Abstract
Introduction
Fixed Flexion deformity (FFD) is a common deformity amongst patients due to undergo TKR. For their correction surgical algorithm is documented. Resection of distal femur and clearing off posterior recess are two essential steps. In balancing these knees it is suggested to resect extra distal Femur to gain extension space.
Aim
To demonstrate full FFD correction without resecting extra distal Femur.
Methods
In this prospective study during the yr. 2009–2010 32 cases were recruited. All the cases were performed by the author and a PS design of the implants were used.
Inclusion Criteria
All cases of Gr2 deformities. (OA or Inflammatory arthropathy.)
Exclusion Criteria
Patients with h/o previous injury, fractures, surgery (ies).
Surgical Technique
Distal Femur is resected as per distal thickness of the implant to be inserted (9 to 11mm). Standard Tibial cut & Femoral AP cut are made using the mechanical jigs. Thus flexion and extension spaces are created. If extension space is tight at this stage, Posterior release is done. Posterior osteophytes are resected and capsule is reflected off the posterior Femur. If FFD still persists then temptation to resect extra distal femur is avoided.
A further more aggressive posterior release is performed. In stepwise manner following structures are addressed. Posterior ledge of the femoral condyles is resected with a curved osteotome. Capsule is reflected further proximally and if need be then resected horizontally at the level of the Tibial resection. Thus extension space is equalized to the flexion space. (Video clipping)
Results
Out of 32 Knees 24 were OA and 8 Inflammatory arthropathy. 27 pt.s were females and 5 were males. Mean age at operation 64.5 years (52.1 to 82.7 yrs) Pre op KSS score was 51 (28 to68). Mean post op KSS 90 (72 to 96).
All but 2 pt.s had full correction of FFD intra op and remained corrected at mean average follow up of 1yr. The patients maintained a night splint for 1 month. They were encouraged to perform static and dynamic quadriceps exercise from day 1.
2 patients had residual 5 degree FFD at the end of the operation. Of this 1 patient was neutral at 1 yr. follow up. One continued to have 5 degrees FFD.
Discussion
FFDs correction requires a careful planning of surgical steps. In following Gap balancing technique, to achieve extension space sometimes there can be erroneous Distal Femoral resection. We have demonstrated here that by addressing posterior structures more aggressively we can achieve extension space equal to flexion space. There are certain advantages of not resecting extra distal Femur namely…
No elevation of Joint line and hence preventing Midflexion laxity
Mismatch of components size of femur and Tibia is prevented
In very small knees (Asian patients) damage to collateral ligament insertion is prevented.
Conclusion
In this study all the patients had full correction. There are clear advantages of not resecting extra distal Femur. We continue to use this technique for Gr.2 FFDs. We suggest change in the current algorithm for correction by not removing extra distal femur.
