High Tibial Osteotomy – Complications 2

HTO-complications2
Persistent pain
– the most important determinant of sustained pain relief is accuracy of correction
– patients with > 15 of varus will likely do poorly, because you will not get them over farenough.
– also, patients with a high adductor moment may not do as well

Patient Selection
– what side is the angular deformity on.
– varus closing wedge osteotomies do poorly for valgus knees – the joint line is made oblique, the nerve is stretched, and if the MCL is stretched out, the closing of the medial side will simply make this more loose – DO THE VALGUS KNEE FROM THE FEMORAL SIDE.
– if there is significant MCL laxity in the varus knee, consider medial OPENING wedge osteotomy
– avoid inflammatory arthritides

Preoperative planning

– beware the calculation of correction based on angles alone. In a short person, a 15o wedge will not create a greater change than in a tall person!
– Try to consider where the osteotomy will put the mechanical axis – it should be shifted into the medial one third of the lateral compartment, approximating a 183 to 185 degree valgus weightbearing axis.

TKA – Approach To Patellar Loosening

TKA – Approach to Patellar Loosening

Factors Associated with Patellar Loosening
1. Cementing into shitty bone 5. Failure of bone ingrowth
2. Component malposition 6. Asymmetric bone resection
3. Patellar instability 7. Loosening of other components
4. Osteonecrosis 8. Metal backing (bad all around!)

– patellar wear is common, but loosening is uncommon, reportedly in 1-2% of cases
– metal backing sucked. Failure of bone ingrowth, delamination, rapid poly wear, metal on metal fretting.

Management

– if symptomatic, they should have it revised
– consider the etiology of the loosening – if there is patellar instability secondary to femoral or tibial malalignment, just revising the patella will not be good enough. You need to revise it all
– the optimal solution for the patella is to remove the component, re-prepare the host bone, and re-implant a new one
– if remaining bone stock is unsatisfactory, you may be forced to just take out the patellar prosthesis, smooth down the bone as best as possible, and leave it articulating with the prosthesis (patellar arthroplasty). Alternatively, do a patellectomy.

The C-Spine Injury With Increased Atlanto-Dental Interval

The C-Spine Injury with Increased Atlanto-Dental Interval

This was a case that Marcel presented to me, in which I killed the patient when I was unable to control the bleeding vertebral artery.

The point to this is the differential of the increased ADI – basically, you must think of ACUTE TRAUMA versus some other NONTRAUMATIC case.

The ACUTE TRAUMATIC injury with this x-ray finding is a transverse ligament rupture. I think this is quite rare, and certainly more uncommon than an odontoid fracture, which would be the more likely outcome from this sort of mechanism. In an adult, the ADI should be 4 mm or less (some say 3). Look for an avulsion on the CT scan. If a bony avulsion is documented by CT scan, the injury has a good chance of healing in a halo. If no avulsion is seen on CT, get an MRI to evaluate the ligament. If the ligament is ruptured, the injury is unlikely to heal, and should probably be fused primarily.

The NONTRAUMATIC causes would include rheumatoid arthritis, os odontoideum, Marfan’s or other connective tissue disorder like Ehler’s Danlos, Morquio’s syndrome, Down’s syndrome. You should think of these – PARTICULARLY RHEUMATOID. The injury that the patient has may not have much to do with their C1-2 instability.

In the case that Marcel presented me, the patient has some sort of rheumatoid disease, and the instability was actually chronic – he chose to treat the patient for symptoms only and is going to follow the instability along. I diagnosed it as an acute transverse ligament rupture (even though there was no avulsion on CT, and I did NOT order and MRI), and basically, after failing conservative Rx (put him in a halo), I bagged the vertebral artery during the C1-2 fusion and killed the patient.

