Isokinetic knee extensor strength deficit following matrix-induced autologous chondrocyte implantation

The biomechanical and functional outcomes of autologous chondrocyte implantation for articular cartilage defects of the knee: A systematic review

PURPOSE

Autologous chondrocyte implantation (ACI) is primarily performed in active, young patients to treat knee pain and functional limitations resulting from articular cartilage injury. Nevertheless, the functional outcomes of ACI remain poorly understood. This systematic review aimed to evaluate the biomechanical and functional outcomes of ACI.

METHODS

Ovid MEDLINE, Embase, and Web of Science were systematically searched using the terms 'Knee OR Knee joint AND Autologous chondrocyte implantation OR ACI'. Inclusion and exclusion criteria were used to screen publications by title, abstract, and full text. Study quality and bias were assessed by two reviewers. Means and standard deviations of all collected variables were calculated and presented in the review.

PROSPERO ID

CRD42021238768.

RESULTS

Nineteen articles including 20 ACI cohorts were included. In general, the average range of motion (ROM) improved with clinical (>5°) and statistical significance (p < 0.05) postoperatively: 130.5 ± 14.8° to 136.1 ± 10.2°. Knee strength significantly improved within the first two postoperative years but remained poorer than control groups at final follow-up. No statistical differences were found between ACI and control groups in their ability to perform functional activities like the 6-minute walk test.

CONCLUSION

Knee range of motion generally improved following ACI. Although, some studies reported that knee strengths remained significantly poorer than healthy controls, particularly >2-years postoperatively, implying that longer-term strength training may benefit patients.However, the volume of research and current level of evidence remain low, thus further research is required to better understand the impact of ACI on knee function and guide future rehabilitative protocols.

Towards Tailored Rehabilitation by Implementation of a Novel Musculoskeletal Finite Element Analysis Pipeline

Tissue-level mechanics (e.g., stress and strain) are important factors governing tissue remodeling and development of knee osteoarthritis (KOA), and hence, the success of physical rehabilitation. To date, no clinically feasible analysis toolbox has been introduced and used to inform clinical decision making with subject-specific in-depth joint mechanics of different activities. Herein, we utilized a rapid state-of-the-art electromyography-assisted musculoskeletal finite element analysis toolbox with fibril-reinforced poro(visco)elastic cartilages and menisci to investigate knee mechanics in different activities. Tissue mechanical responses, believed to govern collagen damage, cell death, and fixed charge density loss of proteoglycans, were characterized within 15 patients with KOA while various daily activities and rehabilitation exercises were performed. Results showed more inter-participant variation in joint mechanics during rehabilitation exercises compared to daily activities. Accordingly, the devised workflow may be used for designing subject-specific rehabilitation protocols. Further, results showed the potential to tailor rehabilitation exercises, or assess capacity for daily activity modifications, to optimally load knee tissue, especially when mechanically-induced cartilage degeneration and adaptation are of interest.

Association Between Isokinetic Knee Strength and Perceived Function and Patient Satisfaction With Sports and Recreational Ability After Matrix-Induced Autologous Chondrocyte Implantation

Background:

Returning to a sound level of activity after matrix-induced autologous chondrocyte implantation (MACI) is important to patients. Evaluating the patient’s level of satisfaction with his or her sports and recreational ability is critical.

Purpose:

To investigate (1) satisfaction with sports and recreational ability after MACI and (2) the role that knee strength plays in self-reported knee function and satisfaction.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Isokinetic knee strength was assessed in 97 patients at 1, 2, and 5 years after MACI to calculate hamstrings-quadriceps ratios and peak knee extensor and flexor torque limb symmetry indices (LSIs). The Sports and Recreation subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS Sports/Rec) was completed. A satisfaction scale was used to evaluate how satisfied the patients were with their ability to return to recreational activities and their ability to participate in sport. Associations between knee strength LSI, KOOS Sports/Rec, and satisfaction with recreational and sporting activities were assessed through use of multivariable linear and logistic regression, with adjustment for confounders. Mediation analysis was conducted to assess the extent to which self-reported knee function mediated associations between strength LSI and satisfaction.

