Surgical Approaches in THR — Posterior, Anterior, Lateral, SPAIRE

Part of The Joint Replacement Guide — Phase 4: The Operation · Article 21 of 44 · Hip

Key Points

  • Several surgical approaches can be used to reach the hip joint, each with potential advantages and disadvantages.
  • No single approach has been shown to be best for every patient.
  • Differences may include the risks of dislocation, fracture, nerve symptoms, muscle weakness and wound problems.
  • Some approaches may offer a modest advantage during early recovery, but differences in pain and function generally become smaller over the following months.
  • The surgeon’s training, experience and ability to perform their chosen approach consistently are important considerations.

What Is a Surgical Approach?

The surgical approach describes the route the surgeon uses to reach the hip joint. The main approaches are from behind the hip, from the front, or through the side. There are also several modifications of these approaches intended to preserve particular muscles or tendons.

The approach is only one part of a hip replacement. Implant selection, component positioning, soft-tissue tension, infection prevention, rehabilitation and the experience of the surgical team can all influence the result.

The terminology is not always used consistently. For example, “lateral,” “anterolateral” and “posterolateral” describe different routes and should not be treated as interchangeable.

Posterior Approach

The posterior approach reaches the joint from behind the hip and is one of the most commonly used approaches to total hip replacement. It provides good access to both the socket and the femur and can be extended if additional exposure is required.

In a conventional posterior approach, some of the short external rotator tendons and the back of the joint capsule are divided to reach the joint. These structures are usually repaired where possible at the end of the operation.

Historically, the posterior approach was associated with a higher risk of dislocation than some lateral approaches. Modern capsular and tendon repair, appropriate implant positioning, larger femoral heads and careful restoration of soft-tissue tension appear to have reduced this risk substantially. However, dislocation risk cannot be eliminated completely and may still vary according to patient, implant and surgical factors.[1,2]

Direct Anterior Approach

The direct anterior approach reaches the hip from the front. It uses a natural interval between muscle groups, which means that major muscles do not usually need to be detached from the bone. This is why it is frequently described as a muscle-sparing approach, although muscles, tendons and other soft tissues can still be stretched or injured during any operation.

Some studies report slightly less pain or faster recovery of walking during the first few weeks after direct anterior hip replacement. These differences are generally modest, and studies have not consistently demonstrated a clinically important advantage in longer-term pain, function, revision risk or implant survival.[3–5]

The approach is technically demanding and has a recognised learning curve. Potential approach-specific problems include numbness or burning over the outer thigh from irritation of the lateral femoral cutaneous nerve. There may also be a risk of fracture around the upper femur, particularly during the learning phase or in patients with difficult anatomy or poorer bone quality.

Some surgeons use a specialised operating table or X-ray imaging during the procedure, although neither is essential in every unit.

Direct Lateral Approach

The direct lateral approach—often associated with the Hardinge technique—reaches the joint through the side of the hip. It involves dividing or lifting part of the abductor mechanism, which includes muscles that help keep the pelvis level during walking.

The approach has traditionally been associated with a relatively low dislocation risk. However, incomplete healing or weakness of the abductor mechanism can occasionally result in a limp, discomfort over the side of the hip or difficulty balancing on the operated leg. Careful repair and rehabilitation are therefore important.

The direct lateral approach remains an established and effective option, particularly where stability is a major concern or where the surgeon considers it best suited to the patient’s anatomy and clinical circumstances.

The SPAIRE Technique

SPAIRE stands for Sparing Piriformis and Internus, Repairing Externus. It is a tendon-preserving modification of the posterior approach, first formally described in 2017.[6]

Instead of releasing all the structures commonly divided during a conventional posterior approach, SPAIRE aims to preserve the piriformis tendon and the combined insertion of obturator internus and the gemelli. The obturator externus and capsule are divided to provide access and are repaired at the end of the operation.

The intended advantages are to preserve more of the muscles and tendons behind the hip while retaining the access and versatility of a posterior approach. Early studies suggest that it is a feasible technique and may support early mobility and hip stability.

