Latest / Deep Dive Ortho — Orthopaedic Surgery, AI & Digital Health Podcast. / Shoulder Instability
Transcript
- 0:00Okay, let's jump straight into it. That moment,
- 0:02your shoulder just gives way, pops out. Awful
- 0:07feeling. Instant pain, major disruption. But
- 0:10what's really frustrating, isn't it, is how often
- 0:12it happens again. That's the real problem, recurrence.
- 0:15We've been digging into the orthopedic literature,
- 0:17JAAS, and others, and some numbers are pretty
- 0:20stark. Yeah. For certain young, active patients,
- 0:23you know, after that first traumatic anterior
- 0:26dislocation, if they don't have surgery, nearly
- 0:30nine out of 10 might dislocate again. That statistic
- 0:33really sums it up. It's the core of what we're
- 0:35looking at today. Shoulder instability. Mostly
- 0:38traumatic anterior instability, right? That's
- 0:40the common one. That's the most frequent presentation,
- 0:42yes. And it's not just about reducing the dislocation,
- 0:46getting the ball back in the socket. No. It's
- 0:48fundamentally about understanding the damage
- 0:50done, often over multiple events, and how that
- 0:53damage makes the shoulder, well, inherently unstable.
- 0:57Exactly. So this deep dive isn't just about a
- 0:59simple repair. It's about how orthopedic thinking
- 1:02has moved on. It has. Towards much more precise
- 1:05diagnosis and really tailoring the management
- 1:08based on exactly what injuries you find. So our
- 1:11mission, pulling from these sources, is to get
- 1:13a handle on the current evidence. Spot on. What
- 1:17are the key factors driving treatment? How do
- 1:19surgeons pinpoint the real underlying problems?
- 1:22And crucially, What does a successful outcome
- 1:24actually look like, especially in stopping those
- 1:27repeat dislocations? That high recurrence rate,
- 1:29particularly in young, active people, it really
- 1:32stands out. It sounds like the who matters as
- 1:35much as the what. Oh, absolutely. Patient selection,
- 1:38understanding their specific risk profile. It's
- 1:40crucial for predicting the outcome and hopefully
- 1:42getting a good one. And what are the big risk
- 1:44factors the literature points to? Well, there
- 1:46are a few key ones that come up consistently.
- 1:49Younger age is a big one, especially under 20,
- 1:51maybe 25. Right. Male sex is another factor.
- 1:55And perhaps, obviously, playing collision sports
- 1:57or just participating in high -level athletics
- 1:59significantly bumps up that risk. So a young
- 2:02male athlete, they're right in the danger zone
- 2:05for it happening again. That's the highest risk
- 2:07group, yes. And because non -operative treatment,
- 2:11just rehab after the first time, it has such
- 2:13a high failure rate in these high -risk individuals,
- 2:17especially the younger ones. The trend is definitely
- 2:20towards surgery becoming the mainstay. Even for
- 2:24the first dislocation sometimes. Often for the
- 2:26primary instability in that demographic, yes.
- 2:29Not just for recurrences. The thinking is to
- 2:32intervene early, break that cycle before more
- 2:35damage occurs. Okay, so... If surgery's often
- 2:38the answer, that initial diagnosis has got to
- 2:40be spot on. You need to know exactly what broke,
- 2:43not just that it popped out. Absolutely foundational.
- 2:45Yeah. Can't stress that enough. It starts with
- 2:47a really meticulous clinical evaluation. Taking
- 2:49a proper history. Detailed history, yes. How
- 2:52did it happen? The mechanism. How many times
- 2:54before? Crucially, how old were they the first
- 2:56time it happened? Age at first dislocation matters.
- 2:58Big time. And also, what are their goals? You
- 3:01know, are they hoping just for pain relief? Or
- 3:03are they trying to get back to playing rugby
- 3:05or competitive swimming? Very different demands.
