The Day I Couldn’t Run Anymore: A speed-bump on a long journey

“Though the road’s been rocky it sure feels good to me” – Robert “Bob” Nesta Marley, Jamaican musician, poet and philosopher.

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Running downhill at the end of the Mt Taylor Ultra.  Running in the mountains is a special kind of freedom.  It is not the running, nor just the mountains, but the marriage of the two. The bow legged stride I exhibited in this run is a sure sign of knee damage.

In the fall of 1971 I decided I would run to high school from my home three days a week.  The decision was driven not by any love of running, but rather my desire to get into outstanding shape and prepare me to make the cut for the JV basketball team at Los Alamos High School.  In those days, I lived about 10 miles from school and the run had a gain in elevation of about 1000’; the run was along a road with a wide shoulder, and I could leave in the dark and make up “the hill” before school started.  This well thought out plan to overcome my lack of athletic ability (and complete inability to jump even a few inches off the ground) by having superhuman endurance crashed back into the boneyard of reality after about 3 weeks.  My knees became inflamed, and I hobbled around the basketball court under the disapproving gaze of the coaches that wondered why I did not just stick to the chess club (which I was a member of, by the way).  My mother took me to the family physician, who in turn, sent me to a specialist.  I was diagnosed with Osgood–Schlatter disease (OSD) – inflammation of patellar ligament just below the knee cap.  OSD is relatively common in adolescents, especially boys, who are undergoing growth spurts.  The pain was intense in the quiet dark hours of the middle of the night, and I became well acquainted with ice packs and the bright red color of skin that feels frozen from the cold.  50 years ago, the treatment regime was “rest” and waiting out the growth spurt.  Eventually I could run again, although I never quite gained the super endurance that would allow me to overcome my lack of coordination.

Today it is known that people that have suffered through OSD are much more likely to develop arthritis, or inflammation of the leg joints – knees and hips – in later life. Arthritis is really a description of symptoms, and there are dozens of “types” of arthritis.  I am cursed with osteoarthritis, which causes the cartilage to breakdown over time. For a lucky few (including me), the breakdown of cartilage is accompanied by the growth of bone spurs, especially on sides and beneath the knee cap. These tiny osteophytes are like small thorns on a rose bush – rub them in the wrong way and they cause pain. Realistically, my osteoarthritis is likely the result of heredity. However, I loved playing basketball, and to a lesser extent football, and this combination of osteoarthritis and sports that impacts joints conspired to make me a punch card for surgeries: I have had enough that surely I qualify for a TV advertisement for Stryker, one of the world’s larger manufactures of prosthetics.

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A fews days post surgery in 1989. My son has sympathetic knee pain, and is propping his knee up to relieve the misery.  2nd knee surgery, and the cartilage was 60 percent gone.

On April 25, 2017 I became a full bionic man – well as far as my legs are concerned.  But the journey to having more metal in my body than is present in most modern automobile bodies began in 1976 I when I was playing in a basketball game. My left knee got twisted and I had my first surgery to remove a tear in the cartilage.  I recovered; in 1989 I repeated the experience, but on my right knee. I went into surgery to remove the tear, but once the surgeon looked at the knee he discovered that lack of cartilage had caused scoring of the bone, and decided to refinish, or smooth the bone.  That was a crummy experience, and caused me to have to delay my honeymoon (which had already been delayed for more than a year due to other reasons) – but I was told on no uncertain terms that I could never run again.  I followed that direction for an entire year, and then I was back to playing basketball 5 to 7 days a week.  But, as an insurance policy I took up bicycle riding in a serious fashion and started riding centuries, my introduction to endurance sports.  It turns out I bought the wrong kind of insurance policy, and I had to have my left hip replaced in 1998 at the tender age of 42.  I never played basketball again.

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X-Ray of my right knee, after my 2009 replacement. The grinding joint is replaced with a smooth surface.  The knee cap has be reshaped and all the bone spurs removed.

Eventually, even though I no longer played basketball, I had to have my right knee replaced in 2009.  The refinish job I had gotten 20 years earlier had extended the lifetime of my knee remarkably, but bone-on-bone eventually won out.  The recovery from knee replacement was difficult and humbling; but the result was transcendental.  Within a year I was climbing mountains with ease where I had struggled before. Magic.  In 2012, I started to run trails, and found a true joy.  I knew that there was advice not to run again with a prosthetic, but I also understood the research on the wear and failure was very conflicting (I wrote about running with artificial joints: https://wallaceterrycjr.com/2014/04/29/conventional-wisdom-and-scientific-fact-the-dilemma-for-a-trail-runner/ ). Frankly, I was far more concerned about my natural knee, as I knew it was the evil twin of my knee that had alreay been replaced.  In 2013-2015 I ran between 2200 and 2500 miles per year.  Check ups of my artificial joints showed no ill effects – but I knew that my left knee was slowly grinding to pulp. I could see my knee cap “growing”, and I was having trouble bending my knee enough to walk up or down steep stairs.

