Subsidence following surgical stabilization of acromioclavicular joint injuries: Should we be concerned?

Table 1 Incidence of loss of reduction after acromioclavicular joint pinning, coracoclavicular screw fixation, hook plate, and tension band wiring in acute acromioclavicular joint disruptions

Ref.	Study design	n	Rockwood type	Technique	Mean follow-up	LOR/re-dislocation
Horst et al[53], 2013	Retrospective	11	Acute (III)	ACJ pinning	6-21 weeks	9.1% LOR
Leidel et al[54], 2009	Retrospective	70	Acute (III)	ACJ pinning	1-10 years	11% re-dislocation, 4% migration
Cetinkaya et al[56], 2017	Retrospective	32 (16 vs 16)	Acute (III)	Bosworth screw vs modified Phemister	93-96 months	Bosworth: 2/16; Phemister: 1/16
Darabos et al[57], 2015	RCT	68 (34 vs 34)	Acute (III)	Bosworth screw vs AC tight-rope	6 months	Bosworth: 11.8%; tight-rope: 5.9%
Bektaşer et al[55], 2004	Prospective	34	Acute (III)	Bosworth screw	35 months	8.8%
El-Shennawy et al[58], 2021	Retrospective	30	Acute (III-V)	TBW	1 year	6.8% partial LOR
Ozan et al[60], 2020	Retrospective	24	Acute (III)	TBW	3.5 years	45.8% residual subluxation
Lateur et al[59], 2016	Retrospective	25	Acute (IV, V)	TBW	12 years	2% LOR
Wang et al[65], 2024	Retrospective	58 (35 vs 23)	Acute (III, V)	Hook plate vs tight-rope	15.4 months	Hook plate: 2.9%; tight-rope: 4.3%
Ko et al[62], 2023	Prospective	61 (36 vs 25)	Acute (III-V)	Hook plate vs tight-rope	7 years	Hook plate: 16.7%; tight-rope: 28%
Amr[66], 2021	Prospective	64 (32 vs 32)	Acute (III-VI)	Hook plate vs reconstruction	64 months	Hook plate: 21.8%; reconstruction: 6.2% subluxation
Nie and Lan[63], 2021	Retrospective	112 (84 vs 28)	Acute (III-V)	Hook plate vs tight-rope	34 months	Hook plate: 11.9%; tight-rope: 7.1%
Shen et al[64], 2021	Retrospective	35 (19 vs 16)	Acute (III-V)	Hook plate vs tight-rope	27-30 months	Hook plate: 0%; tight-rope: 6.3%
Cai et al[61], 2018	Prospective	69 (39 vs 30)	Acute (III)	Hook plate vs tight-rope	12 months	Hook plate: 0%; tight-rope: 10%

LOR: Loss of reduction; RCT: Randomized controlled trial; ACJ: Acromioclavicular joint; AC: Acromioclavicular; TBW: Tension band wiring.

Table 2 Loss of reduction rates following modified Weaver-Dunn procedures and anatomic coracoclavicular ligament reconstructions

Ref.	Study design	n	Rockwood type	Technique	Mean follow-up	LOR/re-dislocation
Hegazy et al[67], 2016	Prospective	20 (10 vs 10)	Chronic (III)	Reconstruction by semitendinosus autograft vs modified WD	27.8 months	ST graft: 0%; WD: 30% early failures
Kibler et al[69], 2017	Retrospective	15	Acute and chronic (III-V)	Reconstruction with allograft + AC ligament docking	36 months	7%
Kumar et al[70], 2014	Retrospective	55 (31 vs 24)	Chronic (III-V)	Reconstruction by synthetic ligament vs Modified WD + CC sling	40 months	WD: 9.7%; synthetic ligament: 4.2% with rupture
Fauci et al[68], 2013	RCT	40 (20 vs 20)	Chronic (III, IV)	Reconstruction by biological allograft vs synthetic ligament	4 years	Biologic: 5% LOR, 5% subluxation; synthetic: 10% LOR, 30% subluxations
Boström Windhamre et al[72], 2010	Retrospective	45 (23 vs 22)	Chronic (III-V)	WD augmented with hook plate vs with PDS-braid fixation	7-9 years	Hook plate: 17.4%; PDS-braid: 13.6%
Millett et al[71], 2009	Prospective	17	Acute and chronic (IV-V)	Coracoacromial ligament transfer using docking technique (modified WD)	29 months	6% re-dislocation after trauma
Tauber et al[75], 2009	Prospective	24 (12 vs 12)	Chronic (III-V)	Reconstruction by semitendinosus autograft vs modified WD	37 months	WD: 41.7%; ST graft: 8.3%
Law et al[73], 2007	Retrospective	5	Acute (III)	Reconstruction by gracilis tendon autograft	26 months	20% subluxation
Pavlik et al[74], 2001	Retrospective	17	Chronic (III)	Modified WD + CC screw	36.6 months	Slight loss: 35%; partial loss: 12%