Posterior Approach To C1-2

Posterior Approach to C1-2

– prone with Mayfield head rest or tongs & bed in reverse Trendelenberg (reduces venous pooling)
– midline incision from external occipital protuberance to C2 spinous process
– incise ligamentum nuchae & paravertebral muscles to expose posterior elements of C1-3
– avoid lateral exposure beyond 1.5 cm on C1 ring to avoid vertebral artery & cervical ganglion
– separate ligamentum flavum (posterior atlantoaxial ligament) from bone off the inferior aspect of C1
– separate posterior atlanto-occipital membrane from bone off superior aspect of C1
– never retract spinal cord at this level

Dangers:
– greater occipital nerve (C2) – runs beneath & over inferior oblique muscle laterally
– suboccipital nerve (C1 – motor only) – runs within suboccipital triangle laterally
– 3rd occipital nerve (C3) – lateral to suboccipital triangle
– vertebral artery – passes from transverse foramen of atlas immediately behind atlanto-occipital joint & pierces lateral angle of posterior atlanto-occipital membrane

ACL – Function

ACL- Function
Title: Factors Contributing to Function of the Knee Joint After Injury or Reconstruction of the Anterior Cruciate Ligament

Reference: AAOS Instructional Course Lectures, Vol 48, 1999

Main Message

Homeostasis is the key to joint function. The injured ACL knee is not normal, and efforts to reconstruct the ligament rarely ever make it “normal”. There are anatomic, kinematic, and physiologic factors that influence joint function, and these somehow balance out to a homeostasis in the normal knee. It is this “cellular homeostasis” that is rarely achieved. Few reconstructed knees are returned to normal, and normal ligaments are not being created surgically.

Points of Interest

The purpose is to discuss the concept of musculoskeletal function and to consider the various factors that contribute to the restoration of knee function after injury or reconstruction of the ACL.

Some studies have shown that the rate of degenerative arthritis is higher in those with ACL reconstructions! One study demonstrated that patients who were treated operatively had more advanced arthritis than those treated nonoperatively who also demonstrated more laxity in their knee than the surgical group at 10 years. (Probably a result of lifestyle differences.) Maybe the only effect of the reconstruction is to allow the athlete to “go back to strenuous sports and ruin the knee.”

Concept of Joint Function: joints are systems that are designed to transmit mechanical loads between components, and yet, by virtue of the fact that they are living structures, to maintain tissue homeostasis over a broad range of physical demands. The knee can thus be viewed as a kind of living, metabolically active, biologic transmission.

Concept of Envelope of Function: a range of loading that is compatible with, and probably inductive of, the overall tissue homeostasis of a given joint. Basically, a load and frequency distribution that defines a safe range of loading for a given joint. ACL injury to the knee redefines this envelope, such that the upper limit is probably not as high as before, but can be improved with rehab, etc.

Factors Contributing to Joint Function

Anatomic Factors: ligaments, tendons, menisci, articular cartilage, muscles, nerves, blood vessels, bone, limb alignment. Our current techniques do not recreate the normal macroanatomy (insertion sites, ligament morphology) or microanatomy (fibril size) of the native ACL. The neuroanatomy is not recreated either, making neuromuscular control different.

Kinematic Factors: tightening characteristics of the ACL fibers, neuromuscular control, muscle strength. Muscle tone influences the stability of the joint. Rehab may improve muscle strength and endurance, but may not restore normal levels of performance because of other factors. Proprioception is a major player.

Physiologic Factors: bone, cartilage, and soft tissue metabolism is altered in acute and chronic ACL knees. This can be documented in bone with bone scanning. Cartilage and soft tissues will respond to the mechanical environment that they are in – a certain amount of stress is good (helps to maintain tissue homeostasis) while too much stress disrupts this balance. The cellular response of chondrocytes and tenocytes is likely to be mediated through some way in which the mechanical environment alters the calcium concentrations within the cell, setting off signals for gene expression.

Thoughts….

