Lambda capsulotomy in total hip arthroplasty: respect the zona orbicularis by restoring it.

 Total hip arthroplasty is a common arthroplasty surgery, only second to the knee arthroplasty

Unlike in the knee, a dreaded complication not only for the patient, but also the surgeon is dislocation of the replaced hip

Surgeons shy away from the posterior approach to the hip (which is an otherwise an excellent technique), for this single reason

In posterior approach to the hip, gluteus medius and minimus are not disturbed, the short external rotators are respected and sutured back

The remaining structure, a surgeon has to address to reduce dislocation is the capsule

It is now proven that the capsulotomy and closure is better than capsulectomy ( which used to be the norm) in  in total hip replacements

Different techniques of capsulotomy and closure has been described, namely Longitudinal, T capsulotomy, Z capsulotomy, longitudinal with two anterior incisions one superior and another inferior

We describe a new technique of capsulotomy of the hip, named Lambda capsulotomy

see illustration 1

This involves making a longitudinal capsulotomy, along the long axis of the neck of femur

then antero superior limb of capsulotomy, parallel to the superior fibres of Ischio femoral ligament is made

This leaves three capsular flaps, namely long posterior flap, antero superior flap and antero inferior flap

The anatomical basis of the capsulotomy and repair is by respecting the ischiofemoral ligament and more importantly the zona orbicularis

The capsule of the hip joint is not cylindrical, but larger diameter at the head level and narrower at the neck level

see illustration 2

The ischiofemoral ligament has longitudinal fibres running obliquely from the ischial part of the acetabulum superiorly to the femoral neck inferiorly

Zona orbicularis is a capsular condensation of circular fibres running around the narrowest part of the femoral neck forming a natural noose. Illustration 3

The lambda capsulotomy allows repair of the ischiofemoral ligament and more importantly restores the natural noose around the femoral neck, namely the zona orbicularis

Illustrations

1.  The Lambda cut

A long longitudinal cut along the long axis of the neck

A smaller antero superior cut running from this longitudinal cut following the natural curvature of the acetabulum

2. The circumference of the capsule at the level of femoral head is more than the circumference of the capsule at the level of the neck

3. Zona orbicularis

4. the lambda capsulotomy

question bank in orthopaedics, worth going through for orthopaedic surgeons: will be updated regularly, do watch out!

 1. What is the reported incidence   of Avascular necrosis in proximal humeral fractures, in three part fractures, in four part fractures and anatomical neck fractures

2. Herbert classification of scaphoid fractures, basis of classification, types and implications in the treatment and prognosis?  ( JBJS 1996, July 78 B, Page 531)

3. what is the recurrence rate of shoulder dislocations. in less than 20 years of age,  20 to 40 years of age?

4. What are the indications for fixation of humeral shaft fractures, and what are the indications for conservative treatment of humeral shaft fractures

5. fix or replace a radial head? in comminuted radial head fractures

6. any guidelines on removal of forearm plates after union of fractures? ( risks involved vs benefits)

7. what are the general and local factors which affect fracture healing

8. what are the biochemical factors which facilitate bone healing ( eg BMPs)

function of ACL anterior cruciate ligament in a weight bearing limb

 Hello blog readers,

welcome back

I would like to share a new concept hitherto not well taught,  with reference to function of  Anterior cruciate ligament

Google " function of ACL", most if not all articles talk about preventing anterior translation of tibia on the femur. Bing it, again talks about the same concept.  Try even Copilot and ask on this, talks about the same, and some articles will add preventing internal tibial rotation.

Try Pubmed, Very few articles if you search well, will talk about the ACL function on a fixed tibia as we are on weight bearing. This is preventing posterior translation of femur on the tibia, preventing posterior rolling of femoral condyle on the tibial plateau.

Even biomechanics studies do not talk about the femoral translation and rotation on a weight bearing limb.

I would like us to understand that more precisely, ACL prevents posterior translation of lateral femoral condyle on the lateral tibial plateau, thus preventing external rotation of femur on the fixed tibia.

Hope this is of help to understand what we are really trying to achieve by reconstructing ACL

references samples

1. Anterior cruciate ligament

Author: Edwin Ocran, MBChB, MSc • Reviewer: Dimitrios Mytilinaios, MD, PhD Last reviewed: October 30, 2023

Reading time: 2 minutes

2.  Sports Biomech. Author manuscript; available in PMC 2024 Jan 1.

Published in final edited form as:

Sports Biomech. 2023 Jan; 22(1): 1–29. 

Published online 2021 May 7. 

LOADING MECHANISMS OF THE ANTERIOR CRUCIATE LIGAMENT

Mélanie L. Beaulieu, PhD,1 James A. Ashton-Miller, PhD,2,3 and  Edward M. Wojtys, MD1

Am J Sports Med. 2023 Apr; 51(5): 1136–1145. 

Published online 2023 Mar 14. 

3.  Role of the Anterior Cruciate Ligament, Anterolateral Complex, and Lateral Meniscus Posterior Root in Anterolateral Rotatory Knee Instability: A Biomechanical Study

Lukas Willinger, MD,* Kiron K. Athwal, PhD,† Sander Holthof, MEng,† Andreas B. Imhoff, MD,* Andy Williams, MB BS, FRCS(Orth), FFSEM(UK),‡ and  Andrew A. Amis, BSc, PhD, DSc(Eng), FREng†§