So we're going to go through osteoarthritis and Keen Box. And just, these are my disclosures again, just to review, I went through a typical 200-question SAE test and then counted for many years how many questions were on each topic. For rheumatoid arthritis, out of 200 questions, they typically had 10 questions in RA, so that was 5%. On osteoarthritis, they typically had 8 questions per 200, so that was maybe 4%. On Keen Box, out of a 200-question SAE test, it was rare to have more than 3 questions on Keen Box. And I could not find anything on factitious disorders, although that may be changing in the future. But that gives you sort of an idea of what the question representation is, and I think these are critical topics, they're very broad, but again, the point of this is to give you a limited domain of just what you need to know for the test. So same concept here, I had a nice animation here. So osteoarthritis, general information, normal cartilage, 10% chondrocytes, 90% matrix, type 2 collagen. Aggregan is the most common protein, it's hydrophilic. The cartilage is a mesh of collagen fibrils, chondrocytes, and matrix. Handles compression very well and allows for motion. Here is the pathology in osteoarthritis. A decrease in type 2 collagen synthesis, a decrease in proteoglycan concentration, disorganization of the collagen framework, inadequate repair, which causes fissuring, and an increase in water content. So water content is the one thing that goes up. You have an increase in an inflammatory mediator IL-6. So interleukin-6 is the thing to remember, and that's the thing that goes up. For some reason, there were questions on the SAE that had, which mediator is the one that goes up? And they had lists 2, 3, 4, 5, and 6. So that was the ultimate factoid. So just keep in the back of your mind, IL-6 is the only thing you have to know that remotely relates to immunohistology. For medications, acetaminophen is probably the thing you would start with. It blocks the release of prostaglandin E2 and CNS. You have NSAIDs, non-selective inhibitors of cyclooxygenase, which catalyze the formation of prostaglandins. The COX-2 inhibitors include siloxigib and rofixacab. That was the one that was taken off the market because it had heart and stroke concerns. That really was Bextra. So the only one that's really left standing is Celebrex, and that's the COX-2 inhibitor. DIP arthritis is the most common OA location in the hand. Highest forces occur with grip at this joint. Initial treatment is splints, anti-inflammatory meds, non-steroidals, etc. Surgical treatment would be arthrodesis. Use K-wires, cerclage, tension band, compression screws. Nonunion rates are about 12%. Most occur in psoriatic arthritis or trauma. Infection rate is 4%. Wound problems are 15%. For mucous cysts, often present in mild osteoarthritis, aspiration and injection of steroid is 40%. So this is the recurrence rate after aspiration and injection after treating a mucous cyst. Recurrence after surgical excision, some say 0%, of course. That's really never exactly true, but its recurrence after surgery is probably the least. The nail ridging may never go away. Remember to excise the little bony osteophyte. Complications from mucous cyst treatment can be numerous. Infection, wound breakdown. You may need to pursue some little rotation flap to cover the wound if the skin is really blown and you have a big wound or an incision. PIP arthritis usually is post-traumatic. You wind up getting initial treatment as splinting or NSAIDs or injection. Surgical treatment would be arthroplasty or arthrodesis. Pain relief is the same. Arthroplasty would be better considered for the long ring and small fingers. Arthrodesis for the index, since its primary function is to oppose the thumb and have a stable post for opposition. For PIP arthroplasty, you could consider semi-constrained, like silicone arthroplasties. Non-constrained would be pyrocarbon or metal with poly. The results of PIP arthroplasty, pain relief is usually very good. Range of motion, interestingly, is only slightly better or unchanged. It has an incredibly high revision rate, ranging from 26% to 58%. Pyrocarbon had initial good results, but don't ever do this operation ever in your lifetime. Peter Stern has made a point of publishing on this repeatedly, that dislocation rate, high loosening rate, and migration rate is very high. If you're going to talk to people and write sort of a freaky test question about what's the most initial weird complication, believe it or not, it would be squeaking of the joint. You know, late complications, my finger fell off my hand. Variable