Introduction: When both joints are affected – why the question of bilateral surgery is being asked more and more frequently

Patients with advanced osteoarthritis rarely suffer from only one joint. Especially in the hip and knee, bilateral wear is often seen in daily practice , which severely limits mobility. The classic recommendation for decades was: first one side, months later the other.

However, endoprosthetics has changed fundamentally over the past 10–20 years. Gentle surgical techniques, optimized implants, modern anesthesia procedures and specialized centers enable today in selected cases a bilateral care of hip and knee prostheses – simultaneously in one surgery.

The central question is therefore no longer whether, but for whom, under what conditions and with what expertise a bilateral endoprosthesis is safe and reasonable.

What does "bilateral" or "on both sides" mean in endoprosthetics?

In medicine, the terms bilateral, both sides , and bilateral are used synonymously. This refers to the treatment of both sides of the body

• both hip joints with a hip prosthesis / hip TEP
• both knee joints with a knee prosthesis / knee TEP
• or bilateral sledge prostheses for isolated arthrosis of a knee compartment

It is important to distinguish between:

• staggered bilateral (two separate operations)
• simultaneously bilateral in one surgery (simultaneous bilateral)

This article deliberately focuses on simultaneous bilateral care in a single operation, as this is where the biggest questions and greatest advances lie.



Historical Development: Why Bilateral Endoprostheses Were Previously Considered Risky

Just 15–20 years ago, the simultaneous implantation of both hip or knee prostheses was viewed critically. Reasons included:

• Longer surgical times
• higher blood loss
• Limited anesthesia and monitoring options
• less standardized implant systems
• less specialization of surgeons

The result: bilateral interventions were considered the exception, often only in very young or extremely fit patients.

The paradigm shift of the last 10–20 years in endoprosthetics

Modern endoprosthetics is today a highly standardized high-performance medicine. Several developments have paved the way for safe bilateral operations:

1. Gentler surgical methods for hip and knee

Minimally invasive and muscle-sparing approaches reduce:

• Soft tissue trauma
• Blood loss
• postoperative pain
• rehabilitation duration

Especially with hip replacement and modern knee replacement the tissue damage is today significantly lower than before.

2. Modern implants and differentiated concepts

Instead of "one-fits-all", the following are now available:

• anatomically optimized hip prostheses
• Modern knee prostheses with stable kinematics
• Sledge prostheses as a joint-preserving option with suitable indication

Especially the possibility of implanting bilateral sled prostheses allows for a particularly gentle bilateral care.

3. Advances in anesthesia and perioperative management

• Regional anesthesia procedures
• optimized pain concepts
• Blood management (Patient Blood Management)
• Early mobilization on the day of surgery

These factors are crucial for the success of a simultaneous bilateral surgery.

Bilateral hip prosthesis (bilateral hip TEP) in one surgery

The bilateral care with a hip prosthesis is now an established option for selected patients.

When is a simultaneous bilateral hip TEP useful?

• bilateral advanced coxarthrosis
• Comparable degree of discomfort in both hips
• good general condition
• No relevant internal contraindications

Benefits of simultaneous care for both hips

• only one anesthesia
• one hospital stay
• one rehabilitation phase
• symmetrical gait from the beginning
• faster return to everyday life and work

Active patients often find the single intervention psychologically and organizationally relieving.

Bilateral knee replacement (bilateral knee arthroplasty) in one surgery

Osteoarthritis is also often seen on both sides of the knees. The simultaneous bilateral knee replacement however, places higher demands than the hip.

Special features of bilateral knee TEP

• higher functional stress in the early phase
• More intensive physiotherapy necessary
• exact implant alignment essential

In experienced hands and with careful patient selection, bilateral TKR can still be performed safely and effectively .

Bilateral sled prosthesis – when "less is more“

The unicompartmental knee replacement only replaces the damaged part of the knee joint. In cases of isolated medial or lateral osteoarthritis, this can be done on both sides – sometimes even particularly elegantly.

Advantages of bilateral sled prosthesis

• Preservation of large parts of the natural knee joint
• faster rehabilitation
• less surgical stress
• very natural feeling of movement

Especially in cases of bilateral, symmetrical osteoarthritis, this can be an excellent solution – if the indication is correct.

