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Distal Clavicle Osteolysis

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Updated May 2026

Distal clavicle osteolysis (weightlifter's shoulder) causes pain at the top of the shoulder, classically with pressing exercises. Kieran Hirpara 4.0

What you're feeling

You likely feel pain at the very top of your shoulder, right where your collarbone meets your shoulder blade. This spot is called the acromioclavicular joint. The ache may start after you lift heavy weights or do repetitive overhead movements. Over time, the bone at the end of your collarbone can wear down or dissolve. This condition is known as distal clavicle osteolysis.

The pain often flares up during daily tasks. You might feel a sharp pinch when you reach across your body to tuck in a shirt. Fastening a bra behind your back can become difficult and painful. Lifting objects above your head, like placing a bag on a high shelf, may trigger a deep ache. Even simple movements, such as reaching for a seatbelt, can irritate the joint.

Nighttime pain is common. You may find it hard to sleep on the affected side. The pressure of your body weight on the inflamed joint can wake you up. Some patients report stiffness when they first wake up in the morning. This stiffness usually eases as you move around, but the pain returns after activity.

If you have had previous shoulder surgery, the symptoms might be more complex. Sometimes, bone loss occurs as a complication from prior procedures. In rare cases, infection with bacteria like Propionibacterium acnes can cause significant bone loss. This type of osteolysis may require specific treatment to stop the bone from dissolving further.

You might also notice instability in your shoulder. If the joint is loose, your collarbone may shift when you move. This can feel like your shoulder is slipping out of place. Horizontal movement of the collarbone becomes noticeable if more than 10 mm of bone has been removed or lost. This instability can make lifting even more challenging.

Not everyone with joint wear-and-tear arthritis needs surgery. Some patients manage symptoms with rest and medication. However, if the pain persists and limits your daily life, your surgeon may discuss removing the end of the collarbone. This procedure, called distal clavicle resection, can relieve pressure on the joint. It is often considered for chronic pain that does not improve with conservative care.

What's actually happening

Your collarbone meets your shoulder blade at a small joint near the top of your shoulder. Think of this joint as a shock absorber that lets your arm move freely. Over time, wear and tear can damage the smooth coating on the bone ends. This condition is called osteoarthritis. The body may react by breaking down the very end of the collarbone, a process known as osteolysis. This creates inflammation and pain when you move your arm across your body or lift objects overhead.

Sometimes, this issue follows an injury. You might have strained or torn the ligaments that hold the collarbone in place. These ligaments act like strong ropes keeping the bones aligned. When they are damaged, the joint mechanics change. Your shoulder blade and collarbone may not move together smoothly. This mismatch can cause grinding, stiffness, and aching. Even if the initial injury seems minor, the altered movement patterns can lead to long-term discomfort. About half of patients with certain types of shoulder disruptions experience impaired function ten years later.

In rare cases, a low-grade infection can cause this bone breakdown. Bacteria may settle in the joint, triggering the body to break down bone tissue. If this happens, removing the damaged bone end and using antibiotics can stop the process. For most people, the pain comes from the joint surfaces rubbing together or the ligaments being overstretched.

Your surgeon will look at how much bone is affected and how your shoulder moves. If rest and therapy do not help, removing the damaged end of the collarbone can relieve the pain. This procedure creates more space for the bones to move without grinding. It is a reliable way to improve comfort for those with persistent pain or arthritis. The goal is to restore smooth movement and reduce the inflammation that limits your daily activities.

What we can do about it

The approach we use for distal clavicle osteolysis reflects how Dr Kieran Hirpara, an upper-limb surgeon at Mater Private Hospital Rockhampton, manages this condition in our clinic. Patients reach our practice through referral from a GP or physiotherapist. We begin with a thorough assessment, including a history, physical examination, and imaging if needed. For degenerative or long-standing issues, we usually start with non-operative care. This gives your body time to settle the inflammation and strengthens the shoulder to support the joint.

You can start by changing activities that cause pain. Avoid heavy lifting or overhead movements for a period of time. Physiotherapy aims to improve your shoulder stability and range of motion. We typically recommend giving this conservative approach a fair trial before considering other options. If pain persists, we may discuss medical management. This can include pain medication and anti-inflammatories to reduce swelling. We may also offer injections, such as cortisone, to calm the joint directly. These treatments help manage symptoms but do not reverse the bone loss.

Surgery is considered when conservative care has not given enough improvement. The most common procedure is a distal clavicle excision, where we remove the damaged end of the collarbone. This relieves pain by stopping the bones from rubbing together. Arthroscopic removal allows for a faster return to activities compared with open surgery, while providing similar long-term outcomes. In cases of chronic instability, we may reconstruct the joint using your own ligaments. For severe, long-standing dislocations, total removal of the clavicle end is an option that yields high patient satisfaction. We discuss these options with you to ensure the plan matches your specific needs and goals.

What to expect

Distal clavicle osteolysis is a wear-and-tear condition where the bone at the end of your collarbone breaks down. This often causes persistent pain in the shoulder. If you have untreated acute injuries, a majority of patients do well without any formal treatment. However, a small percentage may require delayed surgical intervention if symptoms persist.