results. Some authors have abandoned this procedure. That's my nice way of saying that most of the time, this would not be the right answer long term. And most people have abandoned this because the implants tend to have enough migration that after many years, they fall apart completely. So fusion is probably better if you're not doing a silicone arthroplasty. For the MCP joint, it's not as common. If you're getting arthritis here, trauma, gout, and pseudo-gout are common sources of arthritic breakdown. Index and the middle MP joints are the most common. You'd consider, again, arthroplasty for the long, ring, and small. Arthrodesis for the thumb to have a stable post, 10 to 20 degrees of flexion. For the index finger, you could either replace it or fuse it, although my personal preference is to not worry about it and just fuse it. MCP arthroplasties, the legacy implant is silicone. They're good for osteoarthritis and inflammatory arthritis. You generally get better motion alignment and improved extensor lag. Unconstrained implants, you must have good collateral, so they're pretty much contraindication in inflammatory arthritis. You can do unconstrained implants for MP arthroplasties and osteoarthritis. For the unconstrained arthroplasties, you can use cemented with cobalt chrome. You can do bone ingrowth, which is how pyrolytic carbon works. The initial results show improvement in pain and motion. More recent results, again, loosening, subsidence, revision rates pretty darn high, 30%. Resection arthroplasty, not commonly performed, probably a salvage. Might be good for people with osteomyelitis or a failed implant or insufficient bone. You can interpose fasciae latae or an extensor retinaculum. There's limited data, but it shows maybe reasonable pain relief and better motion. For thumb CMC arthritis, here's the giant of the clinical presentations. 25% of women, 8% of men have this. Ligamentous laxity may start the process. The anterior oblique beak ligament may be the primary stabilizer that becomes stretched out. The dorsal radial ligament also is shown to be thicker and stronger. You get CMC subluxation and adduction contracture, secondary MP hyperextension. Eaton and Littler have staged this based on radiographic findings. One, stage one is widening and synovitis. Two is osteophytes less than two millimeters. Three is osteophytes greater than two millimeters. Four is pan-trapezial narrowing or arthrosis. One thing to remember is that many times treatment is not necessarily dictated by the degree of advancement on an x-ray. It is more commonly dictated by what the patients are complaining of. As you all know, many better than I do, patients will come in with severe x-ray changes and in fact not have much complaint. So you have to judge this mostly on what the patients complain of. Initial treatment for CMC arthritis, thermoplastic thumb strap and adduction exercise, standard thumb spica splint and pinch exercises. For some reason, a test question got through the filtering process of what's the best type of splint. And it was like a neoprene sleeve. I'm not convinced that's really true, but that was the right answer. So make a note of it. Steroid injection in three weeks of splinting is another treatment. You get long-term relief for stage one or early arthritic patients. Very little relief for patients who are advancedly arthritic. Highly uronate injections versus steroid. Doesn't seem to be any significant difference in outcome. For stage one or early treatment options, you could consider ligament reconstruction with half of the FCR. 65% of these patients are pain-free at 15-year follow-up. You can do metacarpal extension osteotomy, which shifts the load from palmar to dorsal. Need at least 50% of the cartilage remaining. Long-term results, 75% pain relief, 25% need revision. Arthroscopy, another option. Cinevectomy is a possible hemitrapezectomy. Variable results. All have minor technique variations. The only thing I would say about these operations is they're less common in my actual practice because I don't see people who have stage one disease and actually are too motivated to have surgery. They're usually happy with the non-operative care options. But if you want to get into the weeds about doing something operative for stage one patients, this is what you would consider. For stage two and three disease, you could consider trapezectomy in its plain vanilla flavor. 