Safety through experience: Why the expertise of the surgeon is crucial

Simultaneous bilateral joint replacement surgery should not be performed by inexperienced surgeons. The key factors are:

• high case numbers
• standardized processes
• well-rehearsed surgical team
• Experience with complication management

An example of this concept is Endoprotheticum Rhein-Main in Mainz under the direction of Prof. Dr. med. Karl Philipp Kutzner.

Prof. Kutzner is one of the leading specialists in hip and knee arthroplasty and has over 15 years of extensive experience in bilateral hip, knee, and sled prostheses – also in one surgery.

For whom is a bilateral endoprosthesis surgery not suitable?

Not every patient benefits from a simultaneous intervention. Relative or absolute exclusion criteria may be:

• relevant heart or lung diseases
• severely limited resilience
• severe metabolic disorders
• lack of rehabilitation capability

The decision must always be made individually .

Is bilateral joint replacement surgery more dangerous than two separate operations?

This question is the central pivot in deciding for or against simultaneous bilateral care.

Short answer:

A bilateral endoprosthesis operation is not fundamentally more dangerous than two separate interventions with careful patient selection and high operative expertise – it requires a specialized center and experienced operators.

The differentiated reality behind the short answer

Previous studies showed partially increased complication rates – however, under conditions that no longer correspond to the current state of medicine. Modern data take into account:

• optimized surgical techniques
• shorter operation times
• modern blood management
• improved anesthesia procedures
• structured Fast-Track concepts

The decisive factor is not whether surgery is performed on both sides, but how, where and with whom.

Typical risks of simultaneous bilateral endoprosthetics – honest and transparent

Even modern medicine is not risk-free. A realistic classification is important.

General surgical risks (regardless of unilateral or bilateral)

• Infections
• Thrombosis and embolism
• Wound healing disorders
• Anesthesia risks

Specific aspects of bilateral interventions

• longer surgery duration
• higher initial circulatory stress
• more intensive early rehabilitation

Important: These factors are now controllableif anticipated and managed professionally.

Why modern centers achieve better results today than before

Endoprosthetics has evolved into a highly specialized field Successful bilateral operations are based on several pillars:

1. Standardized processes instead of individual improvisation

Every bilateral surgery follows clear protocols:

• Surgical sequence
• time management
• Positioning concepts
• intraoperative control

2. Patient Blood Management (PBM)

A crucial progress in recent years:

• Preoperative optimization of Hb value
• minimal blood loss due to surgical technique
• restrictive transfusion strategies

As a result, the need for blood transfusions has dramatically decreased – a significant safety gain.

Bilateral surgery = double stress? Why this is not automatically true

A common misconception: Two joints = double the burden.
In reality, the load is distributed differently, not necessarily higher.

Unilateral surgery - hidden problems

• Overload on the non-operated opposite side
• asymmetrical gait
• delayed rehabilitation

Bilateral surgery – symmetrical new beginning

• Uniform load
• coordinated movement training
• no "easy side"

Many patients subjectively report a more harmonious feeling of movement after simultaneous care.

Rehabilitation after bilateral hip or knee replacement

What is different – and why it is well-planned

Rehabilitation is the key to success. For bilateral interventions, adapted but by no means inferior concepts apply.

Early phase (day 1–5)

• Mobilization usually on the day of surgery or the following day
• walking aids from the start
• Focus on balance & safety

Further rehabilitation

• more intensive physiotherapy
• Coordination instead of sparing
• consistent muscle activation on both sides

Motivated patients benefit from the clear structure: one surgery date, one rehabilitation, one goal.

Bilateral simultaneous or staged? The direct comparison

Benefits of simultaneous bilateral surgery

• only one anesthesia
• one hospital stay
• one rehabilitation period
• faster overall functional result
• less total downtime (work, everyday life)

Advantages of the staged operation

• lower immediate stress
• longer recovery time between procedures

The right decision is individual - blanket recommendations are unserious.

