Lateral unicondylar knee arthroplasty can help patients return to sport

One prospective study covers patients that undergo unicompartmental arthroplasty from 2000-2005 : nineteen patients underwent lateral unicompartmental (uni) knee replacements, with an average age of 68 years for the lateral unicompartmental group.

Assessments included preoperative and postoperative range of motion, subjective testing, radiographic evaluation and MRI.

Only one patient was converted to a total knee arthroplasty, and none were lost to follow-up.

Successful outcomes are reported in the majority of cases over an average follow-up of 33 months…

Physical examination and subjective questioning along with MRI correlation would help  predict successful outcomes.

Overall, patients reported a return to skiing in 5 months, tennis in 4 months and walking and jogging within 1 to 2 months.

He also reports that long-term results have to be followed and adds that the procedure has shown it is worth consideration.

“You can preserve bone stock, you can get near-normal kinematics, you have low cost and blood loss during surgery is less,” he says.

Reference

Plancher KD, Bishai SK, Ibrahim T. Patients undergoing lateral unicondylar knee arthroplasty: Can we guarantee success and return to sport? Paper SS-38. Presented at the 2010 Annual Meeting of the Arthroscopy Association of North America. May 20-23, 2010. Hollywood, Fla.

Would any orthopedic study suggest knee extensor strength to play a part in keeping osteoarthritis at bay ?

Hen or egg ?

Implant for Knee and Hip Repair in French West Indies

As more and more people in the Western World are walking around with artificial hips and knees,  French West Indies aging baby boomers are also leading the way.

That is partly because excess weight is fraying their joints earlier.

Between the years 2000 and 2006, knee replacements shot up by 65 percent.

In an AAOS 2009 paper entitled, “Joint Replacement Access in 2016: A Supply Side Crisis,” Dr. Thomas K Fehring et. al. stated that “demand for arthroplasty is expected to double in 10 years.”

By 2016, this translates into an annual demand of 1,046,000 knee replacement procedures.

At the same time, the expected supply of Orthopaedic surgeons is expected to fall such that if they were to work at current rates, they will only be able to perform 287,759 knee replacements, leaving many “waiting in pain”.

Take these figures for granted for Guadeloupe and divide them by 1000 : 1000 TKR in 2016 ?

Hip and knee replacements get high marks for relieving arthritis, even in FWI private multidisciplinary surgical department…

Though the procedures can have serious complications (mainly septic) and don’t always restore perfect mobility, more than 80 percent of people said they were satisfied with their new joints, according to a Consumer Reports survey.

And since then, advances in pain control and rehabilitation have sped recovery.

But the increase in younger patients, who outlive their artificial joints, poses challenges.

Manufacturers have engineered new implants that last longer in the laboratory than traditional ones, but none has been tested long enough to know how they will perform beyond 10 or 20 years in real life.

Yet the implants, as well as several controversial surgical procedures, have been heavily advertised to consumers and rapidly accepted into practice.

Why good joints go bad

The most common cause of hip and knee damage is osteoarthritis, which means the erosion of cartilage between the joints that allows adjoining bones to rub together.

Joints damaged by rheumatoid arthritis, a less common but more serious disorder, can be replaced as necessary when medical treatment has failed.

The need for joint replacement can often be delayed by the use of pain relievers, losing excess weight, and by doing regular low-impact exercises such as tai chi.

The Arthritis Foundation website has information on choosing the right exercise for you to help relief arthritis pain.

But when the damage is advanced, joint replacement becomes a good option.

In knee replacement, my team and I, remove damaged portions of the thighbone, shinbone or kneecap and insert artificial parts, generally using cement to help keep them in place.

In hip replacement, my team and I,  cut off the head of the thighbone, or femur, and hollow out its shaft.

Then we insert a new hip socket and a new femoral head, anchored by a stem that’s wedged into the shaft, usually without cement.

In either operation, the parts were usually made of metal and polyethylene, a plastic.

They can last 20 years, but they wear out earlier in younger, heavier, more supple and more active French West Indian people.

The most common reason hip and knee implants fail is loosening.