The real key is in homeostasis on a cellular level and “envelope of function” on a system/joint level. This is a concept brought forth by the authors. We neither understand the response on the cellular level, nor do we really understand where the boundaries of the envelope of function are and how they are moved by ACL injury or reconstruction. It is interesting that the authors twig to the fact that the mechanical environment will have cellular effects.

MCQs – Upper Extremity/Elbow 1

MCQs-UE/elbow 1
MCQs-UE/elbow
– with respect to the anterior band of the medial collateral ligament – the origins of both the anterior and a posterior bands lies just posterior to the axis of rotation, and hence both are a bit tighter in flexion than in extension. Its lack of isometricity makes it sometimes necessary to release some of the MCL when doing an elbow release (unlike the lateral collateral – which is isometric).

– the posterior elbow capsule is also tight in flexion and thus has an important role as a static stabilizer too

– Baumann’s angle is about 72 degrees – the angle between the physeal line of the lateral condyle and the humeral shaft (does not equal the carrying angle)

– through and through gunshot wound to the forearm with nerve injury – expectant splinting of the wrist and hand; anticipate delayed exploration of the wound if the nerve doesn’t recover. Most nerve injuries in this setting are not transactions – they are concussive injuries from the zone of injury.

– high radial nerve palsy: PT to ECRB; FCU or FCR to EDC; palmaris longus to EPL (Riordan transfer) PL can also be hooked into APL – Brand)

– 18 months after nerve injury – plan tendon transfers! DO NOT do nerve repair.

– a 3 cm gap after injury – cable graft the nerve. DO NOT PULL ON IT TO GET IT APPOSED!

– EMG and NCS studies should be done at 3.5-4 months; some get a baseline at 2-4 weeks.

– remember to splint those with a radial nerve palsy!

– all the following could cause radial nerve entrapment: IM septum (or bands thereof), ganglia or synovial bands from radiocapitellar joint, leash of Henry, proximal arch of ECRB, arcade of Frohse. Anconeus is unlikely to cause entrapment.

– indications to explore radial nerve in humeral shaft fracture – open injury with nerve injury, secondary palsy after reduction, and Holstein-Lewis fracture with associated palsy. The only really well agreed upon one is open fracture with nerve injury. The other two are abit weak.

– for the distal 2/3 1/3 fracture (Holstein Lewis) – stick to your guns and put them in a cast!

– generally accepted rate of nerve growth is 1 mm per day – so about 30 mm per month (just over an inch per month). So for a laceration of the radial nerve 3 inches above the elbow – guess about 3 months for recovery of wrist extensors.

– for high radial nerve injury: order of re-innervation. Complicated question. The brachioradialis and ECRL obvious return first. The PIN goes through supinator and emerges (often giving off ECRB before going through supinator, or ECRB gets it from the superficial branch). As it emerges from the distal end of supinator, there are two main distributions of the PIN – one superficial to the EDC, EDMinimi, and ECU; and one that travels more deep to innervate APL, EPL, EPB, and finally most distally, Ext Indices Proprius. Notice that it looks like EPL might get innervated before EPB. Arguable. In any event, index finger extension will return before thumb retropulsion because EDC is reinnervated before EPL.

– so the order: EDC, EDMinimi, ECU (all the superficial ones); then APL, EPL, EPB, Eindicis (the deep ones)

– best treatment for humeral nonunion – ORIF

– when thinking about whether to amputate or reimplant traumatic amputations of the upper extremity (particularly hand) keep in mind that replanted digits distal to the insertion of flexor digital superficialis (into middle phalanx) do well, but replantation of single digits proximal to the FDS insertion do poorly and seldom restore hand function (because you’ll never get the PIP joint to flex!). Sharp lacerations, transcarpal, transmetacarpal, all thumb amputations should be re-implanted. Also consider replanting those with multiple digit amputations – may have to move the fingers around so that they are at the most functional place.
– “replantation of a single digit proximal to FDS seldom is indicated, particulary if it involves the index finger.” – for these, they might be better off with a ray amputation.

