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Kiran Singisetti
or from gradual laxity of the posterior capsule or
posterior cruciate ligament (PCL) in cruciateretaining (CR) designed implants.
Technical factors that can lead to flexion
instability include too little distal femoral resection in a pre-existing flexion contracture, overly
aggressive posterior condylar resection with
undersized femoral implants, excessive posterior
slope on the tibia or over-release of the PCL in
the CR knee.
An appropriate extension gap can exist but
over-resection of the posterior femur and/or
undersizing or anteriorising of the femoral component will lead to a large flexion gap. This most
commonly occurs when using an anterior referencing system to size the femoral component. As
such, many surgeons prefer a posterior referencing system.
5. Answer C. Posterolateral bundle of ACL
The anterior cruciate ligament (ACL) is composed of two bundles, anteromedial (AM) and
posterolateral (PL). AM bundle of ACL is tight in
flexion and loose in extension. PL bundle of ACL
is tight in extension and loose in flexion.
The pivot shift test is performed with the
patient’s knee starting in full extension.
Maintaining internal rotation of the tibia, a
valgus force is applied while the knee is slowly
flexed to about 30°. The examiner will feel for a
subluxation of the lateral tibial plateau as it
reduces to its normal position. The PL bundle
of ACL is an important contributor to anteroposterior as well as rotational stability of the
knee; deficiency of this component causes a positive pivot shift test.
Robinson J, Carrat L, Granchi C, Colombet
P. Influence of anterior cruciate ligament
bundles on knee kinematics: clinical assessm ent
using computer-assisted navigation. Am J Sports
Med. 2007;35:2006–2013.
6. Answer E. Transverse scars may be crossed with
an incision in a perpendicular manner
If previous longitudinal incisions exist, try to
incorporate the most lateral incision that can
give adequate exposure. Due to the medially
based blood supply, it is better to elevate a fullthickness medial flap rather than a lateral one. If
you are unable to incorporate a lateral incision,
then maintaining the widest possible skin bridge
between incisions, without compromising exposure, is the best solution. Whe n prior transverse
incisions are present, it is safe to cross these
incisions in a perpendicular manner.
Respect the medially based vascular anatomy
of the skin and incorporate previous incisions.
Maintain full-thickness flaps, avoiding dissection
superficial to the deep fascia.
7. Answer E. Lateralisation of the patellar
component
Patellofemoral tracking in total knee replacement
is improved by the following steps: (1) external
rotation of the femoral component, (2) avoidance of internal rotation of the tibial component,
(3) joint line preservation, (4) medialisation of
the patellar component, (5) avoidance of an oversized femoral component, (6) lateralisation of the
femoral component and (7) secure repair of the
medial retinaculum during closure.
Lateralisation of the patellar component will
increase the Q-angle and tendency to cause lateral maltracking of the patella.
8. Answer B. Core decompression is a useful treat-
ment following subchondral collapse
SONK was previously related to ischaemia
leading to necrosis; it is now considered due to
a subchondral insufficiency fracture of the knee.
It is seen more frequently in women (M:F 1:3)
and typically affects those over the age of 55.
Patients often report sudden onset of severe knee
pain without significant trauma. This must be
distinguished from secondary osteonecrosis of
the knee. Bone scan may show a low uptake at
the lesion but has a limited role in diagnosis due
to its low specificity and sensitivity of diagnosis
of the condition. Some association with meniscal
root tears has been reported recently. The initial
treatment is non-operative. Core decompression
has a limi ted role in resistant cases prior to subchondral collapse. Arthroplasty (partial or total)
is considered when there is a progressive degenerative change of the joint.
9. Answer C. Patella baja
Patella baja is a common problem encountered
in total knee replacement following previous
high tibial osteotomy. This is more common in
164
Knee III Structured SBA
a closed wedge compared with an open wedge
osteotomy. Posterior tibial slope should also be
carefully considered, as a previous osteotomy has
a tendency to alter this.
Song SJ, Bae DK, Kim KI, Lee CH.
Conversion total knee arthroplasty after failed
high tibial osteotomy. Knee Surg Relat Res.
2016;28:89–98.