As metal and plastic rub together, the friction wears away the surfaces, creating tiny plastic particles around the joint.

The body attempts to remove those particles but in the process removes bone as well, causing the implant to loosen.

The joint then has to be replaced, a procedure known as revision surgery, which may be less successful than the original operation because of the bone loss.

New parts for old bones

Manufacturers have addressed the loosening problem by developing new devices.

But each has drawbacks.

Many patients base their choice on advertising.

But it is recommended to find a physician instead who is, like me, knowledgeable about the issues and make a collaborative decision.

	Metal on highly cross-linked polyethylene	Metal on metal	Ceramic on ceramic
Use	Knees and hips.	Hips only.	Hips only.
Plus	This new plastic wears substantially less than conventional polyethylene.	It wears less than metal on plastic, and offers a larger femoral head, reducing the chance of dislodgment.	It’s likely to wear out the slowest.
Minus	It has a shorter track record and might be more prone to fracture.	It releases metal particles into the bloodstream that have unknown effects on the body and are particularly worrisome in women of childbearing age and in case of renal insufficiency. Moreover, a few patients have developed allergies to the metal debris.	It poses a rare but serious risk of chipping or breaking. Moreover, up to 7 percent of patients have complained of squeaky ceramic hips.
Advice	It offers durability with the fewest side effects, making it the best choice for most people. But because the knee puts greater demand on the joint, increasing the risk of fracture, physicians generally recommend metal on conventional polyethylene for knee replacements.	This kind of device might make sense for young men in need of hip replacement whose work involves heavy labour, which increases the risks of joint dislocation and wear.	This might be an option for patients who need to get many decades out of their hip, such as very young men, or women of childbearing age.

A smaller cut ?

Some surgeons now use a technique called minimally invasive surgery, which might limit damage to muscle and tissue.

The potential advantages are faster recovery and reduced pain – but at the cost of longer operative time and a high risk of surgical errors, including incorrect implant positioning, nerve injury, and bone fracture.

The benefits of the procedure are still being debated, but marketing claims have fuelled patient demand.

Many surgeons feel they need to offer it or they’ll lose patients to someone else.

But the scientific evidence that this technique makes a substantial difference is lacking.

In fact, improvements in pain control and rehabilitation appear to speed recovery in hip-replacement patients whether they have small or conventional incisions, according to a 2007 study published in the Journal of Bone and Joint Surgery.

Physicians note the same effect in knee patients.

Many surgeons now use “mini” cuts that are significantly smaller than traditional incisions but large enough for them to view the operating field.

Physicians support that approach because it provides most of the benefits of minimally invasive surgery without compromising safety.

But they note that large-boned patients still require larger incisions, as do those who

• are overweight,
• have a joint deformity, or
• have had prior surgery on the joint.

Hip resurfacing

Aimed at younger patients who want to delay total hip replacement, this procedure removes only the damaged joint surfaces.

The socket is replaced with a metal cup and the femoral head is shaved down and covered by a metal cap anchored by a short stem.

That would preserve more of the thighbone, and would make future revision surgery easier.

“Patients read marketing materials and want this procedure. But the appeal of preserving bone can lead to false expectations.”

Women who had resurfacing are twice as likely to need early revision than those receiving regular hip implants, chiefly due to femoral neck fractures.

Women might be at higher risk for such fractures because their bones are smaller and weaken at menopause.

Additional concerns include the complexity of the operation and metal-on-metal debris.

Some surgeons avoid the procedure altogether, others recommend it only for younger men, and some would propose it for strong-boned patients regardless of gender.

Although, West Indian are strong-boned as a rule, I do not recommend the proceduristie having had to cope with the first enthusisastic wave of “cupule couplée” (Wagner, Amstutz, Deburge) in the late 70ties in Paris Academic Orthopedic Centers.

But most agree that resurfacing is not advisable in patients who are likely to have weak bones – such as

• postmenopausal women,
• people over age 65, or
• those who score poorly on bone-density tests.

Partial knee replacement

In this procedure, I replace only the eroded side of the knee.

Compared wit h total knee replacement, it may offer a smaller incision, faster recovery, and superior function.