– distinguishing lateral

Biopsy Techniques – Principles

Biopsy Techniques – Principles

General Principles

– sufficient tissue for diagnosis must be obtained
– the least traumatic method compatible with obtaining the diagnostic tissue should be used
* the procedure should be done in such as fashion as to not compromise the definitive management of the lesion; that is, it should be done with anticipation of the possible surgical resection. (Which is why it should be done by the surgeon who is going to ultimately treat the lesion)

Closed Techniques

Fine needle aspiration
– generates cells for cytologic examination only; do not get an idea of what the histologic architecture of the tumour is.
– good for soft tissue extensions of bone tumors that are likely metastatic or hematogenous in origin.
– requires a pathologist who is good at reading them!

Core needle biopsy: (eg. Tru-Cut core needle, Jamshita needle)
– generates more tissue that is more representative of the tumor
– allows for some evaluation of the tumour architecture
– good for biopsy of soft tissue sarcoma and soft tissue masses arising from probable primary bone tumours.

Open Technique

– time honoured method of getting specimen, particularly intra-osseous lesions

Principles of Performing the Open Biopsy

* the location should be chosen in anticipation of the incision needed for definitive surgical management, and should be done by the surgeon who will definitively manage the case
– incisions should be longitudinal (unless around the iliac crest)
– sharp dissection should be proceed directly to the tumour, with no elevation of skin or subcutaneous flaps.
– the deep dissection should go through the involved muscular compartment in anticipation of resecting it later; uninvolved anatomic compartments, routine intermuscular compartments, and neurovascular structures should be avoided. Basically, you gotta think that whatever you go though needs to come out later if doing a wide resection. If you go through an uninvolved muscle, it will need to come out. If you go between two muscles, they both need to come out. If you go through neurovascular plane, the neurovascular structure will need to come out.
– ie. Go from skin, through deep fascia, through underlying involved muscle, directly to tumour.
– if pseudocapsule is encountered – take pseudocapsule and tumour directly underneath – sharp dissection for everything to avoid crush artifact. Do not put in formalin!
– if no soft tissue component – make a round window in bone with Midas Rex and take specimen

Send specimen for stat frozen section – warn the pathologist ahead of time to be ready for the arrival of the specimen.
– is the tissue adequate to make a provisional diagnosis?
– is it representative of the lesion?
– does the diagnosis make sense?
– is there sufficient tissue to perform the remaining definitive histologic analysis and send for C&S?

– if tourniquet is used, deflate and obtain meticulous hemostatis to avoid wound hematoma
– wound closure should be done in multiple watertight layers to avoid further local contamination with hematoma
– if drain is used, bring it out in line of incision

Rare Forms Of Osteosarcoma

Rare Forms of Osteosarcoma:

Telangiectatic Osteosarcoma:
– 50 yrs)
– prognosis worse than 1o osteosarcoma

Parosteal Osteosarcoma:
– arises from external surface of bone
– usu in 3rd decade of life involving posterior aspect of distal femur
– presents as painless mass behind the knee
– low-grade malignancy – osteoid & woven trabeculae separated by intervening fibroblasic stroma with minimal cytologic atypia
– wide resection has good local control (80% 5 yr survival) without chemo or radiation
Periosteal Osteosarcoma:
– most common on diaphysis of tibia & femur
– presents as a painful mass
– xrays – ill-defined diaphyseal surface lesion with variable matrix mineralization with a �scooped-out� appearance +/- sunburst reaction or Codman�s triangle
– usu no marrow involvement
– histologically, predominant cartilaginous component with neoplastic osteoid production; lobulated with peripheral condensations of spindle cells
– wide resection with neoadjuvant chemotherapy

Proximal Humerus 3

Proximal Humerus 3
be increased (intuitive) by operating on it.

If AVN were to occur, how significant would that be?