10. Answer B. Anterior knee pain
Medial unicompartmental knee replacement is
considered a suitable alternative to osteotomy
for single compartment knee degenerative
changes. The contraindications for this procedure include inflammatory arthritis, ACL deficiency, fixed varus deformity of more than 10°
and stiff knee. Patellofemoral degenerative
changes were previously considered a relative
contraindication, but more recent literature suggests the contrary. The Oxford Group report that
anterior knee pain and early patellofemoral
degenerative changes are not considered a contraindication for the medial unicompartmental
arthroplasty. Severe patellofemoral chondral
changes are still considered a contraindication
for this procedure.
Hamilton TW et al. Anterior knee pain and
evidence of osteoarthritis of the patellofemoral
joint should not be considered contraindications
to mobile-bearing unicompartmental knee
arthroplasty: a 15-year follow-up. Bone Joint J.
2017;99-B:632–639.
11. Answer E. Subvastus approach is an extensile
approach
Medial parapatellar approach is the commonest
approach used for total knee replacement. Lateral
parapatellar app roach can be used in a valgus
knee that is not correctable; the access to the
lateral compartment is good but can occasionally
cause difficulty in distal closure after deformity
correction. Midvastus approach is advocated for
an earlier rehab, as it avoids disruption of VMO
insertion. Both midvastus and subvastus
approaches are less extensile and should not be
attempted in obese patients and stiff knee and
complex knee conditions. MIS knee replacement
involves a smaller skin incision than does the
traditional medial parapatellar approach; it may
have less immediate post-operative pain but has
not been shown to have better function in the
long term.
12. Answer E. More expensive
The metal-backed tibial components are more
commonly used across most arthroplasty registries, although all-polyethylene tibial components have been reported to have better (or
comparable) survival and lower rates of infection, instability, tibial component loosening and
periprosthetic fracture. They are also cheaper
compared with metal-backed tibial components.
The disadvantage of all-polyethylene tibia is the
lack of modularity.
Gudnason A, Hailer NP, W-Dahl A,
Sundberg M, Robertsson O. All-polyethylene
versus metal-backed tibial components – an
analysis of 27,733 cruciate-retaining total knee
replacements from the Swedish Knee
Arthroplasty Register. J Bone Joint Surg Am.
2014;96:994–999.
Houdek MT et al. All-polyethylene tibial
components: an analysis of long-term out- comes
and infection. J Arthroplasty 2016;31:1476–1482.
13. Answer E. Vertical inclination of femoral
tunnel is associated with rotational instability
Too anterior femoral tunnel limits extension.
Likewise, too anterior tibial tunnel causes roof
impingement and limits extension. Too vertical
femoral tunnel can lead to a non-anatomical
femoral graft entry point, which has the potential
to cause rotational instability.
Pinczewski et al. (2008) described the optimal
tunnel position in their series of patients with
good outcome. In the sagittal plane, the femoral
tunnel was a mean of 86% posteriorly along the
Blumensaat line and the tibial tunnel was 48%
along the tibial plateau. In the coronal plane, the
tibial tunnel was 46% across the tibial plateau
and the mean inclination of the graft was 19°.
Pinczewski LA et al. Radiological landmarks
for placement of the tunnels in single-bundle
reconstruction of the anterior cruciate ligament.
J Bone Joint Surg Br. 2008;90:172–179.
14. Answer A. Bone–patella–tendon–bone
autograft
An autograft is tissue obtained from the patient’s
body. An allograft is tissue from a cadaver.
165
Kiran Singisetti
The most common choices available are
bone–patella–tendon–bone autograft, hamstring
autograft, quadriceps tendon autograft and various allograft options. Synthetic graft options are
now uncommon. The bone-to-bone healing with
the patellar graft has an advantage for athletes
who are interested in early return to sports,
although this has the risk of residual anterior
knee pain due to the morbidity associated with
patellar tendon graft harvest. Traditionally, the
bone–patella–tendon–bone graft was considered
gold standard amongst graft options, though
more recent studies have shown comparable
results with hamstring autograft.
Gifstad T et al. Lower risk of revision with
patellar tendon auto- grafts compared with hamstring autografts: a registry study based on 45,998
primary ACL reconstructions in Scandinavia. Am
J Sports Med. 2014;42:2319–2328.
Samuelsen BT, Webster KE, Johnson NR,
Hewett TE, Krych AJ. Hamstring autograft
versus patellar tendon autograft for ACL reconstruction: is there a difference in graft failure
rate? A meta-analysis of 47,613 patients. Clin
Orthop Relat Res. 2017;475:2459–2468.