However, the evidence remains less mature than for the conventional posterior, direct anterior and direct lateral approaches. Much of the comparative SPAIRE research has involved hemiarthroplasty for hip fractures rather than planned total hip replacement for osteoarthritis. Larger, high-quality studies with longer follow-up are needed before it can be said to provide superior outcomes.

What Actually Matters Most?

Research has not identified one surgical approach that consistently gives the best overall results for every patient. Each approach has a different balance of possible benefits and complications, and apparently small differences in published results can be influenced by:

  • the types of patients selected for each approach;
  • the surgeon’s experience and learning curve;
  • implant choice and femoral-head size;
  • component positioning;
  • repair of the capsule and surrounding tendons;
  • the rehabilitation pathway; and
  • how outcomes and complications are recorded.

National registry studies are valuable because they include very large numbers of operations. However, most registry comparisons are observational. They can show associations between an approach and an outcome, but cannot always prove that the approach itself caused the difference.[1]

A surgeon who is experienced and consistent with a particular technique may reasonably recommend that approach rather than changing to a less familiar technique without a clear clinical reason. This does not mean that approach is universally better; it means that experience forms part of the risk–benefit assessment.

Questions You May Wish to Ask

It is reasonable to ask your surgeon:

  • Which approach do you normally use, and why?
  • How much experience do you have with that approach?
  • Is there anything about my anatomy or health that makes one approach more suitable?
  • Are there approach-specific risks that are particularly relevant to me?
  • Will I need any movement precautions after surgery?
  • What should I realistically expect during the first few weeks of recovery?

The aim is not necessarily to request a particular approach based on its name or how it is marketed. It is to understand why the proposed technique is appropriate for you and whether there are reasonable alternatives.

In More Depth

Some trials have found faster early functional recovery with the direct anterior approach compared with a posterior approach, while others have found only small differences. Where an early advantage is present, it commonly narrows by approximately three to six months.[3–5]

Differences in specific complications may nevertheless remain relevant. For example, the direct anterior approach can cause sensory symptoms involving the outer thigh, the lateral approach can affect the abductor mechanism, and the posterior approach has historically attracted concern about dislocation. These risks depend not only on the skin incision but also on how the deeper tissues are handled, repaired and tensioned.

It is therefore more accurate to say that established approaches can all produce good results in appropriately selected patients than to say that they are identical or carry exactly the same risks.

This article provides general information and does not replace individual clinical advice. The most appropriate surgical approach depends on your anatomy, health, previous surgery and the experience and judgement of your surgical team.

References

  1. National Joint Registry. Annual reports and research concerning hip replacement outcomes and surgical approach. National Joint Registry reports.
  2. Jolles BM, Bogoch ER. Posterior versus lateral surgical approach for total hip arthroplasty in adults with osteoarthritis. Cochrane Database Syst Rev. 2006;(3). doi: 10.1002/14651858.CD003828.pub3.
  3. Zhao HY, Kang PD, Xia YY, Shi XJ, Nie Y, Pei FX. Comparison of early functional recovery after total hip arthroplasty using a direct anterior or posterolateral approach: a randomized controlled trial. J Arthroplasty. 2017;32(11):3421–3428. PubMed PMID: 28662957.
  4. Cheng TE, Wallis JA, Taylor NF, et al. A prospective randomized clinical trial in total hip arthroplasty—comparing early results between the direct anterior approach and the posterior approach. J Arthroplasty. 2017;32(3):883–890. doi: 10.1016/j.arth.2016.08.027.
  5. Wang Z, Hou JZ, Wu CH, et al. Direct anterior approach versus posterolateral approach in total hip arthroplasty: a systematic review and meta-analysis of randomized controlled studies. Orthop Surg. 2020;12(4):1065–1073. PubMed PMID: 32558261.
  6. Hanly RJ, Sokolowski S, Timperley AJ. The SPAIRE technique allows sparing of the piriformis and obturator internus in a modified posterior approach to the hip. Hip Int. 2017;27(2):205–209. doi: 10.5301/hipint.5000490.

← Back to the Joint Replacement Guide · Previous: History of Hip Replacement · Next: Cemented, Uncemented and Hybrid Fixation in THR