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INTRODUCTION

Robert Judet and Emile Letournel laid the foundations of acetabular fracture surgery, back in the 60s. They established the fundamental tenets, and described the fracture mechanisms and patterns. The classification drawn up by these two pioneers has been the basis of the modalities evolved for the management of acetabular fractures.

As pointed out by Robert Judet and Emile Letournel, and reiterated by the present authors, successful acetabular fracture surgery is predicated upon an accurate diagnosis of the fracture pattern and a thorough understanding of what can, and what cannot, be achieved with the different approaches to the acetabulum.

While there is agreement on the use of certain incisions for certain fracture and displacement patterns, other approaches remain the subject of controversy:

- Since the beginning of acetabular fracture surgery, there has been universal agreement that simple posterior fractures should be managed through a Kocher-Langenbeck approach.

- On the question of anterior fractures, opinions used to be divided for a long time, with some favouring a Type 1 or Type 2 Smith-Petersen approach, and others recommending an iliofemoral incision. The dilemma was resolved by the ilioinguinal approach described by Emile Letournel in his 1961 thesis and used, in acetabular fracture surgery, since 1965.

- The subject of the approach to be used for associated anterior and posterior lesions is a much more controversial one. Since no one (anterior or posterior) approach can be used to tackle both types, combined approaches, and, above all, extensile approaches have been proposed. The extended incisions are based upon the approach originally devised by Ollier (Sénégas or triradiate approach), or on the anterior Smith-Petersen approach. Marc Siguier devised an enlargement of the Smith-Petersen incision - the iliofemoral approach -, which was published by Robert Judet and Emile Letournel in 1974. This anatomical approach allows excellent exposure of the entire outer aspect of the iliac wing. However, recovery is less rapid than after surgery through specifically anterior or posterior approaches; in particular, there is a risk of heterotopic ossification in the external iliac fossa and around the hip joint. In fact, the risk is so great that routine preoperative irradiation has been recommended, to prevent this ectopic bone formation.

The postoperative problems with which this “highway to the hip” is fraught are in marked contrast to the acknowledged ease of recovery from surgery through an ilioinguinal approach. In common with many other authors, we have adopted a policy of using the ilioinguinal, not only in cases where this incision has always been recommended, but also in three other situations. In two of these other situations, an extensile approach might also be used; the third concerns patients who might be managed nonsurgically.

SITUATION NO. 1 : Primary ilioinguinal, rather than iliofemoral, approach

Whenever the ilioinguinal approach, either by itself or in combination with a supplementary posterior approach, appears to provide sufficient exposure of a complex fracture (e.g. both-column fracture with a large posterior fragment; anterior column plus posterior hemitransverse fracture).

SITUATION NO. 2 : Ilioinguinal approach to complement a Kocher-Langenbeck incision

In these cases, the posterior incision is the first line of approach; however, because of the fracture configuration, difficulties are likely to be encountered with the reduction or the fixation of the anterior portion of the fracture pattern (e.g. certain transverse or T-shaped fractures).

In these two situations, special (lateral) positioning of the patient is required; therefore, the patient’s preoperative radiographs and scans must be carefully analyzed to determine whether an ilioinguinal approach will or may be called for.

SITUATION NO. 3 : Ilioinguinal approach, rather than abstention from surgery

Elderly patients tend to sustain mainly anterior wall or anterior column fractures. As after femoral neck fractures, freedom from pain after surgery, and early mobilization, are crucial, not only to the restoration of function, but to keeping the patients alive. Hip replacement is not an option; immobilization is poorly tolerated; and, frequently, function cannot be restored if there is joint incongruency. In such cases, surgery, with early fixation through an ilioinguinal approach, has proved efficacious and well-tolerated.

A study of 100 consecutive cases of acute acetabular fractures operated on at the Tenon Hospital shows how the ilioinguinal approach is coming back into use:

It was employed in 37 cases; in 28 cases, it was the only approach used; in nine, it was combined with a posterior incision. (In the literature, the rate of anterior approaches ranges from 18 to 32%).

The above-mentioned series had several aspects worth mentioning:

The Kocher-Langenbeck approach was, obviously, the most frequently used (51 cases, of which 43 isolated, and 8 in combination).

The iliofemoral approach (19 cases) has, over the last three years, been gradually superseded by simultaneous combined approaches; its only indication nowadays are old fractures.

In the category of anterior lesions, the proportion of elderly patients was higher: the mean age of patients managed with an isolated ilioinguinal approach was nine years higher than the general mean age of patients in the study (48 years vs 39 years).

This pattern has been reported by many authors. We feel that it calls for a review of the underlying principles, and a reminder of some of the technical points involved in the use of the ilioinguinal approach.

PRINCIPLES AND CAPABILITIES OF THE ILIOINGUINAL APPROACH

The ilioinguinal approach makes virtually the entire internal aspect of the innominate bone accessible to instruments and/or to digital palpation. If necessary, it may be used for the exposure, distally and anteriorly, of the pubic symphysis and the contralateral pubic ramus, while proximally and posteriorly, the sacroiliac joint and the ala of the sacrum may be accessed. The only zone excluded from access is the posteroinferior portion of the obturator ring.