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A view down Bat Canyon from the turn around point of the Canyon de Chelly 55 km ultra. the race climbs and then descends about 1000′ over a rocky trail.

A Fateful Run

In October of 2015 I ran a fantastic 55 km ultra through the scared lands of Canyon de Chelly.  The race is a 17 mile out-and-back through a sandy wash; mile 15.5-17 is a steep climb of 1000 feet out of the canyon to the rim (https://wallaceterrycjr.com/2015/10/12/sacred-land-a-run-through-canyon-de-chelly/ ).  After refueling at the turn-around, the course is a dive back into the canyon; steep and rocky.  Within a hundred yards I knew that something was wrong.  My left knee was swollen, and would not bend – so my decent was less a run and more of a hop, stumble, hop.  The first 17 miles took me 3 hrs and 12 minutes; the reciprocal took me almost 5 hours.  After the race I iced the knee, but 12 hours later it was still stiff and unresponsive. I knew that this a clarion signal that “the time had come”.  However, within a week I could run again, and against all rational judgements I began to believe I could “will” my knee to last a few more years.  In cognitive sciences this is called Unrealistic Optimism or Optimism Bias, which is defined as “cognitive states that are unrealistically optimistic are belief states, whether they are false, and whether they are epistemically irrational.” Most people that have the so called type A personality can relate –  it is the illusion of control, an exaggerated belief in one’s capacity to control independent, external events.  There are lots of benefits to unrealistic optimism – many people call this “extreme will power” – but it rarely results in miracles.

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The last race…the Santa Fe Ultra with Dave Zerkle and Dave Dogruel escorting me through 34 miles of up and down, only to finish DFL.

I continued running ultras for the 10 months after Canyon de Chelly.  In fact, I ran 5 races of 50 km or greater, and logged some 2,100 miles in training.  But the expiration date had passed on my left knee (I assign the expiration date to the  Canyon de Chelly ultra), and my run began to more resemble a hobbled wobble than a graceful galloping gait.  My last race was inaugural Ultra Santa Fe race in the Sangre de Cristo mountains above Santa Fe. The race is a circuit from the top of the ridge line at 12,000′ to the juniper covered arroyos at 7,200′ along the eastern margin of the Rio Grande Valley (https://wallaceterrycjr.com/2016/09/20/the-santa-fe-ultra-lost-climbs-friends/?iframe=true&theme_preview=true ).  This is a tough and beautiful event – I really like this race – but for me it was truly the end. I finished the race DFL, and was incredibly fortunate to be escorted by my friends and faithful running companions Dave Zerkle and Dave Doggrel. The will was there, but the way was not.  The day after the race I began to plan my next journey; one final knee replacement, recovery, and then completing the Noles 14 14ers course in 2019 (I am not stupid – I never thought about doing this ridiculous trek in 60 hours; I am shooting for 120 hours!).

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A cartoon depicting the deterioration of a knee due to osteoarthritis.  The loss of cartilage causes the knee to compensate, and often the victim begins to develop a bowleg stance.  The knee also loses its ability to lock.

Knee Surgery Stinks!

I am not particularly special in having a full knee replacement. Nearly 700,000 people have a partial or full knee replacement annually in the US.  Osteoarthritis is the most common joint disease in adults, and its incidence increases with age.  However, the expression of joint damage is usual minor for the vast majority of the population – only about 8% of the American population develops serious damage, and 75% of those are older than age 60.  My superpower is that I can have been able to destroy cartilage from a very young age.  When my hip was replaced in 1998 the surgeon told me I have the strange combination of a hip joint of an 80 year old, and the bones of a 25 year old; the cartilage was gone, but the bone was extremely healthy as measured by density and strength.  I have been struggling joint issues for at least 30 years – and likely this struggle was associated with pain (I say likely because I have a hard time with identifying joint pain). A recent study in the journal Pain (yes, there is a medical journal with the eponymous tag for something we all experience) looked at the human ability to manage long term pain (Brown et al, 2015).  “The experience of pain in humans is modulated by endogenous opioids, but it is largely unknown how the opioid system adapts to chronic pain states….however, our study is consistent with the view that chronic pain may upregulate OpR availability to dampen pain”.  Although the language is particularly opaque, the summary of the study is that for arthritis sufferers the body adapts to the pain.  This seems pretty logical – but it also one of the greatest sources of frustration when one approaches surgery.  Over and over the question the physician, x-ray tech, physician assistant, etc (including the hospital billing agent!) asks is “please quantify the level of pain you are experiencing in your knee.  They ask you to use the chart below as a guide so you can give the pain level with a numerical value.