82% are pain-free at six years. With the soft tissue interposition, considered to be as good as LRTI. And with the ligament reconstruction, it's the classic. It's still a favorite. Trapezium metacarpal fusion. Again, these are sort of little nitpicking details, and it would be good to maybe remember this because it might be asked. Palmer abduction of 35 degrees. Radial abduction of 15 degrees and slight pronation. And you want to have the thumb pulp be able to touch the radial side of the index P2 when making a fist. Do you do a fusion or LRTI? You wind up getting outcomes that are the same pain relief and grip. LRTI is better opposition and a flatter hand. Fusion is better pinch strength but has higher complication rates. From a question weeding standpoint, fusion is probably a question writer's favorite for somebody who is a young construction worker. LRTI is better when someone is older. What about trapezium metacarpal implant arthroplasty? Ceramic spheres. You wind up getting words in your treatment plan like subluxation, subsidence, and fracture. Pyrolytic carbon, subluxation, dislocation, 33% revision rate. Polyurethaneurea spacer form body reaction. Poor outcomes compared to LRTI. Some metal polyimplant studies in Europe showed 74% survivorship at 26 years. Another study showed loosening in 44%. So by and large, it is difficult to have implant arthroplasty at this joint match the outcomes of the usual resection arthroplasty, fusions, or soft tissue reconstructions. For thumb CMC arthritis, other issues. What about STT arthritis? Trapeziectomy LRTI is the workhorse. You may need to consider proximal trapezoid excision if the trapezoid is involved. No loss of pitch or grip strength occurs from this. This is a favorite question to show you with someone who has pain after a successful LRTI. And the question will be what do you do next or what do you think is wrong? And they'll show you an x-ray, which if you look at it, will show you that the trapezoid is part of the problem. Distal scaphoid excision is an option. You could do an STT fusion. What about thumb MCP hyperextension? If MP hyperextension exists in a patient with CMC arthritis and the thumb extends more than 30 degrees at the MP joint, the consideration would be to treat it, although the clinical outcomes may be the same. You could consider temporary pinning or a soft tissue capsulodesis, or you could consider fusing the MP joint. You would consider fusing the MP joint if it also happens to be arthritic. Extension of less than 30 degrees did not reduce clinical outcomes. So if they hyperextend less than 30 degrees, you can get away with just ignoring it and doing the CMC arthroplasty alone. Thumb CMC arthritis surgery outcomes. Systematic literature reviews have shown that no one procedure is clearly superior to another. The complication rates, ironically, are the lowest with plain old vanilla trapezoidctomy. What about wrist arthritis? This is usually in males, dominant hand. The radial lunate joint is rarely involved. The scapholunate ligament, slack, or scaphoid nonunion snack wrist are frequently the causative problems that can take years to develop or develop relatively quickly. Here is a classic. It's the progression of arthritis in the scapholunate advanced collapsed wrist. Stage one is the distal pole of the scaphoid. Two is the proximal pole. Three is midcarpal or capital lunate involvement. And four is pancarpal arthritis. Remember that in the scaphoid nonunion, stage two tends to spare the proximal scaphoid because it is stuck with the lunate and stays in extension. So here is your classic slide with our progressions. The radial scaphoid area distally. Then the second zone is proximal. The third area to be affected is in the area of the capital lunate interval. And notice the radial lunate interval is still happy. That's spared. For the slack or snack surgical treatments after rest splints, anti-inflammatories have failed, you can deal with the arthritic scaphoid contact zone. For the nonunion scenario, you could consider fixing or grafting the scaphoid. If you do a radial styloidectomy, don't remove more than three to four millimeters of the styloid, another classic test question. For stage two or worse, you would remove the scaphoid to stop the pain and then do either a proximal carpectomy or a four-corner fusion. For stage four, you would do a wrist fusion. What about doing AIN or PIN nerectomies? For stage one, 80 percent of patients reported less pain at two and a half years. Savage procedures, proximal carpectomy, must have intact capitate cartilage. You can interprove soft tissue if you want. Failures occur in patients more so when their age is less than 35 years old at presentation. You can do a radial capitate. Arthritis can still occur over time. And multiple studies show variable results over time. Generally, though, this