CARPAL BONE ALIGNMENT MEASUREMENT

▪︎ The  following  are  the  most  frequently used  measurements  to  define  carpal  bone  alignment- 

1) LC  angle :  This  is  helpful  to  quantify  midcarpal  misalignment. 

• A  normal  LC  angle  should  be  0  ±  15  degrees  with  the wrist  in  neutral . 

2) SL angle : one  of  the  major  determinants  of  SL  dissociation.

• Normal  values  range  from  30  to  60  degrees  (average, 47 degrees).

•Although  angles  greater  than  80  degrees  indicate  SL  ligament  disruption,  lower  readings  do  not  rule  out this  pathology. Values  less  than  30  degrees  are  not  unusual for  patients  with  STT  joint  osteoarthritis.

3) RL  angle :  This  gives  objective  evidence  of  the  dorsal  or palmar  tilt  of  the  lunate.  

•The  normal  RL  angle  should  be  0 ±  15  degrees.

4)  Ulnar Variance : Ulnar  variance  is  usually  measured  on  standard  PA  radiographs,  although  lateral  radiographic  projections  also  offer very accurate readings.  

• When  the   ulna  is  shorter  than  the  radius,  the  ulnar  variance is  negative,  and  when  longer,  it  is  positive.   

5) Carpal Height Ratio :  This  is  another  parameter  in  the  evaluation  of  carpal  collapse.

6) Ulnar  translocation  ratio :  In  some  instability  conditions, there  is  an  ulnar  shift  of  the  carpal  bones.  The  amount  of translocation  can  be  quantified  using  a  variety  of  techniques. 

Very commonly used  technique measures the perpendicular distance from the center of the head of the capitate to a line from the radial styloid, which extends distally and parallel to the longitudinal axis of the radius. The carpal translocation ratio (calculated as the ratio of this distance to the length of the third metacarpal) in normal wrists is 0.28 ± 0.03.

FROSCH POSTEROLATERAL APPROACH KNEE

INTRODUCTION 

* At least 7% of all tibial plateau fractures lie in the region of the posterolateral corner. Fractures in this region, usually cannot be adequately treated by using a lateral or anterolateral approach due to coverage by the fibular head and ligamentous structures in the corner region of the popliteus muscle. 

• To minimize this problem, a lateral approach  was described by Lobenhoffer et al.With this approach, a fibular osteotomy and detachment of the joint capsule and meniscotibial ligaments from the lateral tibial plateau  allow for the exposure and examination of the posterolateral joint surfaces of tibia. 

• Lobenhoffer approach provides a good view of the posterolateral corner of the tibial plateau but leads to extensive trauma of soft tissue there.

• Isolated posterior approaches allow for fragment fixation but visual control of fracture reduction is limited. 

* Therefore a modified surgical technique for the treatment of posterolateral tibial plateau fracture was introduced. Frosch described this posterolateral approach for fracture reduction and fixation combined with a lateral arthrotomy to visually control the fracture alignment and the joint surface. 

SURGICAL TECHNIQUE- 

 POSITION- 

• Patient lies in a lateral position. 

• Knee is supported by thick rolled pillow because the weight of the leg itself apply varus stress which causes the joint gap to be laterally opened. 

INCISION-

• An approximately 15 cm long posterolateral skin incision is required. Fibula head is used as an anatomical landmark. 

•Incision starts 3 cm above the joint line and follows the fibula in a distal direction. 

•Before the popliteal fossa is dissected a lateral standard arthrotomy is performed.

EXPOSURE- 

•The iliotibial tract is incised from the dorsal side and the dorsal fibers are detached from the Gerdy's tubercle. Thereafter, the lateral capsule is incised and the meniscotibial ligament is dissected approximately 2mm away from its insertion in the tibia, parallel to the joint surface.

•The entire lateral tibial plateau, including the posterolateral corner can be viewed by using this lateral arthrotomy. 

•For manipulation of the posterolateral fragment an additional posterolateral exposure of the fragments is necessary.

• Both approaches are performed through one skin incision. 

• After direct incision of the fascia, the peroneal nerve is exposed to the rear edge of the biceps femoris muscle. The nerve should be carefully dissected and gently mobilized for protection during the operation. 

• Blunt dissection of the popliteal fossa is initially performed between the lateral head of gastrocnemius and soleus and inspection begins on the muscle belly of soleus. 

• Popliteal vessels and the popliteus muscle are exposed.The popliteal vessels are protected by the lateral head of gastrocnemius which is retracted by a Langenbeck retractor. 

•Inferior genicular vessels are ligated only if necessary. 

•At distal edge of the popliteal muscle, it is pulled back towards the medial and cranial direction. Then the muscle is carefully detached from the dorsal surface of the fibula. 

•The soleus muscle  should be detached distally until the peroneal nerve at the fibular neck enters into the musculature. The peroneal nerve should not be detached after it enters into the musculature because muscle branches leading off in a atypical fashion can be easily damaged.

FIXATION- 

•Posterolateral fragments are manipulated and reduced from the dorsal side with a raspatory or with pointed reduction forceps. 

•Fragments after reduction are held in place using K wires. 