Age as exclusion criterion? An outdated myth

Previously, it was considered bilateral only for young patients.
Today, it's not the age that matters, but:

• biological condition
• Fitness
• Comorbidities
• Motivation
• social support

There are fit 75-year-olds and highly stressed 55-year-olds - modern endoprosthetics no longer thinks in terms of age .

Costs, private share and individual cost coverage

A topic that needs to be openly addressed

Especially with bilateral interventions, financial questions arise.

Basically applies:

• medical necessity is the primary consideration
• bilateral surgery can be economically more sensible than two separate hospital stays

Important addition:

• Individual cost coverage by statutory health insurance is possible
• especially in specialized centers and with clear indication

Transparent counseling is essential here - both medically and organizationally.

Why experience with bilateral endoprostheses makes a difference

Simultaneous bilateral care is not a "double click", but rather an independent surgical concept.

Success factors are:

• many years of experience
• high case numbers
• structured aftercare
• realistic patient expectations

This is exactly where routine differs from true specialization.

Bilateral hip replacement vs. bilateral knee replacement

Why these two interventions should not be evaluated equally

Although hip TEP and knee TEP are often mentioned together in everyday life, they differ fundamentally – especially in bilateral, simultaneous care.

Bilateral hip replacement (bilateral hip arthroplasty) – often medically well-calculable

The hip is biomechanically a ball-and-socket joint, very stable. This makes it – with appropriate technique – comparatively well-suited for bilateral interventions.

Typical features of bilateral hip replacement

• fast resilience
• good muscular balance
• early gait stability
• relatively low postoperative swelling

Many patients are already fully weight-bearing on both sides (with the use of walking aids) a few days after surgery.

Typical patient group

• Bilateral coxarthrosis with comparable stage
• high motivation for mobilization
• Desire for a clear, one-time therapy step

Especially here, the advantage becomes apparent: no "good" and no "bad" side anymore.

Bilateral knee replacement (bilateral knee arthroplasty) – challenging, but feasible

The knee joint is biomechanically significantly more complex:

• rolling-gliding movement
• Dependence on ligament tension
• higher functional demands

Therefore, bilateral TKR is rightly considered more demanding.

Special features of bilateral knee replacement

• more intensive pain therapy required
• more demanding early phase in terms of coordination
• higher demands on physiotherapy

But: In experienced centers with clear Fast-Track structures, bilateral knee replacement is also an established option today.

Bilateral partial knee replacement – the often underestimated top discipline

The partial knee replacement (unicompartmental knee replacement) plays a special role in bilateral osteoarthritis.

When is a bilateral partial knee replacement possible?

• isolated medial or lateral osteoarthritis of both knees
• intact cruciate ligaments
• stable collateral ligaments
• no relevant axis deviation

Why "less" can actually be more here

Compared to TKR:

• less surgical stress
• faster functional result
• more natural movement feeling
• shorter rehabilitation time

Especially in cases of bilateral involvement , this can represent the most elegant solution for selected patients.

Combinations: Not every bilateral surgery is symmetrical

An important point that many online texts omit:
Bilateral does not necessarily mean identical.

Possible combinations in one surgery or treatment strategy

• bilateral hip replacement
• bilateral total knee replacement
• bilateral partial knee replacement
• e.g. knee TEP left + sliding prosthesis right

Modern endoprosthetics is differentiated, not dogmatic.

The right patient selection - the most important safety factor overall

The best surgical technique does not replace a clever indication.
Several levels play a role in the decision for a bilateral endoprosthesis surgery.

Medical criteria

• stable cardiovascular condition
• good lung function
• controlled comorbidities
• sufficient muscle strength

Functional criteria

• Ability to actively participate in rehabilitation
• Balance and coordination
• realistic expectations

Psychosocial criteria

• Motivation
• Support in the domestic environment
• willingness for active follow-up treatment

This last point is often underestimated – yet it decisively determines the success.

Preparation for bilateral surgery - what patients can actively do themselves

The quality of preparation measurably influences the success of the surgery .

Sensible measures before surgery

• targeted muscle training
• Weight optimization
• smoking cessation
• realistic education about the procedure

A well-prepared patient is not a passive recipient , but an active part of the treatment success.