is excellent for pain relief, modest motion, and good grip strength. If the capitate is too damaged, you could do PRC with modified soft tissue interposition, do an osteochondral graft, or better, do a scaphoid excision and a four-corner fusion. Other salvage procedures, scaphoid excision and the four-corner fusion, you want to make sure the lunate is positioned in neutral, not extended. You can fix it with K-wires, circular plates, or headless screws or staples. Nonunion and hardware loosening rates may be greater with circular plate, but that's older data. The plates have gotten a little bit better designed. You can do a direct comparison of PRC versus four-corner fusion. They, by and large, statistically have the same outcomes in two separate studies for pain relief, motion, grip strength, and satisfaction. So the only way you could really justify picking one or the other, especially on a test, would be if the capitate cartilage is blown, and then you would favor the four-corner fusion. For capital lunate arthrodesis with scaphoid and triquetral excision is possibly another option. Low nonunion rates in one study, although the screws tend to migrate. For fusion and beyond, you can do a wrist arthrodesis. It is super reliable, pain relief, better function and hygiene. Return-to-occupation data is strong. For wrist arthroplasty, this is best in low-demand patients, if for osteoarthritis. Commonly used in RA patients. Complication rates are high, loosening or failure. It's common in RA patients because they have low functional demands. Survival of the arthroplasty is nowhere near that of the data for hip and knee replacements. Five-year survival for wrist arthroplasty is 78 percent. Ten-year survival drops to 71 percent. Now we're going to switch gears. I've got about a dozen slides on Keenbox. This is also asked pretty thoroughly on test tests. It shows up commonly on the test, although the density of questions tend to be less, so you're looking at a few questions on this topic. History originates from Keenbox, who was an Austrian radiologist in 1910, wrote about this. Halton is the next guy who showed up on the literature scene. He was the one who pointed out that he thought 78 percent of his 23 patients had negative ulnar variance. The blood supply, the lunate, 74 percent have palmar and dorsal vessels. You have the Y, the I, and the X pattern. 19 percent have three or four vessel supply. Then you have seven patients, 7 percent, I'm sorry, 7 percent of the patients are at risk with only a single vessel to the lunate. The etiology of Keenbox, despite what all the lawyers may tell you, is unknown. Variable comorbid associations, it doesn't just from car, it just doesn't come from car accidents alone. Ulnar variance, successive joint leveling procedures suggest that ulnar variance may be related. However, as you might guess, multiple studies have shown there's actually no statistical correlation, which is sort of counterintuitive. There we go, my clicker got stuck. Geometry of the radius, lower inclination angle, and or anterior posterior slope may be factors. The geometry of the lunate, this is sort of annoying, but there are actually multiple types of lunate. The type I has a proximal apex, seen in ulnar negative variance, increased risk for fracture, and weaker trabecular pattern. The type II lunate is more rectangular, has an extra articular facet for the hamate, and is associated with neutral or ulnar positive variance. Now, I show a picture of this because I can never remember the types. So here we have the type I, which is more at risk for Keenbox, and the type II, which is on your right, and that's the one that has the extra facet for the hamate, and is thought to be a less risk for Keenbox, because it better manages load. Trauma, you can't tell if the fracture is a cause or effect. AVN can cause mid-lunate fractures that are visible in the coronal planes. It can have macro or micro trauma that may be implicated. Wrist extension increases intraosseous pressures in the lunate. As far as other etiology considerations, instability, again, we don't know if it's cause or effect. Venous stasis could be a predisposing factor. Arterial insufficiency can be caused by trauma, wrist positioning, vascular anatomy. The clinical presentation, it's more common in young males, 20 to 40 years old, several months of wrist pain, swelling, weakness. About 50 percent report low-energy trauma incident. That, again, may just be human nature to pick out something you think happened before your pain started. It's rarely bilateral, and the pain is typically dorsal. Immobilization and rest