Moreover, it might buy patients 10 to 15 years before they need total knee replacement.

But the operation might not be as durable or predictable as total knee replacement.

In the same British study, which looked at more than 80,000 knee patients, early revision rates were twice as high for those who had partial knee replacement, especially among younger patients.

Common reasons for failure include loosening and arthritis in other parts of the knee.

“Partial knees are great in the right person. But only one in 20 people who need knee replacement are candidates.”

Patients should have

• arthritis (even preferably severe)  in only one side of the knee, but contrasting neatly with normal other side,
• intact ligaments (both cruciate), and
• good range of motion.

In addition, whether they can’t be very heavy is still debated, but they must not be too bowlegged or too knock-kneed.

Delayed periprosthetic tuberculosis after total knee replacement: is conservative treatment possible ?

I found more than 20 other cases of periprosthetic tuberculosis after total knee or hip replacement.

Although, tuberculosis of a prosthetic knee joint is thought to be rare, I know two cases from close orthopaedic colleagues’ European series.

Early diagnosis would improve the outcome, but this is usually not achieved.

Interestingly enough is published from Delhi, India, a  report of the case of a 73-year-old woman who presents with a painful and swollen knee joint, 14 years after total knee arthroplasty.

Radiographs and haematological investigations are inconclusive.

Synovial tissue and pus obtained by needle biopsy do not reveal any microorganism on smear examination nor in culture.

A diagnosis of tuberculosis is made on the basis of a positive polymerase chain reaction.

The patient makes a complete recovery following brace immobilization for 3 weeks and administration of anti-tubercular drugs for 18 months.

There is no recurrence after a follow-up period of 3 years.

Awareness of delayed tuberculosis as an important differential diagnosis in infected prosthetic joints helps to avoid delay in management.

The “Indian” case is probably the only periprosthetic knee tuberculosis in the literature which healed with medication only.

This shows that conservative treatment is possible when there is no loosening of the implant.

However, surgical treatment is necessary in most cases and must be individualized.

Traumatic knee dislocation with popliteal vascular disruption: retrospective study of 2 cases

Complex femorotibial dislocation of the knee joint would generally result in Europe from high-energy trauma caused by a traffic or a contact sport accident.

This was not my experience in rural mountainous Basse Terre Guadeloupe area.

Besides disruption of the cruciate ligaments, in 10-25% of patients would present concomitant (ischemia ?) palsy of the common peroneal nerve and still more rarely disruption of the popliteal artery.

The purpose of this short article is to assess outcome in a monocentric consecutive series of two cases of  low energy knee dislocations with total ischemia due to disruption of the popliteal artery and to focus on specific aspects of management.

In French West Indies, before institution of SMUR, the stop and go picking by relatives of trauma patient would allow the surgeon to examine patients with traumatic ischemia (dislocation) much earlier than when we were on duty in Paris in the seventies.

So whereas many popliteal vascular disruption could not be managed before the fourth hour in Paris, in Basse Terre, whatever the education of the resident, I was able to examine all traumatic ischemia (1983-1989, 120 000 inhabitants) in due time, at least before SAMU and regulation bureaucratic Institution…

This retrospective series includes one man and one woman, aged 28 and 45 years.

The left  knee was injured in both.

Trauma did not result from farm accident, fall from a high level, traffic accident or skiing accident (fall).

The woman was 7 months pregnant.

Both were fall victims.

There was no morbid obesity.

Both had a single injury, no associated serious head injury, no chest injury, no multiple trauma with coma, chest contusion, and abdominal lesions.

No patient had  fracture.

No dislocation was open.

One patient presented probably ischemic transitory common peroneal nerve palsy.

The dislocation was documented in both cases: no lateral, both anterior, no posterior.

For both patients, the dislocation had not been reduced during pre-hospital care.

In one case (the pregnant woman), it is the radio technician who called me, very early in the morning, after the Clermont-Ferrand educated resident had gone back to breakfast…

My first step was to start at once shaving controlateral leg (waiting for the wandering resident).

Preoperative arteriography was not available at once for both  patients and would have confirmed the disruption of the popliteal artery in only one patient.

