There are numerous classification systems in the literature that define various pathologic findings associated with the shoulder [
As the knowledge and ability of a specialty expand and improves, it is a natural progression that the classification systems utilized by the profession must evolve. Historically, the rotator cuff was visualized as a single pathologic entity, and classification systems described them as such [
Classification systems for tears of the rotator cuff tendon have been proposed based upon specific characteristics such as size of the lesion, number of tendons involved, and the reparability of the tear [
Individually, these rotator cuff tear classification systems do provide information about the condition of the patient’s shoulder, but are limited in their description of the shoulder as a whole. In addition, none of these systems provides any information about the status of the associated joints, ligaments, tendons, and nerves; their concomitant assessment and treatment are important in optimizing patients’ outcome. The limitations of these current classification systems mandate the development of a new, concise, and expandable classification system that covers all rotator cuff tendon pathology, and is inclusive of the surrounding structures of the shoulder. The 4D code was developed with these explicit goals.
The aim of the 4D code is to provide a logical method of describing shoulder pathology using universal numbers and letters. The 4D code seeks to provide a complete description of the shoulder in a concise format, without sacrificing detail, and allows a practitioner to glean the pertinent information in regards to preoperative, operative, and postoperative condition of the shoulder. This allows the appropriate treatment protocols to be adjusted and optimized for each individual patient in an efficient and comprehensive manner.
The 4D code is one or multiple lines of alpha-numeric text, each line denoting the condition of the shoulder at one point in time. We introduce our methodology by dividing the 4D code into its fundamental elements and secondary elements.
The fundamental elements of the 4D code start with the shoulder sidedness and the time code. Next are the pillar components (Figure
The pillar components of the 4D code. Starting from anterior aspect of the shoulder, the pillar components are subscapularis (SSC), long head of biceps tendon (B), supraspinatus (SS), infraspinatus (IS), and teres minor (TM).
An example of the 4D code which includes the fundamental elements is shown in Figure
An example of a 4D code with its fundamental elements.
The first letter is the sidedness of the shoulder. An “R” or “L” will start all lines of 4D code, so there is consistency in the reporting of the shoulder of interest of a given patient.
The second fundamental element is the time code (Figure D− —before surgery: the code that follows is the condition of the shoulder based on history, examination, radiological, and other studies. D—day of surgery, prior to any repair: this includes the important information gathered from diagnostic arthroscopy. The code may be different from before surgery (time D−) due to evolution or clarification of pathology. D+ —end of surgery: this presents the condition of the shoulder once repair is complete. D+ time—a certain time after surgery: D+6W would represent the time point of 6 weeks postoperatively. M (months) and Y (years) can also be used.
Time code: Time as the fourth dimension in the 4D code system. D− denotes before surgery; D denotes day of surgery prior to repair; D+ denotes immediately after repair. Additional time points can be described, such as D+6W denotes the 6 weeks postoperative visit.
The first of the pillar components describes the condition of the subscapularis tendon. We use the Lafosse classification system, which is based on tear size and location, humeral head concentricity, and degree of fatty infiltration (Table
Subscapularis grading system based on the Lafosse classification [
Type | Descriptions |
---|---|
1 | Partial tear of superior third |
2 | Complete tear of superior third |
3 | Complete tear of superior two-thirds |
4 | Complete tear, head concentric, fatty infiltration 1–3 |
5 | Complete tear, head eccentric, fatty infiltration > 3 |
The 4D code documents the condition of the long head of biceps tendon into the following categories: BN—normal; BP—pathological; BA—absent or tenotomized; BT—tenodesed.
To assess the tear in the coronal plane, the Patte classification system is used to describe the supraspinatus, infraspinatus, and teres minor tendons (Figure
Patte classification system is used to describe tears of the supraspinatus, infraspinatus, and teres minor tendons in the coronal plane [
Putting the fundamental elements of the 4D code together, the example in Figure
The secondary elements expand the descriptive capability of the 4D code system. They add to the shoulder sidedness, time code, and the pillar components. Unlike the fundamental elements which appear with every line of 4D code, the secondary elements are documented only if there is pathology. These structures and conditions include: the acromioclavicular (AC) joint arthritis, glenohumeral joint arthritis, labral pathology, fatty infiltration, and any associated nerve pathology. Additional description of a rotator cuff tear may be added, including shape of a tear, bursal- versus articular-sided, and presence of calcific tendonitis. Figure
An example of a 4D code with both fundamental elements and secondary elements. Fundamental elements are denoted by (*). The secondary elements include descriptions of AC joint pathology, glenohumeral arthritis, labral pathology, fatty infiltration, and neuropathy.
