 
 
Rehabilitation Protocol for ACI Femoral Condyle 
  
This protocol is intended to guide clinicians through the post-operative course for Femoral Autologous Chondrocyte 
Implantation (ACI), a surgical procedure for the treatment of full thickness chondral lesions of the knee joint. The first 
stage is an arthroscopic procedure in which a sample of healthy cartilage is harvested from a non-weight bearing surface 
of the knee joint.  These cartilage cells are preserved and cultivated onto a scaffolding which is sized according to the 
individual's defect. The second stage (performed openly 3-5 weeks later) involves the implantation of these cartilage 
cells / scaffolding into the defect and sealed with fibrin glue.  The cells grow / mature to eventually form hard cartilage 
tissue over the next 24 months. Overall, the phases of the protocol are based on the 4 stages of cartilage maturation:  
Proliferation, Transition, Remodeling, Maturation. The size and location of an individual’s defect guides the 
rehabilitation progression and may change the duration of the phases. Specific intervention should be based on the 
needs of the individual and should consider exam findings and clinical decision making. The timeframes for expected 
outcomes contained within this guideline may vary based on surgeon’s preference, additional procedures performed, 
and/or complications. If a clinician requires assistance in the progression of a post-operative patient, they should consult 
with the referring surgeon. 
  
The interventions included within this protocol are not intended to be an inclusive list of exercises. Therapeutic 
interventions should be included and modified based on the progress of the patient and under the discretion of the 
clinician.  
 
Considerations for the Post-operative ACI Femoral Condyle 
Many different factors influence the post-operative ACI femoral condyle rehabilitation outcomes, including the origin, 
size, and location of the defect as well as concomitant injury. Additional procedures influencing precautions/restrictions 
include high tibial/distal femoral osteotomy and tibial tubercle osteotomy (TTO). It is recommended that clinicians 
collaborate closely with the referring physician. 
 
 
 
 
 
 
 
 
Massachusetts General Brigham Sports Medicine  
 
2 
PHASE I: IMMEDIATE POST-OP (Day 0 - 6 WEEKS AFTER SURGERY) 
Rehabilitation 
Goals 
• Protect healing graft / tissue (joint surface & wound)   
• Decrease knee / lower extremity (LE) swelling   
• Enhance volitional control of quad  
• Achieve full knee extension 
• Gradually restore knee flexion range of motion (ROM)   
• Restore patellofemoral joint mobility  
Weightbearing 
Status/ Brace / 
Things to Avoid 
Weight Bearing:  
• Weeks 0-4: Touch down weight bearing (20-30%) in locked knee brace 
• Weeks 5-6: Progress weight bearing as tolerated with bilateral axillary crutches in unlocked 
knee brace, unless otherwise directed by physician or based on defect location 
- Progress gradually as long there is no persistent pain / swelling and good gait 
pattern  
 
Brace:  
• Locked at 0 degrees for weightbearing (WB) activities for first 2 weeks 
• Removed for continuous passive motion / exercises 
• Gradually open up brace with WB as quad control improves 
• Can discharge brace at 6 weeks if SLR without lag 
 
Things to Avoid: 
• Closed chain exercises involving knee flexion 
• Open chain extension exercises 
• Forceful motion into pain (some mild pain with passive extension is acceptable) 
Intervention 
Pain/Effusion Management:  
• Electrical stimulation for quadriceps  
• Ice, compression, elevation (check with MD: cold therapy) 
• Retrograde massage  
• Ankle pumps 
 
ROM:    
• Restore full passive extension ASAP 
• Patellofemoral joint (PFJ) mobilization 
• Gradually progress flexion ROM:  
- Week 2: 90 degrees 
- Week 3: 105 degrees 
- Week 4: 115 degrees  
- Week 6: 120 degrees 
 
Continuous Passive Motion (CPM): 
• Start 1 cycle per minute at 0-40 degrees 
• Increase CPM range by 5-10 degrees per day based on tolerance  
• Use CPM 6-8 hrs/day in 2-hour blocks  
• Discharge at week 6 
 
Therapeutic Exercise:  
• Heel prop  
• Gluteal sets 
• Heel slides 
• Supine knee flexion 
• Quad sets 
• Hamstring isometrics 
• Straight leg raise (SLR) 
• Sidelying hip abduction 
• Stationary bike (start at Week 2) 
 
Massachusetts General Brigham Sports Medicine  
 
3 
 
Additional Interventions: 
• Biofeedback for quad/VMO control 
• Blood Flow Restriction Therapy (BFRT) with quad set and SLR after 2 weeks to allow superficial 
wound healing 
• Pool walking – axilla/chest deep (25% body weight at Week 4, if wound fully closed) 
Criteria to 
Progress 
• SLR with no lag  
• Full knee extension 
• Knee flexion >120 degrees by Week 6 
• Normal patellofemoral mobility  
• Controlled swelling 
 