initially provide relief. As far as staging is concerned, again, this is sort of a busy slide. Stage 0 is when it only shows up on an MRI. Stage 4 is pancarpal arthritis. And then you have the intermediate stages. One is a normal lunate with evidence of some compression. Two is increased lunate density. That's the classic x-ray where it will look like a normal wrist, and then when you suddenly look at the lunate, it looks darker, but it has a normal shape. The 3A and 3B are the lunate is collapsed. You either have fixed scaphoid rotation and then fixed scaphoid rotation with SL ligament incompetency. So the difference between 3A and 3B is when the lunate shifts more than 60 degrees, and that's sort of an answer, like the scaphoid angle variable that is the threshold for between 3A and 3B is 60 degrees. You have the Stowell lunate index. I don't think it's that practical, but it sometimes is a factoid. You take the diameter of the lunate in the proximal distal diameter and divide that by the front-to-back diameter. That is the thickness of the lunate as seen on a lateral. And if that value is less than 0.53, it's considered to be lunate collapse. Keenbox disease treatment. MRI is the best imaging modality. Gadolinium contrast. Non-surgical treatment is ineffective in preventing deterioration. It may only have a role in pediatric patients. You could surgically rebalance the load by leveling procedures for the joint. You could try to revascularize the lunate or salvage it with a fusion or bone excision. As far as radial shortening, you need to have ulnar negative variants to do that and no surrounding arthritic changes. You can do metaphyseal osteotomies that heal quickly and reliably. For some stage 3B patients, that is fixed scaphoid rotation and carpal collapse, you can also respond to radial shortening too, which is, again, maybe counterintuitive. The appearance of the lunate and the degree of collapse is not altered by radial shortening. What happens is their pain gets better, but the lunate doesn't, like, reinflate itself after you do that operation. As far as ulnar lengthening, it's theoretically equivalent to radial shortening. However, it would require two bone graft junctions, more complicated. One large study showed there's 22% complication rate, so it is generally less popular due to the simplicity and union rates that are superior with radial shortening. For vascularized bone grafts, it requires an intact lunate cartilage shell. It can be used up to and including stages 3B, especially indicated for when you have neutral or positive ulnar variants, that is, when radial shortening is not an option. Lunate fragmentation or stage 4 is a contraindication. The vascular anatomy, you can use intercompartmental superretinacular arteries, or the favorite test question is the 4 and 5 extensor compartmental artery that brings a bone block from the dorsal distal radius. So for Keenbox, the favorite is the 4-5 ECA graft from the distal radius. Again, remember, vascular grafting will not alter your carpal height ratios. For capitate shortening, you have two parallel osteotomies in the waist of the capitate. You could remove 2 to 3 millimeters and use headless screw fixation. This would be approached between the fourth and fifth dorsal compartments. You might add a capitate-hammonate fusion to prevent proximal capitate migration. But the capitate-hammonate ligaments are strong and short, so even without a fusion, little migration occurs. This is sort of, again, a salvage operation just before doing a wrist fusion or something more radical. Now, what about PRC and lunate excision? You need, again, capitate head and lunate facet of the radius have to be in good condition for PRC. These would be in older, lower-demand patients, usually reserved for stage 3 patients or worse, avoiding the young people. You could do a lunate excision and combine that with SC or STT fusion. Some people have tried a lunate implant arthroplasty. Silicone doesn't work very well. Even with an implant, you may have to fuse the SC joint in order to prevent ulnar subluxation of the carpus. The results with lunate excision as a standalone R-variable, radial scaphoid arthritis usually occurs over time. You can see a picture here of a metal lunate replacement. So the treatment summary for stages 1, 2, and 3a with negative ulnar variance, you'd rebalance the lunate load by doing a joint levering procedure. Radial shortening is the fave. Ulnar lengthening is an option. You could also do a vascularized bone grafting in people who do not have ulnar negative variance. For stage 1, 2, or 3 with neutral or positive ulnar variance, you