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Views: 0 Author: Site Editor Publish Time: 2026-07-10 Origin: Site
Introduction
The patella is the largest sesamoid bone in the human body and plays a critical role in knee extension by improving the mechanical advantage of the quadriceps tendon. Patellar fractures account for approximately 1% of all skeletal fractures, with inferior pole fractures representing a relatively uncommon but challenging subtype.
Unlike fractures involving the articular surface, inferior pole patella fractures occur in the extra-articular distal quarter of the patella and are frequently associated with disruption of the extensor mechanism. Because the inferior pole often consists of small and comminuted fragments, achieving stable anatomical reduction remains technically demanding.
Failure to restore patellar length and extensor mechanism continuity may result in:
Patella baja (low-lying patella)
Loss of knee extension strength
Anterior knee pain
Patellofemoral joint dysfunction
Post-traumatic degenerative changes
Although various fixation methods have been introduced, including partial patellectomy, basket plates, mesh plates, locking plates, vertical wiring techniques, and suture-based fixation, there is currently no universally accepted optimal treatment strategy.
This article introduces a modified tension band fixation technique combining Krackow suture, Nice knot fixation, and traditional tension band wiring for the treatment of inferior pole patella fractures.
Quick Answer: What Is the Best Fixation Method for Inferior Pole Patella Fractures?
Inferior pole patella fractures are difficult to fix because the distal fracture fragments are often small and comminuted, providing limited bone purchase. A modified tension band technique combining Krackow sutures, Nice knot fixation, and tension band wiring can improve fixation stability by converting tensile forces from the extensor mechanism into compressive forces across the fracture site, allowing early knee mobilization and reducing fixation failure risk.
Key Takeaways
Inferior pole patella fractures frequently involve extensor mechanism disruption and require restoration of patellar height and function.
Partial patellectomy is generally avoided because it may cause patella baja and alter patellofemoral biomechanics.
Traditional tension band wiring alone may fail because inferior pole fragments often cannot provide sufficient fixation strength.
The modified tension band technique combines Krackow sutures, Nice knot fixation, and tension band wiring to enhance fixation stability.
This technique allows early functional rehabilitation with favorable clinical outcomes.
Inferior pole patella fractures represent approximately 9.3%–22.4% of all patellar fractures.
The inferior pole differs anatomically from the main patellar body:
It has no articular cartilage coverage.
It represents approximately the distal one-quarter of the patella.
It serves as the attachment site of the patellar tendon.
Injury frequently disrupts the extensor mechanism.
Most inferior pole fractures are caused by:
Direct trauma
Sudden eccentric contraction of the quadriceps
High-energy injuries
The quadriceps tendon, patella, and patellar tendon form a continuous extensor mechanism.
When an inferior pole fracture occurs, the quadriceps force transmitted through the patella tendon may cause:
Inferior fragment displacement
Loss of patellar height
Difficulty maintaining reduction
Therefore, the primary surgical goals are:
Restore patellar length.
Reconstruct the extensor mechanism.
Achieve stable fixation.
Allow early postoperative rehabilitation.
Multiple surgical techniques have been described:
Partial patellectomy was historically used for severely comminuted inferior pole fractures.
However, this technique has several disadvantages:
Shortening of the patella
Increased risk of patella baja
Altered patellofemoral biomechanics
Increased contact pressure within the patellofemoral joint
Because of these concerns, modern treatment strategies generally favor patella-preserving fixation techniques whenever possible.
Specialized implants such as:
Basket plates
Mesh plates
Locking plates
have been developed to improve fixation of small inferior pole fragments.
Advantages:
Larger contact area
Improved fragment capture
Early knee motion without external immobilization
However, limitations include:
Implant irritation
Patellar tendon injury risk
Screw loosening or failure
Limited availability in many countries
Yang et al. reported the use of separate vertical wiring fixation in 25 patients with inferior pole patella fractures.
At a mean follow-up of 22 months:
Mean Bostman score: 29.5 points
However, this technique may have limitations in:
Osteoporotic bone
Highly comminuted inferior pole fractures
because the small fracture fragments cannot provide sufficient fixation strength.
