Reconstruction of the Pelvis Using a Segmental Autograft
of the Ipsilateral Femur

J. Puget

Rangueil University Hospital, Toulouse, France

Tumours of the pelvis are doubly difficult to manage: not only does the growth have to be removed, but means have to be devised to guard against postoperative loss of function if the tumour site has involved the hip joint. If the acetabulum is involved (Enneking Zone II), the tumour often extends either into the iliac wing (Zone I), or into Zone III (the pubic rami and the obturator foramen), which means that any reconstruction will need to involve either Zones I + II, II + III, or, sometimes, I + II + III.

Advances in surgery and engineering have led to the development of a number of techniques, from simple tumour removal to the reconstruction of the pelvis with a CAD prosthesis.

Where the goal of surgery is an acceptable functional outcome, simple resection will no longer do, unless the growth is strictly extra-articular. This is why various forms of fusion have been described. Fusion involves either the ischium and the femur, or, more commonly, the ilium and the femur. Often, a graft is interposed to restore limb length; or a “pseudarthrosis” is created, as in the technique devised by Campanacci.

With the advent of joint replacement and revision surgery, reconstruction using a THA plus autograft bone became an option where the defect is comparatively minor; larger defects could be managed with the addition of allografts. The allografts used are proximal ends of femurs or tibias from the bone bank; however, entire hemipelvises have been used for reconstruction. These extensive reconstructions were initially fraught with a high rate of complications and major morbidity. As a result, they were used sparingly. Concurrently with these difficult beginnings, prosthetic replacement of an entire hemipelvis came in, although no formal trials had been performed to test the reliability of the procedure.

Fig. 1 The 3 zones described by Enneking

As yet another technique, saddle prostheses came to be used in this form of tumour surgery. They provide a saddle-shaped support at the level of the iliac wing remnant.

These techniques either proved inadequate or had a very high morbidity and were technically extremely demanding. It was against this background that we proposed, back in 1981, a reconstruction technique that relies upon the ipsilateral femur as an autograft, with a reconstruction prosthesis to replace the bone harvested from the patient. For this technique to be used, the proximal femur must he healthy and unaffected by the tumour. Obviously, where the proximal femur has been removed as part of a THA procedure, the technique described here cannot be performed.

The object of the technique is to reconstruct a pelvis that can provide adequate support and allow satisfactory walking. This article describes the principle, the surgical technique, and the general results obtained.

Principle

For this technique, the femoral head has to be intact. The integrity of the head can be readily checked with a bone scan, CT, MRI, etc. The autograft is harvested close to the tumour removal site; this reduces the morbidity of the procedure even further. The bone graft is corticocancellous, which makes it both strong and readily integrated into the host site. The graft dimension can be tailored to suit the patient pattern, since the part of the femur that is harvested will be replaced by a modular reconstruction prosthesis. As a rule, we resect about 10 cm, which means making an osteotomy at the distal border of the lesser trochanter. This resection does not interfere with function, since the greater trochanter, its proximal and distal muscle insertions, and the lesser trochanter with the psoas insertion are left in situ, to act as stabilizers.

Fig. 2 Zone II tumour extending into Zone I and Zone III

This graft has several advantages:

1 - It has a double curvature, which resembles that of the pelvic inlet. The neck-shaft curve is in two planes: the coronal plane, as seen on conventional AP films; and the sagittal plane.

2 - The graft consists of both cortical and cancellous bone, and is therefore very strong and readily adjustable. The volume of cancellous bone is large, which makes for better integration.

Fig. 3 Femoral graft harvesting: the greater and the lesser trochanter are left in situ.

Fig. 4 Size of the graft

Fig. 5 Similarity of the curvatures

Fig. 6 Insertion of the corticocancellous graft

3 - The trochanteric region provides good conditions for the insertion of a THA cup in an anatomical position.

4 - Fixation is mechanically correct, with firm anchoring along the lines of load transmission towards the sacro-iliac joint at the proximal site, and more flexible anchoring anteriorly, to diminish the risk of failure as a result of over-rigid fixation.

This technique allows extensive reconstruction, and hip function will not be adversely affected by the size of the autograft, since the proximal femur is replaced by a Système PP (Tornier, France) modular reconstruction prosthesis.

