The Stiff Total Knee Replacement: Causes, Treatment, and Prevention

1. The Stiff Total Knee Replacement: Causes, Treatment, and Prevention N. Johanson, M.D. I.C.L. Ch. 46, 1997 Reviewed by: K. Ikram, D.O.

2. Introduction • Stiffness is observer dependent • From surgeon’s perspective, it is inadequate or less than expected ROM • Pt who has 90 deg flexion, and within 10 deg of full ext and no complaints of pain or fxnal difficulties in not considered to have a stiff knee

3. If after 1 yr post op, pt has following problems, must evaluate for underlying knee problems • C/o knee stiffness • Difficulty getting out of chair • Pain on climbing stairs • Stiff knee gait

4. Stiffness is closely related to the pts own motivation to gain a fxnal ROM, and his or her willingness to endure pain to achieve that goal. • Stiffness is nearly always present during early postop period, gradually dec over time, and is a valuable marker of improvement throughout the recovery period • Surgical pain is the most imp cause of early knee stiffness

5. Both quads and hamstrings guard • Passive flexion and extension is difficult to perform • Theoretical basis for implementation of in-hosp CPM • CPM has not conclusively demonstrated to shorten the hosp stay or provide significantly increased ROM. • Its value in early post op period is questionable in view of its cost

6. Post op knee stiffness usually subsides within 6-8 wks • Knee ROM improves steadily thru the first 3 months, then less rapid progress seen in next 9 months • If a limited or deteriorating ROM occurs, consider • Infection • Mechanical complications related to soft tissue or implant • Impending arthrofibrosis • RSD

7. Late onset knee stiffness following a relatively symptom-free period may be suggestive of one of the following: • Infection • Overuse synovitis or tendonitis (esp. in younger pt) • Synovitis secondary to rheumatoid arthritis, particulate wear debris or recurrent hemarthrosis • Implant loosening or breakage

8. Infection • Early infection (within first 6 wks) is characterized by swelling, erythema, and generalized pain, with or without drainage. • Late infection more easily recognized b/c it follows a relatively asymptomatic period • Aspiration and culture required to distinguish an indolent infection from other cuases of synovitis

9. Mechanical Problems (Implant/Soft Tissue) • B/c of the wide variety of available implant designs and rarity of severely stiff TKR’s in published series, overall problem remains enigmatic • Dorr found that pts who had obtained excellent clinical results following either PCL retaining or sacrificing designs continued to walk with a stiff knee gain 2 yrs post op • Suggest that TKR rarely produce a completely normal gait

10. The right balance b/n motion, strength, and stability is the surgical goal for a good fxnal outcome. • Inadequate bone resection combined with persistent lig imbalance or tightness may result in knee stiffness • If tightness is recognized, correct by either revising bone cuts, releasing ligaments, or a combination • If flexion contracture, more distal femur removed or post capsular release

11. Approach to bone resection in TKA is dependent on plan to preserve or sacrifice PCL • If PCL preserved, femur is cut first to preserve the level of the jt line and more closely approximate the normal kinematics of the knee • A potentially dangerous pitfall is reversing tilt of the tibia in the sagittal plane thus causing tightening of PCL in flexion if rollback mech fxns according to design

12. Inadequate release of tight capsular and ligamentous structures is an important cause of stiff TKA • Poor flexion and extension may result from inadequate release or recession of a tight PCL • Medial collateral lig in varus deformities and LCL and iliotibial band in valgus deformities often require release to prevent asymmetric implant wear and promote optimal range of knee motion

13. Patellofemoral dysfxn may cause pain that may promote stiffness b/c of disuse. Following patellar conditions should be considered when evaluating stiff TKA: 1. patella not resurfaced 2. inadequate lateral release 3. Asymmetrical cutting of patella 4. Excessive elevation of jt line 5. Int rotation of fem comp 6. Formation of intra-art adhesions 7. Patella fx or comp loosening

14. Excessive wear debri over a given period of time causes synovitis, pain, stiffness, and swelling • Causative factors include: • Poor quality polyethylene • High pt wt and activity level • Failure to remove cement and bone debris from knee jt • Implant design factors (contract stresses, poly distribution)

15. Patient Related factors • Availability and efficiency of in-hosp P.T. has a significant impact on outcome of TKA • With shorter hosp stays, an increasing reliance on outpt and home P.T. services • An important factor is the pts willingness to undergo a rigorous rehab program • Pt preferences, expectations, and satisfaction are important indicators as to the likelihood of obtaining good outcomes from surgery.