– symptoms and radiographic evidence may be delayed up to 2 years or more!

Þ Gerber, C., Hersche O., Berberat C., The clinical relevance of post-traumatic avascular necrosis of the humeral head., Journal of Shoulder and Elbow Surgery, 7(6): 586-590, Nov-Dec 1998.

· 25 patients with AVN at an average of 7.5 years.

· Group 1 – 13 with anatomic or near anatomic healing of fracture
– functional result comparable to hemiarthroplasty

· Group 2 – 12 with malunion of 1 or more of the fragments
– significantly worse functional (Constant) score than Group 1

Þ Hattrup S.J., Cofield R.H., Osteonecrosis of the humeral head: relationship of disease stage, extent, and cause to natural history, Journal of Shoulder and Elbow Surgery, 8(6): 559-564, Nov-Dec 1999.

· 151 patients with 200 affected shoulders (corticosteroids in 112, trauma in 37, Gaucher’s in 3, sickle cell in 3, radiation in 1, idiopathic in 44).
· 97 shoulders had replacement surgery.
· post-traumatic shoulders required surgery more often – cumulative rate of 77.8% by 3 years.

Clearly, AVN can occur regardless of the treatment (ie – a function of the actual injury). The incidence is increased by performing an open reduction. A wide spectrum of head involvement and severity of collapse exists, with a corresponding spectrum of clinical symptomatology. It would appear that the surgeon can affect some influence on the spectrum of symptomatology by successfully restoring the anatomy. Ie – if one is to undertake internal fixation, it should be acknowledged that the risk of AVN will increase (particularly with an extensive dissection), but that if it were to happen, the clinical significance of it may be reduced by successfully restoring the anatomy.
HEMIARTHROPLASTY

What are the results of acute hemiarthroplasty?

Þ Neer C.S., Displaced Proximal Humeral Fractures: II. Treatment of Three-Part and Four-Part Displacements. Journal of Bone and Joint Surgery, 52A: 1090-1103. 1970

· 117 patients – 61 three-part, 56 four-part
· Followed for 1 to 16 years, average 4.8. 37 followed from 1-2 years, 46 from 2-5 years, 14 from 5-10 years, and 20 from 10-16 years.
· 31 treated with closed reduction
· 43 treated with open reduction
· 43 treated with hemiarthroplasty.
· 100 point scale described in his previous article, based on pain (35 points), function (30 points), range of motion (25 points), and alignment (10 points). Excellent – above 89, satisfactory, above 80, unsatisfactory, above 70, failure, below 70.

11 three-part fractures treated with hemiarthroplasty: 1 excellent
7 satisfactory
1 unsatisfactory
2 failures.

32 four-part fractures treated with hemiarthroplasty: 4 excellent
27 satisfactory
1 failure.

In total, 43 patients with acute hemiarthroplasty, 39 excellent-satisfactory outcomes.

– no one, in North America or Europe,
has since been able to reproduce this success.

Others’ experiences with hemiarthroplasty:

Þ Movin T., Sjoden G.O., Ahrengart L., Poor function after shoulder replacement in fracture patients. A retrospective evaluation of 29 patients followed for 2-12 years. Acta Orthopaedica Scandinavica, 69(4), 392-4, August 1998.

· 29 proximal humerus fractures, average age 71; 18 treated acutely, 11 treated late
· overall poor Constant score means (38)
· substantial rest and activity related pain
· no difference between acute and late.

Þ Zyto K., Wallace W.A., Frostick S.P., Preston B.J., Outcome after hemiarthroplasty for 3 and 4-part fractures of the proximal humerus. Journal of Shoulder and Elbow, 7(2): 85-89, Mar-April 1998.

