Approaches to the hip
The hip can be surgically approached through a number of corridors. These are typically chosen based on the surgeons familiarity and training. It is therefore not uncommon for a surgeon to preferentially state that one approach is superior to another. The reality is with sufficient experience all approaches are probably similar in outcome and the final arbiter of function will be the patients drive and commitment to a better level of function. In recent times the concept of the minimally invasive replacement has become popular nevertheless this remains a controversial modality although they are all variants of standard approaches but only with a smaller incision. It is the authors preferred modality for primary hip replacements for degenerative conditions.
The Posterior Approach
This is probably the best known of the approaches. The patient is placed on the side and an incision running along the axis of the femur and angle at the hip to the posterior superior iliac spine is made. A number of muscles are violated in the process and the external rotators of the hip are detached. Exposure is excellent and the procedure allows all methods cemented or uncemented to be implemented. In the early perioperative period there is an increased risk of hip dislocations and the patients are advised against crossing their legs and sitting on low chairs for up to 3 months.
The Anterior Approach
In this approach the patient can be on the side or back. Exposure is challenging and cementation may require a bigger incision. It is inherently stable as few muscles are violated (Figure 1).
The Lateral Approach
The patient is on the side. The incision is the least traumatic. Deep dissection of the hip is similar to the anterior approach to the hip
Minimally invasive approaches
In general minimally invasive surgery or MIS refers to a group of approaches where the skin incision measures 10cm or less and can be as small as 7 cm (Figure 2). Depending on one's philosophy, this approach is either praised or maligned. The literature suggests that implants in placed in this approach have a higher chance of being malaligned and causing fractures. Cemented implants are difficult to be introduced with this approach. While there is improved mobility in the short term, in the long term results are the same. It is the authors preferred approach in degenerative disease of the hip and has particular utility in patients who need a rapid turnaround - especially foreign patients who need to be mobile as soon as possible and return home (Figure 3). Many patients enjoy the ability of squatting due to limited damage to the surrounding muscle.
Figure 1. In the anterior approach to the hip, the dissection is between muscle planes up to the capsule of the joint. As muscle is not cut we believe the approach is inherently more stable than the posterior approach.
Figure 2. This 60 year-old Caucasian based in Asia had a longstanding arthritic right hip (a). He required hip surgery and an expedient turnaround to return home. Minimally invasive surgery was performed through the anterior approach as in this case(b). Results were excellent and he was able to walk in 3 hours as in this case (c). Such patients are able to squat (d) which is important for the use of toilets in the countryside in Asia and perform extremes of abduction allowing him to get on and off a bicycle (e). The added advantage of ceramic liners allows for long distance cycling with minimal wear (f).
Figure 3. With the MIS anterior approach, the patient is often able to ambulate almost immediately after surgery reducing the risk of problems associated with prolonged bedrest (ie. pneumonia, urinary tract infections, deep vein thrombosis, etc).