extensor mechanism failures post knee replacement

Causes of extensor apparutus dysfunction 

Patellar  fractures

quadriceps tendon rupture

patellar tendon rupture

patellar button loosening

Patellar  fracture

Conservative is  the main stay unless displaced  fracture or loose button

Complications of internal fixation is high

if the fracture and implant is stable - conservative

 if fracture is stable implant unstable. remove loose implant

 if fracture is unstable and implant unstable

 consider conservative first 

 Remove implant and fix

 or Recently  bypass  patella with  neoligamant and remove the implant if patella is unfixable

 

Synovium - The omentum of knee

 If one can harvest synovium derived MSC to augment  meniscal healing we could find a way in avascular tears. Below is a potential technique to do the same with some early  resul

 The technique 

Involves harvest 2 cm2  synovium from the suprapatellar pouch using meniscal scissors. remove the fat and pass a looped pds or fibre wire sutures  thuogh the synovium

ts

 meniscal signs  _ve at 6 weeks

Atypical peri-prosthetic fracture due to longterm use of bisphosphonates)

 

 Young patient post renal transplant on long term use of oral bisphosphonates post bilateral staged THR at 2 year intervals. 

Classic features of a atypical femoral fracture on the right side and an impending fracture on the left. Medical management of the atypical fracture is still unclear.

                                       

6cm distal fixing wagner stem was used with an ETO.

                                      

                                     

Metabolic workup:

Arthroscopic Assisted Lateral Condyle elevation + Percutaneous CC Screw fixation Tibia

 Scoping  within  a few days with  low gravity flow or pressure  and using the shaver in front of the scope to suck out the clots  to see in front of scope is all always possible. Do not raise flow or pressure as it will break up th clots and compromise vision further due to bernoullis effect .scoping  3 days post injury in low velocity fall like above in 89 year old is possible.

Using cement below the graft adds to support and walking.went  PWB with a valgus unloader brace is possible for immediate mobilisation with only screws to avoid major  plates etc in patients with anticogulants etc. .

Scope and using the  acl jig allows to centralise the guide wire precisely at the depressed area and visualise elevation better than xrays specially mild tilts. A coring reamer over the guide wire within half cm below the   depressed fragment gets you a graft which u can insert under the depressed fragment after elavatio  and seal it below with bone cement or substiute

Reversed images due to introp imaging issues

 

meniscal Tumour???

Patient presents with one year history of pain on sitting cross-legged and pseudo locking of one year duration. clinical stable knee with  doubtful ? lateral meniscal mcmurrys positive

 Mri shows a chondral defect joining the solid enlarged anterior horn with a cyst in front of there meniscal belt. wonder if its a meniscal cyst or something else. Planned for a scopic excision biopsy with OATS

 

Trochleoplasty

Trochlear dysplasia as classified by Dejour gives us a guideline on management

 B and D need removal of the bump and lateralisation of the trochlear groove and deepening plasty. the results as far as dislocation are satishfatory but pain and long term OA chances are still grey

the case below is a 3o year old female with  recurrent patellar instability with lax mpfl and trochlear dyspalsia

 

 

 The Results of  acute reconstruction of multiligament knee injuries are mirroring single ligament reconstruction when done acutely one stage all ligament reconstruction and immediate ROM  with braces.

Medial side acute repairs and now we attempt scope assisted repairs seem to do better than reconstruction.

In  lateral side reconstructions do better. Fibular based if tibiofibular joint is normal (arcerio)-fibular based lcl  and poplitius recon or Kim technique if Tibiofibular  joint is also injures which is a tibiofibular based rconstruction

 We need to add meniscal avulsion injuries to this classification