•Plain radiographs need to be performed intraoperatively. 

*After fracture reduction, a conventional radius, T plate can be pinched off with lateral gutters so that a two-hole L-plate is obtained. To buttress the fracture, the plate can be slightly under countered and dorsally fixed with conventional screws. 

The lateral edge of the plate lies immediately next to the fibular Head.

ADVANTAGES- 

1) Visual control of the reduction of the fracture is achieved through a conventional lateral standard arthrotomy, which is accomplished through the same skin incision. The anatomical reduction of the fracture and internal fixation are performed from the dorsal side. Therefore as a result of the modified posterolateral approach, the fragments are not denuded. 

2) The avoidance of fibula osteotomy in most patients with posterolateral tibial plateau fractures is an advantage. 

3) Damage to the upper tibiofibular joint and nerve injuries caused by an oscillating saw blade can be avoided by using the presented technique. 

4) Minimal soft tissue damage compared to Lobenhoffer posterolateral approach with fibular osteotomy. 

Limitation of the modified posterolateral approach - 

 1) It cannot be extended distally because of the trifurcation vessels that traverse the interosseous membrane approximately 5 cm below the joint line. However, because the lateral tibial metaphysis has a posterior inclination angle of approximately 45 degree and the posterolateral split fracture segment is usually less than 4 cm in cortical length, this limitation seems to have no problem in practice. 

2) Difficult to address additional medial plateau fractures when the patient is lying in the lateral position. 

3) Iatrogenic injuries of blood vessels can occur if the posterolateral plate is placed too far distally. 

4) Precise knowledge of the anatomy of the posterolateral corner is required. 

REMPLISSAGE PROCEDURE

The term 'Remplissage' means  'to fill in'.

• 1st described in 2007 by Wolf et al (1) as an adjunct to the arthroscopic anterior stabilisation procedure of the shoulder in order to address a large engaging Hill-

Sach's defect. 

•This technique has been reported to be effective in reducing the incidence of recurrent anterior shoulder instability, when used along with arthroscopic Bankart repair .

Indication- 

• This technique is performed when the Hill-Sachs lesion is very large and engaging the anterior glenoid with little overhead movement (i.e. dislocating very easily due to the large Hill-Sachs lesion, as well as the Bankart lesion). In these situations a Bankart repair alone may not be sufficient. Thus the development of the remplissage technique.

Operative Technique- 

 • The arthroscope is placed through the anterior portal to view the Hill-Sach's lesion on the posterior aspect of the

humeral head. Through the posterior portal, a burr is introduced to decorticate the Hill-Sach's lesion. 

• A triple-loaded large rotator cuff anchor is inserted into the Hill-Sach's defect through

the posterior portal. 

• Sutures are passed through the infraspinatus tendon and the posterior

capsule, which are then tied down with a 'parachute technique', hence successfully filling the defect on the humeral head.

Advantages - 

• The ability to make the Hill-Sach's defect

extra-articular, thereby eliminating engagement of the defect with the anterior glenoid rim. 

• It is ideally suited to instability patients who have large, engaging Hill-Sachs lesions and soft-tissue Bankart tears. These patients are known to have a higher failure rate after surgery than those with smaller lesions. The results of this technique in this difficult subset of traumatic anterior shoulder instability patients are significantly better (10% recurrence rate) than with an

arthroscopic Bankart repair alone (67% recurrence rate). 

Forearm and Wrist Fractures Eponym

Barton f.: an intraarticular fracture of the dorsal rim of the distal radius, usually resulting in subluxation of the radial carpal joint with the fracture site fragment.

chauffeur's f.: oblique fracture of the radial styloid caused by a twisting- or snapping-type injury; also called backfire f., Hutchinson f., and lorry driver's f.

chisel f.: incomplete, usually involving medial head of radius, with fracture line extending distally.

Colles f.: named prior to x-ray technology; implies a fracture of the distal radius, either articular or non-articular, with dorsal angulation of the distal fragment producing a silver fork deformity; generally associated with a fracture of the ulnar styloid.

Corner f.: a small bucket-handle-appearing fracture in the distal metaphyseal corner in a young child, often associated with child abuse.

de Quervain f.: combination of a wrist scaphoid fracture with volar dislocation of scaphoid fragment and lunate.

die-punch f.: an intraarticular fracture of the ulnar (volar) portion of the distal radius, usually caused by direct impaction of the lunate onto the lunate fossa of the distal radius.

Essex-Lopresti f.: a comminuted ¹radial head fracture with an injury to the ²distal radioulnar joint caused by disruption of the ³interosseous membrane, which can cause a proximal migration of the radius if the radial head is excised secondarily.

Galeazzi f.: typically a displaced fracture of the distal third or quarter of the radius with disruption of the distal radioulnar joint; called fracture of necessity because surgical fixation is required for reduction; also called a reverse Monteggia f., Dupuytren f., or Piedmont f.

Kocher f.: fracture of capitellum of distal humerus with possible displacement of fragment into joint.

Laugier f.: isolated fracture of the trochlea of the humerus at the elbow.

lead pipe f: typically in the forearm, a combination of greenstick fracture and torus fracture in the immature skeleton. Such fractures do not penetrate the entire shaft of the bone and have the appearance of a slightly bent lead pipe.