Results:

Satisfaction with the ability to return to recreational activities was achieved in 82.4%, 85.6%, and 85.9% of patients at 1, 2, and 5 years, respectively, and satisfaction with sports participation was achieved in 55.7%, 73.2%, and 68.5% of patients at 1, 2, and 5 years, respectively. Knee extension torque LSIs were associated with KOOS Sports/Rec after adjustment for confounders over 1, 2, and 5 years (5-year regression coefficient, 6.0 points; 95% CI, 1.4-10.7; P = .012). KOOS Sports/Rec was associated with the likelihood of being satisfied at all time points (recreation: 5-year adjusted odds ratio [OR], 2.26; 95% CI, 1.48-3.46; P < .001; and sports: 5-year adjusted OR, 1.98; 95% CI, 1.47-2.68; P < .001). In a multivariable mediation model, the knee extension torque LSI was associated with satisfaction directly (standardized coefficient, 0.16; 95% CI, 0.03-0.28; P = .017) and indirectly via KOOS Sports/Rec (standardized coefficient, 0.19; 95% CI, 0.01-0.38; P = .027), the latter representing 55% of the total association of knee extension torque LSI with satisfaction.

Conclusion:

Knee extensor symmetry was associated with satisfaction in recreational and sporting ability, both directly and indirectly, via self-reported sports and recreation–related knee function. Restoring strength deficits after MACI is important for achieving optimal outcomes.

Rehabilitation before regenerative cartilage knee surgery: a new prehabilitation guideline based on the best available evidence

INTRODUCTION

Focal cartilage defects are an increasingly relevant clinical problem especially in athletes. Cartilage regenerative surgery (CRS) including microfracture and autologous chondrocyte implantation (ACI) to treat such isolated cartilage defects in the knee joint has been well established in the last two decades. In contradiction to high-level evidence concerning the surgical technique, cell-related issues, and clinical results, the knowledge about the optimal rehabilitation process is still sparse although the importance of optimizing the rehabilitation process has recently led to new research focus in this field. The preoperative time frame may be used to start rehabilitation which may fasten the postoperative recovery and optimize clinical outcome ("Prehabilitation"-PREHAB). The aim of this article, therefore, was to review the available literature on prehabilitation concepts and to present a prehabilitation guideline for CRS patients based on the best evidence available.

METHODS

A systemic literature research was conducted on rehabilitation for cartilage regenerative surgery as well as prehabilitation in knee joint procedures. From the available literature a prehabilitation concept was generated and tested in 10 ACI patients.

RESULTS

As the literature search found no studies addressing prehabilitation in CRS patients, an evidence-based PREHAB program has been compiled based on the available evidence from (a) studies addressing postoperative rehabilitation in CRS patients and (b) PREHAB studies on other knee procedures including TKA. This presented prehabilitation guideline has been tested in > 50 CRS patients and was found to be feasible as all of the patients showed a good compliance and were able to perform the protocol as suggested.

CONCLUSION

The presented PREHAB regimen may serve clinicians as a guideline for early rehabilitation of their CRS patients. Obviously, further research is mandatory to quantify its clinical effect and to demonstrate its cost-effectiveness and benefits in surgically treated patients.

Knee Joint Loading in Healthy Adults During Functional Exercises: Implications for Rehabilitation Guidelines