- 3:08Makes sense. And the physical examination, what
- 3:10are you looking for there? The exam is key for
- 3:12assessing the degree of instability. How much
- 3:15does the humeral head, the ball, actually move
- 3:18relative to the socket, the glenoid? How do you
- 3:21test that? We assess glenohumeral translation
- 3:23and use provocative tests. Things like the apprehension
- 3:27and relocation tests, trying to mimic that feeling
- 3:30of instability the patient gets. See if you can
- 3:32make it feel like it's going to pop out. Exactly.
- 3:35And then see if relocating the head, sort of
- 3:37pushing it back gently, makes that feeling go
- 3:40away. We also look for general joint laxity.
- 3:43Like being double -jointed elsewhere. Sort of.
- 3:45Though the source has mentioned general scores
- 3:47like Baton aren't always that helpful, specifically
- 3:49for the shoulder. Things like excessive external
- 3:52rotation or a sulcus sign that little dimple
- 3:55under the shoulder suggesting downward laxity
- 3:57could be more telling for the shoulder joint
- 3:59itself. Okay, so history, exam, then you need
- 4:02to look inside presumably. Imaging. Imaging is
- 4:04non -negotiable, really. It confirms what you
- 4:07suspect clinically, but more importantly it identifies
- 4:09the specific structural damage. Starting with
- 4:12x -rays. Usually plain radiographs, yes. They're
- 4:14good for gross issues alignment, obvious fractures,
- 4:17and specific views like the grassy, axillary,
- 4:21burnigo, striker notch, west point, they help
- 4:24visualize the bone shapes better. Looking for
- 4:27those bony defects? Precisely. But, and this
- 4:30is important, the sources point out standard
- 4:33x -rays often miss more subtle bone loss, especially
- 4:36if it's not a fresh break or a really chronic
- 4:38problem. Right. So x -rays for the big bony picture.
- 4:41What about the soft bits, the ligaments, the
- 4:44labrum? That's where MRI comes in, or M .R. Arthrography
- 4:47MRA. These are essential for evaluating the soft
- 4:49tissues. The labrum, capsule, ligaments. Exactly.
- 4:53And importantly, in patients over 40, the rotator
- 4:56cuff tendons as well. They can tear during a
- 4:58dislocation too. MRA involves injecting dye.
- 5:01Yes. Contrast dye into the joint. It's generally
- 5:03considered more sensitive for picking up more
- 5:05complex or subtle tears, things like pan -laboral
- 5:08tears going all the way around, or SLAP lesions
- 5:10up top where the biceps attaches. And standard
- 5:13MRI. Standard MRI is noted as being particularly
- 5:16good for those anterior labrum tears, the classic
- 5:19bankart lesion. And checking the rotator cuff
- 5:21in older patients is vital. Finding a tear there
- 5:24can definitely change the surgical plan. Okay,
- 5:27MRMRA for soft tissue. What if you suspect significant
- 5:30bone damage that the x -ray didn't really show
- 5:32clearly? That's when CT scans become crucial,
- 5:36particularly 3D CT reconstructions. Why 3D? The
- 5:39sources are very clear on this. The anphase sagittal
- 5:42view you get from a 3D CT reconstruction is the
- 5:45best way to accurately measure to quantify the
- 5:49amount of glenoid bone loss. And getting that
- 5:51measurement right is critical. Absolutely vital,
- 5:54because that number, that percentage of bone
- 5:56loss, heavily influences the treatment decision.
- 5:58And the sources really drive home how important
- 6:01these bony injuries are, don't they? They're
- 6:02not just side effects, they dictate the whole
- 6:04strategy. They really do. The two main bony problems
- 6:07in recurrent instability are glenoid bone loss,
- 6:10GBL, and hill -sax lesions, HSLs. GBL is damage
- 6:14to the socket rim. Yes, wear or a fracture off
- 6:16the front edge of the glenoid socket, the shallow
- 6:19dish the ball sits in. And the hill sex is on
- 6:21the ball part. Correct. It's an indentation,
- 6:23a defect usually on the back, upper part of the
- 6:26humeral head caused when the ball impacts the
- 6:29sharp glenoid rim during the dislocation. It's
- 6:31like the ball hitting the edge of a damaged cup.
