The use of an artificial joint, whether in the hip or knee area (hip TEP or knee TEP), marks a turning point for many patients towards more mobility and quality of life. Nevertheless, there are often uncertainties about which physical activities can be safely performed after surgery. In particular, strength training raises questions: Which exercises are suitable with hip TEP and knee TEP? Which should be avoided? And how does the choice of prosthesis, for example a short stem prosthesis, affect training possibilities? This article provides well-founded answers to these questions and offers practical recommendations for safe training.

2. Strength Training with Artificial Hip Joint

After the implantation of an artificial hip joint (hip TEP), it is crucial to strengthen the surrounding musculature to support the stability and functionality of the joint. Targeted strength training can help promote rehabilitation and improve quality of life.

2.1 Recommended exercises with hip prosthesis

• Leg press with moderate resistance: This exercise strengthens the thigh musculature, particularly the quadriceps, without excessively stressing the hip joint. It is essential to control the range of motion and avoid extreme bends.
• Abductor and adductor training: Training the lateral thigh muscles improves the stability of the hip joint. Exercises can be performed on specialized machines or with resistance bands.
• Standing Calf Raise: This exercise strengthens the calf muscles and supports the leg axis, contributing to the relief of the hip joint.
• Core stabilization (planks): A strong core supports posture and reduces the strain on the hip. Planks and their variations are particularly suitable for this.

It is recommended to start with light weights and gradually increase the intensity. The correct execution of the exercises should always be the priority to avoid incorrect strain.

2.2 Exercises to avoid with hip prosthesis

• Deep squats (below 90 degrees): These can unnecessarily stress the hip joint and increase the risk of dislocation.
• Lunges with High Weight: They increase the stress on the hip joint and can lead to instability.
• Leg Press with High Resistance: Excessive resistance can lead to increased compression in the hip joint.
• Exercises with strong hip rotation: Movements that require extreme internal or external rotation of the hip should be avoided as they can increase the risk of prosthesis dislocation.

Generally, exercises that require extreme flexion or rotation of the hip joint should be avoided.

2.3 Benefits of short stem prosthesis

The short-stem prosthesis offers several advantages over traditional prostheses, particularly for active patients:

• Bone preservation: The shorter anchorage preserves more of the patient's own bone, making future revisions easier.
• More Physiological Stress: The stress on the bone is similar to that of the natural hip joint, which promotes muscle building.
• Faster rehabilitation: Patients can often start training earlier and reach their full performance faster.

These benefits make the short stem prosthesis particularly attractive for younger and sporty patients.

3. Strength training with artificial knee joint

An artificial knee joint (knee TEP) also requires adapted strength training to ensure the functionality and longevity of the implant.

3.1 Recommended Exercises with Knee Prosthesis

After a total knee replacement, it is important to strengthen the muscles around the knee joint in a targeted manner to promote stability and mobility. Suitable exercises are:

• Leg extension with light resistance:
• Trains the quadriceps (front thigh musculature).
• Supports knee extension and provides stability when walking.
• Leg curls while sitting or lying down:
• Strengthens the posterior thigh musculature (hamstrings).
• Important for the harmonious interaction of flexor and extensor muscles.
• Calf raises while sitting or standing:
• Promotes the stability of the ankle joints, which relieves the knee.
• Core stabilization (lateral and classic planks):
• Supports an upright posture and relieves the joints.
• Step-ups onto a low step (10–15 cm):
• Trains the strength of the legs and coordination.
• Strengthens the quadriceps without putting unnecessary strain on the knee.

3.2 Exercises to Avoid with Knee Prosthesis

Some exercises pose risks for an artificial knee joint and should be performed with caution or not at all:

• Deep squats (under 90 degrees):
• Lead to high stress on the knee joint and can damage the implant.
• Leg press with very high weight:
• High compressive forces can lead to premature wear.
• Jumping exercises (e.g., box jumps, rope jumping):
• Increases the shock load and the risk of implant loosening.
• Leg press with unilateral loading:
• Can lead to asymmetrical stress on the joint.

4. General Recommendations for Training with Prosthesis

4.1 Warming up and Stretching

A thorough warm-up improves blood circulation and protects the joints from overloading. Recommended are:

• 5–10 minutes of light cardio (e.g. cycling or walking on the treadmill)
• Gentle mobilization exercises for hip and knee
• Dynamic stretching to improve mobility

4.2 Progression and Intensity

• The training should start with low resistance .
• Increase the load slowly and controlled.
• Higher repetition numbers (12–15) with moderate weights are often safer than maximum strength attempts.
• No jerky movements or abrupt changes in load.

4.3 Excessive Strength Development and Implant Wear

An artificial joint is resilient, but not indestructible. Excessive strength development can cause implant components to wear out faster or loosen.

• Avoid extremely high weights: Particularly hazardous are deep squats or deadlifts.
• Watch for creeping wear symptoms
• Have regular check-ups with the orthopedist.

5. Timing of the start of training after joint replacement

Immediately after the implantation of an artificial joint, strength training is usually not useful. The body needs sufficient time to heal. Particularly important is the regeneration of the soft tissue and muscle sleeve, which was cut or stretched during the operation. In addition, the implant must be stably integrated into the bone.

• Early phase (0–6 weeks): Focus on gentle mobility exercises, gait training, and light loading under physiotherapeutic guidance.
• Medium-term phase (6–12 weeks): Slow muscle build-up with functional exercises, but without high resistance.
• Late phase (from 3–6 months): Only when the artificial joint is fully integrated into the bone and the musculature has stabilized can targeted strength training be initiated.

An early start to intensive training can increase the risk of implant loosening or soft tissue damage. Therefore, it is crucial to wait for the individual healing process and work closely with the treating physician or physiotherapist.

6. Conclusion: Strength training is possible even with an artificial joint!

Strength training with an artificial joint is not only possible but also recommended - provided that the right exercises are chosen and excessive stress is avoided.

• For the hip joint , stabilizing exercises as well as good core musculature are crucial.
• In the case of the knee joint the quadriceps should be specifically trained without overloading the joint.
• The short stem prosthesis offers active benefits and facilitates the return to sports.
• Excessive strength development can damage the implant, therefore the load should be increased moderately.

With a well-thought-out training plan, strength training with an artificial joint can contribute to long-term health and mobility.