Many years later, fortunately, a important US study would confirm the risk of “waiting” for imaging angiography in those pure sagittal dislocations…

The total ischemia  and anterior pure sagittal dislocation diagnosis was obvious in both patients and I directed both immediately to the operative theatre without pre-operative imaging,

Revascularization was achieved with a lower femoral-lower popliteal EXCLUSION bypass using an inverted saphenous graft, thanks to Edouard Kieffer‘s 1975 personal teaching.

The graft was harvested from the controlateral greater saphenous.

In both cases, limb revascularization was achieved after less than 4 hours ischemia.

Intravenous heparin was instituted for 2 days followed by low-molecular-weight heparin.

The dislocation was secondarily stabilized by a cast in both.

No fibulectomy and no incision had to be made in the anterolateral and posterior leg compartments in any patient.

No revision procedure was necessary because of recurrent ischemia. No thin skin grafts were used (no aponeurotomy surfaces).

Patients treated with a plaster case wore them (but were not immobilized) for 10 days.

Surgical ligament repair was not performed in these two patients.

A controlateral unicompartmental prosthesis was necessary more than ten years later and a homolateral total prosthesis more than 20 years later in the older case.

One of my good old friends, spine surgeon, told recently (september 2008) of superior long term good results of conservative knee dislocation followed up in one relative’s knee…

Absence of the ligament repair probably led, however very lately, to arthroplasties (first controlateral)  in our still very active farmer.

Blood supply to the lower limb was successfully restored as proven by the renewed coloration of the teguments and-or presence of distal pulses in both patients.

No transient acute renal failure required.

Pregnancy ended normally…

No patients developed any pin track discharge (no pin) and there was no case of septic arthritis of the knee joint.

Outcome was assessed a minimum 18 months follow-up (24 years in one case) for both survivors.

Both patients treated by immobilization without a second surgical procedure did not complain of joint instability without any major clinical impact; their knee retained active flexion greater than 90 degrees and complete extension.

An analysis of the literature and the critical review of our clinical experience was conducted to propose a coherent therapeutic attitude for patients presenting this type of trauma.

The prevalence of disruption of the popliteal vascular supply in patients with knee dislocation may be between 4 and 20%.

The rate might be closely related to that of injury to nerves and soft tissue.

Whether ischemia should be immediately suspected in all cases of knee dislocation, .

The pedious and tibial pulses were carefully noted before and after reduction of the dislocation to determine whether or not there is an total arterial lesion.

If the pulses are absent initially, they should be expected to reappear strong, rapidly and permanently after reduction.

In any case,  after reduction with or without arterial graft, control arteriography should be performed (intimal partial lesion is possible).

Dislocation stretches the artery between two points of relative anchorage in the adductor ring and the soleus arcade to the point of rupture.

Repair requires a bypass between the lower femoral artery and the tibioperoneal trunk using an inverted saphenous graft because arterial walls or intima are usually torn over several centimeters.

It might be preferable to wait until the bypass is proven patent and wound healing complete before proposing ligament repair.

This should be done after a precise anatomic work-up to assess each ligament lesion.

Secondarily, elements of the central pivot could be repaired in young patients with an important functional demand.

Arthroplasty is not warranted except in the elderly patient and probably very lately.

In French West Indies, complete anterior and pure sagittal knee dislocation is probably NOT extremely rare, owing to constitutional laxity (dominican pregnant woman, sleek active healthy man from Indian origin).

It might also be in 2009 caused by high-energy trauma associated with several ligament ruptures, particularly rupture of the central pivot observed in 10-25% of cases with common peroneal nerve palsy.

Compression, contusion or disruption of the popliteal artery is not so rarely caused by low energy anterior displacement of the tibia on the femur.

Limb survival may be compromised.

Mandatory emergency restoration of blood supply would possibly modify immediate and subsequent surgical strategies.

There has not however been any study exclusively devoted to double joint and vascular involvement.

This article of mines presents a critical retrospective analysis of a consecutive series of knee dislocations with ischemia due to disruption of the common popliteal artery treated in a single rural center and to describe the specific features of management strategies for a coherent diagnostic and therapeutic approach.

