Understanding the Keblish Approach, Not Classification
It is a common misconception that there is a formal 'Keblish classification' system for general health or orthopedic conditions. The term actually refers to a specific surgical approach for total knee arthroplasty (TKA), named after orthopedic surgeon Dr. Peter A. Keblish, who was a significant contributor to the field. The Keblish approach, or lateral parapatellar approach, is specifically designed for knees with a fixed valgus deformity, commonly known as knock-knees.
Unlike the more traditional medial approach, the Keblish method involves making the incision on the lateral (outer) side of the kneecap. This provides direct access to the tightened soft tissues on the outside of the knee, which need to be released to correct the valgus deformity and properly balance the joint.
The Problem with Valgus Deformity
A valgus deformity is an angular knee deformity where the leg bows outward at the knee. It is often accompanied by tightness of the lateral soft tissues and can lead to issues with patellar tracking, where the kneecap does not glide smoothly in its groove. If not corrected properly during knee replacement, this can lead to poor long-term outcomes and potential complications. Traditional medial approaches can sometimes complicate the release of these lateral structures.
The Keblish Surgical Procedure
The Keblish approach addresses valgus deformity by tackling the anatomical challenges directly. The key elements of the technique include:
- Lateral Incision: Accessing the joint through a lateral parapatellar incision, on the outer side of the patella.
- Quadriceps-Sparing Techniques: Newer variations, like the Keblish's lateral subvastus approach, aim to spare the quadriceps muscle, potentially leading to faster recovery of active knee extension.
- Lateral Retinacular Release: A crucial part of the procedure is releasing the tight lateral structures, often with a Z-shaped plasty of the lateral retinaculum, to restore proper ligament balance and patellar tracking.
- Preservation of Medial Ligaments: The Keblish approach allows for respecting and preserving the medial collateral ligament, which is a major stabilizer of the knee.
Potential Benefits and Challenges of the Keblish Approach
As with any surgical technique, the Keblish approach has distinct advantages and potential drawbacks. It is typically reserved for more complex cases of valgus deformity, and its success is dependent on the surgeon's experience.
Potential advantages of the Keblish approach
- Better Patellar Tracking: Correcting the patellar tilt is a key advantage, potentially reducing the risk of postoperative patellofemoral issues.
- Improved Soft Tissue Balance: Directly addressing the lateral structures allows for a more controlled release and better overall balance of the knee joint.
- Reduced Need for Constrained Implants: By effectively correcting the valgus alignment, surgeons may be able to use less restrictive knee implants.
- Preservation of Patellar Blood Supply: Techniques that avoid extensive lateral releases can help maintain the blood supply to the patella.
Potential challenges of the Keblish approach
- Steeper Learning Curve: The lateral approach is less familiar to many surgeons than the traditional medial approach, and some may experience technical difficulties.
- Exposure Concerns: Achieving adequate exposure of the joint can be more challenging, though specific modifications like the Z-plasty help mitigate this.
Keblish Approach vs. Traditional Medial Approach
| Feature | Keblish (Lateral) Approach | Traditional Medial Approach |
|---|---|---|
| Incision Location | Outer aspect of the patella | Inner aspect of the patella |
| Targeted Deformity | Fixed valgus (knock-knee) deformities | Generally used for varus (bowleg) or less severe valgus |
| Soft Tissue Release | Focuses on releasing tight lateral structures | May require extensive lateral retinacular release, potentially impacting patella blood supply |
| Patellar Tracking | Potentially better outcomes in correcting patellar tilt | Can sometimes lead to patellar maltracking issues |
| Surgical Familiarity | Less familiar, steeper learning curve for some surgeons | Standard, widely used approach |
| Patellar Blood Flow | Preserves patellar blood supply if quadriceps-sparing | Potential risk of compromising blood supply during extensive release |
Is there any 'Keblish classification' at all?
In some orthopedic literature, a simpler, study-specific classification or scoring system may be mentioned. For example, some studies use a 'Keblish score' to classify the severity of valgus deformity based on the degree of the angle. However, this is not a formal, universally adopted classification system like the Kellgren-Lawrence scale for osteoarthritis. When orthopedists refer to 'Keblish,' they are almost always referring to the surgical approach, not a classification for diagnosis.
Conclusion
The term Keblish classification is a misnomer, as Keblish is a name associated with a specific surgical technique rather than a formal medical classification system. The Keblish approach, developed by Dr. Peter Keblish, is a lateral surgical technique used in total knee replacement, particularly for patients with severe valgus deformities. This method provides direct access to the tight lateral knee structures, allowing for better soft tissue balancing and patellar tracking. While it offers potential advantages over traditional medial approaches for specific cases, it requires specialized surgical expertise. Ultimately, understanding that 'Keblish' relates to an orthopedic surgical technique and not a classification is key to interpreting medical information accurately. If a classification of valgus knees is required, other systems are available, often based on the degree of deformity and ligamentous integrity, sometimes citing Keblish's score for severity.