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This is the famous “pain chart”.  Please quantify your level of pain, and just in case you are having trouble use a mirror and look at your facial expression.

I usually answer “I don’t really have much pain, I just can’t really walk”.  This leads to an downward spiral of a conversation: “Well, if you don’t have pain then we really should not perform surgery”….”But I can’t walk”….”So, is it painful to walk, and how painful”…”Nothing is as painful as this conversation, just frick’in understand I can’t walk anymore”….”I will record that you have a high level of pain”…”Thank you, and I do believe that I presently have a pain in my butt, level 8 (see the slowly blinking eyes and open mouth in the chart above)”.

Despite this loopy dance about joint pain, make no mistake, once you start down the path to knee replacement it is all about pain.  The damaged joint is painful even if you have adapted to the pain – it effects not only the way you walk and sit, but the way you sleep and stand. The ultimate goal is relieve that pain, but the joint replacement is a violent invasion on the knee, and the new pain, although ephemeral, is hardly trivial.

Comparison of my left knee pre-surgery, and the knee of a “normal” male, 36 years old. My knee, on the right, has bone on bone contact, bone dissolution due to knee-cap aggravation, and a wide gap on the left side due to long term adaptation to the irritation. The wide gap is common, and causes the development of a bow legged gait.

The goal of a full knee replacement is to remove damaged bone and replace it with new materials that allow the knee a full range of smooth motion.  The picture above shows my left knee pre-operation; The femur and tibia are touching on the left side and all the cartilage is gone.  That constant contact has caused a gap in the bones on the right side – this is one of the body’s adaption mechanism to the pain.  Unfortunately, it also changes the biomechanics of leg motion, and caused my leg to become “bow legged”.  Finally, the constant contact of the patella on the knee sans cartilage has prompted some bone dissolution giving the knee an a appearance of limestone fossil.  Several figures above this text is the x-ray of my replaced right knee; the damaged areas have been cut away and replaced with metal and flexible cushion constructed of polyethylene.

The reason knee surgery stinks is the processes involved in placing the prosthetic into the knee – to relieve pain, one must cause pain.  However, I am reminded of words of Benjamin Franklin:  There are no gains without pains. After months of planning, I arrive at the hospital to be checked in for surgery.  Although I have been through this several times before, it is impossible not to be anxious.  Plus, I am a paranoid worrier – I have spent the last two weeks planning for every disaster.  I visited the grandkids, I told my wife what to do with my mineral collection, I cleaned up my office…. Anyway, checkin and finally getting ready for surgery is just the start.

Modern knee replacement is miraculous.  The first process is deadening the legs, and that is done with a spinal block, the injection of anesthesia into the fluid surrounding the spinal cord in the lower part of my back.  Within about 5 minutes my feet feel hot, and then numb.  The numbness rolls up both legs, and within 15 minutes there is absolutely no feeling below the waste.  It is a bit freaky in that there is complete control and feeling from the belly bottom up, but nothing at all below.  Shortly after the anesthesia takes hold I am wheeled into the operating room.  Next to the operating table are several small saws – a frightening sight!  However, the staff give me a mild gas and I am fast asleep.  Next thing I know I am waking up 2 hours later in a recovery room. I missed all the action!  My surgeon sliced my leg open along an 8″ line from slightly above the knee to below.  This slice cut through the quadricep tendon and allowed access to the knee cap. Once the cut is made, my surgeon bends my knee 90 degrees to have access to the bone.  He then uses the saws to remove the bottom of the femur and the top of the tibia.  Another saw is used to reshape the bones to fit the parts of the artificial joint.  The new parts have pegs that are pressed into the bone, and will be eventually inter-grown with the new growth of the bone.  Then my surgeon focused on reshaping my knee cap – removing the spurs and rough spots.  After all this stuff is done the knee is straightened and the muscle is stitched up, and finally staples are applied to pull the wound together.

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Four hours after surgery.  A new knee! blood drain means the bone marrow is still working.  My smile is due to the drugs.