Lenteneur's f.: a distal radial fracture of the palmar rim, similar to Smith's type II fracture.

Monteggia f.: isolated fracture of proximal third of ulna, with anterior or posterior or lateral dislocation of radial head allowing angulation and overriding of ulnar fragments.

Moore f.: like a Colles f.; specifically, fracture of distal radius with dorsal displacement of ulnar styloid and impingement under annular ligament.

Mouchet f.: involves humeral capitellum.

Nightstick f.: undisplaced fracture of the ulnar shaft caused by a direct blow.

Piedmont f.: oblique f. usually at the proximal portion of distal third of the radius; obliquity runs from proximal ulnar to distal radial aspect, allowing distal fragments to be pulled into the ulna by the pronator quadratus muscle; fracture of necessity requiring

operative management.

Radial head f.: involves the most proximal part of the radius, a dish-shaped portion of bone.

radial styloid f.: involves distal radial tip of radius.

reverse Barton f.: dorsal displacement of carpus on radius, with associated fracture of dorsal articular surface of radius. The mechanism and appearance of this fracture are similar to those of a Colles f.

Skillern f.: open f. of distal radius associated with greenstick f. of distal ulna.

Smith f.: fracture of the distal radius in which the distal fragment is displaced volarly; also called reverse Colles f. This fracture was defined before the advent of radiography, and, classically, there are three types:

•Nonarticular

•Intraarticular; also called volar Barton f.

•Oblique nonarticular fracture near the joint line. 

Implants Q & A

 1)BIODEGRADABLE IMPLANTS 

•Metallic osteosynthetic devices have been extensively used worldwide.

•However there are inherent problems with the use of these metallic devices like stress shielding phenomenon, pain, local irritation etc.

•Retained metallic implants are always at the risk of endogenous infection.

•Release of metallic ions from these implants has been documented, though the long term effects of these are not yet known.

•Because of these reasons there is always need for a second surgery for implant removal after the bone has healed.

•The reasons mentioned above led to the evolution of biodegradable implants aiming toward true biologic solutions to reconstructive problems.

•Biodegradable implants are derived by transforming compounds that are present in nature to structural plastics.

•Organic molecules are polymerized to form strong fibers and solid compounds.

•When these polymers are implanted in patients, they degrade and are eliminated from the body in a  period of time.

STRUCTURE, STRENGTH AND PROPERTIES

• Widely used biodegradable materials include polyglycolic acid (PGA), poly-L- lactic acid (PLLA), poly-DL-lactic acid (PDLLA), PGA/trimethylene carbonate compolymers (PGA/TMC), and poly-beta-

hydroxybutyric acid (PBHBA).

• Polyglycolic acid (PGA) is a hard, tough, crystalline polymer with an average molecular weight of 20,000 to 145,000 and a melting point of 224-230°C.

• Polylactic acid on the other hand is a polymer with initial molecular weights of 180,000 to 530,000 and a melting point of about 174°C .

• In orthopaedic implants poly-L-lactic acid (PLLA) has been used more extensively because it retains its initial strength longer than poly-D-lactic-acid (PDLA).

•PGA belongs to the category of fast degrading polymers, and intraosseously implanted PGA screws have been shown to completely disappear within 6 months.

• PLLA on the other hand has a very long degradation time and has been shown to persist in tissues for as long as 5 years post implantation.

• For Orthopaedic usage, the main hindrance to development of bioabsorbable implants has been the question of obtaining sufficient initial strength and retaining this strength in the bone.

• With the use of self reinforcing (SR) technique the material was sintered together at high temperature and pressure, resulting in initial strengths 5 to 10 times higher than those implants manufactured with melt moulding technique.

•Though initial strengths of SR-PLLA screws are lower than SR-PGA, strength retention in the former is longer than the latter.

•Now a days, bioabsorbable implants show no difference in the stiffness, linear load & failure mode when compared with metallic devices.

• PGA is sterilized with ethylene oxide and PLA with gamma irradiation.

ADVANTAGES

•The biggest advantage is that since these implants have the potential for being completely absorbed, the need for a second operation for removal is overcome and long-term interference with tendons, nerves and the growing skeleton is avoided.

•Additionally, the risk of implant-associated stress shielding, peri-implant osteoporosis and infections is reduced.

•An important aspect is that these implants do not interfere with clinical imaging.

• This allows the use of modalities like MRI in knee and shoulder injuries at any stage after surgical implantation.

The other advantages include biodegradability of implants placed across mobile articular surfaces, as plus acceptable biocompatibility and resorption properties that reduces concern about complications.

• Bioabsorbable implants, due to the fact that they may resorb inside tissues, offer specific

advantages in specific fracture fixations; in the foot and ankle, where removal of the hardware is often mandatory prior to mobilization, they maybe beneficial in syndesmotic disruptions and Lisfranc's dislocations.

CURRENT USES

•Biodegradable implants are available for stabilization of fractures, osteotomies, bone grafts and fusions particularly in cancellous bones, as well as for reattachment of ligaments, tendons, meniscal tears and other soft tissue structures.