Direct fixation, with screws or plates, may be performed from the entire surface above and in front of the radiological pelvic brim. Below and behind that line, the remainder of the acetabulum (fossa, posterior column) may sometimes be reduced with direct guided instrumental manoeuvres; if required, a check may be made by palpation. However, fixation can only be performed retrogradely, from the anterior segment of the innominate bone.

As a rule, reduction and fixation are done without a direct visual inspection of the joint; instead, the internal pelvic cortex is checked to ensure that the construct is correct. However, where circumstances (such as the elevation and grafting of an impaction) require an intra-articular access, this may be provided by tilting a fragment of the anterior wall.

TECHNIQUE OF THE ILIOINGUINAL APPROACH

It would be futile to repeat the masterly first description by Emile Letournel and Robert Judet, with illustrations by Madeleine Frantz. The detailed anatomical description and the associated figures very elegantly show what the ilioinguinal approach looks like, and highlights the pitfalls as well as the variants of this access. The text is a must for any surgeon interested in acetabular fracture surgery.

Having learned our craft from Robert Judet and Emile Letournel, and subsequently practised this - often rewarding, sometimes disappointing - surgery, we feel that perhaps a few additional points may be made.

PATIENT POSITIONING

For an isolated ilioinguinal approach
We routinely use a fracture table, even for patients with double fractures of the anterior pelvic ring. In such cases, the required traction is produced by drawing out the fracture table, with the patient’s chest firmly strapped to the head end with four taut tapes. This way, the perineal post cannot deform the pelvic ring; it may be left in situ or removed.

Combined approaches: Lateral positioning
We prefer to perform the two approaches in one session. This dual approach may be done electively, or it may be decided upon if the primary approach fails to provide sufficient reduction. A perineal post that may be raised or lowered by remote control makes it very much easier to work through two incisions. As with the isolated posterior approach, a transcondylar pin will need to be inserted, to provide traction on the slightly flexed knee. Patient positioning must be such as to allow movement of the hip joint through the full range of abduction, adduction, rotation, and flexion. Lateral positioning should provide the same possibility of traction through a table break as described above for supine positioning.

Skin incision (Fig. 1)
The lateral part of the incision may be drawn with a slightly shallower curve than is customarily recommended; the line should be two centimetres below the iliac crest. The scar will be as cosmetic as with the conventional pattern, and will, in fact, be less obvious.

Figure 1 : Bony landmarks, and routing of skin incision

Dissection of the internal iliac fossa (Fig. 2)
This is done from the crest, in a strictly subperiosteal fashion, working in three directions:

==> Backwards, if necessary beyond the sacroiliac joint, which may be inspected and stabilized, care being taken to protect the L5 nerve root (Fig. 4);

==> Downwards, crossing the pelvic brim and reaching the greater sciatic notch, care being taken to protect the gluteal neurovascular structures (Fig. 3);

==> Forwards, with subperiosteal elevation of the anterior border of the innominate bone, in preparation for the mobilization of the iliopsoas.

Figure 2 : : Subperiosteal approach to the internal iliac fossa	Figure 3 : Internal iliac fossa, sacroiliac joint, and greater sciatic notch
Figure 4 : The L5 nerve root in front of the sacral ala	Figure 5 :The incision of the obliquus externus crosses the fibres of the aponeurosis

• Incision of the obliquus externus aponeurosis
  This incision crosses the fibres of the aponeurosis, to finish above the external inguinal ring (Fig. 5).
• Freeing the common internal oblique/transversus origin The incision, as well as the subsequent reconstruction of the inguinal canal, are greatly facilitated by routing the release as low as possible, taking a cuff of inguinal ligament. This applies even more to the medial part of the incision, behind the spermatic cord, where the fibrous portion of the insertion is less well defined than laterally, over the iliopsoas (Fig. 7).
• The iliopectineal fascia (Fig. 8)
  The approach to the two surfaces of this sagittal structure, and the disinsertion of the fascia close to the bone, from the iliopectineal eminence at the front to the sacroiliac joint at the back, is crucial to the mobilization of the iliopsoas laterally and of the vessels medially (Fig. 8).
• The iliopsoas (Figs. 7, 11)
  The lateral femoral cutaneous nerve and the femoral nerve are included with the iliopsoas in the same Penrose drain sling. The mobilization of the muscle is completed by the release of the most anterior fibres of the iliacus muscle origin, just below the medial aspect of the anterior superior iliac spine.
• External iliac vessels and satellite lymphatics (Fig. 9)
  Their mobilization after placement in a rubber sling frequently has to be preceded by the ligation and division of some ascending internal and external branches. Also, a search must be made for the presence of a corona mortis (a retropubic anastomosis between the external iliac system and the obturator artery) (Fig. 10). This pattern, described in textbooks of anatomy, is by no means rare. If present, the anastomosis will be found against the posterior surface of the pubis, beneath the vessels coursing there.
• The pectineal ligament (Cooper’s ligament)
  This ligament runs along the lower part of the anterior border of the iliac bone and along the superior border of the pubis. Once the spermatic cord has been isolated, it may be useful to incise the ligament with a scalpel and elevate it, in order to be able to check fracture lines or apply a plate.
• The four windows, and how to use them (Fig. 11)
  The windows are opened by manipulation of the various structures, to gain access to different parts of the internal aspect of the pelvis. Access will be easier if the structures involved have been liberally mobilized.