If there is presence of AC joint disease, this can be added to the 4D code as a secondary element. We choose to place the following code immediately after the time designation: AC—presence of AC joint arthritis; ACR—status post AC joint resection.
The presence of glenohumeral osteoarthritis is documented using the Samilson classification [
Samilson classification of glenohumeral arthritis [
Stages | Descriptions |
---|---|
1 | Osteophyte < 3 mm |
2 | Osteophyte 3–6 mm |
3 | Osteophyte > 6 mm |
With superior labral pathology, we use Snyder’s classification [ SL SLD: debridement of SLAP lesion; SLR: SLAP repair; L LD: labral debridement; LR: labral repair.
SLAP lesion as classified by Synder et al. [
Types | Descriptions |
---|---|
1 | Degenerative, frayed superior labrum with intact biceps anchor. |
2 | Biceps anchor detachment from the superior glenoid tubercle. |
3 | Bucket-handle tear of the labrum with an intact biceps anchor. |
4 | Bucket-handle tear of the labrum that extends into the biceps tendon. |
5 | Anterior-inferior Bankart that extends superiorly to include an unstable biceps anchor |
6 | Unstable flap tear of the labrum with a detached biceps anchor. |
7 | Superior labral detachment with extension into the middle glenohumeral ligament. |
The shape of the rotator cuff tear can be incorporated into the 4D code. Full thickness tears have been described as U-shaped, V-shaped, or L-shaped in the literature. We use the following designation immediately before the tendon it is associated with: U: U-shaped tear; V: V-shaped tear; AL: anterior L-shaped tear; anterior corner detachment; PL: posterior L-shaped tear; posterior corner detachment.
Partial thickness tears of the supraspinatus, infraspinatus, and teres minor are documented in the 4D code according to the Ellman classification (Table A B I: interstitial tears
Ellman classification for partial thickness rotator cuff tears [
Grades | Descriptions |
---|---|
1 | Partial tear < 3 mm deep |
2 | Partial tear 3–6 mm deep; depth not |
exceeding one-half of the tendon | |
thickness | |
3 | Partial tear > 6 mm deep |
Calcium deposit in the rotator cuff tendon can cause exquisite pain and is an important pathology in the shoulder. If calcific tendonitis is present, the letter C can be placed in the 4D code for the particular tendon involved.
The presence of fatty infiltration in the rotator cuff muscle provides additional information regarding chronicity of the tears and has significant impact on surgical decision making and the potential for return of function [
Fatty infiltration according to Goutallier classification [
Stages | Descriptions |
---|---|
0 | Normal muscle |
1 | Fatty streaks |
2 | Significant fat, but more muscle than fat |
3 | Equal amount of muscle to fat |
4 | Fat is greater than muscle |
If any neuropathy is present around the shoulder based on history, examination, imaging, and neurodiagnostic studies, this can be designated in the 4D code: SSN—suprascapular nerve injury; SSNR—status post suprascapular nerve release; AXN—axillary nerve injury; LTN—long thoracic nerve injury.
Table
Summary of the elements of the 4D code with its possible codes and corresponding descriptions.