•The mechanical properties of the materials permit them to be used with metaphyseal and peri-

articular fractures where the loading is relatively low.

• Therefore, they have mainly been used for treating small-bone fractures such as ankle fractures

•Another suitable anatomic area for application is the elbow joint.

•They may be used for fixing fractures of the radial head, olecranon, capitellum and distal humerus.

•Nonetheless, comminuted fractures in these locations are not good candidates.

•Other conditions for which these implants can be used are fractures of the distal radial styloid, patella, glenoid fossa and acetabulum; osteochondral fractures in the knee, tibial plateaux, phalanx, calcaneus and talus; and also hallux valgus surgery.

•Biodegradable screws or rods may also be used for treating epiphyseal fractures.

•These have been used extensively for ACL reconstruction in the form of interference screws and transfixation screws.

•Meniscal tacks and biodegradable suture anchors have opened new avenues for soft tissue reconstruction in complex knee injuries.

•Biodegradable implants provide viable options for the repair and reconstruction of many intra-articular and extra-articular abnormalities in the shoulder, including rotator cuff tears, shoulder instability, and biceps lesions that require labrum repair or biceps tendon tenodesis.

•In spine surgeries, Bioresorbable implants can be used as interbody spacers in lumbar interbody fusion

•Bioabsorbable anterior cervical plates have been used and studied as alternatives to metal plates when a graft containment device is required. 

DEGRADATION

•Crystalline polymers have a regular internal structure and because of the orderly arrangement are

slow to degrade.

•Amorphous polymers have a random structure and are completely and more easily degraded

•Semi-crystalline polymers have crystalline and amorphous (random structure) regions.

•Hydrolysis begins at the amorphous area leaving the more slowly degrading crystalline debris

•Polyglycolide (PGA), is hydrophilic and degrades very quickly, losing virtually all strength within one

month and all mass within 6-12 months.

•Adverse reactions can occur if the rate of degradation exceeds the limit of tissue tolerance.

•So PGA in isolation is rarely used these days in the manufacture of bioabsorbable implants.

•Poly L Lactic Acid (PLLA), has a much slower rate of absorption.

• This is highly crystalline & has been documented to take more than five years to absorb.

• The ideal material is perhaps one that has a "medium" degradation time of around 2 years, as by that time the purpose for which the implant was put has been served.

DISADVANTAGES

•There are quite a few problems that need to be addressed with the use of these devices.

• Primarily the inadequate stiffness of the device and weakness compared to metal implant can pose implantation difficulties like screw breakage during insertion and also make early mobilization precarious.

•The other potential disadvantages are an inflammatory response described with bioabsorbable implants, rapid loss of initial implant strength and higher refracture rates.

• Problem areas of concern regarding faster resorbed implants are due to the fact that the body mechanisms are not able to clear away the products of degradation, when they are produced at a faster rate.

• This may lead to a foreign body reaction.

FUTURE

• Covalent linking of compounds such as HRP, IL-2, and BMP-2 to plates represents a novel method for delivering concentrated levels of growth factors to a specific site and potentially extending their half-life.

•BMP-2 covalently linked to resorbable plates has been used to facilitate bone healing.

SCAPHOID FRACTURE

INTRODUCTION- 

Views of scaphoid --> X - rotational (pronation/supination);  Y -sagittal  (flexion/extension);  Z - coronal  (radial/ulnar).

•The  treatment  of  scaphoid  fractures  requires  knowledge  of  the blood  supply, surgical  approaches, and  effects  that  fractures  and nonunions  of  the  scaphoid  have  on  carpal  kinematics,  stability, and  arthritis.

• New methods  of  scaphoid  repair have  been  developed  to  minimize  additional  surgical  trauma and  optimize  stabilization  until  healing. 

GENERAL CONSIDERATIONS 

INCIDENCE- 

• Scaphoid is  the  “keystone”  of  the  carpus.

•The  scaphoid  is  not  only  important  but  it  is  the  most  commonly  fractured  carpal  bone.  Scaphoid  fractures  account  for 60%  to  70%  of  all  carpal  fractures  and  are  second  in  frequency of  wrist  fractures  only  to  distal  radius  fractures.

• The  majority of  injuries  are  low-energy  injuries,  either  from  a  sporting  event (59%)  or  from  a  fall  onto  an  outstretched  wrist  (35%);  the remainder  result  from  high-energy  trauma  such  as  a  fall  from a  height  or  a  motor  vehicle  injury. 

• incidence more common in Males than females .

ANATOMY  OF  THE  SCAPHOID

• Skaphos in Greek means Boat, so its a boat shaped bone . Other terms like twisted peanut, as bean shaped are also used to describe this bone.

•Approximately  80%  of  the  scaphoid  is  covered  by  cartilage,  limiting  ligamentous  attachment  and  vascular  supply .

• The  scaphoid  is  divided  into  three  regions: proximal  pole,  waist,  and  distal  pole  (tubercle).

•The  scaphoid  is  oriented  in  the  carpus  with  an  intrascaphoid  angle  averaging  40  ±  3  degrees  in  the  coronal  plane and  32  ±  5  degrees  in  the  sagittal  plane.