15. Answer B. Decrease the size of the femoral
component
Symmetric gap issues (such as tight or loose in
both extension and flexion) are addressed with
proximal tibia. Resecting more proximal tibia
helps with tight extension and flexion.
Using a thicker insert or tibial augmentation
helps if loose in extension and flexion.
Asymmetric gap issues:
Extension good and loose in flexion can be
addressed with an increase in the size of the
femoral component; other options are to
translate the femoral component posteriorly or
to use a thicker insert followed by addressing
tight extension gap.
Extension tight and flexion good can be
addressed by either more distal femoral resection
or posterior capsule release.
Extension good and tight in flexion can be
addressed by decreasing the size of the femoral
component. Other options are to recess PCL and
address posterior slope of tibia if needed.
Extension loose and flexion good can be
addressed with distal femoral augmentation.
Other options are to use a thicker insert followed
by addressing tight flexion gap.
16. Answer C. Isolated posterolateral corner injury
Posterolateral corner (PLC) injuries are generally
associated with other ligament injuries but can
occasionally present as isolated inju ries. Dial test
is a useful assessment for PLC injuries; asymmetry of external rotation of foot on the affected
side at 30 degrees of knee flexion is seen only in
isolated PLC injury. Asymmetry of external rotation of the foot on the affected side at both 30°
and 90° of knee flexion is suggestive of combined
PLC and PCL injury. One of the causes of failure
of an ACL reconstruction is a missed PLC injury.
Ranawat A, Baker CL 3rd, Henry S, Harner
CD. Posterolateral corner injury of the knee:
evaluation and management. J Am Acad Orthop
Surg. 2008;16:506–518.
17. Answer B. Chondral changes
Chondral changes in the absence of osteophytes
is not a contraindication for meniscal transplant.
Osteophytes may interfere with the sitting of the
meniscal graft. Instability and malalignment
should be corrected before meniscal transplantation surgery. Most authors suggest that meniscal transplantation should be considered only in
symptomatic meniscal loss, although some consider this in asymptomatic lateral meniscus loss.
Inflammatory arthropathy, advanced arthritis,
obesity and prior infection are also considered
contraindications.
Figueroa F, Figueroa D, Calvo R, Vaisman
A, Espregueira-Mendes J. Meniscus allograft
transplantation: indications, techniques and outcomes. EFORT Open Rev. 2019;4:115–120.
Getgood A et al.; IMREF Group. International
MeniscusReconstructionExperts Forum(IMREF)
2015 Consensus Statement on the Practice of
Meniscal Allograft Transplantation. Am J Sports
Med. 2017;45
18. Answer B. Distal and anterior to the adductor
tubercle
In a cadaveric study Schottle et al. described the
medial patellofemoral ligament (MPFL) was
:1195–1205.
166
Knee III Structured SBA
found to insert 1.9mm anterior and 3.8mm distal
to the adductor tubercle.
Schottle et al. described the MPFL anatomical
insertion on the femur as the isometric point for
MPFL tunnel placement in reconstruction cases.
In their study, they defined a radiographic point
1mm anterior to a line extending from the posterior cortex and 2.5mm distal to the posterior origin
of the medial femoral condyle and proximal to the
level of the posterior point of the Blumensaat line.
Schottle PB, Schmeling A, Rosenstiel N,
Weiler A. Radiographic landmarks for femoral
tunnel placement in medial patellofemoral ligament reconstruction. Am J Sports Med.
2007;35:801–804.
19. Answer B. Early liner dislocation can be due to
impingement
Lateral unicompartmental knee replacement is at
a higher risk of liner dislocation. He nce, some
authors recommend using a fixed bearing prosthesis on the lateral side. Bearing exchange alone
should be carefully considered in selected
patients having correctable causes such as
impingement by remnant cement or bony spur,
larger gap (thin bearing at the index operation),
loss of entrapment by late bearing wear at the
long-term follow up or acute trauma.
Kim SG, Kim HG, Lee SY, Lim HC, Bae JH.
Redislocation after bearing exchange for the
treatment of mobile bearing dislocation in
medial unicompartmental knee arthroplasty.
Knee Surg Relat Res. 2018;30234–240.
van der List JP, Zuiderbaan HA, Pearle AD.
Why do medial unicompartmental knee arthroplasties fail today? J Arthroplasty 2016;31:1016–1021.