LOR: Loss of reduction; RCT: Randomized controlled trial; WD: Weaver-Dunn; AC: Acromioclavicular; CC: Coracoclavicular; PDS: Polydioxanone suture; ST: Semitendinosus tendon.

Table 3 Loss of reduction rates associated with arthroscopic and arthroscopic-assisted acromioclavicular joint reconstruction techniques

Ref.	Study design	n	Rockwood type	Technique	Mean follow-up	LOR/re-dislocation
Çarkçı et al[77], 2020	Retrospective	36	Acute (III and V)	Arthroscopic double-button	31.4 months	25%
Lee et al[79], 2017	Retrospective	47	Acute (III-V)	Arthroscopic assisted single button	24 months	38.3%
Spoliti et al[83], 2014	Prospective	19	Acute (III-V)	Arthroscopic tight-rope (button + fiber wire)	12 months	15.8%
Tauber et al[42], 2016	Retrospective	26 (12 vs 14)	Chronic (III-V)	Arthroscopic TB vs SB CC reconstruction	29 months	TB: 8% vs SB: 21% recurrence
Nordin et al[81], 2015	Prospective	8	Chronic (III-V)	Arthroscopic assisted Graft-rope	12 months	50% early LOR
Murena et al[80], 2009	Prospective	16	Acute (III-V)	Arthroscopic double-button	31 months	25% partial LOR
Chernchujit et al[84], 2006	Retrospective	13	Acute (IV-V)	Arthroscopic reconstruction with suture anchors + titanium plate	18 months	15% subluxation; 8% re-dislocation

LOR: Loss of reduction; TB: Triple-bundle; SB: Single-bundle; CC: Coracoclavicular.

Table 4 Incidence of loss of reduction following acromioclavicular joint reconstruction using suture anchors or ligament advanced reinforcement system in acute and chronic injuries

Ref.	Study design	n	Rockwood type	Technique	Mean follow-up	LOR/re-dislocation
Ben-Ari et al[89]1, 2024	Retrospective	3	Chronic (III, V)	Open reconstruction with 2 coracoid suture anchors + semitendinosus allograft	6 weeks-12 months	100% early LOR
Mendes Júnior et al[90], 2019	Prospective	30	Acute (V)	Open reconstruction with 2 metallic anchors + CA ligament transfer	≥ 6 months	High rate of subluxation (not quantified)
Tiefenboeck et al[87], 2018	Retrospective	47	Acute (III-V)	LARS reconstruction	7.4 years	17% slight LOR; 11% partial LOR; 2% total LOR
Muccioli et al[88], 2016	Prospective	43	Chronic (III-V)	LARS reconstruction	≥ 24 months	2% re-dislocation; 21% slight LOR
Lu et al[86], 2014	Prospective	24	Acute (IV-V)	LARS reconstruction	36 months	16.7% slight LOR

¹It should be noted that isolated case series with extremely small sample sizes, such as the study by Ben-Ari et al[90], should be interpreted cautiously and not extrapolated to broader clinical populations.

LOR: Loss of reduction; LARS: Ligament advanced reinforcement system; CA: Coracoacromial.

Table 5 Clinical pearls and pitfalls related to postoperative loss of reduction after acromioclavicular joint stabilization

Clinical pearls and pitfalls
Pearls
	LOR must be interpreted with symptoms, not radiographs alone
	Horizontal stability is equally important as vertical alignment
	Functional deficit and overhead pain are the most reliable indicators of true failure
	Identify the mechanism of failure before planning revision
	Combined CC and AC reconstruction enhances revision durability
	Protect the repair during the early healing phase
Pitfalls
	Treating radiographic LOR without clinical relevance
	Misinterpreting mild subsidence as failure
	Reliance on CCD alone without assessing horizontal stability
	Allowing early loading leading to graft stretch or hardware failure
	Failing to correlate radiographic findings with symptoms
	Overlooking coracoid or clavicular fractures

LOR: Loss of reduction; CC: Coracoclavicular; AC: Acromioclavicular; CCD: Coracoclavicular distance.