Revision PAO

Many patients are told after unsuccessful pelvic osteotomy that there are only two options: wait, or have a hip replacement. That is often not true. If the socket is not in the right position, it can be corrected a second time.

The goal of every PAO is to position the socket so that it covers the femoral head correctly – not too little and not too much. Both can cause problems:

• Undercorrection: the socket still does not cover the head enough. The overload at the rim remains, and so does the pain.
• Overcorrection: the socket covers the head too much. When bending, the femoral neck hits the rim of the socket – called impingement. This causes pain and damages cartilage and labrum.
• Wrong rotation (retroversion): the socket is turned backwards. There is too much coverage at the front and too little at the back. Groin pain when sitting and bending is typical.

Often there is a combination. In PAO, the position of the socket determines the result more than anything else – and it is also the technically most difficult part.

• Hip arthroscopy (keyhole surgery): this can treat damage inside the joint, for example to the labrum. But it does not correct the wrong socket position. After PAO, arthroscopy results in studies are therefore often disappointing.
• Hip replacement: the right solution in advanced osteoarthritis. In young people with cartilage that is still good, however, it is a big step – a prosthesis does not last a lifetime, and each revision becomes more complex.
• Revision PAO: the socket is released again and brought into the correct position. Your own joint is preserved. The prerequisite is that the cartilage is still in good enough condition.

We have scientifically analysed the results of revision PAO in Greifswald and published them in Bone & Joint Open in 2026. We compared patients with revision PAO to patients with a first PAO.

Key results:

• Before revision, patients had clearly more pain and worse hip function than patients before a first PAO – a failed first operation is a real burden.
• After revision PAO, pain, function and activity improved significantly. Pain on a scale of 0 to 10 fell on average from 7 to about 3.5.
• The socket could be positioned just as precisely as in a first PAO. Scarring and changed anatomy after the first operation did not compromise the correction.
• The amount of improvement was comparable to a first PAO. The final result was on average somewhat lower – mainly because the starting point was worse.
• No nerve injury, no fracture of the posterior column, no blood transfusion.

Other major centres report similar results: even after a previous pelvic osteotomy, a second PAO clearly improves pain, function and quality of life, although usually not quite to the level of a first PAO.

A revision PAO is more demanding than a first PAO. For you, this means:

• The operation takes longer – about twice as long as a first PAO.
• More screws are usually needed to fix the socket securely.
• The hospital stay, on the other hand, is hardly any longer.
• The pubic bone heals with delay somewhat more often. In our analysis, however, nobody needed another operation because of this.
• Expectations should be realistic: most patients improve considerably, but not everyone becomes completely pain-free.

Results are best when the hip still works well before revision, body weight is in the normal range, and the front of the socket is adequately covered again. The earlier you come, the better your chances. Do not wait for years if your symptoms after a pelvic osteotomy are not improving.

In a revision PAO, nothing is ‘textbook’ anymore: the bone has already been cut and healed, there is scar tissue, old screws and changed anatomy. The socket still has to be positioned with millimetre precision.

In Greifswald we perform more than 300 PAOs per year and have more than 15 years of intensive PAO experience. Patients come to us from all over Germany and abroad after a first operation elsewhere. All revision PAOs in our study were performed by one experienced high-volume surgeon.

Send us your records. For an initial assessment we need:

• Operation report of the first pelvic osteotomy
• X-rays before and after the first operation, if available
• A current AP pelvis X-ray while standing and an axial X-ray of the hip
• Ideally a current MRI of the hip to assess the cartilage
• A CT scan, if one already exists

We will tell you honestly whether revision PAO makes sense – or whether another option suits you better. Write directly to Prof. Wassilew at Ortho-terminvergabe@med.uni-greifswald.de. Appointments can be requested at Ortho-terminvergabe@med.uni-greifswald.de.

• Fischer M, Nitsch A, Goronzy J, Kasabji F, Hofer A, Wassilew GI. Revision periacetabular osteotomy enhances joint function and activity level after failure of redirectional pelvic osteotomy at skeletal maturity. Bone Jt Open 2026;7(7):882–889.
• ANCHOR Study Group. Does previous pelvic osteotomy compromise the results of periacetabular osteotomy surgery? Clin Orthop Relat Res 2015.
• De La Rocha A, Sucato DJ, Tulchin K, Podeszwa DA. Treatment of adolescents with a periacetabular osteotomy after previous pelvic surgery. Clin Orthop Relat Res 2012.