There is no pain for several hours – until the spinal block begins to wear off.  Then all that violence to the bones screams. There is a long tube in my knee that drains the excess blood.  Since the bones were cut, and the prothesis was pressed in, blood continues to ooze out of the joint for 24 hours – in my case it was nearly a quart. Nothing feels good 12 hours after surgery is done.  However, the journey to walking, hiking and running has begun!

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My first steps – not exactly freedom, but way better than bed rest!

First Steps: 18 months of recovery

The day after surgery the recovery begins.  With knee surgery there are so many nerves and muscles cut you have to learn to walk again.  Heel down, rolling to the toe – it seems natural, but I have to think about every step.  The leg that was operated on is weak, stiff and sore.  Walking 100 feet is a chore – but also a delight.  Pushing a walker up and down the hospital hallway is a bit surreal.  But the walker is my friend for 6 weeks.  Crutches don’t teach you to walk; the prothesis corrected my bowleggedness, the goal now is to be able to “lock” the knee.  It has been 10 years or more since I could lock the knee – as the arthritis progress that knee slowly buckles (lay flat on a bed – the back of a normal knee rests on the mattress, but an arthritic knee like mine with have a gap of several cm).

I know that the process of relearning to walk, making the knee functional, and strengthening the leg will take 18 months.  There is no way to shorten the recovery.  Past experience tells me that the first 6 weeks seems like an eternity and progress is frustratingly slow.  But the day the knee locks, then I will know that I am on the cusp of full functionality.  Locked and Loaded.  See you on the trail in 2019!

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Conventional Wisdom and Scientific Fact: The dilemma for a trail runner

It will be convenient to have a name for the ideas which are esteemed at any time for their acceptability, and it should be a term that emphasizes this predictability. I shall refer to these ideas henceforth as the conventional wisdom. John Kenneth Galbraith, Economist, 1958.

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Stephen Lee ( Dark Glass Photography) photograph of a late April 2014 snow dusting of Pajarito Mountain. The 2014 Jemez Trail Run 50 km and 50 mile runs will climb Pajarito Mountain and top out at its 10,440 foot elevation. The Jemez Trail Run is one of the reasons I “got into” trail running.

Conventional wisdom is an ancient high idol – it has been used to guide and misguide people from the beginning of time.  Conventional wisdom is sometimes right, sometimes wrong, but nevertheless shapes core values and beliefs. The power of conventional wisdom is that it sounds right and thus quashes skepticism – even among scientists.  It is surprising how often conventional wisdom turns out to be wrong, or at least miss-applied.  In my case, conventional wisdom gospel collided with a passion to run on mountain trails.

Nowhere is conventional wisdom more often evoked than with all things to do with health.  This is mostly because the human system is so complex that there is a natural desire to deconstruct it into smaller, simpler, components. Often the conventional wisdom is based on some scientific evidence; however, medicine has a long history of poorly understood experiments.  Dr. John Ioannidis, one of the world’s leading medical statisticians states that up to 90% of medical studies that are published in leading research journals are flawed – mostly because variables are not controlled or hypothesis tested were biased to desired outcome. In other words, a prescription based on a “medial study” was actually likely to be wrong……  Although this is harsh, it is not really a criticism of your local physician who is only repeating the oft-cited medical journal results.  It is stunning how often medical journals publish papers which have totally opposite conclusions.  My personal favorite are studies on whether coffee is good or bad for you – a simple google scholar search yields results for hundreds of studies – and the score?  Coffee might be good or might be bad for you.  It is good for me, I can assure you..

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Coffee is a wonder drug as far as I can tell. It certainly has made my life better…..Graphic from the Wall Street Journal

I had my left hip replaced in 1998 at the tender age of 42.  It was a life-changing event for me.  It relieved me of great pain, but it also came with the stern instruction that I could not participate in any high impact sports again.  In 2009 I had my right knee replaced.  Again, the pain it relieved was a godsend, but I was told that my “bionic” state was subject to wear, and it was only a matter of time before I would have to have the metal joints redone.  The only way to delay the return to the surgeon’s table was to minimize impact – no running, jumping, skiing, parachuting, etc.  I totally bought into this physician direction – it certainly made sense!