When symptoms do not settle on their own, your surgeon may recommend removing the outer end of the clavicle. This procedure reliably produces significant improvement in patients with persistent pain or posttraumatic arthritis. You can expect a faster return to activities with arthroscopic surgery compared with open procedures, while obtaining similar long-term outcomes. Both approaches provide significant pain reduction at 1 year.

Recovery feels gradual. In the short term, you may notice a rapid return to function with negligible morbidity. Long-term, good clinical results persist for many years. Fifteen years postoperatively, anatomic reduction is often maintained, though some patients may have asymptomatic bone growth near the ligaments.

It is important to understand that outcomes vary. Incomplete removal of the bone is the most common cause of revision surgery. If more than 10 mm of bone remains, horizontal instability can occur. Patients with severe displacement before surgery may have poorer clinical outcomes. Total removal of the bone end is generally reserved for specific cases like chronic infection or malignancy, as it may not relieve posttraumatic pain effectively despite restoring full movement.

If your condition is caused by a specific bacteria, the combination of bone resection and antibiotics can halt the process. In such cases, patients remain symptom-free at 10 months after surgery. Without treatment, late loss of reduction is common in joint dislocations. With proper management, you can expect relief from the grinding pain and improved shoulder stability. Your surgeon will help you decide if this path is right for your specific injury.

When to see someone

See your GP if you have shoulder pain that does not improve with rest. Ask for a specialist review if you feel weakness or instability in the joint. Watch for locking or a sensation of the shoulder giving way. These symptoms can interfere with sleep or work. Sudden worsening of pain is also a reason to seek care. Your surgeon will check for issues like bone changes or instability. For example, removing more than 10 mm of bone can cause horizontal instability. Incomplete removal of bone may lead to regrowth and the need for further surgery. Early assessment helps manage these risks effectively.

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Reviewed by Dr Kieran Hirpara · 10 June 2026.

Want the clinical detail? Read the clinician version.

Talk to your treating clinician for advice specific to you.

For an appointment with the CQ Hand + Upper Limb team, ask your GP about a referral or visit www.cqupperlimb.com.

Evidence & references

Overview

• Distal clavicle resection combined with antibiotics halted osteolysis in a case of Propionibacterium acnes–mediated distal clavicular osteolysis, with the patient remaining symptom-free at 10 months post-surgery [1].
• Patients undergoing arthroscopic distal clavicle excision via the direct approach for acromioclavicular joint pathology can expect a faster return to activities compared with the open procedure, while obtaining similar long-term outcomes [2].
• Open or arthroscopic distal clavicle resection is necessary to relieve symptoms in appropriately selected patients [4].
• Late loss of reduction was common in acromioclavicular joint dislocations, but clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis [5].
• Arthroscopic distal clavicle resection has provided more 'good or excellent' results than the open procedure, though this finding is comprised of low-level evidence [8].
• A well-performed distal clavicle excision will likely perform better than a poorly performed one, regardless of whether an open or arthroscopic approach is chosen [9].
• Excision of the outer end of the clavicle is preferred for old acromioclavicular joint dislocations, while open reduction and internal fixation are not recommended due to complications and poor functional results [13].
• For chronic symptomatic acromioclavicular joint injuries, partial claviculectomy is believed to be the best procedure, offering negligible morbidity and rapid return to function [14].
• Both arthroscopic and open distal clavicle excisions provide significant pain reduction at 1 year with no significant difference in outcome measures between groups, except for VAS pain score improvement [17].
• Routine distal clavicle excision is not absolutely necessary in patients with symptomatic acromioclavicular joint osteoarthritis undergoing arthroscopic rotator cuff repair [20].
• Total claviculectomy is a possible treatment option for chronic clavicular dislocation, yielding excellent outcomes and high patient satisfaction [22].
• Total claviculectomy yielded good results for patients with chronic osteitis and malignancy but unsatisfying results for those with chronic posttraumatic pain, despite full range of motion being regained in all cases [27].

Anatomy & Pathophysiology

• A precise, easy to use and low-cost non-invasive method able to draw and analyze the kinematics of the shoulder complex has not been developed yet [29].
• Normative kinematic values of scapulothoracic movements in the shoulder girdle have been provided [30].
• No reconstruction strategy completely restores the shoulder girdle to its preinjured state, although each technique restores different elements of joint kinematics [31].
• The trapezoid and conoid ligaments have unique functions in normal shoulder kinematics because of their anatomic attachments [32].
• Kinematic changes could be a potential source of pain and dysfunction in the shoulder with AC joint dislocation [33].
• Scapular and clavicular kinematics were affected in AC separation models [34].
• A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols and for establishing outcomes of the treatment protocols [35].
• The inconsistency of AC joint testing parameters and the lack of thorough translation studies indicate a necessity for increased attention in the overall assessment of shoulder stability to close the gap in the foundational biomechanical research [36].
• Anatomically, the pectoralis minor tendon provides sufficient tissue length, excursion, and width [37].
• Biomechanically, the pectoralis minor tendon is as strong as the coracoacromial ligament [37].
• No significant biomechanical differences in displacement or stiffness were seen between the anatomical landmark technique and the coracoid-based landmarks technique for coracoclavicular stabilization [38].
• New surgical techniques continue to evolve as more biomechanical data emerge and kinematic understanding improves [39].
• Emerging concepts and strategies regarding horizontal and rotational instability and scapular biomechanics aim to lay the foundation for future studies aimed at improving treatment outcomes and patient management [40].
• Preliminary findings revealed no detectable differences between surgically reconstructed and uninjured sides in ACJ biomechanics, range of motion, and isometric strength [41].
• Nonoperatively treated shoulders showed increased internal rotation, upward rotation, and posterior tilting [41].
• Type I and II acromioclavicular joint disruptions impair long-term shoulder function in about half of patients 10 years after injury [43].
• At 150 to 200 N of loading, CAL excision and acromioplasty increase the rotator cuff force required to maintain normal glenohumeral biomechanics by 25% to 30% [44].
• Centre of pressure measurement detected sensorimotor functional deficits following surgical treatment of the shoulder joint in patients with confirmed successful clinical and functional outcomes [45].