16. Pre op education is an important tool for guiding the pt to understanding the goals and risks and benefits of surgery • Educ process gives the surgeon an opportunity to recognize pts with unrealistic expectations or lack of motivation • Host factors that promote arthrofibrosis about the knee jt are not well understood • Inflammatory connective tissue dz have increased incidence of arthrofibrosis

17. Diagnostic Considerations • Most important diagnostic tool in the eval of the stiff TKA is the physical exam • 2 exams should be performed within the first 6 wks to assure acceptable progress with ROM and fxnal status • Plain x-rays should be ordered within the first 6 wks and repeated if stiffness and pain increase. • X-ray findings may include: Inadequate bone resection, oversized fem component, evidence of lig imbalance resulting from asymmetric cement pressurization, or gross maltracking or subluxation of patella

18. Bone scan is indicated in late cases of stiffness • Less useful during early recovery period and throughout first year post op • Cementless implants tend to increase bone scan activity up to 2 yrs • Infection should be ruled out with an aspiration and culture of jt fluid • Neg culture does not absolutely r/o infection • If suspicion high, arthrotomy may be necessary to obtain tissue sample

19. Treatment Alternatives • In a stiff, non infected, radiographically satisfactory TKA, most imp initial treatment is an adequately supervised course of sustained intensive P.T., lasting 3-6 months • If, during the first 3 months, a plateau is reached, manipulation under anesthesia should be considered • Fox & Poss found a group of pts manipulated 2 wks post op and could not see any difference from control at 1 yr post op • Pre op ROM is an imp predictor of post op motion

20. Parsley and assoc reported 17 knees < 75 deg flexion pre op, gained 16 deg post op • 257 knees had > 95 deg flexion and lost a mean of 6 deg of flexion • So knowledge of pre op flexion should assist the surgeon and pt with goals for motion post op • If manipulation does not obtain acceptable ROM, an exploration and debridement may be performed, using open or arthroscopic techniques • Arthroscopy good for localized tethering of patella or patellar clunk syndrome • Results of arthroscopic tx of gen arthrofibrosis have not been as good

21. Revision Surgery • Exchange of modular tibial polyethylene space in conjunction with capsular or ligamentous release may provide improvement of ROM • Deformity should be completely corrected with a new trial spacer in place • If correction not complete, revise tibial and/or femoral components after making new bone cuts.

22. During revision for TKA stiffness, fully release all structures that may have contributed to condition including: • Quadriceps tendon and vastus intermedius adhesion to femur and suprapatella pouch • Medial and lateral gutters • Collateral ligaments • Lateral patellar retinaculum

23. Prevention of Stiff TKA • The most fundamental consideration for prevention of TKA complications in general is the selection of an implant and instrumentation sytem that is complex enough to allow flexibility, yet simple enough to minimize chance for technical error • Based on a published track record of performance over 5-10 yrs • Technical difficulty should be compatible with proficiency and experience of surgeon

24. A design with less inherent stability or constraint will require more exacting bone cuts and ligament balancing to deliver an acceptable result • Applies to many PCL retaining designs • Cemented cruciate substituting designs have more inherent stability and will better tolerate the aggressive ligament releases required to correct severe varus or valgus deformities • Elevation of jt line is also better tolerated in PCL substituting implants

25. Conclusion • Knowledge of pt expectations, goals, and motivations is essential for early detection of potential problems with stiffness following TKA • A poorly motivated pt with little or no pre op education combined with a short hosp stay and marginally delivered home or outpt P.T. constitutes a dangerous mix that may result in a less than optimal surgical result. • More research is needed on this issue.