In 1979, Müller et al. introduced the classic tension band wiring technique for patellar fracture fixation.
The traditional construct consists of:
Two parallel Kirschner wires (K-wires)
A figure-of-eight stainless steel wire loop
The biomechanical principle is based on converting tensile forces generated by the quadriceps mechanism into compressive forces at the anterior fracture surface during knee flexion.
This technique has become one of the most commonly used fixation methods for patellar fractures because of:
Simple surgical procedure
Reliable fixation strength
Low implant cost
Wide clinical availability
Biomechanical studies demonstrated that traditional tension band fixation can withstand loads up to approximately 395 N, exceeding the estimated quadriceps force during knee extension.
However, inferior pole patella fractures represent a special challenge because their fracture characteristics differ significantly from transverse patella fractures.
Although tension band wiring provides excellent results in simple transverse patellar fractures, its application in inferior pole fractures remains controversial.
The main reasons include:
Most inferior pole fractures are comminuted.
The small distal fragments often cannot provide:
Adequate screw purchase
Stable K-wire fixation
Reliable resistance against quadriceps tension
This increases the risk of:
Fixation loosening
Fragment displacement
Loss of reduction
The principle of tension band fixation depends on transforming anterior tensile forces into posterior compressive forces.
However, in inferior pole fractures:
The patellar tendon pulls the distal fragment inferiorly.
The small fracture fragments move anteriorly.
The fixation construct may fail to neutralize extensor mechanism forces.
Previous studies reported that isolated vertical wiring techniques may not effectively convert quadriceps tension into compression at the fracture site.
Traditional metal wire fixation may lead to:
Wire breakage
Implant irritation
Anterior knee pain
Secondary implant removal surgery
Therefore, an ideal fixation technique should provide:
Strong fixation
Preservation of patellar length
Protection of the extensor mechanism
Early postoperative rehabilitation
To overcome these limitations, a modified tension band fixation technique was developed.
The technique combines:
Krackow suture reinforcement
Nice knot fixation
Traditional tension band wiring
The concept is to create a soft tissue–bone fixation system that distributes the extensor mechanism forces more effectively.
The main biomechanical objectives are:
Reduce stress concentration on small inferior pole fragments.
Improve fixation of comminuted fracture fragments.
Convert quadriceps tensile forces into compressive forces.
Maintain patellar height.
Allow early knee mobilization.
Patients are positioned:
Supine position
General anesthesia
Pneumatic tourniquet applied to the proximal thigh
A prophylactic intravenous antibiotic, such as cefuroxime, is administered approximately 30 minutes before tourniquet inflation.
A midline anterior knee incision is performed:
Starting from the superior pole of the patella
Extending toward the tibial tubercle
After separating the medial and lateral soft tissues:
The patellar tendon is exposed.
The fracture site is identified.
Hematoma and debris are removed.
The patellar tendon attachment to the inferior pole fragment is carefully preserved.
Preserving the patellar tendon–bone attachment is essential for maintaining extensor mechanism continuity.
The first nonabsorbable braided suture is placed using the Krackow locking stitch technique.
The suture pathway includes:
Both sides of the patellar tendon
The bone surface of the inferior pole fragment
The posterior aspect of the bone–tendon junction
The purpose of this step is to reinforce the weak inferior pole fragment and distribute tensile forces through the patellar tendon.
A second nonabsorbable braided suture is passed directly behind the bone–tendon junction.
After fracture reduction:
The second suture is tightened using a Nice knot.
The knot maintains reduction of the inferior pole fragment.
The first Krackow suture is then tightened through the proximal patella using surgical knots and multiple square knots.
The Nice knot provides:
Adjustable tension
Strong fixation
Improved load distribution
The proximal patella is temporarily elevated.
Using a 2.5 mm K-wire:
Two parallel bone tunnels are created.
The tunnels start from the anterior aspect of the articular surface.
They exit toward the superior anterior patella.
The distance between the tunnels should not be smaller than the width of the inferior pole fragment.
The Krackow and Nice knot sutures are then passed through these tunnels.