Classification

• The ISAKOS Upper Extremity Committee suggests adding grade IIIA and grade IIIB injuries to a modified Rockwood classification to distinguish between stable type III injuries and unstable grade III injuries with therapy-resistant scapular dysfunction and overriding clavicle [50].
• Methods to diagnose both superior and posterior translation of the clavicle need further debate [15].
• Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes [6].
• Horizontal instability of the clavicle is evident with distal clavicle resection of greater than 10 mm [11].
• Simple excision of the outer end of the clavicle has yielded satisfactory results in this group of patients, with no residual upward displacement disturbing the patients [7].
• Excision of the outer end of the clavicle is preferred for old dislocations, while open reduction and internal fixation are not recommended due to complications and poor functional results [13].
• Severe chronic symptomatic AC joint separations (Rockwood types III through V) can be repaired entirely by arthroscopy safely and effectively by transferring the coracoacromial ligament with a bone block in the distal clavicle [48].
• Incomplete excision and regrowth of the distal clavicle are the most common causes of revision [10].
• A well-performed distal clavicle excision will likely perform better than a poorly performed one, regardless of whether an open or arthroscopic approach is chosen [9].
• The combination of distal clavicle resection and antibiotics halted the osteolysis, and the patient has remained symptom free at 10 months after surgery [1].
• The case highlights the need to consider Gorham-Stout disease in patients presenting with massive osteolysis after shoulder surgery [3].

Clinical Presentation

• Distal clavicle osteolysis can be mediated by Propionibacterium acnes [1].
• Massive osteolysis may occur as a complication following shoulder surgery, such as posterior shoulder capsulorrhaphy [3].
• Segmental fractures of the clavicle are easily missed and may present with acromioclavicular joint disruption [21].
• Late loss of reduction is common in acromioclavicular joint dislocations [5].
• Patients with displacement greater than 100% of the thickness of the distal clavicle have poorer postoperative clinical outcomes [6].
• Horizontal instability of the clavicle is evident with distal clavicle resection of greater than 10 mm [11].
• Subacromial osteolysis following hook plate fixation for acromioclavicular dislocation has a relatively high and variable incidence [12].
• The primary factor influencing the reported incidence of subacromial osteolysis is the radiological assessment method [12].
• Clavicular tunnel widening was observed in 70% of patients at final follow-up after coracoclavicular stabilization surgery [16].
• Clavicular tunnel widening has a higher prevalence in chronic cases than in acute cases [16].
• Radiological assessment may show a statistically significant immediate superior clavicular displacement after hardware removal following acromioclavicular joint stabilization, with an increased incidence in the first year following stabilization [18].
• Methods to diagnose both superior and posterior translation of the clavicle need further debate [15].
• Distal clavicle fracture is a potential complication of misidentification of the AC joint and subsequent aggressive burring during shoulder arthroscopy [26].

Investigations

• Distal clavicle resection combined with antibiotics halted osteolysis in a case of Propionibacterium acnes–mediated distal clavicular osteolysis [1].
• Massive osteolysis after shoulder surgery requires consideration of Gorham-Stout disease as a diagnosis [3].
• Late loss of reduction was common in acromioclavicular joint dislocations, while clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis [5].
• Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes after acromioclavicular joint dislocation treated with the endobutton device [6].
• Simple excision of the outer end of the clavicle yielded satisfactory results in patients with acromioclavicular joint dislocation and subluxation, with no residual upward displacement disturbing the patients [7].
• Horizontal instability of the clavicle is evident with distal clavicle resection of greater than 10 mm [11].
• Subacromial osteolysis following hook plate fixation for acromioclavicular dislocation has a relatively high and variable incidence, with the primary factor influencing the reported incidence being the radiological assessment method [12].
• Methods to diagnose both superior and posterior translation of the clavicle need further debate [15].
• Radiological assessment showed a statistically significant immediate superior clavicular displacement after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system, with an increased incidence in the first year following stabilization [18].
• Weighted stress radiographs significantly increased the measured elevation of the clavicle and the coracoclavicular distance compared to non-weighted views in acute acromioclavicular joint dislocations [47].
• A high index of suspicion is needed to diagnose bone osteolysis following acromioclavicular joint reconstruction using synthetic ligament early before irretrievable bone loss occurs [54].
• Segmental fractures of the clavicle are easily missed [21].