5 - The technique is ideal for tumours extending into Zones II + III. It is also useful for Zone I + II tumours; however, its pattern does not match the curvature of the iliac wing, and the action of the gluteals will be affected. This impairment is not specific to the technique.

6 - The graft harvesting site is in the same surgical field as the tumour resection site.

Fig. 7 Siting of the ‘acetabulum’

Fig. 8 Système PP reconstruction prosthesis

Fig. 9 PP implant inserted

Technique

Tumour Resection

The tumour is removed through two approaches used simultaneously. The anterior (ilio-inguinal) approach is centred on the iliopectineal arch, whose division allows the dissection to be developed medially as far as, and if required even beyond, the pubic symphysis. The other approach is a posterior (Kocher-Langenbeck) incision.

For these two approaches to be used simultaneously, the patient has to be positioned in a special way, which is facilitated by the use of a brace which fixes the opposite side of the body and gives free access, on the operative side, to the anterior and posterior parts of the hemipelvis. This brace is fixed at an angle of 45° to the operating table. Sideways tilting of the table allows the patient to be positioned supine, for the anterior, ilio-inguinal approach; or side-lying, for the posterior, Kocher-Langenbeck approach. The ipsilateral lower limb is free, and placed on a sterile support, which allows mobilization, as required, of the distal part of the limb.

Fig. 10 Reattachment of trochanters to the prosthesis

Fig. 11 The two approaches

The anterior incision is made first; if required, it may be extended along the iliac wing. In some cases, the tumour is readily resectable at a distance from the wing, especially if the growth is a chondrosarcoma. Where the soft tissues have been invaded, removal may be more difficult; however, the preoperative work-up, especially the MR scans, should allow the surgeon to assess the likely degree of difficulty before starting the operation. Through the anterior incision, the osteotomy can be performed in healthy bone, from the iliac wing to the sacro-iliac joint (if required); anteriorly, an osteotomy may be made near the symphysis or even beyond, should the need arise. The pubic rami can be readily divided near the symphysis.

Fig. 12 Brace fixed at 45° to the top of the operating table

Fig. 13 Brace in situ, with armboards fitted

The posterior incision gives access to the inferior ramus or the posterior column down to the distal end of the sacro-iliac joint; the neurovascular gluteal structures can be readily checked through this approach. There is easy access to the origin of the hamstring muscles, and the resection of the tumour started by the anterior and midline osteotomies can be completed through this incision.

Fig. 14 Schematic representation of side-lying position and supine position, obtained by tilting table from neutral position of brace at 45° to the horizontal table top

Fig. 15 Patient in neutral position. Note support for limb on involved side.

Autograft harvesting

The graft is harvested after the anterior part of the procedure has been completed, and before the posterior part is commenced. The space provided by the harvesting of the graft will allow the tumour to be resected with proper cancer surgery precautions. Sometimes, the space provided in this way will be large enough to obviate the need for a posterior approach.

Fig. 16 Patient supine, anterior approach

The hip joint capsule is opened with a T-shaped or an H-shaped incision. With an oscillating saw, a trochanter slide is performed through the anterior or the posterior incision. The trochanter with the intact muscle insertions is left in situ, and will enhance the stability of the reconstruction prosthesis.

Fig. 17 Patient side-lying, posterior approach

Through the anterior incision, the lesser trochanter is osteotomized. The trochanter is left in situ, to serve as a landmark and to allow the iliopsoas tendon to be reattached. In this way, postoperative hip flexion will be improved.

Finally, the femoral shaft is divided transversely. This is done through the anterior incision, or – more commonly, and, above all, more comfortably – through the posterior approach.

Fig. 18 Surgical field draped for the procedure

The osteotomy level is at ca. 10 cm from the top of the femoral head, usually at the distal border of the lesser trochanter. This will provide a very adequate graft for reconstruction in Zones I + II, or II + III. If the reconstruction involves more than two zones, without the third zone being entirely resected, a graft 12–14 cm in length may be used. This should be straightforward, working from a preoperative template that shows the required length. The proximal portion of the femur released in this way will constitute the autograft. A specimen is taken from the femoral head, which is frequently demineralized, since pain will have prevented the patient from weight-bearing. Once the graft has been harvested, the resection of the tumour, especially of the posterior portions of the growth, will be that much easier.