- 6:34It dents the ball and chips the cup rim further.
- 6:37That's a good analogy. It's often a cycle of
- 6:40progressive damage. Each dislocation can make
- 6:42both defects worse. And the sources talk about
- 6:45a newer way of thinking about Hillsac's lesions,
- 6:48on -track versus off -track. Yes, that's a really
- 6:51important concept now. It seems to be a more
- 6:53reliable way to predict recurrence and surgical
- 6:56outcomes compared to the older idea of just engaging
- 6:59versus non -engaging lesions. What's the actual
- 7:02difference, on -track versus off -track? It's
- 7:04about biomechanics. Think about the glenoid track,
- 7:07the contact area on the socket. An on -track
- 7:10Hillsac stays within that contact zone during
- 7:12normal shoulder movements. It's there, but it
- 7:14doesn't slide off the edge. An off -track lesion,
- 7:17however, is big enough or positioned so that
- 7:20when the arm moves into an unstable position,
- 7:22like abduction and external rotation, that defect
- 7:25on the humeral head actually translates medial
- 7:28to the front edge of the glenoid. It essentially
- 7:30falls off the track. It loses the bony stability
- 7:32of the saccharin. So off -track means it can
- 7:35basically slip past the point of no return much
- 7:38more easily, leading to another dislocation.
- 7:41Precisely. Identifying an off -track lesion is
- 7:44critical information. It changes the whole stability
- 7:47equation and really pushes you towards surgery
- 7:49that addresses that humeral head defect too,
- 7:52not just the glenoid side. And the amount of
- 7:54glenoid bone loss is just as critical. Are there
- 7:56specific percentages that trigger different treatments?
- 7:59Yes. The literature talks about definite thresholds.
- 8:01There's a bit of variation. But common figures
- 8:04are, say, less than 10 % or 13 .5 % GBO. OK,
- 8:08minimal loss. And in intermediate zone, maybe
- 8:1013 .5 % up to 20 % or 25 % loss. And then significant
- 8:14loss. than 20 -25%. Crossing these thresholds
- 8:17usually means you need a different surgical approach
- 8:19to get stable. It sounds like knowing these numbers,
- 8:22understanding the bone damage, it almost creates
- 8:23a flow chart for treatment. That's absolutely
- 8:26the direction things are going. An algorithmic
- 8:28approach. The type and amount of bony damage,
- 8:31the GBL percentage, the on -drack -off -track
- 8:34HSL, combined with pager factors like age and
- 8:37activity level, that dictates the best strategy.
- 8:40So arthroscopic surgery isn't always the answer.
- 8:43Arthroscopic stabilization is often the first
- 8:45thought, and it works well for many, but the
- 8:47sources are clear. It's not one size fits all.
- 8:50Especially not when you've got significant bone
- 8:52loss or other high risk factors. Right. So let's
- 8:55walk through the surgical options then. Starting
- 8:57arthroscopically, what's the standard go -to?
- 8:59The foundational arthroscopic procedure is the
- 9:01bank cart repair. Using keyhole surgery scope
- 9:04and small instruments to reattach the torn anterior
- 9:07labrum back to the bone of the glenoid rim. Using
- 9:10little anchors? Using suture anchors, yes. The
- 9:12aim is to restore that bumper effect of the labrum
- 9:15and tighten up the capsule a bit. And when is
- 9:16that the recommended route? Primarily for patients
- 9:19with minimal or no significant glenoid bone loss.
- 9:23Generally cited as, you know, 0 -10 % GPL. Some
- 9:26even suggest considering it for young, high -risk
- 9:29athletes with less than 5 % loss, just because
- 9:32their recurrence risk without surgery is so high.