20. Answer E. Radial tear
Radial meniscus tears lead to decreased hoop
stresses of the meniscus and effectively a nonfunctional meniscus.
Abram SGF, Beard DJ, Price AJ; BASK
Meniscal Working Group. Arthroscopic meniscal surgery: a national society treatment guideline and consensus statement. Bone Joint J.
2019;101-B:652–659.
meniscal repair is the most common technique
and can be performed with a variety of suture
anchor devices. Inside-out technique has conventionally been considered a gold standard, as it
gives a strong repair though this is associated
with surgical risks. In this technique, the tear is
fixed by placement and fixation of the passing
sutures from the intra-articular region with the
use of special cannulae to the extracapsular area
over the capsule with a posterolateral or posteromedial incision. Outside-in technique is useful
for anterior third or horn of meniscus repair,
where the suture ends are tied over capsule.
Transtibial pull-out suture repair is useful for
posterior root avulsions. All-outside repair does
not exist and is a misleading option.
22. Answer C. Skeletally immature patients
respond well to non-operative management
The MRI image in Figure 8.4 shows a presentation of osteochondritis dessicans (OCD) with an
unstable lesion. It is more common in males.
Non-operative man agement is better tolerated
by the skeletally immature compared with young
adults. The knee (distal femur) is the most
common joint for OCD; other sites include the
elbow (distal humerus) and ankle (talus).
Though the image shows a lesion on the me dial
aspect of lateral condyle, it is described most
commonly at the lateral aspect of the medial
condyle (almost 80%). An unstable lesion is best
managed by fixation. Subchondral drilling is an
option for a stable but symptomatic lesion.
The International Cartilage Repair Society
(ICRS) scale of OCD lesions is based on the
arthroscopic assessment:
Type I: Stable lesion with a continuous but
softened area covered by intact articular cartilage.
Type II: Lesion with partial articular cartilage
discontinuity, stable when probed.
Type III: Lesion with complete articular cartilage
discontinuity, but no dislocation.
Type IV: Empty defect, or defect with a
dislocated fragment or loose fragment within the
bed.
21. Answer D. Outside-in
The three main techniques for meniscal repair
are inside-out, outside-in, all-inside. All-inside
23. Answer E. The posterior condylar axis is more
reliable than the transepicondylar axis for setting the correct femoral component rotation
167
Kiran Singisetti
Valgus knee deformity is defined by a tibiofemoral angle of greater than 10°.
The posterior femoral condyle on the lateral
side can be deficient in a valgus knee. Relying on
the posterior condylar axis in lateral femoral
condyle hypoplasia can result in internal rotation
of the femoral component. The anteroposterior
(AP) and the transepicondylar axis are more
reliable reference lines to achieve appropriate
femoral component rotation.
Popliteus release can be considered in knees
that are tight laterally in flexion but not in exte nsion. Iliotibial band release can be considered in
knees that are tight laterally in extension but not
in flexion. Knees that are tight laterally in flexion
and extension have popliteus tendo n or LCL
release (or both).
Lange J, Haas SB. Correcting severe valgus
deformity: taking out the knock. Bone Joint J.
2017;99-B(1 Suppl. A):60–64.
Whiteside LA. Selective ligament release in
total knee arthroplasty of the knee in valgus. Clin
Orthop Relat Res. 1999;367:130–140.
24. Answer D. Reduces risk of future knee arthritis
There is some controversy about conservative
versus surgical management of ACL reconstruction. While a structured rehabilitation programme may be suitable for some patients,
ACL reconstruction has been shown to improve
knee stability and thereby decrease the risk of
further meniscal injuries. There is no significant
evidence to suggest that an ACL reconstruction
protects against future development of knee arthritis. Repair of meniscal tear is more likely to be
successful if an associated ACL deficiency is
managed surgically.
25. Answer D. Sulcus angle of less than 140° may
suggest trochlear dysplasia
TT-TG distance measures the distance between
two perpendicular lines from the posterior cortex
to the tibial tubercle and the trochlear groove; a
value of greater than 20mm is usually considered
abnormal.
Sulcus angle is used to evaluate trochlear
dysplasia; an angle of more than 140° may indicate suspicion of dysplasia. The Insall–Salvati
method helps to assess patellar height. Normal
value is between 0.8 and 1.2.
