Clinical Studies


March 2016

A new clinical study will begin in the 1Q 2017 in a second clinical center in Rambam hospital in Haifa Israel. This study will include 15 patients.

October 2016

So far 64 patients were included in the clinical trial.

The surgery was performed for the first time on young patients aged 42-45.

3.5.2013 1

Ossis company in New Zealand Implanted 50 Polyimide MP1™ acetabular Liners manufactured by MMATECH Ltd. on Ceramic femoral heads in various patients during the period of January 2013 till April 2016.

The surgeries were conducted by Dr James Burn FRACS , specialist orthopedic surgeon, in Christchurch, New Zealand.

The total number of surgeries planned for this clinical study is 100

Recruitment of patients is planned to be finalized by the end of 2016 or by the beginning of 2017.

Up-to-date all patients were released from hospital after 4 days. All primary reports were excellent with no adverse events.

Funding was provided by the COBRA research group. Cobra is in charge of the regulatory aspects and clinical support.

The clinical database is held securely in NZJR (New Zealand Joint Register).

Reports are available to the Ethics Committee at agreed timetables.



Surgeon: Dr James Burn FRACS(Ortho )

Title: Specialist Orthopedic Surgeon, Christchurch, New Zealand

First Patient : MP-1™ LINER SURGERY 20.11.06

Ms P C 63 years old

25.2.97 Bilat OA of the hips

6 .10.98 Left Total Hip Replacement Spectron cemented stem size 2 high offset with +4 mm 28 mm zirconia ceramic head

( S and N) and Duroloc 50 mm od./ Enduron pressfit cup (J and J)

4.5.99 Right THR Spectron cemented stem size 2 high offset again, 0 zirconia 28 mm head and duroloc 50 mm cup and enduron liner.

23.9.05 wear demonstrated in follow up films. Heads eccentric in acetabulum.

28.2.06 Revision of right hip to Reflection alumina ceramic on ceramic 32 mm articulation and new stem recemented in the same cement mantle and grafting of the defects medially with washed femoral head allograft. Partial weight bearing for 2 months due to the extent of bone loss medially. Cement used, Simplex antibiotic ( Stryker)

20.11.06 Revision of the left hip to new spectron size 2 high offset and +4 32 alumina ceramic head with a 52 Refection shell (Smith &Nephew)with 32 mm id MP-1POLYIMIDE LINER. Cement as above.

Histology showed no infection but polyethlyene debris from he previous surgery and 5 day cultures all clear for infection.

Patient discharged home day 3 post op and doing well. To be reviewed at 5 weeks. No transfusion required and patient weight bearing 50% for first 5 weeks. precautionary only. Grafting of the

proximal femoral medial defect with auto graft from acetabular reamings.

6 months Follow up- 6.4.07

Blood test result – Excellent results

X-RAY – Excellent results

3 years follow up -29.10.09

Blood test result – Excellent results

X-RAY –excellent results(see below)

Harris Score – excellent results

X- RAY Follow up – 3 years, the MP1™ liner is on the left side.

6 years Follow up- 6.10.12

Blood test result – Excellent results

X-RAY – Excellent results

Harris score: 100


Post THRs bilaterally. Routine follow up.


Acetabular and femoral components of the bilateral THRs and bilateral acetabular screws remain good and unchanged position.

Minimal lucency related to the right femoral component proximally is stable.

No evidence of interval complication seen.

9 years follow up -29.10.15

Blood test result – Excellent results

X-RAY –excellent results

Harris Score – excellent results

Second Patient : MP-1 LINER SURGERY 5.9.07

Mr. I D A, 65 DOB: 23.05.1943 CHRISTCHURCH

Accident (10.07.00) -Right femur femoral neck fracture

05.09.07 OPERATION

OPERATION: Removal of right CHS and anti rotation screw -conversion to total hip replacement Synergy/Reflection ceramic polyimide Surgeon: James Burn Anaesthetist: Mr C O