- 9:35How well does a standard bank card work on its
- 9:37own? Well, the results vary quite a bit in the
- 9:39literature. Recurrence rates reported anywhere
- 9:41from, say, 6 % up to over 35%. That's quite a
- 9:45range. It is. But here's the crucial bit. tying
- 9:48back to bone loss. Studies show a dramatically
- 9:51higher recurrence rate, sum up to 67 percent,
- 9:53if you do a standard bankart repair in someone
- 9:55who does have significant bony defects. Like
- 9:57that inverted pair glenoid shape from bone loss
- 10:00or an engaging hillsack. Exactly. Compare that
- 10:03to patients with no bone loss beforehand, where
- 10:05recurrence after a bankart can be as low as four
- 10:07percent. Wow. That difference is massive. It
- 10:10totally underlines why you need that precise
- 10:12imaging first. Absolutely. and the risk factors
- 10:15for a bank art repair failing echo the general
- 10:17recurrence risks, but add surgical points. Younger
- 10:20age? male, more prior dislocations, high -level
- 10:23sport, using fewer anchors, more glenoid bone
- 10:26loss, and having a significant HSL or an ALPSA
- 10:30lesion. What's an ALPSA lesion again? It's where
- 10:33the torn labrum heals, but it heals in the wrong
- 10:35place, peeled off, and shifted medially. It doesn't
- 10:38function as a bumper anymore. OK. So if there
- 10:41is some bone loss, say, in that intermediate
- 10:4310 -20 % zone, or a tricky hillsax, but maybe
- 10:46not bad enough for open surgery, Can you boost
- 10:50the arthroscopic approach? Yes, definitely. The
- 10:53literature talks about arthroscopic plus procedures
- 10:55for these sorts of situations. Two common ones
- 10:58are combining the bankart repair with a rimplissage
- 11:00or doing a double -row capsule labral repair.
- 11:03Rimplissage? Interesting name. What does that
- 11:05involve? Rimplissage means filling in in French.
- 11:07It's a technique used for those engaging or critically
- 11:10off -track hill -sax lesions, usually when the
- 11:12glenoid bone loss isn't too severe, maybe under
- 11:1425%. And the goal is to stop that hill -sax catching.
- 11:17Exactly. You arthroscopically stitch the posterior
- 11:21capsule and often part of the infraspinatus tendon
- 11:23from the rotator cuff right into that hill sacks
- 11:26defect on the back of the humeral head. So you're
- 11:29literally filling the dent? Pretty much, yes.
- 11:32Filling it with soft tissue to stop it dropping
- 11:34off the glenoid edge when the arm's in that vulnerable
- 11:36position. Does it work? Studies show good results
- 11:39in preventing recurrence in the right patients.
- 11:42The main potential drawback mentioned is that
- 11:45tethering the tendon there can sometimes limit
- 11:47external rotation slightly. Might be an issue
- 11:49for throwing athletes, for example. Okay. And
- 11:52the double row capsule labral repair? That's
- 11:55suggested for moderate glenoid bone loss. Maybe
- 11:5810 -20 % when the soft tissues are still good
- 12:00quality and there isn't a major hill -sax issue.
- 12:03How's it different from a standard bain -carte?
- 12:05Instead of just one row of anchors on the glenoid
- 12:07rim, you use two rows, one on the rim, and another
- 12:10set further medially on the neck of the glenoid.
- 12:12What's the idea behind that? The idea is to create
- 12:15a much broader, more robust footprint for reattaching
- 12:18the labrum and capsule. Trying to build a stronger
- 12:21buttress, essentially. The sources mention it,
- 12:23but also note there's still limited comparative
- 12:25data. more research needed to really prove its
- 12:29long -term value against other options for that
- 12:32level of bone loss. Right. So arthroscopic options
- 12:34cover minimal loss or can be augmented for moderate
- 12:37loss or specific HSLs. What happens when the
- 12:40glenoid bone loss is really significant over
- 12:43that 20 -25 % mark? When you cross that threshold
- 12:47or sometimes with specific off -track HSLs where
- 12:50other methods won't cut it, the literature generally
- 12:52points towards open surgery. Arthroscopic fixes
- 12:55alone often aren't enough to restore stability
- 12:57then. And what are the main open procedures discussed?