After anatomical reduction:
Two parallel 2.0 mm K-wire holes are created approximately:
5 mm anterior to the patellar articular surface
From the inferior pole toward the superior patella
A 1.2 mm stainless steel wire is passed through the holes to create a figure-of-eight tension band construct.
Important technical point:
The K-wires should not be inserted directly through the inferior pole fragment. Instead, they should enter from below the inferior pole and secure the proximal fracture fragment.
This positioning helps:
Maintain fixation strength
Avoid fragment splitting
Improve compression across the fracture site
Before wound closure:
The knee is passively flexed approximately 45°–60°.
Fluoroscopy is used to confirm reduction.
The surgeon evaluates whether fixation remains stable during motion.
If no displacement occurs, layered closure is performed:
Joint capsule
Subcutaneous tissue
Skin
Fig. 1 Panel (a) shows the passage of Line B through a simple fracture, and panel (b) shows the passage of Line B through a comminuted fracture. Line A was inserted from both sides of the patellar tendon using the Krachow suture technique, reaching the bone–tendon junction of the patella. Line B was also passed through this area at the posterior aspect of the inferior pole of the patella (A). For comminuted fractures of the inferior pole of the patella, Lines A and B were interwoven on the surface of the bone–tendon junction through continuous suturing to form a mesh-like structure (B). Two bone tunnels were created at the proximal end of the patella, through which Lines A and B were passed to the surface of the proximal patella (C). After reduction of the inferior patellar pole, Line B was tightened using a Nice knot to maintain the position of the fracture fragment (D). Line A was secured with a surgeon's knot followed by three square knots (E). Finally, K-wires were implanted with the knee in a flexed position to complete the tension-band fixation technique (F).
All patients underwent surgery under general anesthesia and were positioned supine on the operating table.
A pneumatic tourniquet was applied to the proximal thigh to minimize intraoperative bleeding. Prophylactic intravenous antibiotics (cefuroxime 1.5 g) were administered within 30 minutes before tourniquet inflation to reduce the risk of postoperative infection.
The knee was positioned in slight flexion to facilitate exposure of the patella and optimize visualization of the fracture site.
A standard anterior midline incision was performed from the superior pole of the patella to the tibial tubercle.
After carefully dissecting the subcutaneous tissue, the patellar tendon and fracture fragments were exposed.
The fracture hematoma and interposed soft tissue were thoroughly irrigated and removed to achieve a clear fracture interface.
During exposure, special attention was paid to preserving the attachment of the patellar tendon to the inferior pole fragment.
This step is critical because the patellar tendon attachment provides an important biological and mechanical connection for reconstruction of the extensor mechanism.
The first nonabsorbable braided suture was placed using the Krackow locking stitch technique.
The suture was passed along both sides of the patellar tendon and advanced toward the inferior pole of the patella.
The suture then passed through the posterior aspect of the bone–tendon junction and exited behind the inferior fracture fragment.
This Krackow suture functions as a reinforcement structure to resist the tensile forces generated by the quadriceps mechanism during knee extension.
A second nonabsorbable braided suture was introduced directly through the posterior aspect of the bone–tendon junction.
This additional suture was designed to improve control of the inferior fracture fragment and provide enhanced stability during reduction.
The combination of Krackow suturing and reinforcing sutures creates a soft-tissue support system around the comminuted inferior pole fragment.
The proximal patellar fragment was temporarily elevated to allow creation of bone tunnels.
Two parallel bone tunnels were drilled through the proximal patella using a 2.5 mm Kirschner wire.
The tunnels were created from the anterior aspect of the articular surface toward the superior pole of the patella.
The distance between the two tunnels was maintained to ensure sufficient bone bridge strength.
These tunnels served as pathways for passing the reinforcement sutures and allowed conversion of tensile forces into compressive forces across the fracture site.
After anatomical reduction of the inferior pole fragment, the second reinforcing suture was first tightened using the Nice knot technique.
The Nice knot provides a strong sliding-lock mechanism that allows controlled compression and maintains reduction stability.
After the inferior pole fragment was stabilized, the first Krackow suture was passed through the proximal patellar tunnels.