· 17 three-part, 10 four-part fractures followed for 39 months (average)
· Constant score: 51 for 3-part, 46 for 4-part
· ROM median: flexion 70, abduction 70, IR 50, ER 40
· 9 of 27 with severe or moderate pain
· 8 of 27 with severe or moderate disability

“It is disappointing that the results with respect to

Amputations II – 6

AMPUTATIONS 6
BKA – 25% increased energy expenditure
� decrease in push-off is compensated by increased work for hip extensors.
� increased quadriceps contraction for knee stabilization with increased work by hamstrings.

AKA – 65% increased energy expenditure
� primary concern is in knee stability.
� hip extensors have increased demand to maintain knee stability in stance phase.
� hip flexors have increased demand to accelerate the leg forward in pre-swing phase due to lack of plantar-flexion power.

STUMP PAIN

Stump pain remains a difficult problem in amputees, both in the early post-operative period and in the long-term.

POSTOPERATIVE MANAGEMENT

Continuous Regional Analgesia
Malawer et al. 1991, Clinical Orthopaedics and Related Research
� Bupivacaine infusions into peripheral nerve sheaths via catheters placed intraoperatively. 23 patients compared against matched controls. 11 required no supplemental narcotics; the remainder required a third of the narcotics that the controls required. An overall 80% reduction in narcotic requirement was seen.

LONG TERM MANAGEMENT

Prosthogenic
� By far the most common cause of persistent stump pain.
� Meticulous prosthetic fitting with appropriate training and follow-up is critical

Neurogenic
� Usually from neuroma formation.
� Can be treated with surgical excision, chemical ablation, electrical stimulation, or anticonvulsant medications.
� Phenol injection provides a relatively non-invasive, long-term solution.

Arthrogenic
� Common in the knee joint of BKA’s, and hip joint or SI joints of AKA’s
� Requires optimization of gait via prosthesis adjustment.

Sympathogenic
� Will benefit from sympathetic block when identified early

Abnormal Stump Tissue
� Bony exostoses, heterotopic ossification, adherent scar, ischemia,
� Meticulous surgical detail and careful wound care postoperatively.

AMPUTATION IN THE SETTING OF TRAUMA

Is there a certain population of patients with such severe injuries that they are better off with an amputation and immediate rehabilitation rather than multiple reconstructive procedures with prolonged recovery?

If so, how does one identify these patients?

In an attempt to prognosticate injuries: SCORING SYSTEMS

Mangled Extremity Syndrome Index (MESI)
Gregory et al. 1985 – Retrospective review of 17 patients
> 20 predicted amputation
Limb Salvage Index (LSI)
Russel et al. 1991 – Retrospective review of 70 patients
> 6 predicted amputation
Mangled Extremity Severity Score (MESS)
Johanson et al. 1990 – Retrospective review of 26 patients
>7 predicted amputation
Predictive Salvage Index (PSI)
Howe et al. 1987 – Retrospective review of 21 patients
> 8 predicted amputation

All represent GUIDELINES – None replace clinical judgment.
Based on poorly defined injury criteria, cumbersome application, small numbers, retrospective data, little functional outcome data.

Factors to Consider:
Vascular injury – location, duration of warm ischemia
Bony injury – severity of fracture
Soft tissue injury – crush component, reconstructive requirements,
contamination
Nerve injury – partial vs complete transection
Shock
Age
Injury severity score – ie. Other injuries, particularly to ipsilateral limb
Pre-existing health of patient
Time to operating room
Cost

Most agree that complete loss of sciatic or posterior tibial nerve function is an absolute indication for primary amputation.
AMPUTATION IN THE SETTING OF TUMOUR

PRINCIPLES

Obtain wide margins
– 5-7 cm margin of normal bone marrow

Plan the amputation to ensure viable flaps remain after resection.

Plan to excise the biopsy site and tract in entirety.

Individualize the therapy:

n Sarcomas of bone in lower extremities – often require
hemipelvectomy, hip disarticulation, or AKA

n Soft tissue tumours in lower extremities – may get away with BKA but will require AKA if popliteal neurovascular structures involved (esp. Posterior tibial nerve).