Components | Classification systems | Variables | Descriptions |
---|---|---|---|
Fundamental elements | |||
Sidedness | R | Right | |
L | Left | ||
Time code | D− | Time of presentation | |
D | Before surgical repair | ||
D+ | Immediately postop | ||
D+ |
| ||
Subscapularis |
Lafosse et al. [ |
0, 1–5 | (Table |
Long head of biceps | BN | Biceps is normal | |
BP | Biceps is pathological | ||
BA | Biceps is absent or tenotomized | ||
BT | Biceps is tenodesed | ||
Supraspinatus | Patte [ |
0, 1–3 | (Figure |
Infraspinatus | |||
Teres minor | |||
Secondary elements | |||
AC | AC | AC joint is arthritic | |
ACR | s/p AC joint resection | ||
Glenohumeral arthritis |
Samilson and Prieto [ |
GH1–3 | (Table |
Labrum |
Synder et al. [ |
SL1–7 | SLAP tear (Table |
SLD | Status post SLAP debridement | ||
SLR | Status post SLAP repair | ||
L |
Labral detachment from | ||
LD | Status post labral debridement | ||
LR | Status post labral repair | ||
Tear configuration | U | U-shaped tear | |
V | V-shaped tear | ||
AL | Anterior L-shaped tear with anterior corner detachment | ||
PL | Posterior L-shaped tear with posterior corner detachement | ||
Partial thickness tear | Ellman [ |
A1–3 | Articular-sided tear, (Table |
B1–3 | Bursal-sided tear, (Table | ||
I | Interstitial tear | ||
Calcific tendonitis | C | Presence of calcific tendonitis | |
Fatty infiltration |
Goutallier et al. [ |
G |
Subscapularis, supraspinatus, infraspinatus, teres minor (Table |
Nerve pathology | SSN | Suprascapular nerve injury | |
SSNR | Status post SSN release | ||
AXN | Axillary nerve injury | ||
LTN | Long thoracic nerve injury |
We present two patients from our practice as illustrative examples of the utility of the 4D code.
A 64-year-old lady initially presented in consultation with right shoulder pain. Her symptoms had started insidiously one year earlier. She did not improve with nonoperative treatments and elected to undergo rotator cuff repair. She did well initially; however, she sustained a fall 2 years after surgery and has returned to the office. Using the 4D code, her clinical picture can be summarized as follows. Line 1: RD− 1 BP 2 0 0. Line 2: RD 2 BP 2 1 0. Line 3: RD+ 0 BT 0 0 0 SSNR. Line 4: RD+6W 0 BT 0 0 0 SSNR. Line 5: RD+2Y 0 BT B1 0 0 SSNR.
From these five lines of code, a significant amount of information is conveyed. Line 1 portrays the condition of the right shoulder at time of consultation (D−). Based on examination and three-dimensional imaging, there is partial tear of the upper subscapularis tendon, biceps tendon is diseased, and supraspinatus tendon is torn and retracted to the level of humeral head. Line 2 shows the condition of the shoulder on the day of surgery after diagnostic arthroscopy (time D); superior subscapularis tendon is noted to be completely torn, and in addition to supraspinatus tear, infraspinatus is torn as well without retraction. In line 3, we see the extent of the surgical interventions (time D+), which include tenodesis of the long head of biceps, successful anatomical repair of all rotator cuff tendons, and release of the suprascapular nerve. At the six-week-followup (time D+6W), line 4 shows that the repair is intact. After patient sustained a fall two years later (time D+2Y), examination and additional imaging shows (line 5) that the cuff repair remains intact, but there is a bursal-sided partial tear of the supraspinatus tendon.
No additional secondary elements are listed because this patient had no AC joint or glenohumeral joint arthritis, labrum was normal, and there is no fatty infiltration of the rotator cuff muscles.
This patient is a 58-year-old male with a long history of dominant right shoulder pain and functional limitation. At the patient’s initial visit, he complained one year of worsening right shoulder pain, atraumatic in onset. He had failed to improve despite physical therapy and one subacromial corticosteroid injection. His examination showed a torn subscapularis tendon from positive Lift-off and Bear-hug tests. He also had weakness of the supraspinatus and infraspinatus muscles. He had bicipital groove pain but no AC joint tenderness. His CT arthrogram confirmed and added to the exam findings (Figure
Patient 2 had the following CT arthrogram at time of presentation. It confirmed the exam findings of torn subscapularis, supraspinatus, and infraspinatus. Biceps tendon was diseased.