Treatment

• The combination of distal clavicle resection and antibiotics halted osteolysis in a case of Propionibacterium acnes–mediated distal clavicular osteolysis, with the patient remaining symptom-free at 10 months post-surgery [1].
• Patients undergoing arthroscopic distal clavicle excision via the direct approach can expect a faster return to activities compared with open procedures while obtaining similar long-term outcomes [2].
• Open or arthroscopic distal clavicle resection is necessary to relieve symptoms in appropriately selected patients [4].
• Clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis following late loss of reduction after acromioclavicular joint dislocation [5].
• Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes after acromioclavicular joint dislocation treated with the endobutton device [6].
• Simple excision of the outer end of the clavicle yielded satisfactory results in patients with acromioclavicular joint dislocation, with no residual upward displacement disturbing the patients [7].
• Arthroscopic distal clavicle resection has provided more 'good or excellent' results than the open procedure, though this finding is comprised of low-level evidence [8].
• A well-performed distal clavicle excision will likely perform better than a poorly performed one, regardless of whether an open or arthroscopic approach is chosen [9].
• Subacromial osteolysis following hook plate fixation for acromioclavicular dislocation has a relatively high and variable incidence, with the primary factor influencing the reported incidence being the radiological assessment method [12].
• Excision of the outer end of the clavicle is preferred for old acromioclavicular joint dislocations, while open reduction and internal fixation are not recommended due to complications and poor functional results [13].
• For chronic symptomatic acromioclavicular joint injuries, partial claviculectomy is believed to be the best procedure, offering negligible morbidity and rapid return to function [14].
• Both arthroscopic and open distal clavicle excisions provide significant pain reduction at 1 year with no significant difference in outcome measures between groups, except for VAS pain score improvement [17].
• Routine distal clavicle excision is not absolutely necessary in patients with symptomatic acromioclavicular joint osteoarthritis undergoing arthroscopic rotator cuff repair [20].
• Total claviculectomy is a possible treatment option for chronic clavicular dislocation, yielding excellent outcomes and high patient satisfaction [22].
• Acromioclavicular joint reconstruction with coracoacromial ligament transfer using the docking technique achieved excellent clinical results and decreased the risk of recurrent distal clavicle instability [23].
• Satisfactory outcomes for fracture clavicle with acromioclavicular dislocation depend upon restoring the stability of the clavicle as well as the acromioclavicular joint [24].
• Distal clavicle fracture is a potential complication of misidentification of the AC joint and subsequent aggressive burring during shoulder arthroscopy [26].
• Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate [46].
• Open and arthroscopic distal clavicle excision are both effective surgeries to treat recalcitrant acromioclavicular joint pain, providing similarly good to excellent results regarding patient satisfaction and shoulder function at intermediate-term follow-up [49].
• Less residual pain was found using the arthroscopic technique compared with the open procedure for distal clavicle excision [49].
• High-level studies on treatment modalities for acromioclavicular joint pain are limited [52].

Complications

• Distal clavicle osteolysis mediated by Propionibacterium acnes can be halted by the combination of distal clavicle resection and antibiotics, with patients remaining symptom-free at 10 months post-surgery [1].
• Gorham-Stout disease should be considered in patients presenting with massive osteolysis after shoulder surgery [3].
• Incomplete excision and regrowth of the distal clavicle are the most common causes of revision following distal clavicle resection [10].
• Subacromial osteolysis following hook plate fixation for acromioclavicular dislocation has a relatively high and variable incidence, with the primary factor influencing reported incidence being the radiological assessment method [12].
• Clavicular tunnel widening was observed in 70% of patients at final follow-up after coracoclavicular stabilization surgery, with a higher prevalence in chronic than in acute cases [16].
• Horizontal instability of the clavicle is evident with distal clavicle resection of greater than 10 mm [11].
• Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes after acromioclavicular joint dislocation treated with the endobutton device [6].
• Late loss of reduction was common in patients with acromioclavicular joint dislocation, while clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis [5].
• Simple excision of the outer end of the clavicle has yielded satisfactory results in patients with acromioclavicular joint dislocation, with no residual upward displacement disturbing the patients [7].
• The minimally invasive TightRope system showed reduced risk of subacromial distal clavicle osteolysis compared to the hook plate in the treatment of acute type III acromioclavicular dislocation [51].
• Asymptomatic ossification of the coracoclavicular ligaments can occur 15 years postoperatively following anatomic reduction of acute acromioclavicular joint separations [19].