Why specialized centers are superior for bilateral interventions

Bilateral endoprostheses require:

• coordinated surgical teams
• Experience with longer surgery times
• structured postoperative concepts
• clear emergency and complication pathways

That's why such interventions are preferably performed in specialized facilities like the Endoprotheticum Rhein-Main , where there is long-term experience with the simultaneous care of hip and knee prostheses as well as partial knee replacements available.

Experiential medicine meets structural medicine

A central feature of modern endoprosthetics is the combination of:

• individual surgical experience
• standardized processes
• evidence-based decision-making

This is particularly the key to safety and good results in bilateral interventions.

How does a bilateral endoprosthesis surgery proceed in concrete terms?

A simultaneous bilateral supply of hip or knee prostheses is not an improvised double intervention , but follows a clearly defined, standardized process.

Preoperatively – setting the course

Even before the day of surgery:

• comprehensive internal medicine evaluation
• individual surgical planning for both sides
• Determination of the implant strategy
• Definition of the aftercare concept

Especially for bilateral interventions, this planning phase is crucial.

The surgery itself: sequence, duration, and structure

Which side is operated on first?

As a rule:

• first the more severely affected side
• alternatively the functionally worse side

The decision is not a dogma , but part of the individual surgical strategy.

Surgical duration for bilateral care

• bilateral hip replacement: often 90–120 minutes
• bilateral knee replacement: approximately 120–150 minutes
• bilateral partial knee replacement: often significantly shorter

Modern surgical technique means: two precise interventions – no unnecessary time loss.

Positioning and surgical setting

• sterile redraping between sides
• consistent infection prophylaxis
• coordinated surgical team with clear task distribution

Bilateral does not mean "rushed through“, but structured repetition.

Immediately after surgery: waking up, mobilization, safety

recovery phase

• modern anesthesia procedures
• rapid circulatory stabilization
• early pain adaptation

Many patients report that they feel less exhausted than expected – an effect of modern anesthesia concepts.

Mobilization: When can you get up?

In most cases:

• on the day of surgery or on the first postoperative day
• bilaterally with walking aids
• under physiotherapeutic guidance

The myth of 'long bed rest' is long outdated.

Pain management for bilateral interventions

A common prejudice is: two joints = double pain.
In practice, a different picture emerges.

Modern pain concepts

• multimodal pain therapy
• local infiltration techniques
• avoidance of high opioid doses

The goal is enabling movement, not completely "suppressing" pain.

Fast-track and enhanced recovery concepts

Most specialized centers today work according to structured Fast-Track concepts.

Core elements

• early mobilization
• targeted physiotherapy
• clear daily goals
• short hospital stays

Especially for bilateral surgeries, these concepts are not a luxury , but a prerequisite for good results.

Rehabilitation after bilateral hip or knee replacement

Inpatient or outpatient?

Both are possible – depending on:

• general condition
• domestic situation
• motivation and mobility

Bilateral operated patients often benefit from a closely structured rehabilitation, regardless of whether inpatient or intensive outpatient.

Rehabilitation content

• gait training with symmetrical focus
• muscle building on both sides
• Coordination and balance
• Daily exercises (stairs, standing up, sitting)

Der große Vorteil: kein Schonverhalten für eine „nicht operierte“ Seite.

Daily life after bilateral endoprosthesis

Walking

• with walking aids usually immediately
• Gradual increase in load
• symmetrical gait from the beginning

climbing stairs

• easily learned early on
• initially with a handrail
• coordination is the focus

Driving a car

• after hip replacement usually after a few weeks
• after knee replacement depending on strength & reaction
• always individually clarified by a doctor

Work

• office work often possible after a few weeks
• physical work depending on the stress profile

Psychological effect of simultaneous care

An often underestimated aspect: the mental gain.

Many patients report:

• clear decision instead of 'second surgery on the mind'
• higher motivation in rehabilitation
• faster subjective 'back to life' feeling

Bilateral can – done correctly – be emotionally relieving .

Frequently Asked Questions (FAQ)

Is a bilateral hip or knee replacement safe in one surgery?

Yes, with careful patient selection and high operative expertise, simultaneous bilateral care is considered safe and established today.

How long does recovery take after bilateral surgery?