The lateral patellofemoral angle is a measurement of the patellar tilt; it is the angle between
the line across femoral condyles and a second
line along the lateral patellar facet.
The Q angle is the angle between the line
joining the anterior superior iliac spine and the
centre of the patella and the second line joining
the centre of the patella to the tibial tubercle. It
can be measured both at flexion (15–20°) and
extension; however, it may not be accurate in
extension due to lateral patellar displacement.
Traditionally measured with the patient supine
and quadriceps relaxed, there has not yet been a
standardisation of the position and state of
muscle contraction while measuring the Q angle.
It is an indicator of the net lateral force exerted
on the patella by the quadriceps and the patellar
tendon.
Dejour H, Walch G, Nove-Josserand L,
Guier C. Factors of patellar instability: an ana-
tomic radiographic study. Knee Surg Sports
Traumatol Arthrosc. 1994;2:19–26.
26. Answer C. Medial and anterior displacement of
tibial tubercle
Distal patellar realignment procedures are used
to help with patella compression syndrome. They
can be classed as tibial tubercle anteriorisation
(Maquet procedure), medialisation (Elmslie–
Trillat procedure) or a combination (anterio risation and medialisation, as with Fulkerson procedure). Elmslie–Trillat is contraindicated with
medial patella facet arthritis.
27. Answer D. Raised joint line with decreased pos-
terior condylar offset
The joint line is inadvertently raised due to proximal displacement of the femoral co mponent if
the distal femoral bone loss is not taken into
consideration. This causes joint line elevation
and potentially a smaller revision femoral component being used. A common surgical mistake
is to use a thicker insert as the extension gap is
too large, but this raises the joint line.
Undersizing of the femoral component causes
decreased posterior condylar offset, which is a
cause of flexion instability. Posterior condylar
offset is the maximum thickness of posterior
condyles; some authors measure this as a ratio.
Posterior condyla r offset ratio is defined by Johal
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Knee III Structured SBA
et al. (2012) as the ‘maximal thickness of the
posterior condyle projecting posteriorly to a
straight line drawn as the extension of the posterior femoral shaft cortex, divided by the maximal thickness of the posterior condyle
projecting posterior to a straight line drawn as
the extension of the anterior femoral shaft cortex
on a true lateral radiograph of the distal quarter
of the femur ’.
Restoring joint line is another important consideration in revision knee arthroplasty. Some
landmarks for joint line are previous meniscal
scar, 10–15mm proximal to the tip of fibular
styloid, 25mm distal to the sulcus of the medial
epicondyle and 20mm from lateral epicondyle.
Clement ND, MacDonald DJ, Hamilton DF,
Burnett R. Posterior condylar offset is an inde-
pendent predictor of functional outcome after
revision total knee arthroplasty. Bone Joint Res.
2017;6:172–178.
Johal P, Hassaballa MA, Eldridge JD,
Porteous AJ. The posterior condylar offset ratio.
Knee 2012;19:843–845.
28. Answer D. Open chain (e.g. seated leg exten-
sion) exercises
Post-operative ACL rehabilitation is goal based
rather than time based. Open chain and isokinetic exercises should be avoided in the first few
weeks for ACL post-operative rehabilitat ion.
Closed chain knee exercises are those that are
performed with the foot in contact with the
ground or a machine. Clos ed chain exercises
tend to cause compression of joints, which helps
stabilise the joint. Open chain exercises tend to
involve more shearing force across the joint; this
may risk putting undue stretch on the graft.
There are some differences in a hamstring
(HS) versus bone–patella–tendon–bone (BPTB)
graft on how open chain exercises can be
delivered. For BPTB graft, open chain exercises
can be started from 4 weeks post-operative in a
restricted ROM of 90–45°, and extra resistance is
allowed, for example, at a leg extension machine.
For HS graft, open chain exercises can also be
started from 4 weeks post-operative in a
restricted ROM of 90–45°, but no extra weight
should be added in the first 12 weeks to prevent
graft elongation.
van Melick N et al. Evidence-based clinical
practice update: practice guidelines for anterior
cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus.
Br J Sports Med. 2016;50:1506– 1515.
29. Answer D. There is higher rate of failure in
allograft compared with autograft use in ACL
reconstruction
The transtibial technique involves femoral tunnel
drilling through the tibial tunnel; hence the tibia
is prepared first. The anteromedial technique of
femoral tunnel placement is independent of the
tibial tunnel. The anteromedial technique has
been shown to be more reliable in appropriate
femoral tunnel position compared with transtibial technique, thereby there is better functional
outcome.