☆intrascaphoid angle increases in scaphoid fracture.  

•The  scaphoid  is  the  only  carpal  bone  that  bridges  the  proximal  and distal  carpal  rows  and  acts  as  a  tie-rod.

•carpal  rows are  supported  by  stout  intrinsic  ligaments  and  reinforced  by  a volar and dorsal extrinsic ligaments. 

• The  scapholunate  interosseous  ligament  (SLIL)  is  a  stout ligament  connecting  the  scaphoid  to  the  lunate  and  is  the primary  stabilizer. The  dorsal  region of this ligament  resists palmar-dorsal  translation  and  gap  due to transverse collagen fibres arrangement,  whereas  the  volar  portion resists  rotation due to oblique collagen fibers arrangement.

•Radioscaphocapitate  (RSC)  ligament - 

It acts as fulcrum around which scaphoid rotates , scaphoid can also fracture around this fulcrum from Waist .

• Scaphocapitate and Scaphotrapezial ligaments  function as primary restraints of the distal pole .

•Vascular  Anatomy-  

• The  blood  supply  of  the  scaphoid  bone  is  predominantly  retrograde.  The  major blood  supply  to  the  scaphoid  is  via  the  radial  artery:  70  to  80%  of  the  intraosseous  and  proximal  pole  vascular supply  is  from  branches  of  the  radial  artery  entering  distally through  the  dorsal  ridge  of  the  scaphoid  between  the  proximal and  distal  articular  surfaces.  The  radial  artery  or  the  superficial palmar  arch  also  give  volar  branches  that  enter  in  the  region  of the  tubercle  and  provide  the  blood  supply  to  20%  to  30%  of  the bone  in  the  region  of  the  distal  pole.

• The  proximal  pole  also  gets  blood  supply  from  the  radioscapholunate ligament  (ligament  of  Testut,  a  neurovascular  conduit)  and directs  scapholunate  branches  from  the  palmar  and  dorsal transverse  carpal  arches.

•The  more  proximal  the  fracture,  the  more  likely  the  bone  is to  be  dysvascular  and  the  higher  the  risk  of  nonunion. Proximal pole  fractures  have  been  reported  to  have  an  incidence  of  avascular  necrosis  (AVN)  of  13%  to  50%.

•Combined  palmar  and  dorsal  approaches  taking  off the  soft  tissue  at  the  tubercle  and  the  dorsal  ridge  would  not  be advisable , majority of vessels enter  from these landmarks, to be left intact. 

BIOMECHANICS OF SCAPHOID FRACTURES 

• Hyperextension  past  95  degrees   is  the  usual  position  of  injury,  but  other  mechanisms  such  as  axial  loading  have also  been  postulated  to  produce  scaphoid  fractures. 

• Hyperextension mechanism usually causes Volar waist fractures, whereas Proximal scaphoid fractures occur due to dorsal subluxation  during  forced  hyperextension. 

• Nonunion  occurs in  10%  to  15%  of  all  scaphoid  fractures. 

 The  risk  of  nonunion increases  with: 

1.  Delay  of  treatment  for  more  than  4  weeks 

2.  Proximal  pole  fractures 

3.  Fracture  displacement  greater  than  1  mm 

4.  Osteonecrosis 

5.  Tobacco  use 

6.  Associated  carpal  instability  (DISI  =  dorsal  intercalated segmental  instability  with  a  scapholunate  angle  >  60 degrees  and  a  capitolunate  angle  >  15  degrees)  secondary to  humpback  (flexed  with  intrascaphoid  angle  >  45 degrees;  the  normal  intrascaphoid  angle  is  24  degrees) scaphoid  positioning. 

• For  nondisplaced  waist  fractures  treated  with  casting,  nonunion  rates  are  5%  to  12%. Nonunion  rates  for  displaced scaphoid  fractures  treated  nonoperatively  are  higher,  reaching 50%. 

•Untreated  displaced  fractures  of  the  waist  are  subject  to varying  degrees  of  these  forces  and  will  usually  angulate  as  the volar  bone  is  reabsorbed,  yielding  a  “humpback”  of  flexion  deformity of scaphoid. 

• Extension of lunate with its attachment to triquetrum  results  in  a  DISI deformity.  Ultimate  treatment  of  a  humpback  scaphoid  nonunion  with  DISI  requires  both  restitution  of  scaphoid  anatomy and  reversal  of  the  secondary  changes  in  carpal  kinematics.

• Untreated  scaphoid nonunion  progesses to scaphoid nonunion advance collapse (SNAC) and ultimately Pancarpal Arthritis. 

CLINICAL PRESENTATION- 

• pain and swelling  on  the  radial  side  of  the wrist .

• history  of  trauma,  such  as  falling  on  an  outstretched hand,  collision  of  the  wrist  against  a  person  or  heavy  obstacle, or  possibly  a  direct  blow  against  an  object.

 PHYSICAL EXAMINATION-

• On visual  INSPECTION , Wrists  with acute  fractures  may  have  swelling  and  bruising  in  the  radial aspect.