The patient was indicated for surgery, and photographic documentation was done during diagnostic portion of the arthroscopy (Figure
Patient 2’s diagnostic arthroscopy documentation. (a) Initial inspection shows an absent medial biceps pulley and a tear of at least the upper one-third of the subscapularis tendon. (b) There is intratendinous extension of the tear as demonstrated by the arthroscopic probe. (c) Inferiorly, the upper two-thirds of the lesser tuberosity is exposed after debridement. There is significant fraying of the dislocated biceps tendon on the right-hand side. There is also the “comma sign” from the medially retracted anterior-superior rotator cuff tear. (d) This is the articular view of the grade 2 supraspinatus tear retracted to level of the humeral head. (e) This is a lateral view of the exposed humeral head with the grade 2 infraspinatus tear. (f) Infraspinatus tendon has delaminated into two layers.
The pathology was addressed with an anatomic, arthroscopic repair of the rotator cuff, and arthroscopic proximal biceps tenodesis. Final pictures are shown in Figure
Patient 2’s final arthroscopy pictures documenting rotator cuff repair. (a) The posterior cuff is restored anatomically to the footprint of the greater tuberosity. (b) There is an anatomic repair of the supraspinatus and subscapularis tendons with an open rotator interval.
The patient has done well postoperatively. At his 3-year-followup, he complained of minimal pain. His constant score was 90, with full, symmetric ranges of motion, but mild weakness in the right supraspinatus muscle. He also showed mild tenderness at the AC joint. CT arthrogram was obtained (Figure
Patient 2’s 3-year-followup CT arthrogram. (a) The subscapularis tendon repair and the tenodesed long biceps tendon in the bicipital groove remained intact. (b) There is a grade 1 retear of the supraspinatus tendon and degenerative changes of the AC joint. (c) There is a grade 1 partial, articular-sided retear of the infraspinatus tendon. (d) The sagittal view confirms the grade 1 supraspinatus retear. (e) The sagittal view shows the grade 1 articular-sided infraspinatus tear has mild interstitial extension. (f) Axial image shows the arthritic AC joint.
These two examples demonstrate how a small number of lines of 4D code can provide a global view of this patient’s history in an efficient and concise manner. There is minimal need to review numerous clinical dictations or operative notes, and communication between surgeons can be simple as well as comprehensive.
An exponential increase in the knowledge of pathologic conditions affecting the shoulder has allowed us to define the natural history of various disease processes. Similarly, surgical techniques have evolved to address the uniqueness of each element of the rotator cuff and surrounding structures. The expansion of knowledge and improvement of techniques require a parallel improvement in classification and communication methodology about the shoulder.
Multiple grading and classification systems described in the literature are often complex and cumbersome to use, while only providing a partial view of the shoulder. The 4D code was developed to provide a comprehensive three-dimensional perspective of the shoulder at various time points of treatment. It has distilled the essence of several previously validated classification and grading systems into reproducible alpha-numeric lines of text which is internationally understood. By consolidating previously validated schemes, the basic tenets of an effective classification system—simplicity, accuracy, and applicability—are maintained.
The premise of utilizing such a code to create a three-dimensional image is derived from the same concept of the binary code that computers use to perform their necessary functions. Just as a computer can process a picture from a combination of 0’s and 1’s, we have established a systematic grouping of letters and numbers to allow the human mind to formulate a complete picture of the shoulder. Additionally, to our knowledge, this is the first description system in the literature that incorporates the dimension of time, which is a progressive and necessary step forward.
Its reproducibility and simplicity permit communication between physicians, therapists, and other members of the care team. Its flexibility and adaptability should have wide appeal. Our experience with the 4D code thus far has shown providers of all levels have been able to easily learn, apply, and clearly communicate with the system. Ultimately, it is a significant step forward in how shoulder pathology is evaluated, documented, and discussed.
The 4D code is developed to provide a concise yet comprehensive view of the shoulder pathoanatomy. It provides a three-dimensional picture and incorporates the element of time. It consolidates previously validated classification and grading systems into lines of alpha-numeric text that is easily conveyed. Its simplicity and completeness aid patient care between members of a care team as well as communication between surgeons internationally. We think the wider adoption of the 4D code can be a large step forward in the documentation of shoulder pathology and the exchange of this information.