There is no donor site morbidity with use of
allograft but it has the disadvantage of higher
failure rate. The incidence of anterior knee pain
and difficulty in kneeling is more common with
the patellar tendon (BPTB) autograft.
30. Answer E. Soft tissue grafts are better for trans-
physeal technique
There are increasing literature reports about the
risks of delaying surgery in symptomatic knee s
for the skeletally immature; this has the risk of
meniscal and chondral injuries. Both transphyseal- and physeal-sparing techniques have been
shown to have similar and low risk of growth
disturbance in skeletally immature patients. The
risk factors for growth disturbance involve highspeed drilling, use of interference screws, overtension of graft, large tunnel size and oblique
tunnel position. Soft tissue grafts with slightly
more vertical tunnels in the transphyseal technique reduce the risk of growth disturbance.
31. Answer E. Vertical incision has higher risk of
injury compared with oblique incision
The saphenous nerve is the longest sensory
branch of the femoral nerve (L1, L2, L3), supplying sensation to the medial aspect of the leg and
foot. Injury to the IPBSN in ACL reconstruction
is not related to age, gender or physique. An
oblique incision has been shown to reduce the
risk of injury to the IPBSN (Figure 8.8).
169
Kiran Singisetti
Table 8.1 Biomechanics properties of ACL grafts
Tissue Ultimate Tensile Load (Newton) Stiffness (N/mm) Cross-sectional area (mm2)
Intact ACL 2160 242 44
Bone-patella-tendon-bone 2977 620 35
Quadrupled hamstring 4090 776 53
Quadriceps tendon (10mm) 2352 463 62
Patella tendon allograft 1403 224
Achilles allograft 1189 74111 105
Figure 8.8 Knee arthroscopy incisions
Henry BM et al. Oblique incisions in ham-
string tendon harvesting reduce iatrogenic injuries to the infrapatellar branch of the saphenous
nerve. Knee Surg Sports Traumat Arthrosc.
2018;26:1197–1203.
Sanders B, Rolf R, McClelland W,
Xerogeanes J. Prevalence of saphenous nerve
injury after autogenous hamstring harvest: an
anatomic and clinical study of sartorial branch
injury. Arthroscopy 2007;23:956–963.
32. Answer D. Irradiated allografts have no donor
site morbidity but are more likely to fail
A BPTB graft has high donor site morbidity with
anterior knee pain being a common problem.
Most autografts have a higher tensile strength
than an intact native ACL. Allografts have the
lowest tensile strength but no donor site morbidity. Hamstring graft is commonly used for
double bundle ACL reconstruction. Allografts
are useful for multi-ligament reconstruction.
A hamstring graft takes a longer time for bonegraft integration.
33. Answer A. Acute ‘killer turn’ of the graft is
encountered in transtibial technique
The transtibial tunnel technique is the most
prevalent fixation method for the tibial side of
the graft tendon. However, the biggest drawback
of this method is the formation of a severe acute
angle in the posterior tibia, in which this acute
angle could decrease the thickness of graft
tendon, leading to permanent graft elongation
and ineffective graft pretension, resulting in
increased posterior knee laxity. The more acute
the ‘killer turn’ for the graft emerging into
the joint from a tibi al tunnel, the higher risk
of abrasion against the anterior ‘lip’ of the
internal tibial tunnel aperture, leading to the
enlargement of the tunnel inlet and attenuation
of the graft.
