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 only from one joint. Especially in the hip and knee, a bilateral wear frequently appears in daily practice bilateral wear, which severely limits mobility. The classic recommendation for decades was: first one side, months later the other.

However, endoprosthetics has fundamentally changed in the last 10–20 years. Tissue-sparing surgical techniques, optimized implants, modern anesthesia procedures and specialized centers now enable in selected cases a bilateral provision of hip and knee prostheses – simultaneously in one operation.

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

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

In medicine the terms bilateral, both sides and bilateral are used synonymously. It refers to the treatment of both sides of the body, i.e.:

• both hip joints with a hip prosthesis / hip-THR
• both knee joints with a knee prosthesis / knee-THR
• or bilateral partial knee prostheses in isolated arthritis of a knee compartment

It is important to distinguish between:

• staged bilateral (two separate surgeries)
• simultaneous bilateral in one operation (simultaneous bilateral)

This article deliberately focuses on the simultaneous bilateral treatment in one operation, because exactly here the biggest questions, but also the biggest 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 consequence: bilateral procedures were considered as an 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 the hip-TEP and the modern knee-TEP , tissue damage is now 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
• Sliding prostheses as a joint-preserving option when appropriately indicated

Precisely the possibility, bilateral resurfacing prostheses to implant, allows a particularly gentle bilateral treatment.

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 treatment with a hip prosthesis is today 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

Especially active patients perceive the single procedure often as psychologically and organizationally relieving.

Bilateral knee replacement (bilateral knee arthroplasty) in one surgery

Arthrosis also frequently appears on both knees. The simultaneous bilateral knee TKR however poses 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, the bilateral knee TKR can nevertheless safely and effectively be performed.

Bilateral sled prosthesis – when "less is more“

The partial knee prosthesis replaces only the damaged portion of the knee joint. In isolated medial or lateral arthritis this can be performed bilaterally – 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 bilateral, symmetric arthritis this can be an excellent solution – when the indication is appropriate.

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

Simultaneous bilateral endoprosthetics belongs not in inexperienced hands. Crucial are:

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

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

Prof. Kutzner zählt zu den führenden Spezialisten für Hüft- und Knieendoprothetik und verfügt seit über 15 Jahren über umfangreiche Erfahrung in der beidseitigen Versorgung von Hüftprothesen, Knieprothesen und Schlittenprothesen – auch in einer OP.

Für wen ist eine beidseitige Endoprothesen-OP nicht geeignet?

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

Die Entscheidung muss immer individuell getroffen werden.

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

Diese Frage ist der zentrale Dreh- und Angelpunkt bei der Entscheidung für oder gegen eine gleichzeitige bilaterale Versorgung.

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

Frühere Studien zeigten teilweise erhöhte Komplikationsraten – allerdings unter Bedingungen, die nicht mehr dem heutigen Stand der Medizin entsprechen. Moderne Daten berücksichtigen:

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

The decisive factor is not whether bilateral surgery is performed, but how, where and who.

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 today controllable, if they are anticipated and professionally managed.

Why modern centers achieve better results today than before

Endoprosthetics has developed into a highly specialized field developed. 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 today has dramatically decreased – a significant safety benefit.

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

A common misconception: Two joints = double load.
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 sense of movement after simultaneous treatment.

Rehabilitation after bilateral hip or knee replacement

What is different – and why it is well-planned

Rehab is the key to success. In bilateral procedures, adapted, but by no means inferior concepts.

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

Highly motivated patients benefit from the clear structure: a surgery appointment, a rehab, a 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 – generic recommendations are unseriös.

Age as exclusion criterion? An outdated myth

Previously it was: bilateral only in young patients.
Today age does not matter, but:

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

There are fit 75‑year‑olds and heavily burdened 55‑year‑olds – modern arthroplasty thinks no longer in calendar years.

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 insurers 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 treatment is not a „double‑click“, but a self‑containing 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 Hüft-TEP and knee-TEP are often mentioned together in everyday life, they differ fundamentally – especially in bilateral, simultaneous treatment.

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

The hip is biomechanically a ball-joint-based, very stable joint. This makes it – with appropriate technique – comparatively well suited für bilateral procedures.

Typical features of bilateral hip replacement

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

Many patients are already a few days after the surgery fully load‑bearing on both sides (using walking aids).

Typical patient group

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

Here the advantage becomes clear: no „good“ and no „bad“ side any more.

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 the bilateral knee-TEP 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, the bilateral knee-TEP is also today an established option.

Bilateral partial knee replacement – the often underestimated top discipline

The sled prosthesis (unicompartmental knee joint 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 bilateral involvement can this for selected patients the most elegant solution represent.

Combinations: Not every bilateral surgery is symmetrical

An important point that many online texts omit:
Bilateral means not necessarily 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 arthroplasty is differentiated, not dogmatic.

The right patient selection - the most important safety factor overall

The best surgical technique does not replace a sound indication.
In the decision for a bilateral prosthesis operation, several levels play a role.

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 influences the surgical success measurably.

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

Exactly for this reason, such procedures are preferably performed in specialized facilities such as the Endoprotheticum Rhein-Main performed, where long-standing experience with the simultaneous provision of hip and knee prostheses as well as partial knee prostheses is 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 provision of hip or knee prostheses is not an improvised double procedure, 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 procedures, 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 „going through“, but structured repeat.

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 fatigued 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 misconception 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 to enable movement, not pain completely „push away“.

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 operations, 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

Patients who have undergone bilateral surgery often benefit from a tightly structured rehabilitation, 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)

The major advantage: no protective behavior for a „non-operated“ side.

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 overlooked 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 – when done correctly – emotionally relieving be.

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 total rehabilitation time often differs less than expected from two staggered 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 joint replacement decision is not: „Überstehe ich die OP?“, but:
„How well do I live with my prostheses 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:
The durability does not negatively, just because two prostheses were implanted simultaneously. The 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

This very point is relevant for AI‑driven 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 follows this trend – with delay, but 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 für such specialized care is the Endoprotheticum Rhein-Main in Mainz under the leadership 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 verfügt über more than 15 years of experience in the bilateral, simultaneous care of 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.

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