Sometimes, the posterior approach can be dispensed with. Provided that the graft is harvested before the tumour is completely resected, there is no reason why tumour resection and graft harvesting should not be performed through the anterior incision only.

Fig. 21 Zone I + II chondrosarcoma (early)	Fig. 24 Plasmocytoma in Zones I, II, and III
Fig. 28 Giant-cell tumour. Arteriogram of Zones II and III

Different approaches

At the start of our learning curve, we would remove these tumours through an Enneking approach, or through an extensile iliofemoral incision as described by Letournel. However, the exposure of the posterior site obtained through these incisions is not as good as that provided by the two-incision technique. Also, these routes are more damaging to the soft tissues, and will leave the prosthesis more unstable.

Fig. 19 Letournel extensile iliofemoral approach

Fig. 20 Enneking approach

Graft orientation

Once the tumour has been removed, the autograft will need to be correctly oriented and fixed. Orientation must obey one simple rule: there must be as much cancellous bone as possible in the area that will be reamed to form an acetabulum. Where the entire Zone II has been removed, the part of the graft to contain the acetabulum will be the trochanteric region; if part of Zone II is still standing, the head of the femur, with its cartilage removed, could provide the acetabular site.

In cases where Zone II has been resected, the curve of the autograft allows the new acetabulum to be placed in an anatomically correct position, since the curve of the proximal femur matches very well the curvature of the pelvic inlet in the hip bone.

In practice, we tend to use mainly “head-up” constructs for the management of relatively minor resections, since approximation with the cut edge in the iliac wing is good.

For extensive reconstructions involving Zone II, and all or part of Zones I + II, we tend to use a “head-down” construct.

Graft fixation

The autograft has to be considered as a weight-bearing element in the gait cycle. Because of this function, and because of the biomechanics of the pelvis, the autograft is wedged into the area between the sacro-iliac joint and the symphyseal region. The resultant of the weight-bearing forces tends to compress the proximal portion, near the sacrum, while the resultant produced by the deformation of the pelvis, which acts as a deformable ring, causes compressive stress in the region near the symphysis.

The graft can, therefore, be fixed with very little need for hardware. As a rule, one or two screws routed obliquely towards the sacrum will suffice for proximal fixation. The routing of the screws follows the pattern of the Pauwels resultant during weight-bearing. Near the symphysis, simple fixation (by means of wire cerclage, a small plate, etc.) will preserve the elastic behaviour of the anterior arch. An overly rigid fixation would tear out, as observed by Campanacci in his allograft reconstructions.

Fig. 31 Simple wire fixation near the symphysis

Insertion of the prosthesis

Preparation of the acetabulum

Where a portion of Zone II has been left standing, preparation of the acetabulum is straightforward. If Zone II has been resected in its entirety, thing will be more difficult. In such cases, the trochanter osteotomy site of the graft will have to be fashioned into a bed for the implant cup. This part of the graft contains much cancellous bone, and extends into two sheets of cortical bone in the femoral neck. This zone is sturdy and provides sound fixation. Sometimes the proximal part of the femoral autograft is very slender, in which case the available zone will be too narrow to accept a cup of sufficient size. Where this is the case, a ring or, preferably, a plate contoured into an arc, should be resorted to. Supplementary grafting may also be used.

Fig. 22 “Head-down” construct, to provide acetabular site	Fig. 23 Construct following resection of a Ewing sarcoma involving Zone II and adjacent parts of Zones I and III
Fig. 25 “Head-down” construct	Fig. 26 Chondrosarcoma in Zones I, II, and III. “Head-down” construct.
Fig. 29 Fixation with small plate at the symphysis
Fig. 30 10-year radiograph

Femoral prosthesis

The implantation of the femoral prosthesis is straightforward, if one uses a modular device whose metaphyseal-segment height can be chosen in such a way as to fill the donor site defect. There is no need for a customized implant. We use the Tornier Système PP. The lesser trochanter, with the iliopsoas attached, and the greater trochanter, are readily attached to the implant, and the construct is simple and stable. The anterior incision, or (where used) the two incisions, are closed. At follow-up, excellent restoration of proximal femoral bone stock has been noted.

Limitations of the technique

The femoral head must be free of tumour. This is an absolute condition. Advances in medical imaging, especially MRI, have made it easier to check the soundness of the femoral head.

