The Walch classification of glenoid morphology is used to stratify the outcomes of shoulder arthroplasty for varying pathologic glenoid types as well as assisting in preoperative planning to recognise morphologies that may pose intraoperative difficulties. 

Usage

The Walch classification in primary glenohumeral osteoarthritis is the most commonly used system to describe this pathology ^ref. 

It was initially measured on 5 mm thick slices on axial CT scans of the shoulder ¹, which had mixed results for inter- and intra-observer agreement but this has improved with the modified classification system (which includes B3, C2, and D) using 3D CT reconstructions ^2,3.

Classification

• type A: centred humeral head, concentric wear, no subluxation of the humeral head

  • A1: minor central erosion

  • A2: major central erosion, humeral head protruding into the glenoid cavity

• type B: humeral head subluxated posteriorly, biconcave glenoid with asymmetric wear 

  • B1: narrowing of the posterior joint space, subchondral sclerosis, osteophytes

  • B2: biconcave aspect of the glenoid with posterior rim erosion and retroverted glenoid

  • B3: monoconcave and posterior wear with >15° retroversion or >70% posterior humeral head subluxation, or both

• type C

  • C1: dysplastic glenoid with >25° retroversion regardless of the erosion

  • C2: biconcave, posterior bone loss, posterior translation of the humeral head

• type D

  • glenoid anteversion or anterior humeral head subluxation <40°