Hip-inspired implant for revision of failed reverse shoulder arthroplasty with severe glenoid bone loss

Figures & data

Table 1. Patient characteristics and clinical details

A	B	C	D	E	F	G	H	I	J
1	61/M	FS	48	U	Combined	34	Staged revision ^a	U
2	69/F	PCTA	60	C	Combined	40	Single stage	C	Aseptic humeral stem loosening; underwent revision and re-cementing of the stem at 12-month follow-up.
3	78/F	PCTA	78	U	Central	29	Single stage	C
4	75/F	PCTA	84	C	Combined	28	Staged revision ^b	C
5	84/M	PCTA	72	C	Combined	34	Staged revision ^a	C	Early prosthetic dislocation treated with open reduction at 2-week follow-up.
6	72/M	PCTA	72	U	Combined	36	Single stage	U
7	69/F	FS	48	U	Central	32	Staged revision ^b	C
8	71/F	PCTA	60	C	Central	36	Staged revision ^b	C	Periprosthetic fracture at the tip of the humeral stem; under-went internal fixation with a locking plate at 6-month follow-up.
9	73/F	FS	36	U	Combined	38	Single stage	C
10	58/F	FS	48	C	Combined	33	Staged revision ^b	C
11	79/F	PCTA	30	C	Combined	42	Staged revision ^b	C	Protrusion of cement mantle, causing pain and discomfort; removed surgically at 18-month follow-up.

A Patient no.

B Age (at revision) /Gender

C Indication for RSA:

  FS – Fracture sequelae

  PCTA – Primary cuff-tear arthropathy

D Time from RSA to revision (months)

E Reverse shoulder arthroplasty stem fixation

  C – Cemented

  U – Uncemented

F Glenoid bone loss (all severe) based on intraoperative findings according to the classification described by Antuna et al. (2001).

G Follow-up post-revision

H Single stage/ Staged revision

   ^a Infection was suspected.

   ^b Glenoid bone quality could not be determined preoperatively or assessment changed based on intraoperative findings.

I CAD/CAM stem fixation

  See E

J Post-revision complications

Figure 1. The CAD/CAM shoulder (Stanmore Implants, Elstree, UK). A custom-made, constrained hip arthroplasty-inspired implant. The implant comprises an uncemented titanium glenoid shell mated to a cobalt-chrome tapered humeral stem (cemented or uncemented with a 28-mm or 32-mm head) with a high-molecular-weight polyethylene liner (cemented into the glenoid shell). A. A preoperative drawing. B. The actual implant.

Figure 2. A 72-year-old man (patient 6) presented with severe pain and limited function 6 years after reverse shoulder arthroplasty for primary cuff-tear arthropathy. Shoulder radiographs at presentation showed loosening and migration of the baseplate (panel A). The prosthesis was revised using the CAD/CAM shoulder with significant pain relief and improvement in functional scores at the 36-month follow-up (panels B and C).

Table 2. Summary of outcome measures before and after revision

	Before revision	After revision	Difference (95% CI)	p-value ^c
Oxford shoulder score	50 (4)	33 (6)	17 (11, 21)	< 0.001
Subjective shoulder value, 0–100% scale	17 (11)	48 (17)	31 (19, 42)	< 0.001
Pain at rest, 0–10 scale	5.3 (1.6)	2.3 (1.3)	3.0 (1.7, 4.3)	< 0.001
Pain during activity, 0–10 scale	8.1 (1.6)	3.8 (1.7)	4.3 (2.6, 5.9)	< 0.001
Active range of motion
Forward flexion (°)	25 (12)	54 (17)	29 (18, 39)	< 0.001
External rotation in adduction (°)	9 (10)	21 (9)	12 (5, 18)	0.002
Internal rotation hand behind back ^a	2.3 (1.0)	2.8 (0.9)	0.5 (–0.2, 1.3)	0.1
Ability to reach “functional triangle” ^b , n	3	6	–	0.3

Values presented are mean (SD). The difference between pre-revision score and post-revision score is presented in absolute values.

^a 1-thigh, 2-buttock, 3-sacroiliac joint, 4-waist, 5-T12, 6-scapula.

^b A functional triangle consisting of the mouth, opposite armpit, and ipsilateral buttock.

^c Values were compared using the paired 2-tailed t-test. “Functional triangle” values were compared using the 2-tailed McNemar test.

Antuna SA, Sperling JW, Cofield RH, Rowland CM. Glenoid revision surgery after total shoulder arthroplasty. J Shoulder Elbow Surg 2001; 10 (3): 217-24.

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