•“Snuffbox tenderness " which  applies  predominantly  to  waist  fractures,  represent  70%  of  scaphoid  fractures. 

•The  second most  common  type  of  scaphoid  fracture  is  proximal  pole  fracture,  at  20%. The  least  common is distal  pole  fracture, at  10%.

PALPATION - 

•To  palpate  the  anatomic snuffbox  for  the  waist  examination, palpate  just  distal  to  the  radial  styloid  in  the  “soft  spot.”

•Distal  pole  should  be  palpated  at  the  scaphoid  tubercle  on  the palmar  aspect  of  the  wrist  just distal to anatomic snuffbox .

•The  proximal  pole  is  palpated  dorsally  in  line  with  the second  ray  just  distal  to  the  dorsal  radius lip. 

☆  Scaphoid Shift Test / Watson test - 

- In  normal  wrists,  the scaphoid  cannot  flex  because  of  the  external  pressure  by  the  examiner’s  thumb. This  may  produce  pain  on  the  dorsal  aspect  of  the  scapholunate  (SL)  interval  owing to  synovial  irritation. 

- A  “positive”  test  is  seen  in  a  patient  with  an  SL  tear  or  in  a patient  with  a  lax  wrist;  the  scaphoid  is  no  longer  constrained  proximally  and subluxes  out  of  the  scaphoid  fossa  (straight  arrow).  When  pressure  on  the  scaphoid is  removed,  it  goes  back  into  position  and  typically  a  clunk  occurs. 

- Scaphoid shift test has  low specificity,  in  local  problems  inducing  local  synovitis  (e.g., occult  ganglion  or  dorsal  RS  impingement),  this  test  may  also provoke  sharp  pain  making  it  difficult  to  discern  whether  there is  an  abnormally  subluxable  proximal  scaphoid. 

DIAGNOSTIC IMAGING -

Radiography.

•five radiographic  views  for  the  assessment  of  scaphoid  fractures: wrist  posteroanterior  (PA),  lateral,  and  oblique  views;  scaphoid view;  and  clenched  pencil  view.

•true scaphoid  pisiform  capitate  (SPC)  lateral  radiograph taken for carpal alignment assessment. 

Scaphoid View

Clenched pencil view 

Computed  Tomography.

•Computed  tomography  (CT)  scanning is  helpful to delineate  scaphoid  fracture  displacement,  bony  morphologic  findings,  gapping,  sclerosis,  cysts,  and  evidence  of  healing(usually preferred to take at 3 months) . CT is  particularly  helpful  in  addressing  nonunions.  It  is  important  that  CT  scans  are  taken  with  overlapping  1-mm  cuts  along the  long  axis  of  the  scaphoid  and  with  coronal  and  sagittal reconstructions. 

•evaluating  the  vascularity  of  the  proximal pole  of  the  scaphoid.

Magnetic  Resonance  Imaging.  

•Magnetic  resonance  imaging (MRI)  is  best  to  determine  whether  there  is  occult  scaphoid fracture.  Specificity  is  90%  and  sensitivity  is  between  90%  and 100%,as  opposed  to  bone  scintigraphy,  which  is  92%  to  95% sensitive  and  60%  to  95%  specific.

•MRI  with  or  without contrast  enhancement  might  be  helpful  in  assessing  the  vascularity  of  the  bone,  but the  patient  history  and  CT  imaging must be taken into account. 

SCAPHOID FRACTURE CLASSIFICATION- 

•Scaphoid  fractures  have  been  classified  by  fracture  location (proximal,  waist,  or  distal),  plane  (transverse  or  oblique),  and stability  (stable  or  unstable). 

• fracture  classification  helps in management  of  injuries,for  rapid healing  with  minimal  complications  and  rapid  return  to  routine activities .

•following classification are used- 

1)Russe classification - 

The Russe classification predicts instability according to the inclination of the fracture line; for example, vertical oblique fractures. 

2)AO classification -  The AO classification breaks the fracture down into simple anatomic location (distal pole, waist, proximal pole) and comminution.

3)Herbert and Fisher classification -proposed a classification intended to identify those fractures most applicable for operative fixation and is commonly used throughout the literature .

Herbert  and  Fisher  classified  scaphoid  fractures according  to  their  stability.

4) Mayo classification- 

criteria for instability according to mayo is as follows: 

• >1 mm of fracture displacement

• A lateral intrascaphoid angle of  >35 degrees 

•Bone loss or comminution 

•Fracture malalignment 

•Proximal pole fractures 

•DISI deformity 

•Perilunate fracture-dislocation.

NOTE- 

* Displaced fracture --> displacement  is  defined  as  DISI  malalignment  of  1  mm [DISI  =  dorsal  intercalated  instability  with  scapholunate angle  >  60  degrees  and  capitolunate  angle  >15  degrees].

SCAPHOID NONUNION CLASSIFICATION 

1) Slade and Geissler Classification 

2) Lichtman Classification 

3) Alnot Classification 

MANAGEMENT OF SCAPHOID FRACTURES -

 •Up to 25% of scaphoid fractures are not visible on initial radio-graphs.