Figure 6 : Approach of the common origin of internal oblique and transversus abdominis and of the external inguinal ring from the inside of the obliquus externus aponeurosis. The lower edge of the aponeurosis is tented and reflected forward on two Kocher clamps; the scalpel tip is poised over the common origin of the internal oblique and transversus abdominis muscles on the inguinal ligament. On the right, the spermatic cord is seen coursing towards the inside of the external inguinal ring.	Figure 7 : The psoas sheath is opened above the inguinal ligament. Note the lateral femoral cutaneous nerve medial to the iliac spine.
Figure 8 : The iliopectineal fascia between the psoas (under the retractor) and the vessels (under the index finger) is being cut close to the iliopectineal eminence and the pelvic brim, all the way back to the sacroiliac joint.	Figure 9: The external iliac vessels are dissected free complete with their surrounding cellular tissue containing the lymphatics; on the right, the spermatic cord.

Figure 10: The retropubic corona mortis is hidden behind the vessels and the pubis. The external iliac vessels have been drawn upwards and forwards by a Farabeuf retractor and a white sling (on the left). A malleable blade (on the right) is inserted behind the pubis, to display the retropubic anastomosis.	Figure 11 : Iliopsoas, femoral nerve, and lateral femoral cutaneous nerve laterally; vessels in the centre; spermatic cord medially. All structures placed in Penrose drain slings.

- Mobilization of the iliopsoas This mobilization is facilitated by placing the lower limb in external rotation or in flexion. Injury to the lateral femoral cutaneous nerve is a nuisance, but not a disaster. If the nerve has been subjected to much stretching, it may be cut at a site away from the surgical field, and repaired.

- The femoral nerve: This nerve is well protected, and not at great risk of injury.

- The vessels: The vessels must be handled gently; traction must be released at regular intervals, and the vessels inspected repeatedly.

- The spermatic cord: This is a compliant and easily mobilized structure; however, it is easily injured, and must be treated with the utmost care.

MOBILIZATION, REDUCTION, AND FIXATION OF FRACTURES

Prior to any fixation, a check must be made, as in any acetabular fracture procedure, to ensure that every fracture line is accessible, that every fragment can be mobilized, and that the result of reduction can be checked.

Definitive reduction and fixation are started at the iliac wing. If necessary, this work may start at the sacroiliac joint, which is reduced under direct vision, while fixation is performed percutaneously, with screw placement from the gluteal region.

FIXATION OF THE WING, THE ROOF, AND THE ANTERIOR COLUMN
As a rule, this calls for plates and screws; it is our practice to contour the plates on the spot, in order to obtain optimum moulding to the patient’s innominate bone. Whenever possible, plating is supplemented by direct screw fixation; screws may also be used instead of plates. Where isolated screw fixation is possible, it constitutes a means of stabilization that is as accurate as plating, while often being more solid, and invariably more elegant, than plate fixation.

THE POSTERIOR COLUMN
The posterior column will need to be tackled in cases where the ilioinguinal approach has been used for the management of both-column fractures, T-shaped fractures, or anterior column plus posterior hemitransverse fractures. In order for the reduction to be checked, visually, with instruments or with finger palpation, between the iliopsoas and the vessels, the high origins of the obturator internus on the quadrilateral surface must be subperiosteally elevated with meticulous care. Reduction is facilitated by the division of the sacrospinous ligament. The surgeon will need the entire range of reduction instruments - elevators, MacEwen chisels, asymmetrical Farabeuf clamps, if need be Matta clamps, and a (small) bone hook (since a large bone hook may endanger the posterior structures, in particular the sciatic nerve).

FIXATION OF THE POSTERIOR COLUMN
This can be done only by lagging from the anterior column, either with isolated screws or using plate-and-screw fixation. The wound is closed in meticulous fashion, with the same attention to the anatomical structures as during the fashioning of the approach; the lateral and anterior parts of the abdominal wall are carefully restored (Fig. 12).

Figure 12 : Closure of the flat abdominal muscles using an overlapping technique, after reinsertion of the muscles on the iliac crest with transosseous sutures. Medially, the internal inguinal ring is anatomically restored at the correct distance from the external ring.

CONCLUSION

All the users of the ilioinguinal approach have found this incision to work well in many different indications, and to be comparatively free from complications. We feel that whenever it is seen to constitute a sound alternative to an extensile approach, it should be used. Since it causes very little trauma, it may be employed in elderly patients with displaced anterior column fractures. It should not, however, be forgotten that - like all acetabular fracture surgery - this is a demanding procedure.

Acknowledgements We are indebted for the illustrations to the Fer à Moulin dissecting room (Prof. Y. Aigrain).