Recovery

• Patients undergoing arthroscopic distal clavicle excision via the direct approach can expect a faster return to activities compared with open procedures, while obtaining similar long-term outcomes [2].
• Late loss of reduction was common in patients with acromioclavicular joint dislocation, but clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis [5].
• Simple excision of the outer end of the clavicle yielded satisfactory results in patients with acromioclavicular joint dislocation, with no residual upward displacement disturbing the patients [7].
• For chronic symptomatic acromioclavicular joint injuries, partial claviculectomy is believed to be the best procedure, offering negligible morbidity and rapid return to function [14].
• Incomplete excision and regrowth of the distal clavicle are the most common causes of revision after acromioclavicular joint resection [10].
• Total claviculectomy yielded good results for patients with chronic osteitis and malignancy but unsatisfying results for those with chronic posttraumatic pain, despite full range of motion being regained in all cases [27].
• A majority of patients with untreated acute grade III acromioclavicular separation will do well without any formal treatment, though a small percentage may require delayed surgical intervention [56].
• Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes following acromioclavicular joint dislocation treated with the endobutton device [6].
• Fifteen years postoperatively, good clinical results persisted and anatomic reduction was overall maintained after arthroscopically assisted 2-bundle anatomic reduction of acute acromioclavicular joint separations, often with asymptomatic ossification of the coracoclavicular ligaments [19].
• Radiological assessment showed a statistically significant immediate superior clavicular displacement after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system, with an increased incidence in the first year following stabilization, though this may not negatively influence the results of acromioclavicular joint stabilization in a clinically relevant way [18].
• Clavicular tunnel widening was observed in 70% of patients at final follow-up after coracoclavicular stabilization surgery, with a higher prevalence in chronic than in acute cases [16].
• The short-term follow-up of 15 patients treated with minimally invasive coracoclavicular ligament augmentation using a flip button/polydioxanone repair revealed excellent radiologic and clinical results, with no subluxations or dislocations of the acromioclavicular joint noted [25].
• Satisfactory outcomes for fracture clavicle with acromioclavicular dislocation depend upon restoring the stability of the clavicle as well as the acromioclavicular joint [24].
• The combination of distal clavicle resection and antibiotics halted Propionibacterium acnes–mediated distal clavicular osteolysis, and the patient remained symptom free at 10 months after surgery [1].