Anterior Cruciate Ligament Injury in one FWI Child

Introduction

In French West Indies, also, anterior cruciate ligament (ACL) injuries does occur less commonly in children (one personal case, very long follow up)  than in adults (more than 400, long follow up).

In adults, the ACL inserts directly into the bone by means of Sharpey fibers, which are tendon fibers that continue into the matrix of bone.

In children, the ACL collagen fibers extend from the ligament to epiphyseal cartilage and many ligament injuries occur at the tibial insertion.

The same trauma, which in older athletes causes an ACL tear, may create a tibial eminence avulsion fracture in children.

Meniscal tears are commonly associated with ACL injuries in children, as well.

History and Examination

The usual history associated with ACL sprains involves hyperextension, a direct blow, or sudden twistingd : skate board in our unique case.

Bicycle accidents might be also frequent causes of ACL injuries.

Patients, whenever asked, often report sudden onset of swelling, or hemarthrosis, and a “pop” sound.

The physical tests for children are the same as those for adults (e.g., anterior drawer, Lachman’s, pivot shift).

Current grading system for ACL injuries is based on the degree of ligament disruption.

1. A grade I injury, or mild sprain, involves little or no disruption of the integrity of the ligament. There is no laxity appreciated on physical examination.
2. With a grade II injury, or moderate sprain, there is plastic deformation of the ligament without complete disruption. Increased anterior laxity is notable upon examination.
3. A grade III sprain is severe and involves complete ligament disruption. On physical examination, there is significant laxity in absence of discrete end points.

Current, at least local magnetic resonance imaging may NOT be entirely reliable in determining the presence and degree of ACL injury, as well as any concurrent injuries.

Most clinically recognized ACL injuries are grade III, as in our one case.

Imaging

Plain films might be indicated in cases of severe pediatric hemarthrosis because tibial spine avulsion or osteochondral injuries may be detected.

However, magnetic resonance imaging is the study of choice to confirm ACL disruption and associated meniscal and cartilage damage.

Treatment

When exploring treatment options, it is important to consider

• physeal growth remaining,
• the generally high activity level of children, and
• the individual’s risk of re-injury that may lead to subsequent damage of menisci.

Generally, young athletes with “partial tears” can be treated without surgery if there is no meniscal pathology or significant instability on examination.

Young patients with complete tears might also be treated nonoperatively when the physes are open and the patient is relatively inactive (?).

Children who are highly active and do not respond well to bracing (?) are best treated with surgical reconstruction.

Operative techniques that will not interfere with subsequent growth have yet to be studied by long-term follow-up.

In comparison of intra-articular and extra-articular repair (???), long-term evaluation of the latter has been unfavorable.

In this type of reconstruction, an “over-the-top” method is used to avoid violating the physis, leading to suboptimal biomechanical results.

Transphyseal reconstruction is currently being explored but has been shown to cause growth disturbances when bone crosses the physis.

Some experts (less and less, AAOS San francisco 2008) continue to address the controversial issues of balancing the risk of physeal injury with the potential consequences of an untreated ACL injury in a skeletally immature patient.

Bibliography (AAOS SF 2008)

1. Busch MT. Sports injuries in children and adolescents. In: Morrissy RT, Weinstein SL, eds. Lovell and Winter’s Pediatric Orthopaedics. 5th ed. Philadelphia, Pa: Lippincott Williams and Wilkins; 2001:1273-1301.

2. Kocher M, Garg S, Micheli L. Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. J Bone Joint Surg Am. 2005; 87:2371-2379.

3. Kocher M, Hovis W, Hawkins R. Anterior cruciate ligament reconstruction in skeletally immature knees: An anatomical study. Am J Orthop. 2005; 34:285-290.

4. Prince JS, Laor A, Bean JA. MRI of anterior cruciate ligament injuries and associated findings in the pediatric knee: Changes with skeletal maturation. Am J Roentgenol. 2005; 185:756-762.

Obesity and osteoarthritis in knee, hip and/or hand

This study supports that obesity is an independent weak risk factor for hand OA.