The suture was secured using a surgical knot followed by three square knots.
This sequential tightening strategy allows progressive compression of the fracture site while minimizing displacement of small comminuted fragments.
After provisional fixation, fluoroscopy was used to confirm fracture reduction.
The knee was positioned at approximately 45°–60° flexion.
Two parallel 2.0 mm bone tunnels were created approximately 5 mm anterior to the articular surface, extending from the inferior pole toward the superior patella.
A 1.2 mm stainless steel wire was passed through these tunnels and configured into a figure-of-eight tension band construct.
Unlike conventional techniques, the Kirschner wires were not inserted directly through the inferior fracture fragment.
Instead, they were introduced from the distal aspect and directed into the proximal fracture fragment.
This modification avoids additional fragmentation of the inferior pole and improves fixation reliability.
Following fixation, passive knee flexion and extension were performed under direct visualization.
The surgeon evaluated:
fracture stability;
maintenance of reduction;
integrity of the fixation construct;
absence of displacement during knee motion.
The joint capsule, subcutaneous tissue, and skin were then closed layer by layer using absorbable sutures.
The modified tension band technique combines three mechanical concepts:
1. Soft Tissue Reinforcement
The Krackow suture reconstructs the patellar tendon–inferior pole connection and reduces stress concentration at the bone–tendon interface.
2. Controlled Fragment Compression
The Nice knot provides strong and adjustable compression, especially useful for comminuted inferior pole fragments.
3. Conversion of Tensile Force Into Compression Force
The tension band construct transforms anterior tensile forces generated during quadriceps contraction into compressive forces across the fracture site.
This principle follows the classic biomechanical concept of tension band fixation described by Müller et al.
Compared with conventional tension band wiring alone, this modified technique provides several advantages:
Improved control of small inferior pole fragments;
Reduced risk of postoperative fragment displacement;
Preservation of patellar height;
Enhanced fixation strength in comminuted fractures;
Allows early knee range-of-motion exercises;
Avoids partial patellectomy and its associated biomechanical problems.
By combining soft tissue reconstruction with tension band principles, this method provides a reliable option for challenging inferior pole patella fractures, particularly those with comminution and extensor mechanism disruption.
A total of 15 patients with inferior pole patella fractures were treated using the modified tension band fixation technique combining:
Krackow suture reinforcement;
Nice knot fixation;
Figure-of-eight tension band wiring.
All patients completed at least 12 months of postoperative follow-up.
The average follow-up period was:
13.73 ± 1.71 months
Radiographic bone union was defined as the disappearance of the fracture line and restoration of continuous trabecular bone across the fracture site.
The average time to fracture healing was:
9 weeks (range: 8–13 weeks)
The average hospital stay was:
9 ± 1.7 days
No patients developed:
anterior knee pain;
inferior pole re-fracture;
tension band wire breakage;
fixation failure.
At the final follow-up, all patients achieved satisfactory knee function without significant limitation.
The average knee range of motion was:
128.46° ± 7.07°
(range: 113.4°–137.8°)
This indicates that the modified fixation method can provide sufficient stability to allow early functional rehabilitation after surgery.
Functional outcomes were assessed using the Bostman scoring system.
The Bostman score evaluates:
knee range of motion;
pain;
working ability;
quadriceps muscle atrophy;
walking assistance;
joint effusion;
giving-way symptoms;
stair climbing ability.
The scoring system includes:
Excellent: 28–30 points;
Good: 20–27 points;
Poor: <20 points.
At the final follow-up:
The average Bostman score was:
28.40 ± 1.29 points
(range: 26–30 points)
Clinical results:
11 patients achieved excellent outcomes;
4 patients achieved good outcomes.
No patient experienced poor functional recovery.
Inferior pole patella fractures represent a special type of extra-articular avulsion fracture.
Unlike transverse patella fractures, these fractures:
usually involve the distal non-articular portion of the patella;
frequently present with comminution;
often disrupt the patellar tendon attachment;
may cause loss of patellar height.
