Wrist arthroplasty

1. Total Wrist Arthroplasty
By Dr Kota Gandhi
II yr PG Orthopaedics
Kamineni Institute of Medical Sciences

2. • Total wrist arthroplasty (TWA) is an evolving procedure for the treatment of
arthritis of the wrist joint.
• Total wrist replacement maintains itself and provides good pain relief and
functional motion.
• Wrist arthroplasty provides the potential of improving hand strength secondary to
maximizing resting muscle tension as well as better positioning the hand for
functional use in daily activities.

3. Indications
• Destructive and painful wrist conditions resulting from rheumatoid
arthritis (RA), osteoarthritis (OA), or trauma
Contraindications
• Contractures of the wrist from tendon imbalance or spasticity because of
the potential abnormal loading on the implant
• Prior wrist infections or ongoing infection
• High demand occupations such as farmers or manual laborers; these
patients are better suited for a total wrist fusion
• Severely osteopenic or osteoporotic bone because poor bone stock will
not support the implant
• Unstable wrists owing to poor soft tissue envelopes because this will not
stabilize the implant

4. • Total wrist arthroplasty has traditionally required large bone resection from
the carpus and distal radius, and the results have been fraught with
difficulties including proximal and distal component prosthetic loosening and
instability.
• Problems related to implant loosening and instability have limited the clinical
application of TWA.
• New designs for TWA that are lower profile and more anatomic and utilize
minimal bone resection and a resurfacing arthroplasty concept are now
available.
• Over the past decade, a newer generation of wrist implants have been
developed that includes minimal resection of the distal radius, preservation
of the distal radio-ulnar joint, and resection of only the proximal carpal row.
• The resectional arthroplasty has had a recent history of failure whereas
reports of resurfacing arthroplasty are limited.

6. Clinical Examination
• One must evaluate active and passive wrist range of motion to determine any
presence of carpal subluxation or dislocation and distal radioulnar (DRU) joint
stability.
• Additionally, the integrity of the flexor and extensor tendons of the wrist and
hand should be assessed.
• One must perform a detailed history of the patient’s functional demands, activities,
occupation, hobbies, and home circumstances. Patients should be given a
trial of splint immobilization, and arthroplasty should be considered for those
who find that period of immobilization intolerable.

7. Imaging
• Posteroanterior, oblique, and lateral radiographs of the wrist are essential to
determine extent of wrist destruction. Conditions such as scapholunate
advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC)
should be noted.
• Additional views of the wrist or computed tomography can be obtained to
further evaluate arthritis or to assess less obvious intercarpal arthrosis.
• Wrist arthroscopy may determine whether limited wrist fusion is preferable.
Patients with a preserved radiocarpal joint should be considered for
motionsparing wrist procedures such as four-corner bone fusion or proximal
row carpectomy.
• Rheumatoid patients with radiocarpal arthritis but a preserved midcarpal joint
may be eligible for radiolunate or radioscapholunate fusion to maintain
midcarpal motion.

8. • The implant design consists of two components.
• The carpal component is fixated with two screws.
• The radial component has an articular inclination of 15 degrees to simulate the
anatomy of the distal radius.
• Distal and proximal stems are porous coated, which has the theoretical advantage of
allowing osteo-integration of the components.
• The size of the implant placed can be estimated preoperatively from the wrist
radiograph.

9. Positioning
• The procedure is performed under axillary block anesthesia with
sedation under tourniquet control with the patient in the supine
position and the extremity abducted with the hand on a hand table.
• A mini C-arm is mandatory to check the position of various implant
components intra operatively.

10. Exposures
• An 8-cm incision is made on the dorsal wrist,
centered on the axis of the long finger
metacarpal.
• Radial and ulnar skin flaps are elevated, and the
extensor retinaculum is visualized.

11. • The entire extensor retinaculum is elevated
from the sixth dorsal compartment all the
way to the radial attachment over the first
compartment.
• The septa between the compartments are
taken down to create a continuous flap of
extensor retinaculum. The elevation of the
extensor retinaculum stops between the
first and second compartments.

12. • The extensor tendons are then retracted to expose the wrist.
• The wrist capsule is elevated subperiosteally proximal to the radiocarpal joint as a
rectangular flap.
• The purpose of the wrist capsular flap is to cover and to provide stout capsular support for
the implant.

13. Step 1
The wrist is flexed to have an end-on view of the radius articular surface. A bone awl is
placed 5 mm below the dorsal articular surface of the radius just slightly radial to the Lister
tubercle.
The radial alignment guide is inserted into the cavity created by the awl, and
fluoroscopy is used to confirm that the guide rod is centered in the radius, both in the
anteroposterior and lateral planes.

14. Step 2
After confirmation of the position of the
alignment guide, the articular surface
of the radius is cut. The radial cutting bar
is slipped on the alignment guide, and
the radial cutting block is then mounted
onto the guide bar for positioning.
Kirschner wires are used to stabilize the cutting
guide block against the radius.