could do a capitate shortening with or without capital hamate fusion. Again, vascularized bone graft and or a combination of the above. For stage 3b with no lunate fragmentation or extrusion, you'd do a scapho-cap fusion or again the bone grafting with vascularized attachment or a combination of the above. For stage 3b where the lunate is not salvageable, you'd excise the lunate and maybe do a SC fusion. And for stage 4 for pancorporeal arthritis, you'd do a PRC or a wrist fusion. Whoa. So now we're going to go again through about 10 sample test questions. The following meteor is consistently elevated in osteoarthritis. You know, kooky question. It's, yeah, hello to the factoid, IL-6. Can't explain it. Got to turn this way to read this one. A 75-year-old patient presents with increasing thumb pain after a failure of non-surgical treatment. X-rays shown, which is the most appropriate operative procedure to address the pain and deformity? And this would be a CMC arthroplasty and MCP volar capsulodesis. And again, you're going to treat that because the MP joint is so extended. And they don't give you MP fusion as a choice. Molecular changes in the composition of articular cartilage secondary OA compared to effective aging result in which of the following increase? Sorry, increase in which of the following? That would be water content, which causes protoglycan concentration to decrease. In a slack wrist, which articulation develops the earliest radiographic signs of post-traumatic arthritis? That would be the distal radioscaphoid. What is the maximum amount of bone that can be safely resected while performing a radiostyloidectomy? Four. In the treatment of thumb basal joint arthritis, the splint that most consistently provides improved patient satisfaction while spurring wrist motion is? Yeah, okay. I'm sort of there. But again, I'm showing this because it was a question that showed up and may show up again. And, you know, this is about trying to focus your time as efficiently as you can in studying. What is the recurrence rate of digital mucus cysts after aspiration? Forty percent. What is the threshold radioscaphoid angle that differentiates stage three from A, Again, I think this is nitpicky, but the answer is 60 degrees. A 32-year-old patient presents with a four-month history of wrist pain. Range of motion exam demonstrates extension 45 degrees, flexion 45 for pronosupination. Radiographs shown in Figure 1. The surgical option that best improves wrist range of motion and provide pain relief is radioshortening osteotomy. So look at that X-ray. You can see the scaphoid is, I'm sorry, the lunate is dense. It looks like a white density. And you can see that there's ulnar negative variance, and so a radioshortening osteotomy is your best bet in that particular degree of Keenbox, which is not more than stage two or early as 3A. The use of a vascularized distal radius bone graft and treatment of Keenbox based on a common origin in the fourth and fifth extensor compartment arteries rise from which of the following vascular structures? This turns out it is the AIA, the anterior anterior osteous artery. You might want to make a note of that, because I think that might be the one factoid that did not make it into my notes, although I think I edited it last night to add it into the text. But the 4-5 ECA comes from the posterior branch of the anterior anterior osteous artery. I looked that up repeatedly to make sure I got that detail correct. Again, that's a little bit of an anatomy factoid. And that's it. Again, this is my comment to maintain perspective. I have a hard time preparing for this test myself, because I sort of freak out and try to study too much, or I get overwhelmed with the information. I made extreme effort to make these handouts and the detail in my talk comprehensive enough to protect you, but not to overdo it and fill you with sort of irrelevant factoids. So there's actually a fair amount of detail and facts in the handouts, but I don't think you need to know a lot more than what I've put in there in order to get these questions right. And I've gone through the last six years of tests to make sure that none of the test questions that have shown up on the SAE exams are outside the domain of the handouts I've created. Again, if you want any more information or want more copies of this material, either the slides, the handouts for the slides, or the sample questions, or the domain of the past six years of sample questions, you can email me at this address and I will send them to you.

osteoarthritis

Keen box

rheumatoid arthritis

SAE test

medications

surgical procedures