•All clinically suspected scaphoid fractures are treated as fractures with short-arm thumb spica cast immobilization until the cause of the symptoms is clarified since failure to treat a stable scaphoid fracture within 4 weeks increases the nonunion rate.

• Follow-up clinical examination and radiograph are taken at 2 weeks .

• MRI is done for diagnosing occult and acute fractures and is generally diagnostic within 24hrs of injury . 

SCAPHOID CAST - 

• position of immobilization- wrist slightly extended, and the proximal phalanx of the thumb included in a position of slight opposition (“scaphoid cast”).

☆ See here for Scaphoid Surgical Methods .

Mechanics  of  Fracture  Fixation - 

• Since  majority  of  the  scaphoid  is  covered  with  cartilage, fracture  callus  is  not  produced,  so  primary  bone  healing  is entirely  dependent  on  rigid  stabilization  of  the  fracture  fragments  until  healing.

•The  mechanical  effectiveness  of  internal  fixation  is  determined  by  the  bone  quality,  fracture  geometry,  fracture  reduction,  choice  of  implant,  and  implant  placement.

•Fracture  reduction  and  placement  of  the implant in the biomechanically  ideal  position  are  the  most important of  the five variables.

•screws  centrally  placed  in  the  proximal  fragment  of  the scaphoid  had  superior  results  compared  with  screws  placed  in an  eccentric  position. 

•Biomechanically,  the  longer  the  screw,  the  more  rigid  the  fixation,  because  longer  screws  reduce  forces  at  the  fracture  site and  bending  forces  are  spread  along  the  screws.

• Augmentation with K wires or mini headless screw necessary when central screw placement alone cannot provide rigid fixation. 

Techniques  for  Rigid  Fixation 

Implants  for  Rigid  Fixation  of  Scaphoid  Fractures -

•Implants  used  included  Kirschner  wires,  AO  compression screws,  headless  compression  screws,  plates,  and  bioabsorbable implants. 

SCREWS 

☆The  difference  in  pitch  between  the  leading  thread  (P1)  and  the trailing  thread  (P2)  of  the  Herbert  screw  governs  the  rate  of  “take-up,”  or  drawing together,  of  the  two  bone  fragments  to  produce  compression.

SURGICAL METHODS- 

•Click here for SCAPHOID SURGICAL METHODS 

1) Scaphoid  Open  Reduction  and  Internal  Fixation  From  the  Dorsal Approach/Mini-Open  Approach.

2) Scaphoid Mini-Open  Screw  From  the  Palmar  Approach - 

Technical points- 

•  Place  the  guidewire  as  centrally  as  possible  in  the  scaphoid. 

•  Consider  using  an  antirotation  wire. 

•  Common  error  is  using  a  screw  that  is  too  long. 

•  Subtract  at  least  4  mm  from  the  measured  distance. 

•  A  common  screw  length  for  an  adult  male  is  20  mm. 

•  Do  not  ream  past  the  far  cortex .

•  If  feeling  a  lot  of  resistance  (especially  when  reaming  over  wire),  stop  and look.  The  wire  may  be  bent  and  break  or  the  drill  bit  may  break .  

•  Beware  of  hoop  stresses.  Use  countersinking  to  avoid  excessive  hoop stresses  that  can  fracture  the  near  fragment. 

•  Consider  the  use  of  joysticks  to  gain  reduction. 

•  If  needed,  reduce  and  pin  the  lunate  in  neutral  (out  of  DISI) 

•  Consider  supplemental  fixation  for  more  stability.

Delayed presentation of Scaphoid waist fractures  - 

•Surgery  is  generally  indicated  for  delayed  presentation  of  a scaphoid fracture 4 to 6 weeks or more following injury. 

• patients with delayed presentation have a higher rate of non union .

COMPLEX SCAPHOID FRACTURES 

1)Combined fractures of Scaphoid and distal radius - 

• Early Surgery is planned in these patients with ORIF of distal radius fracture and mini open approach and fixation for Scaphoid fractures. 

2) Transscaphoid  Perilunate  Fracture-Dislocations 

•Perilunate fracture-dislocations  represent  approximately  5%  of  wrist  fractures  and  are  about  twice as  common  as  pure  ligamentous  dislocations.  •Transscaphoid perilunate  fracture-dislocation  is  the  most  common  type  of complex  carpal  dislocation.

• ORIF (via  Dorsal approach  or Palmar  or Proximal row carpectomy ) of these injuries have a good prognosis. 

Technical Consideration-

•It  is  imperative  during  reduction  to  restore  Gilula’s  lines  in  coronal  plane and  attain  neutral  radiolunate  and  capitolunate  alignment  in  the  sagittal plane.

COMPLICATIONS   of  Scaphoid  Fracture  Treatment - 

•The  most  common  complications are -

 1)delayed  union, 

 2) nonunion, 

 3) arthritis,  

 4) reduced  wrist  motion, and 

 5) loss  of  strength etc . 

MANAGEMENT OF SCAPHOID NONUNION- 

☆ Scaphoid Nonunion criteria 

failure  of  union  following  cast immobilization  or  surgical  treatment  of  6  months’  duration.

