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Peak Performance Physical Therapy & Sports Training EVIDENCE-BASED PRACTICE UPDATE (October 2023) Reducing Knee Adduction Moment During Gait via PT Exercises: What does the newest evidence say? by Mike Napierala, PT, SCS, CSCS, FAFS Clinical Scenario...What would you do? A 59 yr old female with a 7 year h/o progressive L > R medial knee pain and swelling/stiffness, with no recent trauma episodes, comes in for evaluation and treatment recommendations. Plain films show IKDC Grade C (2-4mm jt space) degenerative changes in medial compartment and mild Grade B changes in lateral compartment. She has a 1+ jt effusion and AROM on L knee is 5-1250 vs R knee at 2-1400 with L PROM ext only to 20. Meniscus provocation maneuvers are (-). Single squat is L 350 limited by pain with palpable crepitus and R is 55° without pain. Her L knee shows mild varus asymmetry vs the R. The patient’s goals are avoiding TKA for as long as possible, resuming doubles pickle ball and bowling (R handed), playing with her 5 and 3 yr old grandchildren, and travelling with her husband including light hiking. My clinical thinking is: Begin NSAID’s, instruct regarding activity modification and FU in 4 wks. Prescribe PT - providing sheet of local providers for ease of proximity. Perform cortisone injection and FU in 4 wks. Prescribe customized PT including biomechanical assessment and exercises, manual therapy, and laser trial. Recommend viscosupplementation injection/series - initiate insurance authorization request if pt agrees. CURRENT EVIDENCE: Cottmeyer DF, Hoang BH et al. Can exercise interventions reduce external knee adduction moment during gait? A systematic review and meta-analysis. Clinical Biomechanics. (109) 2023. 1-8. https://www.clinbiomech.com/article/S0268-0033(23)00195-X/pdf (We’d love to hear your professional insights on this topic. Let me know your thoughts after reading this summary at PT@PeakPTRochester.com or if you have a patient case you'd like to discuss) SUMMARY: Physicians frequently see patients with medial joint OA and associated varus deformity for evaluation and treatment recommendations. Aside from general OA clinical decision making surrounding early handling of which treatment approach makes sense research relevant to this population has considered whether knee adduction forces can be altered with physical therapy. To the extent varus forces are considered a precursor to medial degeneration and not simply a result, these studies become pertinent in this clinical decision making. Cottymeyer et al in the above systematic review and meta-analysis attempt to discern the body of literature on this topic. A first read of their findings easily leads physicians and therapists alike to the conclusion that knee adduction moment (KAM) during gait is not significantly altered by physical therapy exercise; however, in females there may be some effective KAM reduction possible. Only one of the nine final accepted studies showed a significant KAM reduction vs control groups and that one utilized ankle proprioceptive training compared to TENS/hot packs. These conclusions could easily mislead physicians and therapists to ignore more in-depth evaluation and biomechanical treatment approaches in favor of simple, generic “exercise” that fails to address those KAM forces contributing to ongoing pain and deterioration. Like many studies, systematic reviews, and meta-analyses, caution must be used in reading and accepting conclusions as a basis for directing clinical decision making. The authors here, I believe, have overgeneralized the term “exercise” and the included studies did not specifically utilize targeted/customized approaches aimed specifically at evaluation based findings for those patients. Exercises were generic in nature. They mainly focused on strengthening rather than efforts at restoring joint mobility through manual therapy and ROM/stretching of biomechanically relevant pathways that would promote knee abduction capacity (i.e., reversal of existing KAM forces). The hypothesis that generic strengthening, whether at the knee, locally or including hip/ankle muscles as well as a means to alter KAM fails to address the more obvious biomechanical influences directly impacting KAM. The knee cannot experience increased lateral joint loading (i.e. medial unloading) without the hip’s frontal plane adduction and transverse plane IR capacity being available. The same is true for subtalar joint eversion/foot pronation. These ranges of motion are necessary biomechanically for knee abduction directed forces to occur. Physical therapy for medial knee OA cases with and without visible KAM deformity, based on our experience in the clinic with these patients, is often far more successful when biomechanically authentic exercise focused on medial unloading is used. This must include restoration/improvement of hip and ankle frontal/transverse plane capacity that allows for potential knee abduction directed loading. Many failed cases we see that have not improved with more generic therapy approaches utilized in the studies examined above do, in fact, see significant progress when more customized biomechanical approaches are used. Therefore, in this case, I would urge caution in too quickly accepting the conclusions of Cottymeyer et al’s study, which failed to more carefully define that generic strengthening exercises are inadequate at improving KAM with gait, a subtle but critical distinction that can have important impacts on clinical treatment decisions for patients. Background: Knee adduction moment (KAM) is considered a contributing factor in medial knee OA progression and a potential focus of treatment interventions, especially physical therapy exercise intentions. Purpose: This systematic review and meta-analysis is aimed at determining if exercise interventions are effective at reducing KAM during gait. Methods: Nine RCT studies published up until May 2023 met inclusion criteria and yielded 24 effect sizes for exercise vs control groups utilizing numerous subgroups (sex, BMI, exercise type, muscle group targeting, training