Hospital: Burwood Hospital

PROCEDURE: General anaesthetic, patient positioned right side up, the hip was exposed through a posterior approach extending into the old scar, the CHS plate and screws were removed -they were very tight and there was an asnis screw which had to be taken out with pliers due to non availability of any suitable screw drivers for this particular implant in Christchurch. The hip was dislocated prior to the final removal of the metalware to make sure there was no spiral fracture risk of the femur. The capsule was released anteriorly and the neck resected, it was collapsed right down due to the avascular necrosis of the head. The leg was short about 12-~5mm. The acetabulum was reamed to 50 and deepened at 49 and a 50 Reflection ceramic shell was inserted, trial liner used, the femur was reamed up to take a Size 13 high off-set Synergy stem. The range of motion was checked with a standard head Size 32 and then the definitive polyimide liner 50 was inserted, the 32 ceramic biolox forte Smith and Nephew head was then applied. The hip was stable in all positions. The capsule was repaired posteriorly with fibrewire through transosseous sutures using the Star drill. The leg was lengthened approximately 11 mm and no change in off-set. Closure over two Lovac drains. Patient has got arterial disease and is for Clexane 20mg daily, Asprin and foot pumps.

Report from Surgeon: Dr. P. James Burn FRACS

Mr A is a 65 yr old retired air traffic controller who sustained a subcapital fracture of his right femoral neck on 10 July 2000. He under went a compression hip screw fixation at the time. This healed but he was left with a shortened right leg of 10mm and an arthritic hip. Cementless total hip replacement was recommended by myself.

He was offered a ceramic on ceramic hip and as well the possibility of having the 2nd polyimide on ceramic articulation total hip replacement in the world. He chose the latter to help medical science understanding that there were no known toxic effects in animals, but that the tissue response of wear products was unknown, and should this occur he would be changed to ceramic on ceramic.

Surgery was uncomplicated, but his hip was stiff and required lengthening. No modification to a standard surgery or rehabilitation was made. He noticed an occasional “squeak” from his hip in the first 2 weeks and this has disappeared. I postulate this being due to the hip being tight and poor lubrication from no micro-separation occurring. This disappeared and has not returned.

A CT scan was done at 6 months post operatively. This was in response to the patient having some buttock pain which subsequently was considered to be referred from the lower lumbar spine.

The CT scan shows the holes in the acetabular cup for screws ( Smith and Nephew Reflection FSO for ceramic inserts) which have no “blanking” caps. No osteolysis is seen though this is very early but promising.

The patient continues to be asymptomatic with no restrictions and remains under close clinical follow-up. The 9 month blood results are normal apart from a marginally raised gamma GT at 57 IU/L (n 0-50)

Follow up

1 Year follow up -29.10.08

Excellent Blood test results.

X-RAY –Excellent results(see below)

2 years follow up – 14.9.09

Excellent blood tests results

X-RAY –Excellent results

Harris score 100 out of 100.

Clinical report – video film demonstrating excellent walking and climbing steps

(see below).

The 2nd patient died in 2014 from a disease not connected to the implant. He agreed to have histology. The results after 6.5 years of implantation showed:

no osteolysis,
no osteoclasts
no measurable wear
The soft tissues around the hip were very bland without fibrosis or reactive macrophages.

The CT scan of the specimen showed:

no osteolysis even through the cup screw holes.

The MP1 liner implant was undamaged and had no dimensional change after 6.5 years.

Adjacent bone X4 power

“ The adjacent bone shows” minimal remodelling of the cement lines but is essentially normal.

X-RAY Mr IA 1 year follow up

Video film demonstrating excellent walking and climbing steps

5 years follow up – 14.9.12

Excellent blood tests results

X-RAY –Excellent results

Harris score 97 out of 100.

Blood screening (screen, LFTs,U&E, RFTs and CRPs), serial radiographic weight-bearing films, Modified Harris Hip scores and Oxford Hip scores. There have been no features to suggest particle disease and osteolysis, or interference with osseointegration. Wear on magnified weight bearing radiographs is not seen.