Using the Anterior Approach to address Crowe Type IV Developmental Dysplasia

I’m often asked about the limitations of anterior approach as there’s a perception that it is not suited for complex surgeries. However, with familiarity with this approach, there are many situations where it actually presents advantages for complex arthroplasty. For example in this case of a high hip dislocation where correct acetabular positioning and stability are challenging as the typical landmarks are malformed or absent and there are torsional challenges with the femoral component. Using an anterior approach offers more control in terms of how we tackle these challenges - with the inter operative use of fluoroscopy and digital assistance from Depuy Synthes' #Velys further enhancing precision.
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Transcript
This particular case is of a 40-year old female. She's got the typical history of a high dysplastic - she's been very active, she was born abroad, she always had a leg length inequality and a limp. She notes a history of casting but no prior surgeries.
Her physical exam is important in this case because it demonstrates that she's very flexible. In these particular cases, I perceive that as somewhat accommodating to lengthening. I also see that she's got a little bit of excessive torsion on that left hip that's seen in our prone internal external rotational evaluation.
In this particular case, I've opted to use an anterior approach largely because of the ability to control acetabular component positioning, acetabular preparation screw placement and also the ability to fine tune the leg lengths. The other benefit is if I had to proceed with the subtrochanteric osteotomy I could precisely place that where I wanted based upon implant and healing considerations. Another benefit that's not commonly talked about is that the hip in the dysplastic patient is typically more of an anterior structure.
One of the most important tools that we have as we do anterior approach is the ability to use live intraoperative fluoroscopy to guide the procedure. And in this particular case making the neck cut under fluoroscopy eliminates one other point of variability - when you are dealing with abnormalities of torsion the lesser trochanter may be harder to find and it may be difficult to assess your neck osteotomy level. This allows it to be incredibly precise - you mark the anterior neck with the edge of an osteotome and make your neck cut exactly where you wish to have it done based on fluoroscopic evaluation.
Once the neck osteotomy is complete and the head is out of the way, reaming proceeds in a very controlled manner. We begin with a reamer directed medially and in fact distally sometimes to achieve a more normal hip center. It's here where some of the facilitating technologies available to us can be quite advantageous as I typically use the Velys system to help guide the acetabular component - giving us relative landmarks as a target for acetabular component inclination and anteversion.
Cut positioning similarly is done under direct fluoroscopic guidance. The initial stability of the cup is placed between the acetabular columns and a single screw is placed. In this case we elected to go with a Bantam 44 shell. Typically with a dysplastic you're going small and medial with the acetabular component. I opted to go with an anatomic hip center - I think it reduces the complexity postoperatively - but rather opted to tailor my lengthening so as to not overly lengthen. I anticipated probably leaving her a few millimeters shy of equal to the contralateral limb. One of the other strategies that I wanted to do in this particular case is to reduce the global offset quite a bit so as to ease some of the soft tissue tension as we anticipated lengthening her quite a bit.
The femoral components are placed again under fluoroscopy. In this case, an S-Rom stem was used to control the torsional variables. The spa sleeve gave us quite a bit of control over this given the unique anatomy typically presented with the dysplastic femur. Again you can see we use the Velys system to guide the femoral component to control for variabilities such as the hip center and reconstruction of leg length and offset.
The thing that is most attractive to me with the anterior approach is the ability to reliably produce a very good post-operative X-ray. Here we are at two years follow-up showing a stable osteo-integrated implant in an ideal position with good reconstruction of leg length and offset. The final result here side by side demonstrates the correction of leg length and femoral position as well as reconstruction of the anatomic hip center. There's ideal acetabular component positioning and reproduction of the anatomic hip center.

[@jazzbonewest]

Fascinating, I'm just a layman and your explanation was easy for me to follow.

[@ajaymane482]

You are phenomenal doctor, nice video