volume, PT supervision). Findings: The effect size of exercise interventions on KAM during gait was similar to controls (ES=0.004, P=0.946). Subgroup analysis showed studies with females only did show a positive effect size versus those with combined sexes. Author's Conclusion: Exercise may not be effective in altering KAM during gait. Clinicians should consider alternative treatment options for decreasing KAM in patients with medial knee OA and need to explore further the mechanisms for females having a more positive response. THE PEAK PERFORMANCE PERSPECTIVE Physicians frequently see patients with knee OA issues that require careful evaluation and assessment of the best course of treatment. Medial joint degenerative changes are most common and these are often associated with knee adduction deformity. Sharma et al found that knee varus was not only associated with development of incident knee OA compared to valgus deformity but that the risk of progressing medial joint degeneration was greater in the presence of knee varus or adduction. The question arises as to whether non-operative measures prior to TKA or HTO can have any significant influence on knee adduction forces. This study by Cottmeyer et al reviewed existing data on exercise interventions via physical therapy based care and its impact on measured knee adduction moment (KAM) during gait. While their efforts are admirable and valuable to the body of knowledge this study represents another example of how great care must be taken before making sweeping or generalized conclusions about a given modality such as “exercise” because it significantly influences the decision making of both referring physicians along with physical therapists themselves, possibly to the detriment of the patient. Studies up until May 2023 measuring KAM during level walking after exercise interventions were found, involving patients with diagnosed knee OA, and included control groups receiving passive care or no treatment. Out of an initial 1272 studies eventually 9 RCT studies met criteria for meta-analysis. Hedges g Effect Size was calculated. Moderator variables examined included sex, muscle groups targeted, type of exercise (strength vs neuromuscular) , PT presence (supervision) level, BMI, and training volume of intervention group. Hip and ankle targeted exercise approaches were too few to be included in ES assessment. Of the 15 “intervention groups” subsets of data developed there were 10 performing exercise supervised by a PT and 5 without a PT. Adherence/attendance varied from not reported up to 100%. Cottmeyer et al’s meta-analysis found only one of the nine studies showing significant reduction of KAM - found with 1st and 2nd peaks during gait for the ankle proprioception training group vs the TENS/hot packs control group. The subgroup analysis showed sex, specifically only females, had significant ES vs studies with males + females. No other moderator variables were found significant. The authors concluded that while exercise in general does not appear effective at reducing KAM during gait that it may reduce KAM for females specifically. While on the surface this study seems in line with prior published literature indicating KAM cannot be altered by exercise interventions (ie PT) these conclusions break the rules surrounding external validity in a significant way that can negatively impact physicians’ perspectives on the potential value of PT in OA cases and also may serve to hasten the tendency toward higher level medical interventions that also themselves have limited efficacy based on current research evidence and also carry with them greater costs and sometimes risk profiles. Careful reading leads us to pumping the brakes on their conclusions in the several important ways. The studied groups were not standardized regarding the amount of knee varus malalignment they began with for entry into the study. Varying levels of knee angulation certainly can impact the lever arm potentiation of greater varus/adduction moment that would increasingly be expected to have lesser potential for modification during or through exercise and resultantly with gait. Another very key factor is that exercise types were highly variable and generic in nature. They did not specifically target contributory or causative areas toward the knee adduction moment - specifically attempting to address optimizing hip adduction, hip internal rotation, and subtalar joint eversion capacities in order to reduce knee varus/adduction tendency. Without these adjacent limb/joint capacities a knee joint cannot be expected to shift loading toward the lateral compartment since the limb is biomechanically tending toward varus alignment without them. The only mediating factor then becomes proximal trunk lean in the frontal plane. The studies did not expressly involve added manual therapy to promote quicker or more effective restoration of those typically reduced ROM areas noted above, nor specific stretching/PROM exercises to that same effect. Knee varus deformity patients consistently, in the clinic based on our experience, demonstrate significant ROM loss in one and often all of those areas. Approaches that lack specific targeting, much like generic PT programs, may help some limited percent of patient cases but will likely miss another substantial subset who did have good rehab potential but were not addressed with customized and biomechanically based approaches. I would caution orthopedists and primary care physicians who may have read systematic reviews like this one or other RCT’s suggesting similar conclusions to be wary of falling into the trap of fully trusting the authors’ conclusions. Deeper questioning often reveals carelessness in overgeneralizing results that can negatively impact how you care for your patients and the outcomes achieved. I’d submit that a better conclusion would have been that “in knee OA cases where variable amounts of KAM in gait are treated with only generic knee exercises do not show clear evidence of significant KAM reduction in gait except potentially for females only - further study is needed for biomechanically based custom