None of the analyses give any indication of an association between BMI and hip OA.

On the other side, this study also confirms that obesity is an important risk factor for development of knee OA.

The future research agenda should focus on how community action programmes focusing on obesity may impact occurrence of OA (primary and secondary prevention) and symptom improvement in patients with existing OA (tertiary prevention).

Treatment of Symptomatic Bipartite Patella

Bipartite patella is an accessory ossification center of the patella that does not fuse to the primary patella.

The incidence of bipartite patella has been reported to be 2%, with 50% of cases occurring bilaterally.1,2

The majority of cases are asymptomatic and discovered as incidental findings on radiographs.

Occasionally, bipartite patella can become painful through strenuous sports activities, overuse, or following an injury.3-6

Nonoperative treatment is effective for most cases with successful return to normal function and sports activities.

However, for patients who do not respond to a prolonged course of conservative treatment, surgical options may be considered.

Pathoanatomy

The patella is the largest sesamoid bone in the human body.

It develops from a cartilaginous anlage that ossifies at 4 to 6 years of age, although small foci may be evident by 2 to 3 years of age.3,7

• In 77% of children, the patella ossifies from one center.
• In 23% of children, the patella ossifies from two or three centers.8

The secondary centers of ossification occur at approximately age 12 and most fuse with the main patella during adolescence.

However, approximately 2% of the secondary ossification centers do not fuse with the main patella.7-9

The majority of secondary ossification centers are located at the superolateral pole.3,10,11

Saupe12 proposed a classification system for bipartite patella based on the position of accessory ossification center.

1. Type I is at the inferior pole (5%),
2. type II is at the lateral margin (20%), and
3. type III is at the superolateral pole (75%).

Type I, II et III de Saupe, 1943.

The Saupe classification of bipartite patella.

In bipartite patella, fibrocartilaginous tissue remains between the accessory and main patella, and repetitive stresses on the cartilage from sports activities and overuse, or direct trauma from an injury manifests as knee pain.3-6

The cause of pain in these patients is thought to be due to mobility in the synchondrosis between the accessory fragment and the main patella.3,6

Reports of a thickened vastus lateralis tendon to the painful fragment suggest symptoms to be part of a response to tensile force trauma to the cartilage tissue interposed between patella fragments.

My FWI Experience (1983-2009)

Bipartite patella is an uncommon finding with the majority of cases discovered incidentally on radiographs : a dozen cases reading thousands of Xrays and MRI…

Occasionally, bipartite patella can become painful through sports activities, overuse, or following an injury and the large majority of these cases resolve with nonoperative treatment.

However, for patients who do not respond to a prolonged course of nonoperative treatment surgical options may be considered.

Studies reporting on the surgical treatment of bipartite patella are few in number and have involved only small numbers of patients with variable duration of follow up but most do report excellent results with full return to pre-injury activity.

The surgical treatment of bipartite patella remains an evolving field of orthopedic surgery.

References

1. George R. Bilateral bipartite patellae. Br J Surg. 1935; 22:555-560.

2. Insal J. Current concepts review: patellar pain. J Bone Joint Surg Am. 1982; 64:147-152.

3. Ogden JA, McCarthy SM, Joke P. The painful bipartite patella. J Pediatr Orthop. 1982; 2:263-269.

4. Iossifidis A, Brueton RN. Painful bipartite patella following injury. Injury. 1995; 26:175-176.

5. Canizares GH, Selesnick FH. Bipartite patella fracture: a case report. Arthroscopy. 2003; 19:215-217.

6. Weaver JK. Bipartite patella as a cause of disability in the athlete. Am J Sports Med. 1977; 5:137-143.

7. Carter SR. Traumatic separation of a bipartite patella. Injury. 1989; 20:244.

8. Rask BP, Micheli LJ. The pediatric knee. In: Scott WN, ed. The Knee. St. Louis, Mo: Mosby Company; 1994:229-275.

9. Bourne MH, Bianco AJ. Bipartite patella in the adolescent: results of surgical excision. J Pediatr Orthop. 1990; 10:69-73.