Study Design Controlled laboratory study. Background The inclusion of specific exercises in rehabilitation after knee injury is currently expert based, as a thorough description of the knee contact forces during different exercises is lacking. Objective To quantify knee loading during frequently used activities such as squats, lunges, single-leg hops, walking stairs, standing up, and gait, and to grade knee joint loading during these activities. Methods Three-dimensional motion-analysis data of 15 healthy adults were acquired during 9 standardized activities used in rehabilitation. Experimental motion data were processed using musculoskeletal modeling to calculate contact and shear forces on the different knee compartments (tibiofemoral and patellofemoral). Using repeated-measures analyses of variance, contact and shear forces were compared between compartments and exercises, whereas muscle and average maximum femoral forces were compared only between exercises. Results With the exception of squats, all therapeutic exercises imposed higher forces to the tibiofemoral joint compared to gait. Likewise, patellofemoral forces were greater during all exercises when compared to gait. Greater compartmental contact forces were accompanied by greater compartmental shear forces. Furthermore, force distribution over the medial and lateral compartments varied between exercises. With increased knee flexion, more force was imposed on the posterior portion of the condyles. Conclusion These results suggest that with careful selection of exercises, forces on an injured zone of the joint can be reduced, as the force distribution differs strongly between exercises. Based on the results, a graded exercise program for progressive knee joint loading during rehabilitation can be conceptualized. J Orthop Sports Phys Ther 2018;48(3):162-173. Epub 6 Jan 2018. doi:10.2519/jospt.2018.7459.

Quadriceps Strength in Patients With Isolated Cartilage Defects of the Knee: Results of Isokinetic Strength Measurements and Their Correlation With Clinical and Functional Results

Background:

Recent studies have found a significant deficit of maximum quadriceps strength after autologous chondrocyte implantation (ACI) of the knee. However, it is unclear whether muscular strength deficits in patients with cartilage damage exist prior to operative treatment.

Purpose:

To isokinetically test maximum quadriceps muscle strength and quantify the impact of possible strength deficits on functional and clinical test results.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

To identify clinically relevant muscular strength deficits, 24 patients (5 females, 19 males; mean age, 34.5 years; body mass index, 25.9 kg/m²) with isolated cartilage defects (mean onset, 5.05 years; SD, 7.8 years) in the knee joint underwent isokinetic strength measurements. Maximal quadriceps strength was recorded in 3 different testing modes: pure concentric contraction (flexors and extensors alternating work; con1), concentric-eccentric (only the extensors work concentrically and eccentrically; con2), and eccentric contraction in the alternating mode (ecc). Results were compared for functional performance (single-leg hop test), pain scales (visual analog scale [VAS], numeric rating scale [NRS]), self-reported questionnaires (International Knee Documentation Committee [IKDC], Knee Injury and Osteoarthritis Outcome Scale [KOOS]), and defect size (cm²).

Results:

Compared with the uninjured leg, significantly lower quadriceps strength was detected in the injured leg in all isokinetic working modes (con1 difference, 27.76 N·m [SD 17.47; P = .003]; con2 difference, 21.45 N·m [SD, 18.45; P =.025]; ecc difference, 29.48 N·m [SD, 21.51; P = .001]), with the largest deficits found for eccentric muscle performance. Moderate negative correlations were observed for the subjective pain scales NRS and VAS. The results of the IKDC and KOOS questionnaires showed low, nonsignificant correlations with findings in the isokinetic measurement. Moreover, defect sizes (mean, 3.13 cm²) were of no importance regarding the prediction of the strength deficit. The quadriceps strength deficit between the injured and the uninjured leg was best predicted by the results of the single-leg hop test.

Conclusion:

Patients with isolated cartilage defects of the knee joint have significant deficits in quadriceps muscle strength of the injured leg compared with the uninjured leg. The single-leg hop test may be used to predict quadriceps strength deficits. Future research should address whether preoperative strength training in patients with cartilage defects of the knee could be effective and should be taken into consideration in addition to surgical treatment.

Patient Experiences of Recovery After Autologous Chondrocyte Implantation: A Qualitative Study

CONTEXT

The recovery process after autologous chondrocyte implantation (ACI) can be challenging for patients and clinicians alike due to significant functional limitations and a lengthy healing time. Understanding patients' experiences during the recovery process may assist clinicians in providing more individualized care.

OBJECTIVE

To explore and describe patients' experiences during the recovery process after ACI.

DESIGN

Qualitative study.

SETTING

Orthopaedic clinic.