PHASE II: INTERMEDIATE POST-OP (6 – 12 WEEKS AFTER SURGERY) 
Rehabilitation 
Goals 
• Protect healing graft 
• Return to full weightbearing with normalized gait pattern 
• Progress quad strength and lower extremity control  
• Good mechanics without pain during sit to stand, squats, and stair climb 
Weightbearing 
Status / 
Precautions 
Weight Bearing:    
• Weeks 6-9: continue to progress weight bearing as tolerated. Crutches and unlocked knee brace 
as needed to maintain proper gait patten and protect graft 
- Progress gradually as long there is no persistent pain / swelling and good gait pattern  
 
Precautions:  
• No weightbearing flexion >90 degrees 
- Anterior Femoral Condyle Lesions: May perform exercises in deeper range of motion 
(not >90 degrees) but avoid hyperextension 
- Posterior Femoral Condyle Lesions: Avoid exercises in flexion >45 degrees until Phase III 
Additional 
Intervention 
*Continue with 
Phase I 
interventions as 
indicated 
Therapeutic Exercise: 
*ensure proper dynamic control with all exercises to avoid excessive shear on joint 
• Standing heel raise 
• Bridging 
• Terminal knee extension 
• Short arc knee extension 
• Mini squats, Wall slides, Sit to Stand 
- Begin at Week 8 for anterior grafts, Week 12 for posterior grafts 
• Step ups 
• Lateral step down: begin at Week 10 (0-45 degrees flexion at most for posterior graft until Week 
12)  
• Resisted side stepping (band at thighs) 
 
Balance/Proprioception Exercise:  
• Single leg balance: begin at Week 8 
- Static – shoes on / eyes open 
- Varied surface  
- Vision – eye / head movements, eyes closed 
- Task (throw and catch)  
• Single leg balance with lower extremity swings 
• Single leg balance with upper extremity reach: Begin at Week 10 
 
Aerobic Exercise: 
• Stationary bike – continue to build time with minimal resistance 
• Deep water running 
• UBE 
 
Massachusetts General Brigham Sports Medicine  
 
4 
Criteria to 
Progress 
• Full knee ROM 
• Minimal/no swelling at baseline 
• Normal gait mechanics 
• Pain-free sit to stand and alternating stair climb with normal mechanics  
 
 
PHASE III: LATE POST-OP (12 – 24 WEEKS AFTER SURGERY) 
Rehabilitation 
Goals 
• Protect healing graft 
• Progress single leg strength, control, and load tolerance 
• Initiate aerobic exercise  
• Progress balance/proprioception work in all 3 planes of motion  
Precautions / 
Things to Avoid 
Precautions: 
• Significant pain during activity 
• Significant swelling after activity 
• Post activity soreness > 24 hours 
 
Things to Avoid: 
• Exercises into knee flexion > 90 degrees 
• Plyometrics 
• Cutting/pivoting 
• Sport-specific activities 
Additional 
Intervention 
*Continue with 
Phase I-II 
Interventions as 
indicated 
Therapeutic Exercise:  
• Single leg heel raise 
• Single leg dead lift 
• Leg press <90 degrees flexion 
• Single leg squat  
• Seated hamstring curl machine 
• Mini lunge <90 degrees flexion 
• Lateral lunge <90 degrees flexion 
 
Balance/Proprioception Exercise:  
• Progress single leg balance with lower extremity reaching 
 
Aerobic Exercise: 
• Elliptical  
• UBE 
• Aqua jogging 
• Stationary bike 
Criteria to 
Progress 
• Bilateral squat to 90 degrees flexion with good mechanics without pain 
• Single leg squat depth to at least 60 degrees knee flexion with good control without pain 
• All activities of daily living (ADLs) performed without pain or swelling 
 
PHASE IV: ADVANCED STRENGTHENING (6-9 MONTHS AFTER SURGERY) 
Rehabilitation 
Goals 
• Hamstring and calf strength within 80% of the contralateral limb 
• Ability to ambulate long distance (5-10 km) without pain 
• Ability to effectively negotiate uneven terrain 
• Return to pre-operative low-impact recreational activities 
Additional 
Intervention 
• Progression of phase II-III exercises incorporating increased knee flexion (now permitted to flex 
>90 degrees as appropriate) 
Criteria to 
Progress 
• No effusion/pain after exercise 
• Return to low-impact recreational activities without pain or swelling 
• Ability to perform bilateral and single leg squat in increased range of motion with good control 
without pain 
• LSI of Quads, Hamstring and Glute Med all >80% 
 