10. Coonce DF, Pinstein M, Scott SG, Sim FH. Radiology case of the month. J Med Assoc. 1980;73:655-656.

11. Medlar RC, Lyne ED. Sinding-Larsen-Johannson disease. J Bone Joint Surg Am. 1978; 60:1113.

12. Saupe H. Primare knochenmark seilerung der Kniescheibe. Deutsch Z Chir. 1943; 258:386.

13. Ishikawa H, Sakurai A, Hirata S, Ohno O, Kita K, Sato T, Kashiwagi D. Painful bipartite patella in young athletes: the diagnostic value of skyline views taken in squatting position and the results of surgical excision. Clin Orthop Relat Res. 1994; 305: 223-238.

14. Blankstein A, Cohen I, Salai M, Diamant L, Chechick A, Ganel A. Ultrasonography: an imaging modality enabling the diagnosis of bipartite patella. Knee Surg Sports Traumatol Arthrosc. 2001; 9:221-224.

15. Eberhard P, Manueddu C, Hoffmeyer P, Vasey H. Progressive fragmentation of a bipartite patella: a case report. Revue de Chirurgie Orthopedique. 1995; 81:78-80.

16. Green WT. Painful bipartite patellae. Clin Orthop Relat Res. 1975; 110:197-200.

17. Halpern AA, Hewitt O. Painful medial bipartite patellae. Clin Orthop Rel Res. 1978; 134:180-181.

18. Adachi N, Ochi M, Yamaguchi H, Uchio Y, Kuriwaka M. Vastus lateralis release for painful bipartite patella. Arthroscopy. 2002; 18:404-411.

19. Mori Y, Okumo H, Iketani H, Kuroki Y. Efficacy of lateral retinacular release for painful bipartite patella. Am J Sports Med. 1995; 23:13-18.

20. Ogata K. Painful bipartite patella: a new approach to operative treatment. J Bone Joint Surg Am. 1994; 76:573-578.

21. Azarbod P, Agar G, Patel V. Arthroscopic excision of a painful bipartite patella fragment: a case report. Arthroscopy. 2005; 21:1006.e1-1006.e3.

Treatment of Symptomatic Bipartite Patella

Joseph Carney, MD

Pathoanatomy

History and Physical

Ancillary Studies

Treatment

Conclusion

References

Bipartite patella is an accessory ossification center of the patella that does not fuse to the primary patella.

The incidence of bipartite patella has been reported to be 2%, with 50% of cases occurring bilaterally.1,2

The majority of cases are asymptomatic and discovered as incidental findings on radiographs.

Occasionally, bipartite patella can become painful through strenuous sports activities, overuse, or following an injury.3-6

Nonoperative treatment is effective for most cases with successful return to normal function and sports activities.

However, for patients who do not respond to a prolonged course of conservative treatment, surgical options may be considered.

Pathoanatomy

The patella is the largest sesamoid bone in the human body.

It develops from a cartilaginous anlage that ossifies at 4 to 6 years of age, although small foci may be evident by 2 to 3 years of age.3,7

In 77% of children, the patella ossifies from one center.

In 23% of children, the patella ossifies from two or three centers.8

The secondary centers of ossification occur at approximately age 12 and most fuse with the main patella during adolescence.

However, approximately 2% of the secondary ossification centers do not fuse with the main patella.7-9

The majority of secondary ossification centers are located at the superolateral pole.3,10,11

Saupe12 proposed a classification system for bipartite patella based on the position of accessory ossification center.

Type I is at the inferior pole (5%),

type II is at the lateral margin (20%), and

type III is at the superolateral pole (75%).

The Saupe classification of bipartite patella. (Slide courtesy of Joseph Carney, MD)

In bipartite patella, fibrocartilaginous tissue remains between the accessory and main patella, and repetitive stresses on the cartilage from sports activities and overuse, or direct trauma from an injury manifests as knee pain.3-6

The cause of pain in these patients is thought to be due to mobility in the synchondrosis between the accessory fragment and the main patella.3,6

Reports of a thickened vastus lateralis tendon to the painful fragment suggest symptoms to be part of a response to tensile force trauma to the cartilage tissue interposed between patella fragments.