- 13:00Well, one is specifically for when there's a
- 13:02displaced glenoid fracture fragment that represents
- 13:04significant bone loss, say over 20%, that's glenoid
- 13:07open reduction and internal fixation or IF. Fixing
- 13:10the broken teeth back on. Exactly. Open up, put
- 13:12the bone fragment back where it belongs, and
- 13:14fix it with screws or maybe a small plate. How
- 13:16does that fare? The evidence base is a bit smaller
- 13:18compared to other procedures. One study showed
- 13:21no redislocations if you get good fixation in
- 13:23the right fracture types. But it also noted some
- 13:26patients had hardware issues or maybe didn't
- 13:28get full function back. It's really reserved
- 13:30for those acute displaced fractures where fixing
- 13:33the original bone makes most sense. Okay. And
- 13:36the other big open procedure, the one often mentioned
- 13:39for significant bone loss. The Latarjet. Ah,
- 13:42yes, the Latarjet. Definitely a key procedure
- 13:45when glenoid bone loss is substantial over that
- 13:4820 -25 % mark, usually, or for certain off -track,
- 13:52hill -sax lesions where other options aren't
- 13:54suitable. It's really designed for significant
- 13:57bony deficiency. Remind us what the Latarjet
- 13:59actually does. It involves taking a piece of
- 14:02bone called the coracoid process. It's part of
- 14:04the shoulder blade along with its attached tendons.
- 14:06The biceps and corcabrachialis. That's right,
- 14:09the conjoined tendon. transferring that whole
- 14:11unit, the bone block and tendons, to the front
- 14:14of the glenoid socket, fixing the bone block
- 14:16there with screws. And that creates stability
- 14:17how? It gives you what's called a triple blocking
- 14:19effect. First, the bone block itself extends
- 14:23the glenoid surface, acting as a physical buttress.
- 14:26Stops the ball sliding forward. Yes. Second,
- 14:28the transferred conjoined tendon acts like a
- 14:30dynamic sling, tightening up when the arm goes
- 14:33into abduction and external rotation, that unstable
- 14:36position. Right, a check screen effect. And third,
- 14:38you usually repair the capsule over the transfer
- 14:40as well, adding more stability. So it's bone,
- 14:43dynamic tendon sling, and capsule repair. A combined
- 14:46approach. Very much so. And the sources report
- 14:49good success rates in terms of restoring stability,
- 14:53preventing recurrence, often 0 % to maybe 9 %
- 14:56recurrence in those difficult cases with significant
- 14:59bone loss. It's very effective for stability
- 15:02when the bone structure is compromised. So why
- 15:04isn't it the first choice for everyone with bone
- 15:07loss, given how stable it makes things? Well,
- 15:09it's a bigger operation. It's open surgery more
- 15:12involved in arthroscopy. And it does carry a
- 15:14higher risk of complications. Like what? Things
- 15:16like nerve injury, there are important nerves
- 15:18nearby infection, or problems with the bone graft
- 15:21healing or the screws. Reported complication
- 15:23rates can be up to 25 % in some series. So it's
- 15:26a trade -off, stability versus risk. Exactly.
- 15:29That higher risk profile is why it's generally
- 15:32reserved for cases where the indication is really
- 15:34strong, that significant bone loss, or maybe
- 15:37a failed previous surgery, or an off -track HSL
- 15:40that can't be managed arthroscopically. It's
- 15:43usually not the first line treatment for all
- 15:45instability. Are there other ways to add bone
- 15:47to the glenoid apart from letarget? Yes. The
- 15:50source has mentioned free bone block procedures.
- 15:52Using bone graft, either from the patient themselves,
- 15:55often the iliac crest, the hip bone, or using
- 15:57donor bone, allograft, and fixing that to the
- 16:00anterior glenoid. These are sometimes suggested
- 16:02as potentially having a lower nerve risk than
- 16:04letarget, theoretically, and they're also good
- 16:07options if a previous letarget or other bone
- 16:09block has failed. We focused a lot on traumatic
- 16:12anterior instability. What about other types,
- 16:15like being unstable in multiple directions, or
- 16:18dealing with kids whose bones are still growing?
