This case report describes a 36-year-old male who underwent an AMP for bilateral avascular necrosis of the hips in 1988. He later required a total hip replacement on the left side in 1990. In 2009, following a traffic accident, he suffered a Vancouver B3 peri-prosthetic fracture requiring revision surgery with a Mennen plate and Solution stem. In 2012, a crack was discovered in the original AMP stem, showing signs of metal fatigue after 24 years. The AMP stem had stood the test of time without causing pain.

1. Broken AMP stem
A case report
Vinod Naneria
Girish Yeotikar
Arjun Wadhawani
Choithram Hospital & Research centre, Indore,
India

2. Case summary
• 36 yrs Male had Bilateral AVN hips
• AMP done in 1988 rt side at the age of 36 yrs
• Triad - cemented THR was done on left side in
1990 at the age of 38 yrs.
• Advised revision of cup due to poly wear 2005
• Met with Road traffic accident in June 2007.

3. Case summary
• Vancouver B3 type peri-prosthetic fracture
• Revision THR for shattered femur by Mennen
plate with non cemented Solution hip and
bone grafting in acetabular wall defects.
• Sciatic palsy
• Removal of Mennen plate and wires in April
2009 after fracture union.

4. Case summary
• Persistent pain in hip and knee since revision.
• Hip ultra-sonography in April 2009 – small
pocket – aspiration negative.
• No relief with antibiotics.
• Removal of Solution hip in Sept 2009.

5. Case summary
• Last follow up Nov 2014.
• Showing metal fatigue with broken stem of
AMP.
• Patient has no pain in thigh.
• A crack is seen in April 2012 as a incidental
finding on x-rays.
• AMP stood the test of time.

6. Case summary
• Walking with stick.
• Sciatic nerve is improving with active toes and
ankle dorsiflexion.
• Main complaint was limitation of knee
movement, which is from 0 – 90 degree lt.
• This is due to repeated surgery, muscle scaring
and adherence to bone.
• X-ray knee joint was normal

7. 36 M AVN
AMP – 1988
THR – 1990

8. 14 years post THR

11. Vancouver B3

12. Surgery
• Removal of implant.
• Removal of cement from femur
• Severe bone loss from acetabular walls
• Iliac bone grafts were packed
• Revision of acetabular cup was done and was
fixed with three screws

13. Surgery
• Shaft pieces were approximated with cerclage
wires over a solution stem.
• A Mennen plate was used to hold the pieces
together and further enforcement was done
by few screws and wires.
• Post op sciatic palsy.
• Immobilization continued for 3 months

14. Mennen plate fixation device
CMW Laboratories,
Exeter, England.
Solution Hip Stem
Depuy – J & J

21. June 2012
Incidental finding
Signs of metal fatigue

23. Comments
• Poly wear is a problem in THR in spite of being
a well fixed implant.
• Vancouver type three can be management
with Mennen type plates and wire.
• Non cemented stem needs good quality bone
for incorporation.
• Broken AMP stem is not a failure.

24. Non cemented AMP
• In early AMP stem fracture is due to fixed
distal stem and slight loose proximal head
neck segment.
• The bone has not grown in fenestrations.
• In late AMP stem fracture, the proximal part is
well fixed and the distal part seems loose.
• The bone has grown in the fenestrations.
Cyclic loading

25. References
• Modes of failure' of cemented stem-type femoral components: a radiographic
analysis of loosening.
Gruen TA, McNeice GM, Amstutz HC.
Clin Orthop Relat Res. 1979 Jun;(141):17-27.
Prosthesis & nails are different ball games.
Can galvanic corrosion play a role?
Scratches occurred at screw holes during insertional attempts of interlocking
screws with screw hole acting as a stress riser. Many a times the nail may have
broken long before,Its perceived on the xrays only later.
Prosthesis on the other hand is continuously subjected to cyclical loading.Distally
well fixed prosthesis(typical Gruen's type IV) failure occurs ultimately when the
fatigue limit of the metal exceeds the no. of cyclical loads it can bear.Laser etching
marks(company marks etc)exactly at the high stress zones(i.e upper 1/3 rd & lower
2/3rd area) , air bubbles in the metal alloy typically as occurs in stainless
steel(316L) make the prosthesis more prone to it.
Dr. Mohan M Desai
Professor,Seth GSMC,KEMH,Mumbai

26. Segmental Fracture Of A Cemented Femoral Stem - A
Case Report And Review Of Litrature
R Sen, A Mootha, R Saini, V Kumar
• incidence of 0.23% of femoral stem fracture in arthroplasty.
• Various factors are excessive weight, high physical activity, long
necked prosthesis, varus position of stem, metallurgical defects and
scoring of the stem by a drill bit for wire fixation.
• 316 L stainless steel stems were associated with high incidence of
stem fractures, and expenimental studies on the fatigue strength of
this alloy have indicated a direct relationship to grain size.
• The most common cause of stem failure is considered to be loss of
support by cement and bone in the proximal third, with the stem
subject to cantilever forces that fatigue the metal.
• These cantilever forces are considered to be increased in varus
position of the stem. The antero-lateral side of the stem is
considered to be site with maximum tensile stress and thus most of
the times the fracture line initiates on the antero-lateral surface of
the stem.

27. references
• A 1995 survey study reported 172 stem
fractures out of 64,483 cases (including both
cemented and cementless prostheses), for an
incidence of 0.27%.
• Gruen et al. postulated that cantilever
bending of a cemented stem that is well fixed
distally but loose proximally could lead to a
fatigue fracture.

28. DISCLAIMER
Information contained and transmitted by this presentation is
based on personal experience and collection of cases at
Choithram Hospital & Research centre, Indore, India. It is
intended for use only by the students of orthopaedic surgery.
Views and opinion expressed in this presentation are
personal. Depending upon the x-rays and clinical
presentations viewers can make their own opinion. For any
confusion please contact the sole author for clarification.
Every body is allowed to copy or download and use the
material best suited to him. I am not responsible for any
controversies arise out of this presentation. For any
correction or suggestion please contact naneria@yahoo.com