However, life was not that simple for me.  I could ride a bike and I could swim; but that is not what I wanted in my life.  I loved being in the mountains, on a trail, climbing a peak.  I discovered trail running, and found a special joy.  I started slowly (well, I am still a very slow runner, and will always be), but besides the spiritual peace I found with trail running I began to feel physically better than I had in decades.  Back pain disappeared, my non-replaced knee stopped aching, and I felt like a “million bucks”. At some level this made no sense, but I began to wonder if the knee replacement and the fitness from running had corrected a long present biomechanical problem.  Trail running in New Mexico is far different than road running — the trails are rough so there is no rhythmic pounding.  There is lots of “stepping” in climbs and descents.  I was pressed by many who care about me to stop the nonsense of trail running or risk the wrath of prosthesis fatigue.  I decided to really investigate the facts behind the prohibition of running with artificial joints, and was extremely surprised to find that conventional wisdom was based on flimsy evidence.

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Running in the Jemez Mountains after an early fall snow. The peace and joy of nature is an immeasurable factor in quality of life.

The Path to Replacement

I have always enjoyed sports – almost every sport I tried.  I am not athletic, but I am dedicated.  I enjoyed running, cycling, football, etc., but after high school my passion was basketball.  I am short and slow, but if you play enough you will have seen everything and experience is a nice equalizer.  For 25 years I played basketball at least 4 times a week – and played hard.  Conventional wisdom says that if you play basketball regularly then you will be injured regularly….a stray elbow, a turned ankle, a jammed finger.  I believe that in this case conventional wisdom is a universal truth. Along the way I had several knee surgeries to remove torn cartilage, and my knees began to really get sore.  But not sore enough that I wanted to give up playing.  In 1989 I was given a prescription for indometacin (a non-steroid anti-inflammatory), and the daily doses meant that I could run up and down the court.  In 1996 I began to get numbness in my left foot, and finally went into a doctor to find out what was wrong.  After a number of diagnoses, mostly wrong, my hip was x-rayed.  In the words of radiographer “I had the hip of an 80 year old arthritic man – heavily scored and damaged”.  Only way to stop the pain was to get a total hip replacement.  My response was emotional, but the real issue for me was “why?”.  The answer always came back the same – sports damaged your joint.  I accepted this conventional wisdom, but today I believe it is far more complicated that just “sports”.

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My hip xray 11 years after replacement. The two common modes of failure are wear of the ball joint, and separation of the stem from the femur. Neither mode is present in the slightest after a decade.

Recovery from hip surgery was not actually that difficult.  I was riding a bike within 10 days, and I could not believe how much better I felt.  Mostly, I remember that I could finally sleep through the night!  My knees still hurt and I was limited in my hiking.  I never played basketball again (but had to avoid going any where near the Bear Down Gymnasium at the University of Arizona for fear that I would be sucked into a pick up game).  Over the next ten years my knees slowly got worse.  My kneecaps seemed to grow (they are/were huge), and finally in 2009 I followed the advice and had my worst knee (the right side) replaced.  Getting a knee replaced is much, much more difficult than a hip.  It took a long time to recover and be pain free.  Along the way, both my parents died, Los Alamos was evacuated due to the largest wild fire in New Mexico history, and my job seemed to consume me.  I gained weight, and physically began to feel old.  I decided to start climbing the hills around Los Alamos – slowly at first, but pretty soon I was trotting.  I lost the weight, but much more surprising, I the aches and pains I attributed to age began to ease.  By the winter of 2012 I was feeling physically strong, and able to do 20 to 25 mile trail runs with no ill effects except exhaustion.

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Xray of my right knee shortly after surgery. The “picket fence” on the right side of the image are the staples to close the incision. The replacement includes implants both on the femur and the tibia bones. The knee cap is also reshaped and spurs and growths were removed.

Biomechanics and Stress Loads on Hips and Knees

Artificial hips and knees are relatively common place in the United States; earlier this year the total number of prosthetics was estimated to top 7 million with a ratio of 2 knee replacements for every hip (in fairness, most of the knee replacements are “partials” vs total). The owners of these replacements are skewed towards those over age 60, although the demographics is shifting to younger ages rapidly.  It is very difficult to get good statistics on the failure rates of the prosthetics; there are different kinds, and all have peculiarities.  On average, about 2 percent of artificial hips fail or need to be replaced after 5 years, and about 6 percent after 15 years (so more failures early).  For knees, the 15-year failure rate is slightly lower, about 5%.  The statistics for these failures are robust.  However, there is a paucity of large scale, longitudinal studies examining the cause of failure.  Most reports are largely anecdotal, and the overwhelming correlation is with obesity and inactivity, which would seem to be counter to conventional wisdom.