Evaluation  of  Scaphoid  Nonunion - 

•following things to be considered-

1.  Site  of  nonunion , At  the  waist  or  at  the  proximal pole? - more  proximal  the  fracture,  the  more  likely the  proximal  bone  will  be  dysvascular.

2.  Is  the  nonunion  displaced ?

3.  Is  there  a  humpback  deformity?

4. Is  DISI  present? 

- If  there is  humpback  deformity  and  carpal  malalignment,  they  may have  to  be  corrected  at  the  time  of  bone  grafting  and  fixation.

5.  Is  there  comminution,  cyst  formation,  or  cavitation? 

 • If  the  nonunion  is stable  and  well  aligned  and  bone  loss  is  minimal,  limited opening  in  the  nonunion  site,  curetting  as  necessary,  and cancellous  bone  grafting  may  be  appropriate,  followed  by  internal  fixation  by  a  headless  compression  screw. 

6.  Was  there  previous  surgery? 

-Any  previous  surgical  or  other  treatments should  be  taken  into  account  because  they  would  make  further treatment  more  complex.

7.  Does  the  proximal  pole  look  dysvascular?   

-In cases of diminished vascularity bone grafting have to be considered. 

- According  to  Green,  vascularity  was  best  determined  by punctate  bleeding.  MRI also helpful .

8.  Is  there  arthritis  (SNAC  wrist)?  If  so,  at  what  stage? 

- if  early  arthritis  (SNAC  I)  is  confined  to  the  radial  styloid,  radial  styloidectomy  and  scaphoid  bone  grafting  could  be  considered. 

- In advanced  arthritis with mild symptoms,  nonoperative  management  is  considered .  

- In arthritis  with severe symptoms ,  other  options may  include  partial  denervation  or  salvage  procedures  such  as scaphoid  excision  and  four-bone  fusion,  proximal  row  carpectomy,  total  wrist  fusion,  hemiwrist  arthroplasty,  and  total  wrist arthroplasty.

9.  Is  the  scaphoid  deformed  or  salvageable?

- sometimes the proximal or distal pole has fragmented and is not usable .

Treatment algorithm- 

HYBRID RUSSE PROCEDURE- 

The  hybrid  Russe  procedure  is  advantageous  because  it  is  effective  for  humpback  scaphoid  nonunions  with  DISI.

Steps - 

• Exposure of nonunion site 

• uptake of bone graft 

• Packing of Graft into the Nonunion site 

• Internal fixation with headless screw 

VASCULARIZED BONE GRAFTING 

Common choices are - 

1. 1,2  intercompartmental  supraretinacular  artery  (ICSRA) pedicle  (Zaidemberg)

2.  Pedicled  on  the  volar  carpal  artery  (Mathoulin) 

3.  Dorsal  capsular  pedicle  (Sotereanos) 

4.  Free  medial  femoral  condyle  graft  (Doi,  Bishop  and  Shin, Higgins 

Surgical  Fixation  of  Scaphoid  Nonunion  With Nonvascularized  Bone  Graft  (Distant)  Wedge  Graft 

Fernandez-Fisk  wedge  graft. - 

• This procedure is use to treat scaphoid nonunion with carpal instability. 

STEPS - 

(1)preoperative  calculation  of  the exact  scaphoid  length  and  form  based  on  comparative  radiographs  of  the  opposite  wrist,  (2)  the  use  of  a  palmar  approach, (3)  the  insertion  of  a  wedge-shaped  corticocancellous  graft from  the  iliac  crest  after  resection  of  the  pseudarthrosis,  and  (4) the  use  of  internal  fixation. 

Anterior Wedge Grafting - 

Unsalvageable Scaphoid Proximal Pole Nonunion  - 

Rib osteochondral autograft reconstruction of the proximal pole. 

Salvage  Procedures  for  Scaphoid  Nonunion   Advanced  Collapse

1) Radial Styloidectomy . - good for  stage  I  SNAC  arthritis  when  combined  with  procedures  to heal  scaphoid  nonunions.

2) Distal  Scaphoid  Resection  Arthroplasty.

•Indicated in waist fracture  nonunion  with  SNAC  I  styloscaphoid  arthritis  with significant  loss  of  wrist  dorsiflexion  and  radial  deviation  and pain  on  wrist  loading,  gripping,  and  range  of  motion.

3) Proximal  Row  Carpectomy .

• it is a simple motion preserving salvage operation done ideally in  a relatively  low-demand  patient  older  than  40  years  with  stage II  or  III  SNAC  with  no  to  minimal  capitolunate  degenerative disease. 

• removal of proximal row starts with Scaphoid then Lunate and then Triquetrum  with taking care not  to  damage  the  articular surface  of  the  head  of  the  capitate.

• Avoid injury to RSC ligament that prevents postoperative Ulnar translocation of the carpus. 

4) Intercarpal  Fusion.- Fourbone  (capitate-lunate-hamate-triquetrum)  fusion  with  scaphoid  excision  satisfactorily  treats  degenerative  SNAC  arthritis affecting  the  radioscaphoid  and  midcarpal  joints  while  preserving  an  anatomically  congruous  radiolunate  joint.

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