PATIENTS OR OTHER PARTICIPANTS

Participants from a single orthopaedic practice who had undergone ACI within the previous 12 months were purposefully selected.

DATA COLLECTION AND ANALYSIS

Volunteers participated in 1-on-1 semistructured interviews to describe their recovery experiences after ACI. Data were analyzed using the process of horizontalization.

RESULTS

Seven patients (2 men, 5 women; age = 40.7 ± 7.5 years, time from surgery = 8.7 ± 4.2 months) participated. Four themes and 6 subthemes emerged from the data and suggested that the recovery process is a lengthy and emotional experience. Therapy provides optimism for the future but requires a collaborative effort among the patient, surgeon, rehabilitation provider, and patient's caregiver(s). Furthermore, patients expressed frustration that their expectations for recovery did not match the reality of the process, including greater dependence on caregivers than expected.

CONCLUSIONS

Patients' expectations should be elicited before surgery and managed throughout the recovery process. Providing preoperative patient and caregiver education and encouraging preoperative rehabilitation can assist in managing expectations. Establishing realistic goals and expectations may improve rehabilitation adherence, encourage optimism for recovery, and improve outcomes in the long term.

A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

Injuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health.

Significantly worse isokinetic hamstring-quadriceps ratio in patellofemoral compared to condylar defects 4 years after autologous chondrocyte implantation

PURPOSE

Detailed biomechanical analysis including isokinetic muscle strength measurements after autologous chondrocyte implantation (ACI) are still rare, but might be of crucial importance for long-term outcomes. The present prospective study was performed to evaluate whether defect location had any influence on clinical and biomechanical outcomes 4 years after ACI.

METHODS

Forty-four patients with full-thickness cartilage defects ICRS grade III B and C underwent ACI and were assigned to two groups, the femoral condyle group or the patellofemoral joint group. Clinical scores were gathered preoperatively and 6, 12 and 48 months after implantation using the International Knee Documentation Committee (IKDC) score and the International Cartilage Repair Society (ICRS) form. Isokinetic strength measurements were performed 48 months postoperatively comparing healthy and operated knee joint of each patient.

RESULTS

Clinical scores (ICRS, IKDC) showed continuous significant (p < 0.05) improvement over the study period for both groups. Isokinetic muscle strength measurements showed significantly reduced maximum strength capacities for the operated knee joint compared to the healthy knee in both groups (p < 0.05). Hamstring-quadriceps ratios of the operated extremity revealed a significant change in physiological muscle balancing (ratios >1.0) based on significantly impaired extensor muscle strength in the patellofemoral joint group.

CONCLUSION

All patients showed significant strength deficits on the operated extremity 4 years after ACI. Furthermore, the patellofemoral compartment in particular showed significantly worse hamstring-quadriceps ratios compared to condylar defects. Consequently, more efforts should be made to restore muscular strength especially of the quadriceps and the rehabilitation protocol should be adjusted accordingly.

LEVEL OF EVIDENCE

II.

Prospective clinical and radiologic evaluation of patellofemoral matrix-induced autologous chondrocyte implantation

BACKGROUND

While matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee chondral defects, there remains little available research specifically investigating its use in the patellofemoral joint.

PURPOSE

To prospectively evaluate the clinical and radiologic outcome of MACI in the patellofemoral joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In 47 consecutive patients undergoing patellofemoral MACI, clinical (Knee injury and Osteoarthritis Outcome Score, 36-Item Short Form Health Survey, visual analog scale for pain, 6-minute walk test, knee range of motion, and strength assessment) and magnetic resonance imaging (MRI) assessments were undertaken before and 3, 12, and 24 months after surgery. The MRI was performed to assess graft infill and determine an overall MRI composite score. Results were analyzed according to (1) the patient sample overall and (2) after stratification into 4 subgroups per implant location (patella or trochlea) as well as whether or not adjunct tibial tubercle transfer for patellofemoral malalignment was required.