Therefore, the tibial inlay technique through
the direct posterior approach has been introduced to prevent frictional loss of the graft
tendon. However, there has been debate over
the comparison of the outcome between the
transtibial tunnel technique and the tibial inlay
170
Table 8.2 Advantages and disadvantages of various ACL grafts
Graft Advantages Disadvantages
BPTB
Hamstrings
Quadriceps
Allograft
I.A.B. (Intraarticular brace)
Excellent tensile strength
Good bone integration
Good return to
preoperative condition
Good tensile strength
Good return to
preoperative condition
Larger graft diameter
Integrity of the
extensor mechanism
Low patellar tendon morbidity
No damage to the infra-patellar
branch of the saphenous nerve
Lower incidence of anterior
knee pain
Reduction of surgical time
Lack of donor site morbidity
Less post-operative pain
Reduction of surgical time
Lack of donor site morbidity
Less post-operative pain
Quicker recovery
Extensor mechanism morbidity
Quadriceps weakening
Anterior knee pain
Longer recovery time
Lower mechanical strength
Longer time for bone-graft integration
Poor mechanical strength
Lack of long-term follow up studies
Lack of meta-analysis
Infection risk
Immune reaction risk
Delayed bone integration
Delayed bone integration
Immune reaction risk
Only for selected patients (>40 years, motivated,
symptomatic, needing quick recovery)
Knee III Structured SBA
(a) (b)
Figure 8.9 PCL reconstruction. (a) The tibial-inlay technique tries to avoid an acute turn with a bone plug in the extremity of the graft,
securing bone-to-bone tibial attachment with an anchor or screw. Femoral fixation is accomplished through 2 bone tunnels placed at the
1o’clock position and 3 o’clock position. Both strands are fixed at 90° of knee flexion. (b) The transtibial tunnel technique aims to simulate the
tibial and femoral anterolateral bundles’ (ALB) origins PCL
technique. Single bundle PCL reconstruction is
tensioned at 90° of flexion (Figure 8.9).
Owing to the anatomy of the PCL and the
complex nature of PCL injuries, there is no
consensus for a specific operative technique
when considering PCL reconstr uction.
Variations between the different reconstructive
techniques depend primarily on tunnel
171
Kiran Singisetti
placement, graft choice, graft positioning and
fixation, and the choice of an arthroscopic or
open surgical approach.
Winkler PW et al. Evolving evidence in the
treatment of primary and recurrent posterior
cruciate ligament injuries, part 2: surgical techniques, outcomes and rehabilitation. Knee Surg
Sports Trauma Arthrosc. 2021;29:682–693.
Zhang X et al. Evaluation of the theoretical
optimal angle of the tibial tunnel in transtibial
anatomic posterior cruciate ligament reconstruction by computed tomography. BMC
Musculoskelet Disord. 2018;19:436.
34. Answer E. Range of movement knee exercise in
a supine position in early stages
Hamstring exercises should be avoided in the
early stage to prevent increased posterior translation of the tibia.
Range of motion exercises initially should be
performed in the prone position to avoid stressing the healing ligament from hamstring activation causing posterior translation of the tibia.
Agolley D, Gabr A, Benjamin-Laing H,
Haddad FS. Successful return to sports in ath-
letes following non-operative management of
acute isolated posterior cruciate ligament injuries: medium-term follow-up. Bone Joint J.
2017;99-B:774–778.
Wang D, Graziano J, Williams RJ 3rd, Jones
KJ. Nonoperative treatment of PCL injuries:
goals of rehabilitation and the natural history of
conservative care. Curr Rev Musculoskelet Med.
2018;11:290–297.
35. Answer D. Histology shows haemosiderin
stained multinucleated giant cells
The MRI shows PVNS which is characterised by
an exuberant proliferation of synovial villi and
nodules. Haemosiderin disposition in the synovium gives the classic MRI appearance. It can be
a localised or diffuse presentation. Both male and
females are affected equally. Arthroscopic synovectomy gives good clearance of tissue in local
PVNS but not in the diffuse form. Local recurrence is common. External beam radiation is
sometimes used to reduce recurrence. Total joint
arthroplasty is useful in advanced degenerative
changes. Histology reveals mononuclear stromal
cells infiltrating the synovium, highly vascular
villi, haemosiderin stained multinucleated giant
cells and pigmented foam cells (histiocytes).
Metastasis of PVNS, both malignant and benign,
is extremely rare. However, there have been
documented cases of metastasis to the lung,
muscles and lymph nodes. The synovial proliferation of PVNS begins as a focal mass. The abnormal synovium is prone to haemorrhage with
minor trauma, resulting in haemorrhagic effusions. Thus, radiographs or MRI of early disease
may show only a focal mass and a joint effusion.
The classic MRI finding is of large effusion and
synovial masses with variably low signal intensity
on all MRI sequences because of haemosiderin
deposition related to prior haemorrhage. The
differential diagnosis includes infection and
other monoarticular arthritides such as gout,
amyloidosis, nodular synovitis, haemophilic
arthropathy and synovial chondromatosis.
Tan YC , Tan JY, Tsitskaris K. Systematic
review: total knee arthroplasty (TKA) in patients
with pigmented villonodular synovitis (PVNS).
