Article Summary: Post-Operative Sport Participation and Satisfaction with Return to Activity After Matrix-Induced Autologous Chondrocyte Implantation in the Knee

Post-Operative Sport Participation and Satisfaction with Return to Activity After Matrix-Induced Autologous Chondrocyte Implantation in the Knee

Purpose: 

• To investigate: 

1. The level and improvement in activity in patients at two years after matrix-induced autologous chondrocyte implantation (MACI), 
2. What factors are associated with post-operative (and improvement in) activity level, and 
3. Whether patients are satisfied with their ability to participate in recreational and/or sporting activities."

Methods:

• Study Design: 

• Prospective Cohort (level of evidence: 3)

• Population: 

• 150 patients that underwent MACI (Started with 160 but 10 were unable to be found for 2 year follow up so were excluded)
• 83 tibiofemoral lesions
• 63 medial femoral condyle
• 20 lateral femoral condyle
• 67 patellofemoral lesions
• 35 patella
• 32 trochlea
• 92 patients had undergone prior surgery, most commonly arthroscopy and meniscectomy (88 arthroscopy, 61 meniscectomy, assumed that all meniscectomies are also in the arthroscopy group)
• Patients recruited from July 2005 - April 2014
• Age: 15-65
• Pre-op MRI performed to determine location, size and severity of chondral defect.
• No MACI in presence of ligamentous instability unless it was to be addressed during surgery
• 40 participants (26.7%) had another concomitant surgery along with their MACI.
• Most common was lateral patellofemoral retinacular release with anteromedial tibial tubercle transfer (TTT) (n = 26)
• All PF realignment procedures were in the group with PF MACI.
• Excluded if: prior extensive meniscectomy (>1/3 of meniscus), inflammatory arthritis and/or varus/valgus lower limb malalignment (> 3 degrees of TF anatomic angle)
• Who performed the surgeries?: 6 different orthopedic surgeons (at least 8 years of experience each)
• Deemed suitable for MACI IF:
• Grade III - IV unipolar chondral lesion (using International Cartilage Repair Society Classification)
• For more information, view the ICRS Cartilage Injury Evaluation Package

• Surgical Procedure:

• Graft Harvest / Culture
• Initial arthroscopy to harvest articular cartilage from non weight bearing area of the knee
• Chondrocytes cultured for 6-8 weeks.
• Open Arthrotomy
• Defect prepared and the loaded membrane was fixed to the subchondral bone.

• Post-op Management: 

• Outpatient PT until 12 weeks post-op with ongoing advice and education up to 12 months and beyond.  Rehab performed by 2 primary therapists with 5 total therapists
• Rehab sessions became less frequent after initial 3 months (did not discuss specific frequency up to or after 3 months).
• Home and pool based supplemental exercises were provided (the authors did not discuss compliance with HEP or a pool program)
• View the full rehab guidelines here
• Weight bearing progression:
• Weeks 1-2: 20% BW
• Weeks 3-6: 60% for TF lesions; 100% for PF lesions
• Weeks 7-12: Progress to FWB as tolerated
• For these types of surgeries, it is important to understand lesion location to help better guide exercise prescription and progression. Be sure to get an op-report and discuss lesion location with the surgeon if the op-report is not clear.

• Outcomes:

• Tegner Activity Scale (TAS): pre-surgery and at two years post surgery.
• 0-10 knee function scale: 
• 0 = very low function / disability
• 1 = Sedentary Work
• 2 = Walking forward on uneven ground
• 3 = Light Labor
• 4 = Moderately Heavy Labor and/or light sports 2x/wk
• 5 = Heavy Labor; competitive low impact aerobic type sports; recreational jogging 2x/wk.
• 6 = Recreational sports at least 5x/week; can involve some cutting and pivoting with minimal contact
• 10 = National level / elite sports participation
• When interpreting Tegner scores, it is important to remember that everything above a 6/10 is more based around returning to a very high level. Scores of 7-10/10 deal with high level athletes returning to a high level of sport, often including contact. We would not expect this as the mean, or even desire to achieve this as a goal unless our population was professional or high level college (maybe high school) athletes.
• MDC for Tegner Activity Scale is not known for cartilage repair, but is reported to be 1 ACL and meniscal lesions. 
• View the Lysholm Knee Questionnaire and Tegner Activity Scale here
• Knee Injury Osteoarthritis Outcome Score (KOOS):
• The KOOS is a fairly long questionnaire mostly used for research purposes.  You can view the KOOS here.
• It is broken up into 5 subscales including: Symptoms; Pain; ADL function, sports and recreational activities; and Quality of Life.
• They further analyzed the KOOS Sport Subscale which was more important for this study as they wanted to see ability to return to sport.
• MDC of 10 points for KOOS subscale is commonly used.
• Self-Administered Patient Satisfaction Scale (SAPSS):
• Investigated satisfaction with:
• MACI surgery overall
• Ability to return to recreational activities
• Ability to participate in sport
• Reported as:
• Very Satisfied
• Somewhat Satisfied
• Somewhat Dissatisfied
• Very Dissatisfied

Results:

• View results table here
• Defect size did not seem to affect post-operative Tegner score or amount of improvement in Tegner score
• Larger lesions seemed to be present on the trochlea when compared to the patella but those with trochlear lesions had higher post-op tegner scores than those with patellar lesions (4.5 compared to 3.8)
• Male Tegner scores post-op were higher and improved more from pre-op than women.
• Both those with small and large defects had symptoms for many years prior to getting surgery but those with larger lesions seemed to get surgery a little earlier suggesting that either their lesions were more symptomatic or the surgeons were more likely to pursue surgery in these larger lesions.
• Younger age (< 40 seemed to have slightly smaller defect sizes and also had higher Tegner scores as well as Tegner improvement post-op.
• When comparing PF MACI with and without realignment procedure:
• Without TTT: longer duration of symptoms; smaller lesion size; greater post-op Tegner scores and Tegner score improvement
• With TTT: shorter duration of symptoms; larger lesion size; lower post-op Tegner scores and less Tegner improvement.
• KOOS Sport Results:
• Across the entire cohort:
• KOOS Sport
• Pre-surgery = 27.5 +/- 23.1 (range 0-95)
• At 2 year follow up = 61.1 +/- 27.3 (range 0-100)
• 121 patients (80.7%) improved by > 10 points (deemed MDC)
• 74 TF patients (89.2%)
• 47 PF patients (70.2%)
• Association between TAS and KOOS
• r = .40 (moderate correlation)
• KOOS Sport questions involve disability pertaining to
• Squatting; Running; Jumping; Twisting/pivoting on the injured knee; and Kneeling.
• Difficulty is rated on a 5 point scale ranging from: no difficulty to extreme difficulty.  You do not need to return to high level recreational activities or sport to have a significant improvement in your KOOS Sport so these results can be misleading and if not interpreted cautiously can lead to unreasonable expectations for success due to "improvement" on the the KOOS indicating a "successful" outcome.
• Level of Satisfaction: view here 
• 85% very satisfied or somewhat satisfied with their ability to return to recreational activities
• 66% very satisfied or somewhat satisfied with their ability to participate in sport
• 45/150 (30%) very satisfied
• Mean TAS: 5.18 +/- 1.79 (range 3-9)
• Mean TAS improvement: 1.98 +/- 1.75 (range -3 to 6)
• 54/150 (36%) somewhat satisfied.
• Mean TAS: 3.80 +/- 1.22 (range 1-7)
• Mean TAS improvement: .82 +/- 1.39 (range -1 to 5)
• The mean TAS were about the same in the somewhat satisfied and somewhat dissatisfied with their return to sport (3.80 somewhat satisfied, 3.89 somewhat dissatisfied).

Limitations and Causes for Caution with Interpretation:

• Wide standard deviations across many of the results.  May have been nice to see an "effect size" calculation since that would have taken the large standard deviations into account.
• No 6 month or 1 year follow up to see some shorter term results.  Would especially be nice to have seen the sport subscale scores at 1 year compared to 2 as well as an analysis to see if any of those that returned to sport prior to 1 year or at one year had any adverse reactions that may be linked to early high impact / high volume loading.
• Did not assess pre-injury activity level so unable to report on return to prior level of activity, just the level of activity post-op.  With long duration of symptoms in this population, it may have been good to assess pre-symptomatic level of activity and desired level of activity if knee pain or symptoms were not a factor.
• A lot of patients (26.7%) underwent another surgery at the time of their MACI adding another layer and potential contributing factor to the results.

Author's Conclusions:

• "The TAS and KOOS Sport significantly improved in patients two years after MACI, though only 59% of patients improved ≥1 TAS point. Despite this, 85% and 66% of patients were satisfied with their ability to return to recreational activities and participate in sport, respectively. Age, DOS and gender were associated with post-operative activity. These findings can be used to provide realistic activity expectations to patients undergoing MACI."

My Conclusions:

• This is a good article to frame some fairly reasonable expectations for return to activity and return to sport after MACI.  Causes for concern are the very wide standard deviations of the results which means that if we treat a few of these, there is a chance that some will do great while others....not so much.  It is hard to know what the causes of these wide ranges of outcomes might be.  
• I liked that there was a sample post-operative protocol, but something that I think should be looked into for future studies is standardizing the protocol based on lesion location and size.  A lesion on the medial patellar facet will have a much different progression than a lesion on the posterior lateral femoral condyle that may only engage at flexion ranges > 60 degrees. 
• I really liked how they focused less of their attention on the results of the KOOS sport, and more attention on the satisfaction of the patient.  
• "Meaningful improvements" on many outcome measures do not often indicate a return to desired level of function.  An athlete will always want to return to his or her sport at the highest level possible and undergoing surgery can be a huge risk.  The decision to undergo surgery should not be made solely on the grounds of a surgery meeting the MDC on a subjective questionnaire when the consequence may be never getting to play his or her sport at a high level again.
• Our patients will often come to us looking for some sort of guidance as to whether or not to pursue surgery.  There is a lot of data in this article; and there is a lot of room for speculation and future research of causes for certain results; but it serves as a good starting point for expectations and management of patients that undergo MACI.

Citation:

Ebert, J. R., Janes, G. C., & Wood, D. J. (2020). POST-OPERATIVE SPORT PARTICIPATION AND SATISFACTION WITH RETURN TO ACTIVITY AFTER MATRIX-INDUCED AUTOLOGOUS CHONDROCYTE IMPLANTATION IN THE KNEE. International Journal of Sports Physical Therapy, 15(1), 1.