Key Evidence

• [Case_report] The combination of distal clavicle resection and antibiotics halted the osteolysis, and the patient has remained symptom free at 10 months after surgery. [1] (10.1016/j.jse.2015.03.004)
• [L3] Among patients undergoing distal clavicle excision for acromioclavicular joint pathology, those having an arthroscopic procedure, specifically through the direct approach, can expect a faster return to activities while obtaining similar long-term outcomes compared with the open procedure. [2] (10.1016/j.arthro.2009.12.007)
• [L4] The case highlights the need to consider this diagnosis in patients presenting with massive osteolysis after shoulder surgery. [3] (10.1016/j.jse.2012.05.024)
• [L5] In appropriately selected patients, open or arthroscopic distal clavicle resection is necessary to relieve symptoms. [4] (10.5435/00124635-199905000-00004)
• [L3] Late loss of reduction was common, and clavicular resection reliably produced significant improvement in patients with persistent pain or posttraumatic arthritis. [5] (10.2106/00004623-198769070-00013)
• [L3] Patients with displacement greater than 100% of the thickness of the distal clavicle had poorer postoperative clinical outcomes. [6] (10.1186/s12891-025-09190-x)
• [L3] Arthroscopic distal clavicle resection has provided more 'good or excellent' results than has the open procedure, but is comprised of low-level evidence. [8] (10.1097/blo.0b013e31802f5450)
• [L5] A well-performed distal clavicle excision will likely perform better than a poorly performed one, regardless of whether an open or arthroscopic approach is chosen. [9] (10.1016/j.arthro.2018.03.004)
• [L4] Incomplete excision and regrowth of the distal clavicle are the most common causes of revision. [10] (10.1016/j.arthro.2009.06.010)
• [L4] Horizontal instability of the clavicle is evident with distal clavicle resection of greater than 10 mm. [11] (10.1016/j.xrrt.2021.05.003)
• [L1] Subacromial osteolysis has a relatively high and variable incidence, and the primary factor influencing the reported incidence is the radiological assessment method. [12] (10.1016/j.jse.2024.03.018)
• [L4] Excision of the outer end of the clavicle is preferred for old dislocations, while open reduction and internal fixation are not recommended due to complications and poor functional results. [13] (10.2106/00004623-196345080-00024)
• [L4] Methods to diagnose both superior and posterior translation of the clavicle need further debate. [15] (10.1016/j.jseint.2019.11.006)
• [L1] Clavicular tunnel widening was observed in 70% of patients at final follow-up, with a higher prevalence in chronic than in acute cases. [16] (10.1016/j.jse.2023.09.037)
• [L1] Arthroscopic and open distal clavicle excisions both provide significant pain reduction at 1 year with no significant difference in outcome measures between groups, except for VAS pain score improvement. [17] (10.1016/j.jse.2006.10.006)
• [L4] Although radiological assessment showed a statistically significant immediate superior clavicular displacement after this rarely required procedure, with an increased incidence in the first year following stabilization, this may not negatively influence the results of ACJ stabilization in a clinically relevant way. [18] (10.1007/s00167-022-06978-5)
• [L3] Fifteen years postoperatively, good clinical results persisted and anatomic reduction was overall maintained, often with asymptomatic ossification of the coracoclavicular ligaments. [19] (10.1177/03635465251355958)
• [L2] Routine distal clavicle excision is not absolutely necessary, even in patients with symptomatic ACJ osteoarthritis. [20] (10.1007/s00167-020-06098-y)
• [Case_report] The case highlights that segmental fractures of the clavicle are easily missed. [21] (10.1177/1758573214564496)
• [Case_report] Total claviculectomy is a possible treatment option for chronic clavicular dislocation with excellent outcomes and high patient satisfaction. [22] (10.1016/j.xrrt.2021.03.007)
• [L4] Excellent clinical results were achieved, decreasing the risk of recurrent distal clavicle instability. [23] (10.1186/1471-2474-10-6)
• [L4] Satisfactory outcome depends upon restoring the stability of the clavicle as well as the acromioclavicular joint. [24] (10.1111/j.1758-5740.2010.00102.x)
• [L4] The short-term follow-up of 15 recently operated patients reveals excellent radiologic and clinical results, with no subluxations or dislocations of the acromioclavicular joint noted. [25] (10.1016/j.arthro.2006.12.015)
• [L4] Distal clavicle fracture is a potential complication of misidentification of the AC joint and subsequent aggressive burring during shoulder arthroscopy. [26] (10.1016/j.arthro.2009.02.008)
• [L4] Total claviculectomy yielded good results for patients with chronic osteitis and malignancy but unsatisfying results for those with chronic posttraumatic pain, despite full range of motion being regained in all cases. [27] (10.1016/j.jse.2006.07.007)
• [L5] Despite technology innovations, a precise, easy to use and low-cost non-invasive method able to draw and analyze the kinematics of the shoulder complex has not been developed yet. [29] (10.1177/17585732221090226)
• [L5] This study provided normative kinematic values of scapulothoracic movements in the shoulder girdle. [30] (10.1016/j.jseint.2022.09.014)
• [L5] Although each technique was able to restore different elements of the joint kinematics, none of the strategies completely restored the shoulder girdle to its preinjured state. [31] (10.1177/03635465221095231)
• [L5] The trapezoid and conoid ligaments have unique functions in normal shoulder kinematics because of their anatomic attachments. [32] (10.1016/j.arthro.2009.12.031)
• [L5] The kinematic changes could be a potential source of pain and dysfunction in the shoulder with AC joint dislocation. [33] (10.1177/0363546512458571)
• [L5] Scapular and clavicular kinematics were affected in AC separation models. [34] (10.1016/j.jse.2013.01.004)
• [L5] A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols and for establishing outcomes of the treatment protocols. [35] (10.1177/17585732221122335)
• [L4] The inconsistency of AC joint testing parameters and the lack of thorough translation studies indicate a necessity for increased attention in the overall assessment of shoulder stability to close the gap in the foundational biomechanical research. [36] (10.1016/j.xrrt.2024.06.009)
• [L5] Anatomically, it provides sufficient tissue length, excursion, and width, and biomechanically, it is as strong as the coracoacromial ligament. [37] (10.1016/j.jse.2006.09.007)
• [L5] No significant biomechanical differences in displacement or stiffness were seen between the anatomical landmark technique and the coracoid-based landmarks technique. [38] (10.1177/23259671221132541)
• [L5] New surgical techniques continue to evolve as more biomechanical data emerge and kinematic understanding improves. [39] (10.5435/jaaos-d-16-00776)
• [L5] By exploring emerging concepts and strategies regarding horizontal and rotational instability and scapular biomechanics, the article aims to lay the foundation for future studies aimed at improving treatment outcomes and patient management. [40] (10.1016/j.jseint.2023.11.018)
• [L4] Preliminary findings revealed no detectable differences between surgically reconstructed and uninjured sides in ACJ biomechanics, range of motion, and isometric strength, while nonoperatively treated shoulders showed increased internal rotation, upward rotation, and posterior tilting. [41] (10.1177/23259671241274707)
• [L4] Type I and II acromioclavicular joint disruptions impair long-term shoulder function in about half of patients 10 years after injury. [43] (10.1177/0363546508319047)
• [L5] At 150 to 200 N of loading, CAL excision and acromioplasty increase the rotator cuff force required to maintain normal glenohumeral biomechanics by 25% to 30%. [44] (10.1016/j.jse.2015.10.022)
• [L3] Centre of pressure measurement detected sensorimotor functional deficits following surgical treatment of the shoulder joint in patients with confirmed successful clinical and functional outcomes. [45] (10.1007/s00167-021-06751-0)
• [L4] Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate. [46] (10.1186/s12891-021-04841-1)
• [L4] Weighted stress radiographs significantly increased the measured elevation of the clavicle and the coracoclavicular distance compared to non-weighted views. [47] (10.1016/j.jseint.2023.06.011)
• [L4] Severe chronic symptomatic AC joint separations (Rockwood types III through V) can be repaired entirely by arthroscopy safely and effectively by transferring the coracoacromial ligament with a bone block in the distal clavicle. [48] (10.1016/j.arthro.2009.08.008)
• [L3] Open and arthroscopic distal clavicle excision are both effective surgeries to treat recalcitrant acromioclavicular joint pain, providing similarly good to excellent results regarding patient satisfaction and shoulder function at intermediate-term follow-up, though less residual pain was found using the arthroscopic technique. [49] (10.1177/0363546511419633)
• [L5] The ISAKOS Upper Extremity Committee suggests adding grade IIIA and grade IIIB injuries to a modified Rockwood classification to distinguish between stable type III injuries and unstable grade III injuries with therapy-resistant scapular dysfunction and overriding clavicle. [50] (10.1016/j.arthro.2013.11.005)
• [L3] However, the minimally invasive TightRope system showed further benefits such as reduced reoperation for implant removal and reduced risk of subacromial distal clavicle osteolysis. [51] (10.1155/2022/8706638)
• [L2] High-level studies on treatment modalities for acromio-clavicular joint pain are limited. [52] (10.1177/1758573217700839)
• [L4] A high index of suspicion is needed to diagnose such complications early before irretrievable bone loss to osteolysis. [54] (10.1111/sae.12035)
• [L2] A majority of patients with untreated acute grade III acromioclavicular separation will do well without any formal treatment, though a small percentage may require delayed surgical intervention. [56] (10.1177/03635465010290060401)

