Dr.A.K.Venkatachalam

MS Orth, DNB Orth, FRCS, M.Ch Orth

Consultant Orthopedic surgeon

Associate professor

Chennai

THR in mal-united acetabular fractures-

role for short stem prostheses

THR in malunited acetabular fracturesIntroduction

Acetabular fractures occur in young patientsTHR requires acetabular reconstruction, bone

grafting and reconstructionLimb length discrepancy needs to be addressed-due

to proximal femoral migration, protrusio, proximal femoral bone loss

Possible to correct LLD on acetabular side with protrusio alone by auto graft, allograft, synthetic bone substitutes, metal

Hence opportunity to preserve bone on femoral side Hence role for short stem femoral prostheses

instead of THR.

THR in mal-united acetabular fracturesMaterials and methods

Case1-25 year male, longstanding mal-united acetabular fracture with protrusio grade 3. Femoral side normal.

Acetabular reconstruction with peripheral cup capture, bone grafting with morsellized femoral head autograft. Cup lateralized to anatomical center

Short stem femoral prosthesis with ceramic on metal bearings

Residual LLD- 1.5cm.

Malunited acetabular fracturesCase 2- 42 year old male, transverse fracture

acetabulum with ORIF.Acetabular reconstruction w/o bone grafting,

short stem femoral and uncemented cup. Ceramic on metal bearings.

No post op LLD.LLD

Mal-united acetabular fractures

Case 3-47 year old female, transverse fracture acetabulum with absorption of femoral head, proximal & central migration with protrusio acetabuli

THR –Acetabular reconstruction with peripheral cup placement, bone grafting.

Femoral reconstruction with THR as head was partially resorbed. Metal on poly bearings

No LLD post op

Mal-united acetabular fractures Case 4- 30 year old male, posterior wall & roof fracture,

proximal femoral head migration. Pre op LLD of three inches

THR with posterior wall & roof acetabular reconstruction with femoral head cortico-cancellous slice, Recon plate on acetabular side, conventional uncemented femur. Ceramic on ceramic bearings.

No post op LLD. Post op sciatic N. palsy

Malunited acetabular fracturesGeneral pre op, op and post op issues with Hip

replacementDiscussion

Myositis ossificans post op.Sciatic nerve palsy. Keep knee flexed during surgery. Limb length discrepancy.? Retention / removal of previous metal ware.Hindrance during acetabular preparation from previous

metal ware. May need screw cutting rather than removal.Bone graft required- femoral autograft, cryo allograft, Synthetic bone substitutes- Hydroxy apatite, Calcium

sulphate Metal restrictors- trabecular metal, Augments, cages.

Cement not preferred as most patients are young. Acetabular reconstruction with Jumbo cups, cages,

augments, restrictors, recon plate, bone graft.

Hip replacement in neglected Acetabular fractures-Discussion

THR has been standard procedure. Uncemented THR preferred as most patients are young.

When gross LLD is present, due to combination of acetabular and femoral fractures, total hip replacement is procedure of choice

If LLD is mainly due to acetabular protrusio and femoral anatomy is preserved, possible to do a short stem hip replacement.

Hard on hard bearings preferred as most patients are young.

Hard on cross linked poly in middle aged.

Malunited acetabular fractures Acetabular side issues

Previous metal work- can be left alone if Myositis present, Other wise can be removed

Pre op swabs for possible wound infection from previous metal ware

Acetabular defects analysed by Paproski classification. Peripheral cup placement in protrusio. Cup should be lateralized. Jumbo cup used. Central bone grafting

Peripheral bone grafting in posterior wall and roof fractures. Roof and wall reinforcement with metal & bone prior to hip replacement.

Possible to use TM augments, but since most patients are young, bone graft preferred.

Cup requires screw fixation rather than Mono block cups. Standard or multi hole shells depending on bone loss.

Malunited acetabular fractures Femoral side issues

LLD may be present from long standing proximal and central migration of proximal femur

Proximal femoral bone loss from AVN, Femoral head & neck bone deficiency due to fracture.

Neck anatomy may be altered precluding short stem prostheses.

Malunited acetabular fracturesRole & advantages of short stem femoral prostheses

Conclusion

Short stem prosthesis are possible when proximal femoral anatomy is preserved, minimal LLD( <2”)

Advantage is femoral bone preservation in carefully selected cases.

Limb length < 1inch can be addressed with variable neck lengths in non modular and modular femoral prosthesis.

Versatility of bearing combinations like ceramics, metal, poly.

Femoral side conversion to primary THR in future eliminating or reducing need for a revision femoral implant.

Increased cost of short stem prosthesis is a factor.