Knee Surg Relat Res. 2021;33:6.
36. Answer C. Posterior condylar axis
The valgus knee is different from the varus knee
because bone loss occurs on the lateral femur
(in contrast to varus knee that shows anteriormedial tibial bone loss). The posterior condylar
axis taken alone as a reference is unreliable as
the lateral femoral condyle can be significantly
hypoplastic. Whiteside or transepicondylar
axis is more reliable but usually it is a combination of multiple reference points used in a
valgus knee.
This is important to identify if the surgeon is
measuring femoral rot ation by posterior referencing, which typically adds 3° to compensate for
the difference in sizes between the medial and
lateral femoral condyle. In the case of a hypoplastic LFC, the posterior referencing system
may need to dial in 5° or more to prevent
internal rotation of the femoral component.
Additionally, if there is more than 5mm of deficient bone on the posterior or distal femoral cut,
augments should be considered because a cement
mantle this large will lead to early loosening.
In a gap balancing technique, the tibial cut is
made first; this then acts as gu ide to plan the cuts
for the distal femur and posterior femur.
172
Knee III Structured SBA
Computer navigation allows a more consistent tibial cut and also assures a neutral leg
alignment.
Grifka J, Baier C, Maderbacher G. Improved
femoral component rotation in total knee arthroplasty: an anatomical study with optimized gap
balancing. Arch Orthop Trauma Surg.
2021;141:1669–1675.
37. Answer E: Pie-crusting to release the MCL
The pie-crust technique involves repetitive puncturing with a spinal needle on the medial aspect
of the knee. This allows for partial release of the
MCL thereby increasing the medial space to
allow safe passage of arthroscopic instruments.
This is done using an 18-gauge needle and by
making multiple puncture holes just proximal to
the joint line.
Bert JM. First, do no harm: protect the
articular cartilage when performing arthroscopic
knee surgery! Arthroscopy 2016;32:2169–2174.
Outside-in technique – passing sutures were
passed through the previously passed two spinal
needles from the meniscal rim to the meniscal
body across the meniscal tear. The two ends of
the passing sutures were tied onto the capsule,
under direct vision. The improper apposition of
the ends of the meniscal tear is an important
disadvantage of this technique. This technique
is useful for an anterior horn tear.
All-inside technique has been an increasingly
used method for most meniscal tears due to its
advantages: avoidance of opening accessory portals
and additional incisions, easy applicability, use of
bio-absorbable implants and relatively less risk for
injury to posterior neurovascular structures.
To enhance healing after meniscal repair, a
variety of augmentation techniques and biological
products have been introduced: needling, trephination, platelet-rich plasma, bone marrow aspirate,
hyaluronan-collagen scaffold, fibrin clot, fibrin
glue, mesenchymal stem cells and growth factors.
Doral MN, Bilge O, Huri G, Turhan E,
Verdonk R. Modern treatment of meniscal tears.
EFORT Open Rev. 2018;3:260–268.
Figure 8.10 Pie-crusting technique
38. Answer E. Smaller size femoral cutting block
with posterior referencing
The benefit of anterior referencing is that it
reduces the risk of anterior femoral notching
but the disadvantage is the risk of flexion
instability. The benefit of posterior referencing
is that it helps to recreate the posterior condylar
offset but it has the disadvantages of an increased
risk of femoral notching or overstuffing of the
anterior compartment.
39. Answer D. Outside-in meniscal repair
Inside-out technique has the strongest repair
(was first described by Henning), this is considered the gold standard for meniscal repair.
40. Answer C. More distal femoral resection
Symmetric gap issues:
Addressed with proximal tibia. Resecting
more proximal tibia helps with tight extension
and flexion.
Using a thicker insert or tibial augmentation
helps, if loose in extension and flexion.
Asymmetric gap issues:
Extension good and loose in flexion can be
addressed with an increase in the size of the
femoral component; other options are to
translate the femoral component posteriorly
or to use a thicker insert followed by
addressing tight extension gap.
Extension tight and flexion good can be
addressed by either more distal femoral
resection or posterior capsule release.
Extension good and tight in flexion can be
addressed by decreasing the size of the
femoral component. Other options are to
recess PCL and address posterior slope of
tibia if needed.
Extension loose and flexion good can be
addressed with distal femoral augmentation.
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