The tribunal has also reprimanded Dr Richard Hocking for attempting to "cover-up" the flawed surgery on the 13-year-old girl by writing a second, more favourable post-operation report once he realised there had been complications.

Dr Hocking, who has since left Canberra and largely given up paediatric surgery, has been locked in a lengthy legal battle with the Medical Board of Australia, which led to a hearing in the ACT Civil and Administrative Tribunal earlier this year.

The tribunal handed down a lengthy decision on allegations relating to two of Dr Hocking's patients on Friday afternoon, finding against him for cutting away bone during the hip surgery, but clearing him on allegations he should not have used an experimental plasma injection treatment on a nine-year-old boy with Perthes' disease.

It also relaxed restrictions on his practice. finding he had retrained, and that a period of close supervision had achieved its purpose.

The 13-year-old girl was referred to Dr Hocking for treating her hip dysplasia, a congenital dislocation or misalignment of the hip, in 2011.

The surgeon told her and her family he would embark on a two-step treatment to repair the hip.

The first stage involved a left hip arthroscopy, a procedure designed to assess cartilage and redirect the surface of the hip socket, where the hip joins with the rounded ball at the top of the thigh bone.

He performed the surgery at Calvary Public Hospital in 2012.

The operation, however, was far from a success.

The young girl reported an irritable hip and a limp, and struggled to recover properly from the surgery.

It was later discovered that bone had been removed from the girl's hip socket, causing a "rapidly progressive joint destructive process".

Her left hip was "critically destabilised" and dislocated.

A total hip replacement was later required.

Dr Hocking, upon becoming aware that a complication had arisen, wrote a second post-surgery report some three to four months later.

The tribunal found that he had tried to recast the surgery in a more favourable light in the second report, which he disguised as contemporaneous.

Dr Hocking had denied removing any bone during the surgery, but that was rejected by the tribunal.

It found his actions in removing bone from on and above the acetabular rim increased the likelihood of hip instability, leading to the rapid deterioration in the patient.

"The Tribunal is aware that unfortunate complications occur in surgery, and are not always due to the technical incompetence of the surgeon," presidential member Elizabeth Symons wrote.

"However... the Tribunal finds that Dr Hocking's conduct fell below the standard of skill, and care reasonably exercised by someone of an equivalent level of training or experience and did amount to unsatisfactory professional performance."

Dr Hocking was cleared over allegations he should not have used an experimental platelet rich plasma injection on a nine-year-old boy with Perthes' disease, a condition with no known cause that inflames the inside of the hip joint.

After the operation occurred, Dr Hocking was referred to the Medical Board for "unwarranted therapeutic experimentation" that placed the patient at risk for no reason.

The tribunal cleared Dr Hocking for using the treatment, finding it was used in Australia for conditions not dissimilar to Perthes' disease, and that the surgeon did not fall below the standard reasonably expected of a medical practitioner.

Dr Hocking will have some remaining restrictions on his registration for the 12 months.

He must discuss complex cases with suitably qualified surgeons before he operates, and must practice within a departmental setting in public hospitals and within a group session when working privately.

Dr Hocking must also organise his major cases to allow for a second surgeon to join in if required.

The surgeon must also prepare a report in June next year to show his compliance with the restrictions.