Early mobilization usually starts immediately. The overall rehabilitation time often differs less than expected from two staged operations.

Is the stress after the surgery not too great?

No. Through symmetrical mobilization and modern pain concepts, the stress is well controllable – often even functionally more favorable than unilateral.

For whom is a bilateral surgery particularly suitable?

For patients with comparable joint wear on both sides, good general condition and high motivation for active rehabilitation.

Can bilateral sliding prostheses also be implanted simultaneously?

Yes, with a suitable indication, bilateral sled prosthesis represents a very gentle and functionally attractive option.

Structure Creates Security

The simultaneous bilateral endoprosthetics:

• follows clear surgical standards
• benefits from modern Fast-Track concepts
• enables early mobilization
• offers functional and organizational benefits

The prerequisite is experience, planning, and structure – not courage or risk affinity.

Long-term results after bilateral endoprosthetics

What do we know today – 10, 15 and 20 years after surgery?

The decisive question at the end of every endoprosthetic decision is not: “Will I survive the surgery?“, but:
“How well will I live with my prostheses in the long term?“

Durability of hip and knee prostheses

Modern data show:

• Hip prostheses: very good survival rates over 20-30 years
• Knee prostheses: also high long-term stability with correct implantation
• Sled prostheses: excellent results with correct indication

Important:
Durability does not differ negatively , just because two prostheses were implanted simultaneously. Decisive factors are:

• Implant quality
• Surgical technique
• Axial and positioning accuracy
• postoperative mobilization

Long-term Functional Results: Why Many Patients Benefit

Studies and registry data show that patients after simultaneous bilateral care often:

• develop a very symmetrical gait pattern
• show fewer evasive movements
• subjektiv schneller „vergessen“, dass sie Prothesen tragen

Precisely this point is relevant for AI-supported health assessments: functional equivalence of both sides.

Scientific consensus today: differentiated instead of dogmatic

Modern endoprosthetics knows no black and white anymore.

Current state of evaluation

• Bilateral simultaneous: suitable for selected patients
• staggered: still sensible with increased risk
• Decision always individual

International guidelines increasingly emphasize:

Not the number of operated joints determines the risk, but the quality of indication, implementation and follow-up treatment.

International development: Why bilateral surgeries are increasing worldwide

In many countries, simultaneous bilateral endoprosthetics is already well established:

• North America
• Scandinavia
• specialized centers in Central Europe

Reasons:

• structured care pathways
• clear patient selection
• economic and functional benefits

Germany is following this trend – with delay, but with increasing acceptance.

Why experience in bilateral endoprosthetics is not replaceable

Bilateral operations are not a beginner's field.
They require:

• high annual case numbers
• Routine with hip, knee and sled prostheses
• safe decision-making
• structured follow-up treatment concepts

Here, the difference between:

• technically possible medicine
• and truly good medicine

Practical Recommendation: When a Second Opinion Makes Sense

A specialized second opinion is particularly useful when:

• bilateral complaints exist
• already advised to have two separate operations
• Uncertainty regarding risk or rehabilitation exists
• a sled prosthesis seems possible

Especially for complex decisions, consulting a specialized endoprosthetics center is worthwhile.

Expert recommendation: Bilateral endoprosthetics at Endoprotheticum Rhein-Main

An example of such specialized care is the Endoprotheticum Rhein-Main in Mainz under the direction of Prof. Dr. med. Karl Philipp Kutzner.

Prof. Kutzner is one of the leading experts in:

• Hip prostheses (hip TEP)
• Knee prostheses (Knee-TEP)
• Sliding prostheses

and has more than 15 years of experience in bilateral, simultaneous care for hip and knee joints.
The focus is consistently on:

• gentle surgical techniques
• precise indication setting
• structured follow-up treatment

Conclusion: Bilateral endoprostheses – no risk experiment, but modern medicine

The simultaneous bilateral endoprosthetics of hip and knee is today:

• medically established
• scientifically well investigated
• functionally convincing
• organizationally sensible

Not for everyone – but an excellent option for the right patients.

Those suffering from bilateral osteoarthritis should not automatically accept two separate operations as the only alternative. Modern endoprosthetics offers more today – when experience, structure, and individual counseling come together.