Because the inferior pole plays an important role in maintaining the extensor mechanism, improper treatment may result in:
patella baja;
reduced quadriceps efficiency;
anterior knee pain;
limited knee flexion;
patellofemoral degeneration.
Therefore, the primary goal of surgical treatment is:
Preserve patellar length;
Restore extensor mechanism continuity;
Achieve stable fixation;
Allow early knee rehabilitation.
Partial patellectomy was historically used for severely comminuted inferior pole fractures.
However, removing the inferior pole decreases patellar height and alters normal patellofemoral biomechanics.
This may increase vertical loading forces across the patellofemoral joint and accelerate degenerative changes.
Therefore, current literature generally discourages partial patellectomy whenever reconstruction is achievable.
The modern treatment trend has shifted toward:
preservation of the inferior pole and restoration of the extensor mechanism.
Various implants have been developed for inferior pole patella fractures, including:
basket plates;
mesh plates;
angle-stable locking plates;
specially designed inferior pole plates.
These implants can provide stronger fixation and allow early mobilization.
However, several limitations remain:
irritation of the patellar tendon;
anterior knee discomfort;
screw-related complications;
implant prominence;
limited availability in some regions.
For these reasons, simple and reproducible fixation techniques remain clinically valuable.
Vertical wiring techniques have shown acceptable clinical outcomes.
However, biomechanical limitations exist.
Traditional vertical wire fixation may fail because:
tensile forces from quadriceps contraction are not effectively converted into compression;
inferior fragments may migrate anteriorly;
small comminuted fragments may lack sufficient purchase.
Previous studies reported that fragment displacement and wire failure could occur, particularly in highly comminuted fractures.
The modified tension band fixation technique was designed to overcome these limitations by combining:
The Krackow stitch provides strong fixation along the patellar tendon and distributes tensile forces across the bone–tendon interface.
This reduces stress concentration on small inferior pole fragments.
The Nice knot allows:
controlled tightening;
stable compression;
improved fixation of small fragments.
Because the sutures surround the comminuted fragments like a soft tissue cage, small bone fragments do not need to be removed.
This helps preserve the biological environment for fracture healing.
The combination of:
Krackow sutures;
Nice knot fixation;
figure-of-eight tension band wiring;
allows anterior tensile forces generated during knee extension to be converted into compressive forces at the fracture site.
This follows the fundamental principle of tension band fixation.
One important advantage of this technique is that the stable fixation construct allows early postoperative knee movement.
Early rehabilitation provides several benefits:
prevents knee stiffness;
improves quadriceps recovery;
reduces postoperative adhesion;
accelerates return to daily activities.
In this study, patients achieved excellent functional outcomes without requiring prolonged immobilization.
Although the modified tension band fixation technique showed promising clinical outcomes, several limitations should be acknowledged.
Small Sample Size
This study included only 15 patients.
A larger patient population is required to confirm the reliability of this technique.
The study did not directly compare this method with:
basket plate fixation;
mesh plate fixation;
traditional tension band wiring;
suture anchor techniques.
Future comparative studies are needed.
Although clinical outcomes were favorable, additional biomechanical testing is required to evaluate:
maximum failure load;
displacement under cyclic loading;
fixation strength compared with other techniques.
The treatment trend of inferior pole patella fractures is moving toward:
preservation rather than excision;
biological fixation rather than extensive hardware;
early rehabilitation rather than prolonged immobilization.
Future developments may include:
stronger suture-based fixation systems;
customized low-profile implants;
biomechanical optimization of tension band constructs.
The combination of soft tissue reconstruction and modern fixation principles may provide safer and more reliable solutions for complex inferior pole patella fractures.
The modified tension band fixation technique combining Krackow suture reinforcement, Nice knot fixation, and tension band wiring provides stable fixation and satisfactory functional recovery for inferior pole patella fractures.
The technique offers several advantages:
preserves patellar height;
maintains extensor mechanism function;
improves fixation stability;
supports early knee rehabilitation;
avoids complications associated with partial patellectomy and bulky implants.
Although further biomechanical and comparative clinical studies are required, this method represents a promising and practical option for the surgical treatment of inferior pole patella fractures.