RESULTS

The overall patient sample, as well as each of the 4 procedural subgroups, demonstrated clinically and statistically significant (P < .05) improvements over time for all clinical scores. Graft infill and the MRI composite score also demonstrated statistically significant (P < .05) improvements over time, with no evidence of a main effect for procedure group or interaction between procedure group and time. At 24 months after surgery, 40.4% (n = 19) of patients exhibited complete graft infill comparable with the adjacent native cartilage, with a further 6.4% (n = 3) demonstrating a hypertrophic graft. A further 31.9% (n = 15) of patients exhibited 50% to 100% tissue infill, and 17% (n = 8) demonstrated <50% tissue infill. Two patients (4.3%) demonstrated graft failure. At 24 months after surgery, 85% (n = 40) of patients were satisfied with the results of their MACI surgery.

CONCLUSION

These results demonstrate that MACI provides improved clinical and radiologic outcomes to 24 months in patients undergoing treatment specifically for articular cartilage defects on the patella or trochlea, with and without concurrent realignment of the extensor mechanism if required.

Functional outcomes after surgical management of articular cartilage lesions in the knee: a systematic literature review to guide postoperative rehabilitation

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To systematically review the literature relative to muscle performance, knee joint biomechanics, and performance-based functional outcomes following articular cartilage repair and restoration surgical procedures in the knee.

BACKGROUND

Articular cartilage injuries are associated with functional limitations, poor quality of life, and the potential for long-term disability. This review systematically evaluates evidence related to muscle performance, joint biomechanics, and performance-based functional outcomes following articular cartilage procedures, and discusses their implications for rehabilitation.

METHODS

The online databases of PubMed (MEDLINE), CINAHL, SPORTDiscus, and Scopus were searched (inception to September 2013). Studies pertaining to muscle performance, knee joint biomechanics, and performance-based measures of function following articular cartilage procedure in the knee were included.

RESULTS

Sixteen articles met the specified inclusion criteria. Seven studies evaluated muscle performance, all showing persistent deficits in quadriceps femoris muscle strength for up to 7 years postprocedure. Quadriceps femoris strength deficits of greater than 20% were noted in 33% and 26% of individuals at 1 and 2 years following microfracture and autologous chondrocyte implantation (ACI), respectively. Two studies evaluated knee mechanics post-ACI, showing persistent deficits in knee kinematics and kinetics for up to 12 months postprocedure compared to uninjured individuals. Seven studies showed improved functional capacity (6-minute walk test) over time, and 3 studies showed persistent performance deficits during higher-level activities (single-leg hop test) for up to 6 years postprocedure. Five studies comparing weight-bearing protocols (accelerated versus traditional/current practice) following ACI found few differences between the groups in function and gait mechanics; however, persistent gait alterations were observed in both groups compared to uninjured individuals.

CONCLUSION

Significant quadriceps femoris strength deficits, gait deviations, and functional deficits persist for 5 to 7 years following ACI and microfracture surgical procedures. Future research regarding rehabilitation interventions to help mitigate these deficits is warranted. Level of Evidence Prognosis, level 2a-.

Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral joint

Autologous chondrocyte implantation (ACI) has become an established technique for the repair of full-thickness chondral defects in the knee. Matrix-induced ACI (MACI) is the third and current generation of this surgical technique, and, while postoperative rehabilitation following MACI aims to restore normal function in each patient as quickly as possible by facilitating a healing response without overloading the repair site, current published guidelines appear conservative, varied, potentially outdated, and often based on earlier ACI surgical techniques. This article reviews the existing evidence-based literature pertaining to cell loading and postoperative rehabilitation following generations of ACI. Based on this information, in combination with the technical benefits provided by third-generation MACI in comparison to its surgical predecessors, we present a rehabilitation protocol for patients undergoing MACI in the tibiofemoral joint that has now been implemented for several years by our institution in patients with MACI, with good clinical outcomes.

Accelerated weightbearing rehabilitation after matrix-induced autologous chondrocyte implantation in the tibiofemoral joint: early clinical and radiological outcomes

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has become an established technique for the repair of full-thickness chondral defects in the knee, although best patient outcomes appear limited by a lack of evidence-based knowledge on how to progressively increase postoperative weightbearing (WB) and rehabilitation exercises.

