The general aim of fracture management is to obtain proper reduction and alignment (axial and rotational), followed by fixation, which should eventually lead to fracture union in an accepted position that helps the patient return to his/her preinjury level of activity and function.1

These aims could be more challenging when dealing with intra-articular fractures, where fracture reduction should be anatomic to avoid secondary osteoarthritis; this makes acetabular fractures to be one of the most challenging intra-articular fractures to treat owing to their complex anatomy, various injury patterns, and patient-related factors such as obese or muscular patients, which adds to the complexity of the surgery.2,3

To obtain an anatomic reduction of complex acetabular fractures, a lot of reduction assisting tools and clamps were introduced, such as the ball spike pusher, Farabeuf clamp, pointed reduction forceps, and offset clamps.4

Here, we describe a modification we performed on a standard cancellous bone impactor to be used more efficiently during open reduction and internal fixation of acetabular fractures.

TECHNIQUE

The cancellous bone impactor is formed of a broad blunt (mostly rectangular) distal end, which is attached to a cylindrical handle by a shaft (Figs. 1A, B). This instrument is mainly used for impacting bone grafts while managing bone defects. We introduced 3 modifications to this instrument to be suitable and easily used for assisting the reduction and fixation of acetabular fractures regardless of the type of fracture or the approach used.

A little curve on the undersurface of the rectangular distal end, so it is better fitted over contoured bony surfaces (Fig. 1B). Machining of the undersurface so that the surface is roughened to prevent slippage over smooth bony surfaces (Fig. 1C). Two fenestrations on the rectangular distal end on either side of the handle shaft (Figs. 1C, D). These were made at about 15 degrees in relation to the handle. The reason for this angulation is to create a space between the proximal end of the handle (where the surgeon holds the handle) and the body of the power drill (where the K-wire is mounted), which is held by the surgeon’s other hand to introduce a wire for preliminary fixing the reduced fracture till final fixation using plate and screws (Fig. 1E). An example of intraoperative usage of the modified impactor is shown in Figures 2 and 3. FIGURE 1:

The modified cancellous bone impactor. A, The original design of the cancellous bone impactor with a flat distal rectangular end. B, The modified cancellous bone impactor with a curved distal end. C, An end-on image of the impactor distal end showing the fenestrations (red arrowhead) and the roughed surface (yellow arrowhead). D, An image from above showing the fenestrations (red arrowhead) on either side of the impactor shaft. E, A demonstration showing a threaded wire passing through the fenestration and the clear space between the proximal end of the wire and the impactor handle, which is about 15 degrees.

FIGURE 2:

Preoperative imaging studies of a female patient 35 years old presented after a motor car accident with a central dislocation of her right hip and a T-shaped acetabular fracture. A, Pelvis anteroposterior view after reducing the hip. B, Obturator view of the right hip. C, Iliac view of the right hip. D, CT scan showing the amount of displacement and the multifragmentary nature of the fracture.

FIGURE 3:

Operative details and postoperative imaging. This patient was operated upon through a modified Stoppa approach. A, The black arrowhead is pointing to the displaced fragment. B, A trial of reduction using a ball spike impactor. C, Reducing the fragment using the modified impactor. D, Trying preliminary fixing the fracture using a K-wire while holding the fracture using the ball spike impactor, notice that there is no space between the surgeon’s hand holding the impactor and the other hand holding the power drill (green arrowhead). E, Preliminary fixing the fracture using a K-wire passed through the fenestration of the modified impactor, notice enough space between the surgeon’s hand holding the impactor and the other hand holding the power drill (blue triangle). F, The easy distraction of the impactor after leaving the K-wire holding the fracture. G, Intraoperative fluoroscopic view shows accepted fracture reduction fixed by temporary K-wires. Postoperative imaging: anteroposterior view(H); obturator view (I); iliac view (I).

Expected Outcomes

Optimum anatomic reduction of the acetabular fracture and preservation of the hip joint congruency results in better outcomes and reduces the incidence of post-traumatic hip arthritis.5 Various reduction techniques were introduced to achieve these goals using several instruments and reduction tools.4

Bone impactors had been used as an assistant reduction tool during open reduction with internal Fixation of acetabular fractures; however, the modifications we introduced to the instrument could help better and more efficient use of this tool. First, the curve we added to the undersurface of the rectangular part of the instrument helped better fitting of the instrument when pushed against curved bony surfaces (which are most present when dealing with acetabulum fractures); second, the scoring we performed on the undersurface of the instrument helped to roughen this area, which assisted in better stability of the instrument when used to push a slippery bony fragment. Third, the fenestration on either side of the rectangular segment created a more secure passage for the K-wire or threaded wire used for temporarily stabilizing the fracture till the definitive fixation. It created a safe passage to protect against adherence of the soft tissue while the wire is being introduced; the surgeon could hold the impactor with one hand and the wire through this fenestration with the other hand, which gives better control over the instruments and prevent slippage of the tip of the wire over the bony surfaces. The angulation of the fenestration in relation to the body of the impactor created an offset so that the hand of the surgeon holding the power drill could have enough space away from the proximal end of the impactor handle. Lastly, the rounded, flat undersurface of the impactor’s rectangular part will help distribute the pressure over the impacted bony fragment and prevent fragmentation, especially in the osteoporotic bone, which could occur with ball spike impactors.

CONCLUSIONS

The modification we introduced to this simple cancellous bone impactor could help surgeons operating on various types of acetabulum fractures through any approach to better reduce and control the fracture fragments.

ACKNOWLEDGMENTS

The authors thank Prof Osama Farouk, the head of the Pelvis trauma unit at our institution, for approving the idea and for the continuous support and encouragement. The authors also thank Eng. Othman Hassan for assisting in modifying the impactor as we required.

REFERENCES 1. Mansour A, Givens J, Whitaker JE, et al. Immediate outcomes of early versus late definitive fixation of acetabular fractures: A narrative literature review. Injury. 2022;53:821–826. 2. Audretsch C, Trulson A, Höch A, et al. Evaluation of decision-making in the treatment of acetabular fractures. EFORT Open Rev. 2022;7:84–94. 3. Ziran N, Soles GLS, Matta JM. Outcomes after surgical treatment of acetabular fractures: a review. Patient Saf Surg. 2019;13:16. 4. Mast JW Marvin Tile DLH, Kellam JF, Vrahas M. Techniques of reduction and fixation for acetabular fractures: open methods. Fractures of the Pelvis and Acetabulum, 4th ed. Thieme; 2015;639:660; chap 6. 5. Cahueque M, Martínez M, Cobar A, et al. Early reduction of acetabular fractures decreases the risk of post-traumatic hip osteoarthritis? J Clin Orthop Trauma. 2017;8:320–326.