15. There are three rows of K-wire fixation points that correspond to a distance of about 2
mm between the rows. This is to allow placement of the guide bars more proximally or
more distally if necessary to achieve the appropriate amount of bone resection,.
After scoring the dorsal radius with the oscillating saw, the cutting block and the K-wires
are removed, and the radius cut is completed.

16. Step 3
The medullary cavity is broached to prepare the cavity.

17. A mallet is used to place the broach flush with the cut surface of the radius. A trial implant
is inserted and tapped with an impactor to fully seat it.
In most cases, this system is press-fit without the use of cement. An appropriate-sized trial
implant should not extend past the radial and ulnar corners of the distal radius.

18. Step 4
The carpal osteotomy is now performed at the level of the capitate head and across the
waists of both the scaphoid and the triquetrum.
To facilitate the carpal osteotomy, one should first remove the lunate. If the scaphoid and
the triquetrum are mobile, provisional K-wires are placed over the volar cortices of both
carpal bones to stabilize them during the procedure and to avoid interfering with the
osteotomy.

19. An appropriate carpal drill guide corresponding to the chosen implant size is selected. The
drill guide plate is placed over the long finger metacarpal, and a 2.5-mm drill bit is drilled into
the capitate. The depth of the drill hole corresponding to the implant size is marked on the
drill.

20. Step 5
The drill guide is removed, and the hole is countersunk. The cutting guide bar is inserted
into the hole in the capitate, and the cutting guide block is placed over the cutting guide
bar for carpal osteotomy.
K-wires are placed through the cutting guide block to stabilize the carpal bone similarly to
the surgical sequence in the radial component. The osteotomy is made a few millimeters
distal to the head of the capitate across the waist of the scaphoid and the proximal
portion of the hamate. The carpal component is inserted into the capitate hole. The
dorsal edge of the carpal component must be flush with the dorsal cortex of the capitate.

21. Step 6
Screws are inserted into the radial and ulnar
screw holes of the carpal component. A drill
guide with the saddle sitting on the index
metacarpal will be placed over the radial hole of
the carpal component.
A 30- to 35-mm long 2.5-mm drill hole is drilled
into the trapezoid across the carpometacarpal
(CMC) joint of the index metacarpal. A 4-mm
screw is inserted into the radial screw hole. The
ulnar hole is drilled in similar fashion, but the
screw does not cross the CMC joint. The 2.5-mm
drill bit is drilled into the triquetrum and the
hamate. A 4-mm screw that is 20 mm in length is
inserted into the triquetrum and the hamate.

22. A polyethylene trial component is inserted
over the carpal component. One should
feel a “pop” when the polyethylene
component fits snugly over the metal trial
component.

23. Step 7
Range of motion and stability are evaluated. The wrist should rest in a neutral position, and
one should observe 35 degrees of extension and 35 degrees of flexion with about 10 degrees
of radial- and ulnar-deviation angles. If the wrist feels lax, a thicker polyethylene implant is
inserted to add more volume to the wrist and impart more stability.
The trial components are removed. We place drill holes on the dorsal cortex of the radius to
accommodate three 2-0 braided permanent sutures for dorsal capsular repair to the radius.

24. Step 8
The carpal component is then inserted into the capitate, and the appropriate
length screws are placed.
The radial component is press-fit and impacted into the radius. An appropriate sized
component is fitted over the carpal component using an impactor. One must feel a
“pop” as the polyethylene component fits securely into the groove in the carpal
component.
If there is motion between the carpal bones because these bones have not fused
previously, a small bur is used to remove the articular surface between the triquetrum,
hamate, capitate, scaphoid, and trapezoid. Previously removed bone graft is packed
into the carpal intervals to achieve intercarpal fusion.

25. Step 9
The dorsal capsule is reattached to the distal margin of the radius.
The extensor retinaculum is sutured over the extensor tendons and secured either to the
remnant of the retinaculum or over drill holes in the distal ulna if the distal ulna was resected.
If the dorsal wrist capsular closure is not sufficiently tight, half of the extensor retinaculum can
be placed under the extensor tendons to augment the wrist capsular closure.

26. If there is arthritic change involving the DRU joint, a Darrach procedure is performed
by resecting the distal ulna at a 45-degree oblique apex-ulnar angle.
RA patients often have DRU disease, and distal ulna excision is performed to alleviate
future problems.
For OA patients with only radiocarpal disease, the radioulnar joint can be preserved.

28. Postoperative Care and Expected Outcomes
The wrist is immobilized in a short-arm splint for 2 to 4 weeks
depending on stability of the implant. A removable short-arm
splint is used for another 2 to 4 weeks.
During the splinting period, the patient will start active flexion,
extension, pronation, and supination exercises several times a
day. After 8 weeks, strengthening and passive exercises can be
started. After 2 to 3 months, unrestricted exercises are
initiated, but the patient is cautioned against repetitive strong
loading and hard work.

29. Thank You!