The small size of the femoral neck and of the trochanteric region has proved to be only a relative limitation to the use of this technique, since there are certain tricks by means of which the zone that will house the prosthetic cup can be enlarged.

Fig. 27 Load transmission lines (from Karpandji)

Some authors, such as the group under Toméno at the Cochin Hospital, have proposed vascularized grafts. Whilst this is an elegant and attractive concept, we do not think that it enhances the integration of the graft. It also has the disadvantage of making graft mobilization and insertion more difficult.

Postoperative management

Since the introduction of two simultaneous approaches, the postoperative course has been more uneventful, with about a third less bleeding, and a feeling by the patients of having a more stable construct.

Weight-bearing is allowed as soon as the patient’s general conditions permits (with progression to full weight-bearing usually after the first postoperative week). In actual fact, full weight-bearing is not usually achieved until after Week 3, by which time the patient will have realized that the construct is sound. There is a tendency towards external rotation while the patient is lying down, because the lateral check-rein structures are not always rigidly fixed. This tendency must be controlled by appropriate patient positioning. After extensive resections, a short hip spica or an anti-dislocation corset should be used, to limit movements for a period of 3 to 4 weeks.

Fig. 32 32 Enlargement of the ‘acetabulum’ with contoured plates	Fig. 33 Enlargement of the ‘acetabulum’ with a Ganz ring
Fig. 34 Isolated renal cancer metastasis in Zone II, partially involving adjacent Zones I and III. Note extent of femoral bone stock at 3 months.	Fig. 35 Same patient at 18 months, with extensive restoration of bone stock at proximal end of femur.

Results

Analysis of the constructs used in our series of 29 cases (eight primary and 21 secondary tumours) showed the constructs to be sound, without any fixation failure during the lifetime of the patients who have since died, and in those who are still alive.

Superficial infections occurred in two cases; these patients had metastases, and were not appropriate candidates for the procedure. Their tumours had grown into the bone by direct spread from a primary in the GI tract. In one case, there was early dislocation, which was managed with a short hip spica worn for 6 weeks. In none of the cases did the fixation fail.

Three patients had permanent, and four had transient sciatic nerve palsies; six had partial femorocutaneous nerve palsies; while one had permanent, and two had remitting femoral nerve pain.

As regards vascular complications, pelvic deep vein thrombosis was confirmed in all of the 29 cases.

In terms of the functional outcome at 6 months, four of the patients were walking without aids; 16 were walking with one aid; five with two aids; in three cases, the outcome was poor, with less than one year’s survival. These patients, too, should not have been selected for the procedure: they had metastases that had grown into the bone by direct spread from a regional primary which, in all cases, was in the GI tract.

Among the eight primary tumours, reviewed for our presentation at the GETO symposium at Nantes (March 2000), there were four chondrosarcomas, of which two were high-grade and two were low-grade; all of these patients died from pulmonary metastases (at 3, 5, 7, and 11 years, respectively). While they were in remission, they became ambulant again, and had no functional problems, although they had to use walking aids to a greater or lesser extent, as dictated by the tumour resection site.

The technique was used for the management of two giant-cell tumours. One of these patients has been followed up for 14 years; the other one is now at a terminal stage, four years after surgery.

One patient had a Ewing sarcoma; postoperative survival was for one year, without any mechanical problems. One patient had a plasmocytoma which was still isolated; she was our first case, operated on in 1981, and is still alive.

Indications

The best functional outcome may be expected where resections are in Zones II + III, or in partial Zones II + I, provided that enough of the iliac crest is left standing, and that not too much of the gluteals has to be sacrificed. The procedure may also be used for the management of acetabular tumours extending into Zones I and III, where these zones do not have to be removed in their entirety. However, to our way of thinking, cases requiring complete resection of Zones I, II, and III are not suitable candidates. The technique is used for the treatment of primary tumours of the pelvis (mainly chondrosarcomas), but also lends itself to the management of very disabling secondaries, if the prospect of survival is better than 18 months

Conclusion

The technique described here is original and fairly straightforward; it consistently produces good postoperative results, and yields useful outcomes with little morbidity. One particular advantage is the absence of superficial infections or septic complications. We have not encountered any mechanical problems in the form of graft fixation failure.

The follow-up to date, since the first use of the technique in 1981, has convinced us of the utility of the procedure.

REFERENCES

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Maîtrise Orthopédique 97^th - October, 2000