- 16:20Good point. The sources do touch on these. Multidirectional
- 16:23instability, MDI, is a different beast altogether.
- 16:27How so? It's usually instability in two or more
- 16:29directions, front, back, or down. Often linked
- 16:32more to general ligament looseness, you know,
- 16:35being naturally hypermobile rather than one big
- 16:38traumatic tear. So the cause is different? Often,
- 16:40yes. And distinguishing MDI from traumatic unidirectional
- 16:44instability is vital because the treatment starts
- 16:47differently. How do you manage MDI initially?
- 16:50Almost always starts with non -operative treatment,
- 16:53a really intensive, focused physiotherapy program,
- 16:56strengthening the rotator cuff, the muscles around
- 16:58the shoulder blade to improve dynamic control.
- 17:01And surgery? Surgery, usually tightening the
- 17:03capsule arthroscopically, a cascular placation
- 17:06or shift, is really only for cases where a prolonged,
- 17:09dedicated rehab program hasn't worked. And even
- 17:13then, the literature suggests surgical outcomes
- 17:15for MDI can be less predictable, maybe not quite
- 17:18as good as for traumatic instability. And what
- 17:20about the youngsters? Skeletally immature patients
- 17:23with open growth plates. That must be tricky.
- 17:26It absolutely adds complexity. You've got to
- 17:29protect those growth plates, the physis. Prompt
- 17:31reduction of the dislocation and some immobilization
- 17:34is standard first aid. But what about surgery?
- 17:37Well, for athletic teenagers, say 14 or older,
- 17:41who have a traumatic dislocation and a clear
- 17:43bankart tear is found. The sources suggest early
- 17:46surgery might be warranted. Even though they're
- 17:48still growing. Yes, because their risk of recurrence
- 17:51without it is just so high. For younger children,
- 17:55it's less clear cut after a first dislocation.
- 17:57But if they start having recurrent instability,
- 18:01surgery is generally considered, though the techniques
- 18:03have to be adapted very carefully to avoid injuring
- 18:06the growth plate. Okay. So pulling all this together,
- 18:08then, if you had to summarize the main message
- 18:10from this deep dive into how we manage shoulder
- 18:12instability now. I think the core message is
- 18:15that the whole field has evolved. It's way beyond
- 18:17just fix the labrum. While arthroscopic repair
- 18:21is still common, the absolute game changer, the
- 18:23critical factor driving strategy and outcome.
- 18:25is identifying and accurately measuring the bony
- 18:28damage. Specifically the glenoid bone loss and
- 18:31the hill -sax lesion. Exactly. Especially quantifying
- 18:34that GBL and understanding if the hill -sax is
- 18:37on track or off track. That information is paramount.
- 18:41And that bony picture dictates the treatment
- 18:43algorithm. Precisely. The amount of GBL, primarily,
- 18:46tells you whether a simple arthroscopic repair
- 18:49is likely enough, or if you need an arthroscopic
- 18:52pluses procedure like remplussage, or if you
- 18:54really need to go to an open reconstruction like
- 18:56a latarjet or free bone block to restore proper
- 18:59bony stability. It's incredible, really, how
- 19:02understanding the bone in such detail changes
- 19:04everything for what seems like a common injury.
- 19:07It really underscores the complexity, doesn't
- 19:09it? And, you know, the sources remind us it's
- 19:11still evolving. We need more research to validate
- 19:13some techniques like the double row repair and
- 19:15always looking for ways to improve outcomes and
- 19:17reduce complications for the bigger procedures
- 19:19like Le Tarjet. It makes you think, doesn't it?
- 19:22Considering how much this precise, lesion -specific
- 19:25understanding of bone changes the game for shoulder
- 19:28instability, how could Applying that kind of
- 19:31detailed algorithmic thinking based on the specific
- 19:34damage help us tackle other complex problems.
- 19:36Maybe not just in medicine, but in other fields
- 19:38too.