References

[1] Propionibacterium acnes–mediated distal clavicular osteolysis: a case report. Journal of Shoulder and Elbow Surgery. 2015. DOI: 10.1016/j.jse.2015.03.004 [2] Open Versus Arthroscopic Distal Clavicle Resection. Arthroscopy. 2010. DOI: 10.1016/j.arthro.2009.12.007 [3] Gorham-Stout disease as a complication of posterior shoulder capsulorrhaphy. Journal of Shoulder and Elbow Surgery. 2012. DOI: 10.1016/j.jse.2012.05.024 [4] Painful Conditions of the Acromioclavicular Joint. Journal of the American Academy of Orthopaedic Surgeons. 1999. DOI: 10.5435/00124635-199905000-00004 [5] Dislocation of the acromioclavicular joint. An end-result study.. The Journal of Bone & Joint Surgery. 1987. DOI: 10.2106/00004623-198769070-00013 [6] Predicting reduction loss risk after acromioclavicular joint dislocation treated with the endobutton device. BMC Musculoskeletal Disorders. 2025. DOI: 10.1186/s12891-025-09190-x [7] Complete Dislocation and Subluxation of the Acromioclavicular Joint: End Result in Seventy-three Cases.. The Journal of Bone and Joint Surgery. American Volume. 1961. [8] Surgical Treatment of Symptomatic Acromioclavicular Joint Problems. Clinical Orthopaedics and Related Research. 2007. DOI: 10.1097/blo.0b013e31802f5450 [9] Editorial Commentary: The “Mumford” & Sons: For Distal Clavicle Excisions, What Are Our Young Surgeons Doing, and How Well Are They Doing It?. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.03.004 [10] Open Versus Arthroscopic Acromioclavicular Joint Resection: A Retrospective Comparison Study. Arthroscopy. 2009. DOI: 10.1016/j.arthro.2009.06.010 [11] The reverse coracoacromial ligament transfer for “horizontal” acromioclavicular joint instability. JSES Reviews, Reports, and Techniques. 2021. DOI: 10.1016/j.xrrt.2021.05.003 [12] Subacromial osteolysis following hook plate fixation for acromioclavicular dislocation: a systematic review and meta-analysis. Journal of Shoulder and Elbow Surgery. 2024. DOI: 10.1016/j.jse.2024.03.018 [13] COMPLETE DISLOCATION OF THE ACROMIOCLAVICULAR JOINT. The Journal of Bone & Joint Surgery. 1963. DOI: 10.2106/00004623-196345080-00024 [14] Acromioclavicular-Joint Injury: AN END-RESULT STUDY.. The Journal of Bone and Joint Surgery. American Volume. 1966. [15] Methods used to assess the severity of acromioclavicular joint separations in Japan: a survey. JSES International. 2020. DOI: 10.1016/j.jseint.2019.11.006 [16] Clavicular tunnel widening after coracoclavicular stabilization surgery: a systematic review and meta-analysis. Journal of Shoulder and Elbow Surgery. 2024. DOI: 10.1016/j.jse.2023.09.037 [17] Arthroscopic versus open distal clavicle excision: Comparative results at six months and one year from a randomized, prospective clinical trial. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2006.10.006 [18] Low rate of substantial loss of reduction immediately after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system. Knee Surgery, Sports Traumatology, Arthroscopy. 2022. DOI: 10.1007/s00167-022-06978-5 [19] Long-term Follow-up After Arthroscopically Assisted 2-Bundle Anatomic Reduction of Acute Acromioclavicular Joint Separations. The American Journal of Sports Medicine. 2025. DOI: 10.1177/03635465251355958 [20] Acromioclavicular joint arthritis is not an indication for routine distal clavicle excision in arthroscopic rotator cuff repair. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-06098-y [21] Segmental clavicle fracture and acromio-clavicular joint disruption: an unusual case report. Shoulder & Elbow. 2014. DOI: 10.1177/1758573214564496 [22] A four-year-old neglected traumatic bipolar clavicular dislocation: a case report. JSES Reviews, Reports, and Techniques. 2021. DOI: 10.1016/j.xrrt.2021.03.007 [23] Acromioclavicular joint reconstruction with coracoacromial ligament transfer using the docking technique. BMC Musculoskeletal Disorders. 2009. DOI: 10.1186/1471-2474-10-6 [24] Fracture Clavicle with Acromioclavicular Dislocation: A Complex Injury. Shoulder & Elbow. 2011. DOI: 10.1111/j.1758-5740.2010.00102.x [25] Minimally Invasive Coracoclavicular Ligament Augmentation With a Flip Button/Polydioxanone Repair for Treatment of Total Acromioclavicular Joint Dislocation. Arthroscopy. 2007. DOI: 10.1016/j.arthro.2006.12.015 [26] Distal Clavicle Fracture as a Complication of Arthroscopic Distal Clavicle Resection. Arthroscopy. 2009. DOI: 10.1016/j.arthro.2009.02.008 [27] Outcome of total claviculectomy in six cases. