The transferred fibula have been growing at a rate of 1.02 cm per year. The ratio between the fibular head and the caput ulnae remained unchanged thus indicating a symmetrical growth of the two bones.

Fig. 10D.6. Distal radius reconstruction after resection of osteogenic sarcoma. The transferred fibula have been growing at a rate of 1.02 cm per year. The ratio between the fibular head and the caput ulnae remained unchanged thus indicating a symmetrical growth of the two bones.

Fig. 10D.7. Reconstruction of the proximal two thirds of the humerus after resection of osteogenic sarcoma. The total growth after 62 months of follow up amounts to 4 cm with a growth rate/year of 0.77cm.

by means of postoperative bone scan. Thus, our experience seems to validate the hypothesis that the anterior tibial vascular network is able to supply the proximal two thirds of the shaft of the fibula and that there is no need to include the peroneal artery in the described surgical model.

The amount of growth of the transferred bone have been assessed evaluating the distance between a fixed point, usually the plate or a screw, and the tip of the epi-physis (Fig. 10D.5). The overall growth and the growth rate per year have been the parameters taken into account in all cases. In our population of neoplastic patients some inhibition of growth at any level, which is supposed to be related to the use of adjuvant chemotherapy,23 should be considered as long as such a therapy is applied. The growth rate of controlled patients with a follow up period longer than 2 years ranges between 0.75 and 1.33 cm per year (Figs. 10D.6, 10D.7). In a current research, we are processing the data related to the growth trend of the grafts with the aim to identify those variables which are involved in determining the progressive lengthening of the bone. The age of the patient at surgery, the recipient site, the blood supply, and the approaching to skeletal maturity are some factors which seem to play some role in the amount of growth registered every year.

A failure in longitudinal growth and premature closure of the growth plate have been observed in 5 patients. In two cases the graft was supplied by the peroneal artery which is a controversial pedicle in order to vascularize the epiphysis. Our experience seems to confirm the opinion of those authors who state that the peroneal artery supplies only the shaft of the fibula and that the peroneal pedicle should be enhanced with an epiphyseal artery, usually the descending genicular artery, when the epiphysis is a component of the graft.24

The plastic properties of the epiphysis after its transfer in heterotopic location have been evaluated comparing radiographs and three-dimensional T.C. scans taken at different times. The remodeling observed in wrist reconstruction have been quite significant in most cases. Probably as a consequence of axial load, the fibular epiphysis is able to adapt its articular surface to the shape of the proximal carpal row developing a concave surface and progressively improving stability and range of motion. Such a remarkable finding has not been observed in case of proximal humerus

Fig. 10D.8. Wrist motion seven years after surgery. Excellent results can be achieved in distal radius reconstruction. A nearly normal range of motion on all planes have been recovered in all the cases.
Fig. 10D.9. (A, B). In order to provide a satisfactory recovery of pronation and supination, it is suggested a pretty lax suture of the soft tissue which stabilize the distal radio-ulnar joint.

replacement, where the fibular head remains substantially unchanged even several years after surgery.

From a functional point of view, excellent results can be achieved in distal radius reconstruction (Fig. 10D.8). In all cases where the ulna could be spared during tumor resection, the range of motion was almost fully recovered after an adequate period of rehabilitation. Furthermore, due to the above mentioned plastic properties

Fig. 10D.10. This three dimensional T.C. Scan reconstruction shows a proximal displacement of the fibular head in a subacromial location. Anatomical mismatching and technical problems related to soft tissue repair are the reason of this relatively frequent complication.

of the fibular physis, we observed a progressive improvement of the performance of the reconstructed joint up to several years postoperatively.

In order to maintain a satisfactory pronation and supination, we suggest to avoid a too tight soft tissue reconstruction between fibula and ulna (Fig. 10D.9 A, B). In our experience no ulna subluxation have been noted even at long term follow up despite the apparent laxity of the joint at the end of the surgical procedure.

The functional outcome which can be expected in case of upper humerus replacement is certainly less satisfactory because of anatomical and technical reasons. The proximal fibular epiphysis is quite different in size and shape from that of the humerus and the biomechanical features of the gleno-humeral joint do not promote a significant remodeling, as it can be observed in case of wrist reconstruction. In addition, the soft tissue repair around the fibular head is not always adequate to provide a sufficient stability to the joint with the consequence of a proximal migration of the fibular head in a subacromial position (Fig. 10B.10).

However, the functional impairment claimed by the patients is usually limited to a reduction of abduction which in our experience ranges between 80° and 110°. The overall range of motion resulted to be adequate to accomplish daily activity, including sports involving the upper limb, in the majority of the patients.

As far as the morbidity at the donor site is concerned, damage to the motor branches of the peroneal nerve is the most common and severe complication. As above mentioned, the distribution of the nerve around the vascular bundle sometimes forces the surgeon to consciously interrupt some muscular branches in order to dissect the vessels. In that eventuality, neurorraphy or direct neurotization of the

severed branch can usually provide a good functional recovery. In our experience the majority of the patients suffered only a temporary palsy of the peroneal nerve.

The restoration of the knee joint stability is a second critical point. The lateral collateral ligament must be preserved and meticulously reinserted into the lateral aspect of the methaphysis of the tibia by means of transosseous stitches. The residual strip of the tendon of biceps femoris should be used to reinforce the ligament. Such a reconstruction resulted to be reliable in all the cases and no patient claimed instability of the knee joint.

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