Massachusetts General Brigham Sports Medicine  
 
5 
 
PHASE V: EARLY RETURN TO SPORT (9-12 MONTHS AFTER SURGERY) 
Rehabilitation 
Goals 
• Quadriceps strength within 90% of the contralateral limb 
• Ability to perform all activities of daily living pain free 
• Initiate return to running program 
Additional 
Intervention 
*Continue with 
Phase II-IV 
interventions as 
indicated 
• Begin sub-maximal sport-specific training in the sagittal plane 
• Initiate small hops beginning double leg and progressing to single leg, gradually increasing 
impact 
• Interval running Program 
- Return to Running Program 
- Can begin when above criteria are met as well as able to perform small SL vertical hop 
with proper form 
• Progress to plyometric and agility program 
- Agility and Plyometric Program 
Criteria to 
Progress 
• Clearance from MD and ALL milestone criteria have been met 
• Completion of jog/run program without pain/effusion/swelling 
• Functional Assessment: 
- Quadricep/hamstring/glute index >90% HHD mean or isokinetic testing at 60 
degrees/second 
- Hamstring/quad ratio >66% 
- Hop testing >90% compared to contralateral side, demonstrating good landing 
mechanics 
 
PHASE VI: UNRESTRICTED RETURN TO SPORT (12-18 MONTHS AFTER SURGERY) 
Rehabilitation 
Goals 
• Continue strengthening and proprioceptive exercises 
• Symmetrical performance with sport-specific drills 
• Safely progress to full sport  
Additional 
Intervention 
*Continue with 
Phase II-V 
interventions as 
indicated 
• Multi-plane sport-specific plyometrics program 
• Multi-plane sport-specific agility program 
• Include hard cutting and pivoting depending on the individuals’ goals 
• Non-contact practice → full practice → full play  
Criteria to 
Progress 
• Functional Assessment: 
- Quadricep/hamstring/glute index >90% HHD mean or isokinetic testing at 60 
degrees/second 
- Hamstring/quad ratio >66% 
- Hop testing >90% compared to contralateral side, demonstrating good landing 
mechanics 
• KOOS-sports questionnaire > 90%  
• International Knee Committee Subjective Knee Evaluation > 93 
   Revised 12/2022 
 
Contact 
Please email MGHSportsPhysicalTherapy@partners.org with questions specific to this protocol 
References: 
 
 
1. 
Edwards PK, Ackland T, Ebert JR. Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral 
joint. J Orthop Sports Phys Ther. 2014 Feb;44(2):102-19. doi: 10.2519/jospt.2014.5055. Epub 2013 Oct 30. PMID: 24175609. 
2. 
Hurley ET, Davey MS, Jamal MS, Manjunath AK, Alaia MJ, Strauss EJ. Return-to-Play and Rehabilitation Protocols following Cartilage Restoration 
Procedures of the Knee: A Systematic Review. Cartilage. 2021 Dec;13(1_suppl):907S-914S. doi: 10.1177/1947603519894733. Epub 2019 Dec 19. 
PMID: 31855062; PMCID: PMC8808781. 
3. 
Krych AJ, Robertson CM, Williams RJ 3rd; Cartilage Study Group. Return to athletic activity after osteochondral allograft transplantation in the knee. 
Am J Sports Med. 2012 May;40(5):1053-9. doi: 10.1177/0363546511435780. Epub 2012 Feb 7. PMID: 22316548. 
4. 
Nho SJ, Pensak MJ, Seigerman DA, Cole BJ. Rehabilitation after autologous chondrocyte implantation in athletes. Clin Sports Med. 2010 
Apr;29(2):267-82, viii. doi: 10.1016/j.csm.2009.12.004. PMID: 20226319. 
5. 
Reinold MM, Wilk KE, Macrina LC, Dugas JR, Cain EL. Current concepts in the rehabilitation following articular cartilage repair procedures in the 
knee. J Orthop Sports Phys Ther. 2006;36(10):774-794. doi:10.2519/jospt.2006.2228 
 
Massachusetts General Brigham Sports Medicine  
 
6 
6. 
Tyler TF, Lung JY. Rehabilitation following osteochondral injury to the knee. Curr Rev Musculoskelet Med. January 2012. doi:10.1007/s12178-011-
9108-5 
7. 
Wagner KR, Kaiser JT, DeFroda SF, Meeker ZD, Cole BJ. Rehabilitation, Restrictions, and Return to Sport After Cartilage Procedures. Arthrosc Sports 
Med Rehabil. 2022 Jan 28;4(1):e115-e124. doi: 10.1016/j.asmr.2021.09.029. PMID: 35141543; PMCID: PMC8811518. 
 