targeted approaches that include more clinical care consistent based hybrid/encompassing approaches such as manual therapy/PROM-stretching/strengthening/neuromuscular/functional exercise based care. We frequently find that even acutely during exercise portions, specifically for squat based WB quad strengthening drills, where OA based knee pain is most frequently problematic, that utilizing biomechanically sound movement principles can immediately alter symptoms and afford patients less or no symptoms during mini lunges, split squats, step ups, step downs, leg press, wall/hangback squat etc. type drills. For example, a medial knee OA case will typically have fewer symptoms when lateral loading can be increased and medial loading decreased. This is accomplished in numerous ways by trial and error but often involve trunk lean ipsilaterally, ER of the foot/leg, mild medial drifting of the knee, BUE support across midline, pelvic shifting contra laterally, lateral wedging heel among others. These frontal and transverse plane adjustments, while non-traditional, implement sound biomechanical principles toward the goal of unloading the painful and sensitive medial joint. We often find that in “failed cases” of non-operative OA knee care, these approaches are highly beneficial to the patient in optimizing function and reducing symptoms. The case below illustrates a recent example of this approach. The case below illustrates an example of the opposite issue; predominant lateral joint pain issues with radiographic OA findings plus MRI confirmed degenerative meniscus issues. The same biomechanical principles underlying KAM and preferred lateral joint loading efforts are mutually reversed in this patient’s case. They were found very effective at optimizing comfort during WB squat based strengthening drills and ultimately promoted a dramatic increase in her squat function and resulting ADL capacity. This case demonstrates the value of both a patient focused customized biomechanically authentic treatment, and especially exercise based, program along with ongoing supervised care versus premature transition to a simple HEP alone. THE PEAK PERFORMANCE EXPERIENCE Basilike said: “My pain has really decreased and now I can do stairs more easily and I walked 5 miles in NYC on a recent trip without any pain!!” HX: 78 yr old female with 2+ yrs of progressive (B) knee pain, slightly worse on L, had two prior bouts with physical therapy but only very limited benefit. Several cortisone injections provided up to 2 mo relief and recent gel injections provided only 10% reported net improvement. Subjective: L knee 8/10 and R 7/10 max sx with reported fxn of 25% L and 35% R. CC is desc>asc stairs, walking 1 lap @ Cobbs Hill Reservoir, getting up after sitting 5min. WOMAC 44%. Objective: (*=pain) Eval 6 mo ReEval Flexion AROM 1290 / 1250 1370/1350 Extension AROM 10 / 40 00/10 Isometric Quads 14.2*/16.9* kg 22.2/23.7 kg Ober TFL Mod R> L Very min Hip rot PROM IR>> ER NT Calcaneal Eversion WNL NT Squat 300/400 * (B) 700/600 * (R) SLB Static - R STJ control ↓ Rot’s: F+ control (B) Anterior Stepdowns NT 4” w 5# wts 20x/17x *(R) only Key Findings: R>L lateral joint line tenderness more so than medial jt line along with R knee ITB at LFC as well. Both knees lacked good flexion ROM but extension was mostly limited only on the R knee. Hip PROM rot’s showed IR > ER consistent with retroversion influence but ER was 120/200. TFL tightness was worse on R. Her squat fxn was painful/limited L > R but biomechanical testing for sx reduction showed L improved with frontal + transverse plane knee adduction stimulus via UE reaching/trunk positioning and R w transverse plane knee add stimulus (via opp cross reach) - both consistent with lateral joint unloading techniques. WB DF was slightly limited on R. Treatment: BIW early frequency included manual therapy joint mobilization for R TCJ DF, R knee extension, and prone hip ER. Stretching/ROM work included knee flexion (B), R knee ext, hip ER, functional TFL and R soleus/gastrocnemius. SLB rotational control work promoting pronation deceleration for general foot-ankle control was initiated, consistent also with desire to minimize knee abd forces due to predominant lateral knee sx. A key component in early strengthening was PWB - - - > FWB- - -> eventually externally loaded squat-based PRE. These were consistently found to be pain-free or pain-minimized by producing knee adduction or varus forces utilizing pelvic shift-trunk tipping and rotational pre-positioning of either the foot or opposite UE in order to promote medial joint WB. NWB quad PRE were also incorporated. Outcome: Pt was able to advance from BIW to q1-2wk FU visits and ratings of 80% L and 70% R knee function, including 5 mi walk in NYC w/o issues, improved stairs function, and reduced pain max to L 3/10 and R 3.5/10 at reduced frequencies. WOMAC reduced to 21%. Pt is being DC in the next few wks to her (I) HEP. You can trust the Physical Therapists at PEAK PERFORMANCE to do a thorough evaluation, to search for related but underlying contributing factors to kinetic chain dysfunction, and to design exercise progressions that both respect tissue healing and creatively use biomechanics principles to prevent symptoms and optimize carryover to your patients' functional goals. Call us at 218-0240 to discuss your patient's specific needs. Peak Performance is just minutes away from your patients in Penfield, Fairport, Pittsford, Brighton, Rochester, and of course, East Rochester. We promise Individualized, hands-on and biomechanically appropriate Physical Therapy for your patients. No "one-size-fits-all" approaches. We WILL go the extra mile and "dig deeper" to discover underlying causes for injury risk and delayed recovery using the most advanced Evidence Based methods available and, we’re able to make unique adjustments to exercise prescriptions to speed the return to function and to minimize or prevent symptoms from interfering. No surprises. No hassles. Confident your patient is in the right place. COME VISIT US AT 161 E Commercial St Just 1 mile off 490 exit (585) 218-0240 www.PeakPTRochester.com