There are two oft-cited studies that made an attempt to examine prosthetic failure to physical activity.  The first  is a 2010 study presented at the American Academy of Orthopaedic Surgeons that looked at knees.  The sample size was small – 218 patients – but it found that those that ran after surgery were 20 percent  less likely to have mechanical failure. The second study was done at the  Sainte-Marguerite Hospital in Marseille, France and had a similarly small sample size: 210 patients, with 70 “active” in high impact sports and 140 that were not and focused on hip replacements.  The metric was “survivability” of the hips 15 years after replacement.  80% of the active sports participants had high performing hips, while 94% of the low activity participants had high performing hips.  This would suggest that high impact sports had a negative impact on the prosthetic – the opposite of the 2010 study.  So, who is right?  Is there a difference between hips and knees?  Is there a difference between French and Americans?  I have read both studies, and a number of analysis of these studies, and am struck by the very poor quality in control of the complex variables.  Different types of artificial hips (metal-on-metal, coated metal, etc) were mixed, there was no quantification of level of activity other than self reporting, and there was no details of the type of failures.  At best, it would seem to indicate that there is NO EVIDENCE that running is worse than walking for the survivability of hips and knees!

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The simple gaits of running vs walking. When running force or stress increases and decreases throughout the gait and involves a transfer from the foot/ankle to the knee to the hip.

If the studies are ambiguous about whether running causes prosthetics to fail, where does the conventional wisdom come from?  The best explanation is in biomechanics – the human engineering of running.  The gold standard for biomechanics is a 1997 review paper by Tom Novacheck, The biomechanics of running (a pdf can be found here: http://www.elitetrack.com/article_files/biomechanicsofrunning.pdf). Stress is generated and transferred to the body in several ways. With the first strike (FS in the figure above) the full weight of the body comes into contact with the ground – impact stress – and is transferred up through the ankle to the knee and into the hip. The running gait then pushes the body off the ground (Toe Off, of TO in the figure), which generates a similar set of stresses.  The stresses on the joints are a combination of the weight of the runner and the contraction of the muscles.

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Force on impact during a running gait. There are two keys: body weight and length of time in contact with the ground.

Experimental studies have quantified the forces on a runner as the foot strikes and then leaves the ground – the figure above is a classic “average runner”.  The first little peak is due to the shock of striking the ground and then some of shock is absorbed in the padding of the running shoe.  The y axis is the nominal force which is scaled to the body weight;  it pays to be a light weight when running!

There has been much work done to see how this force load is accommodated within the body, and the classic “average human” works the hip, knee and ankle — and does this differently for walking, running and sprinting.  This figure is shown below.  The difference between walking and running is dominated by the engagement of the knee – in the graphic the overall stress is indicated by the size of the pie chart. In simple terms, more stress when running, and that stress is really experienced in the knees.

The partition of energy (stress x time) between leg joints for walking, running and sprinting.

The partition of energy (stress x time) between leg joints for walking, running and sprinting.

It is this figure more than anything else that drives the conventional wisdom that running wears out prosthetics.  Running generates more stress than walking, and this leads to the conclusion that higher stress results in more wear. But why?  That is not true in bone – in fact, for bones increased stress promotes growth and stronger joints.  Although metal, ceramics and plastic can’t “grow”, aren’t they engineered to withstand the modest stresses of a 155 pound man running at the leisurely pace of 6 miles an hour?

The question of running and artificial joint wear is murky, and there is no strong evidence that modest running leads to more wear.  I am confident that my trail running is not accelerating my demise.  On the other hand, I am equally confident that eventually my knee and hip will eventually deteriorate – maybe when I am 65, maybe when I am 70, but it will happen.  However, the quality of life trumps the possibility of extending the prosthetics a few years.  I feel I can answer the question I get all the time — aren’t you concerned that you are ruining your artificial joints by running on the trail?  The answer is “not really”.  I believe that my original joint arthritis was not caused by “sports” but by a biomechanical misalignment within my body.  Surgery corrected that (probably unintentionally) — it is a gift.  I celebrate that gift every trail run.  The surgeries did effect me in other ways – cut nerves, changed muscles, and made me weaker.  I will never be a fast runner, but that is just fine.  Conventional wisdom says a “happy man is a healthy man”.

Mark Twain was one of the most keen observers of the human condition.  He said: “When even the brightest mind in our world has been trained up from childhood in a superstition of any kind, it will never be possible for that mind, in its maturity, to examine sincerely, dispassionately, and conscientiously any evidence or any circumstance which shall seem to cast a doubt upon the validity of that superstition. I doubt if I could do it myself.”