The bikini incision: an anterior hip replacement that hides its scar

A bikini incision is a direct anterior hip replacement done through a short oblique skin incision along the groin crease instead of a vertical one down the thigh. It is for patients who want the muscle-sparing anterior recovery and a scar that hides under a swimsuit waistband. Dr. Paul Norio Morton offers the bikini incision for robotic anterior hip replacement at Pacific Bone & Joint in Honolulu; recovery is the same as any anterior hip — walking the day of surgery for most. Individual results vary.

A bikini incision is a cosmetic variation of the direct anterior approach to hip replacement. Instead of the standard vertical incision down the front of the thigh, the skin incision is turned to run obliquely along the natural groin crease — the line a swimsuit or underwear waistband follows. It is comparable in length to a standard anterior incision; what changes is direction and placement, not the surgery beneath it.

The orientation matters because of Langer's lines, the natural tension lines in your skin. Incisions that run with these lines are under less tension as they heal, so they tend to mature into thinner, flatter, less visible scars. A vertical anterior incision crosses those lines and can widen or thicken as it matures; a bikini incision follows them. The result is a scar designed to fade into a crease you already have — visible if you go looking, easy to miss if you don't.

Only the skin incision changes — everything beneath it is the standard direct anterior approach. Once through the skin, the deep exposure runs in the usual direction, between muscle planes, without detaching anything from bone. Every benefit of anterior surgery carries over: less early pain, same-day walking for most patients, lower dislocation risk, and usually no hip precautions.

Dr. Morton pairs the bikini incision with robotic assistance, the same technology he used to perform the first robotic hip replacement in Hawai‘i. The robot's 3D planning and real-time verification of cup position and leg length do not depend on the skin incision's direction — so choosing the cosmetic option costs you nothing in precision, stability, or implant longevity.

The bikini incision was popularized by the Swiss hip surgeon Michael Leunig and colleagues, whose two published comparisons are the standard references. In the first series (Clinical Orthopaedics and Related Research, 2013), 59 patients had an anterior hip replacement through either the classic vertical incision or the new oblique one: the bikini group had objectively shorter and narrower scars and was substantially more satisfied with their appearance, while function, blood loss, cup position, and outer-thigh nerve symptoms were no different.

The larger follow-up (The Bone & Joint Journal, 2018) surveyed 964 patients two to four years after surgery. Hip function scores were the same in both groups; the bikini group reported higher satisfaction with the scar and less numbness in the scar (7.5% versus 14.5%); and implant position, heterotopic bone formation, and revision rates (1.5% versus 2.3%) did not differ. The authors' one caution — that the oblique incision is less extensile, so surgeons should adopt it only after mastering the classic anterior incision — is exactly why it belongs with a surgeon who performs the anterior approach every week.

Like any scar, a bikini incision takes time to mature — expect it to soften and fade over the first year rather than the first month. This is not a trade-off between looks and safety. It is the same total hip replacement, with the incision placed where skin biology and clothing lines both work in your favor.

The bikini incision carries the same risks as any anterior hip replacement — blood clots, infection, fracture, dislocation, leg-length difference, nerve or vessel injury — which the hip replacement guide states plainly. Three points are specific to the incision itself:

• Outer-thigh numbness. The lateral femoral cutaneous nerve, which supplies feeling to the outer thigh, runs near any anterior incision and can be stretched during surgery. Temporary numbness or tingling is the most common anterior-approach nuisance; it usually fades over weeks to months, occasionally persists, and does not affect strength. In the largest bikini series it was reported less often than with the vertical incision, but it can still occur.
• Wound healing in the groin fold. The incision sits in a crease that is warmer and moister than the front of the thigh. For patients with a large overhanging abdominal fold, diabetes, or other conditions that slow healing, Dr. Morton weighs that carefully — sometimes a standard incision is the safer choice.
• Exposure comes first. The oblique incision is slightly less extensile than the classic one. If anatomy demands more room during surgery, Dr. Morton extends or converts to a standard anterior incision rather than compromise implant position — the scar is never allowed to dictate the surgery.

Recovery follows the same timeline as any anterior hip replacement, because underneath the skin it is the same operation. Most patients walk the day of surgery, go home the same day through the outpatient joint replacement pathway or after one night, return to driving around two to four weeks, and are back to most activities by about three months — usually with no formal hip precautions along the way. The first year after hip replacement covers golf, the ocean, and travel month by month.

The incision itself asks only for common sense: keep it clean and dry until it is fully healed, hold off on soaking — including the ocean and pools — until Dr. Morton clears you, and protect the fresh scar from the Hawai‘i sun as it matures. Some bruising and swelling near the groin is normal in the first weeks and settles on its own. Your follow-up visits track both the hip and the scar, so small wound questions get answered early.

Anyone can reasonably prefer a hidden scar, but the bikini incision tends to matter most to patients who are younger, active in the ocean or at the beach, prone to prominent scarring, or simply unwilling to carry a visible daily reminder of surgery. In Hawai‘i, where swimwear is practically a uniform, it is one of the most requested options in Dr. Morton's practice — not a separate procedure, just a decision made with you when the surgery is planned.

What happens next. Bikini-incision hip replacement is planned at Dr. Morton's Honolulu (Ala Moana), West O‘ahu (Kunia), Hilo, and Kona clinics — call (808) 439-6201 or book an orthopedic consultation online. Bring a photo ID, your insurance card, and any prior X-rays; managed-care and Medicaid/Quest plans may require a referral from your primary care physician (insurance plans accepted). When an in-person visit isn't practical, neighbor-island patients can start with a telehealth visit. Dr. Morton reviews your imaging, your options, and what your recovery and your scar are each likely to look like.