HYPOTHESIS

To determine the safety and efficacy of an accelerated WB regimen after MACI in the tibiofemoral joint.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Clinical and radiological assessments were performed in 28 knees at 12 months after MACI to the medial or lateral femoral condyle. Both rehabilitation interventions sought to protect the implant for an initial period and then incrementally increase load bearing. Under the "accelerated" (AR) protocol, patients reached full WB at 6 weeks after surgery compared with 8 weeks for what was considered to be the current "best practice" (CR) WB regimen based on previous research. Assessments included the Knee Injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey (SF-36), visual analog scale, 6-minute walk test, and active knee range of motion (ROM). High-resolution magnetic resonance imaging (MRI) was used to describe the quality and quantity of repair tissue via the assessment of pertinent parameters of graft repair as well as an MRI composite score.

RESULTS

Patients in both groups demonstrated significant improvement (P < .05) in all clinical measures over the preoperative and postoperative timeline from before surgery to 12 months after surgery. The AR group reported significantly better (P < .05) SF-36 physical component scores at 8 weeks and significantly greater (P < .05) KOOS quality of life scores at 6 and 12 months postoperatively. Although no differences (P > .05) were observed between the 2 groups for active knee ROM, the AR group did achieve full active knee extension as early as 4 weeks compared with the CR group at 12 weeks. There was no difference (P > .05) in graft quality as assessed by MRI (MOCART composite score: AR, 3.34; CR, 3.04), with no patients suffering any adverse effects from the implant up to 12 months, regardless of the rehabilitation protocol employed.

CONCLUSION

The AR approach that reduced the length of time spent ambulating on crutches resulted in improved general physical function and quality of life and an earlier attainment of full active knee extension when compared with the CR approach. There were no graft complications ascertained through MRI. This regimen appears safe and may potentially speed up the recovery of normal gait function. A larger patient cohort and follow-up are required to observe long-term graft outcomes.

The feasibility of a 3-month active rehabilitation program for patients with knee full-thickness articular cartilage lesions: the Oslo Cartilage Active Rehabilitation and Education Study

STUDY DESIGN

Case series.

OBJECTIVES

To evaluate the feasibility of an active rehabilitation program for patients with knee full-thickness articular cartilage lesions.

BACKGROUND

No studies have yet evaluated the effect of active rehabilitation in patients with knee full-thickness articular cartilage lesions or compared the effects of active rehabilitation to those of surgical interventions. As an initial step, the feasibility of such a program needs to be described.

METHODS

Forty-eight patients with a knee full-thickness articular cartilage lesion and a Lysholm score below 75 participated in a 3-month active rehabilitation program consisting of cardiovascular training, knee and hip progressive resistance training, and neuromuscular training. Feasibility was determined by monitoring adherence to the program, clinical changes in knee function, load progression, and adverse events. Patients were tested before and after completing the rehabilitation program by using patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation Form 2000) and isokinetic muscle strength and hop tests. To monitor adherence, load progression, and adverse events, patients responded to an online survey and kept training diaries.

RESULTS

The average adherence rate to the rehabilitation program was 83%. Four patients (9%) showed adverse events, as they could not perform the exercises due to pain and effusion. Significant and clinically meaningful improvement was found, based on changes on the International Knee Documentation Committee Subjective Knee Evaluation Form 2000, the Knee injury and Osteoarthritis Outcome Score quality of life subscale, isokinetic muscle strength, and hop performance (P<.05), with small to large effect sizes (standardized response mean, 0.3-1.22).

CONCLUSION

The combination of a high adherence rate, clinically meaningful changes, and positive load progression and the occurrence of only a few adverse events support the potential usefulness of this program for patients with knee full-thickness cartilage lesions. This study was registered with the public trial registry ClinicalTrials.gov (NCT00885729).

LEVEL OF EVIDENCE

Therapy, level 4.