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2006.07.007 [29] Evaluation of the range of motion of scapulothoracic, acromioclavicular and sternoclavicular joints: State of the art. Shoulder & Elbow. 2022. DOI: 10.1177/17585732221090226 [30] Kinematic analysis of scapulothoracic movements in the shoulder girdle: a whole cadaver study. JSES International. 2023. DOI: 10.1016/j.jseint.2022.09.014 [31] Differences between Coracoclavicular, Acromioclavicular, or Combined Reconstruction Techniques on the Kinematics of the Shoulder Girdle. The American Journal of Sports Medicine. 2022. DOI: 10.1177/03635465221095231 [32] A Biomechanical Analysis of the Native Coracoclavicular Ligaments and Their Influence on a New Reconstruction Using a Coracoid Tunnel and Free Tendon Graft. Arthroscopy. 2010. DOI: 10.1016/j.arthro.2009.12.031 [33] The Function of the Acromioclavicular and Coracoclavicular Ligaments in Shoulder Motion. The American Journal of Sports Medicine. 2012. DOI: 10.1177/0363546512458571 [34] Acromioclavicular joint ligamentous system contributing to clavicular strut function: a cadaveric study. Journal of Shoulder and Elbow Surgery. 2013. DOI: 10.1016/j.jse.2013.01.004 [35] Acromioclavicular joint injuries revisited: Pathoanatomy, pathomechanics, and clinical presentation. Shoulder & Elbow. 2022. DOI: 10.1177/17585732221122335 [36] Acromioclavicular joint biomechanics: a systematic review. JSES Reviews, Reports, and Techniques. 2024. DOI: 10.1016/j.xrrt.2024.06.009 [37] Anatomy of the pectoralis minor tendon and its use in acromioclavicular joint reconstruction. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2006.09.007 [38] Comparing the Anatomical Landmarks Versus the Coracoid-Based Landmarks Techniques for Coracoclavicular Stabilization After High-Grade Acromioclavicular Injury: A Biomechanical Study. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221132541 [39] Challenges in Treating Acromioclavicular Separations: Current Concepts. Journal of the American Academy of Orthopaedic Surgeons. 2018. DOI: 10.5435/jaaos-d-16-00776 [40] Current trends in surgical treatment of the acromioclavicular joint injuries in 2023: a review of the literature. JSES International. 2024. DOI: 10.1016/j.jseint.2023.11.018 [41] Using Dynamic Stereo X-ray Imaging for In Vivo Acromioclavicular Joint Kinematics Assessment: A Preliminary Investigation. Orthopaedic Journal of Sports Medicine. 2024. DOI: 10.1177/23259671241274707 [43] Long-Term Shoulder Function after Type I and II Acromioclavicular Joint Disruption. The American Journal of Sports Medicine. 2008. DOI: 10.1177/0363546508319047 [44] The effect of coracoacromial ligament excision and acromioplasty on the amount of rotator cuff force production necessary to restore intact glenohumeral biomechanics. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2015.10.022 [45] Center of pressure (COP) measurement in patients with confirmed successful outcomes following shoulder surgery show significant sensorimotor deficits. Knee Surgery, Sports Traumatology, Arthroscopy. 2021. DOI: 10.1007/s00167-021-06751-0 [46] Os acromiale may be a contraindication of the clavicle hook plate: case reports and literature review. BMC Musculoskeletal Disorders. 2021. DOI: 10.1186/s12891-021-04841-1 [47] Position of scapula and clavicle in acute acromioclavicular joint dislocations: depressed scapula or elevated distal clavicle?. JSES International. 2023. DOI: 10.1016/j.jseint.2023.06.011 [48] All‐Arthroscopic Weaver‐Dunn‐Chuinard Procedure With Double‐Button Fixation for Chronic Acromioclavicular Joint Dislocation. Arthroscopy. 2009. DOI: 10.1016/j.arthro.2009.08.008 [49] Arthroscopic Versus Open Distal Clavicle Excision. The American Journal of Sports Medicine. 2011. DOI: 10.1177/0363546511419633 [50] ISAKOS Upper Extremity Committee Consensus Statement on the Need for Diversification of the Rockwood Classification for Acromioclavicular Joint Injuries. Arthroscopy. 2014. DOI: 10.1016/j.arthro.2013.11.005 [51] Comparison of the Hook Plate versus TightRope System in the Treatment of Acute Type III Acromioclavicular Dislocation. Advances in Orthopedics. 2022. DOI: 10.1155/2022/8706638 [52] Managing acromio-clavicular joint pain: a scoping review. Shoulder & Elbow. 2017. DOI: 10.1177/1758573217700839 [54] Bone Osteolysis Following Acromioclavicular Joint Reconstruction Using Synthetic Ligament (Surgilig™). Shoulder & Elbow. 2014. DOI: 10.1111/sae.12035 [56] A Prospective Evaluation of Untreated Acute Grade III Acromioclavicular Separations. The American Journal of Sports Medicine. 2001. DOI: 10.1177/03635465010290060401