8.1.2 Patient Demography

First it should be defined whether non-healing of the repaired RC is a true complication or if it is, to a certain degree, matter of fact within the nature of the pathology. Besides the above mentioned, certain demographic and behavioral factors seem to have an impact on the success of RC repair and should be anticipated or communicated to the patient before surgery.

Several clinical and radiographic studies identified demographic factors such as the patient’s age, that seem to be associated with the non-healing of the RC [7–13].

Some studies have described increased re-tear rates for patients aged >60–65 years [7, 14–16]. However, to date, patients from different age groups with arthroscopically manageable RC lesions are submitted to RC repair, and favorable clinical results have recently been described for RC repairs in elderly patients, even beyond the age of 65–70 years [17–20].

The same conflict of results is found when it comes to further demographic factors such as patients gender: a sex-related effect was advocated by some authors [10, 21], but others have found no such association [11, 13, 22, 23].

Beyond non-healing of the tendon, the risk of direct medical complications and hospital readmission is increased for male gender, increased age and medical comorbidities [24–27], which will be discussed later in the respective subchapter.

8.1.3 Approach, Indications, Informed Consent

Choosing the surgical approach for indicated RC-repair, it should be noted that—despite comparable clinical outcomes—the general complication rate is significantly higher after (mini-) open compared to arthroscopic (ASC) procedures. In two studies with more than 10,000 patients each, the benefits of the ASC-group were a significantly lower rate of superficial and deep infection, a lower incidence of return to the operating room within 30 days, and a lower risk of hospital readmission [24, 25].

Ignoring clinical problems and concomitant side pathologies, such as AC-arthritis, subacromial impingement, LHB instability, concomitant stiffness, etc. before ASC will most likely lead to their insufficient therapy, possibly resulting in deteriorated overall patient satisfaction postoperatively. Finally, incomplete patient information and/or incomplete written informed consent regarding treatment of such concomitant pathologies (such as LHB tenotomy or partial RC repair) should be avoided before scheduled RC repair.

8.2 Intraoperative Complications

Many intra- and postoperative complications during RC repair are overlapping with general complications during and following arthroscopic shoulder surgery and have been introduced over the respective chapters in this book. As stated earlier, these occur in 5–10% of cases and include—among the acute ones—instrument breakage, hardware failure, fluid extravasation [28].

Further intraoperative factors are incorrect portal placement, iatrogenic lesions to cartilage or bone, or even to the suprascapular nerve during scope introduction or extensive RC tendon mobilization.

Some other complications are more specific to RC-repair and therefore should be regarded more detailed:

Suture anchor pullout strength generally depends on quality of the bone, the inclination of the anchor and the friction of the anchor-bone interface [29].

Acute anchor loosening may occur in cases of severe osteopenia/osteoporosis of the trabecular structures underneath the footprint. For RC-intact shoulders, age >70 years and female gender predispose for tuberosity osteopenia [30]. But particularly in long(er) standing retracted RC tears and ongoing chronicity, significantly higher osteopenic changes occur in the greater tuberosity [31], which negatively affect anchor pullout strength.

Caution should be exerted during tuberosity decortication with a burr, since matched-pair analyses revealed a significantly decreased pullout strength after this procedure [32]. This fact should also be remembered before microfracturing (or “Crimson duvet”-techniques) at the footprint.

If weak bone is assumed, the surgeon can establish the bone socket for the anchor by pushing the awl manually to get a feel for the bone strength. To finally assess the anchor stability before RC-perforation, a sincere pull on the suture tails in the direction of load may help to verify a stable setting (Fig. 8.2).

If the awl for anchor socket placement was used too firmly or in a wrong direction, it is possible to break into humeral head cartilage (if the insertion angle is oriented too horizontal) or to cause an iatrogenic fracture of the greater tuberosity (if the insertion angle is too vertical). For several reasons, mostly for load transmission after RC refixation, an insertion angle of about 45° was proposed (“deadman’s angle”) [33]. However, Itoi et al. suggested that this calculation is not always applicable because of bone deformation and that a threaded anchor should be inserted at 90° [29].

Recent biomechanical analyses suggest that the use of all-suture anchors in the setting of RC repair and possibly weaker bone at the tuberosity is associated with high rates of anchor pullout, decreased failure load and increased displacement when compared to traditional threaded suture anchors [34]. These results suggest the use of other than all-suture anchors for RC repair or to restrict their use for the medial-row.

Another potentially fatal iatrogenic complication is mis-placement of suture anchors, obviously by mis-understanding “extraanatomical medialization” of anchor placement. Figure 8.3 shows MRI- and intraoperative pictures of a patient with ongoing complaints following a “RC repair” with metal anchor placed centrally in the humeral head cartilage.

Proper suture management is one key to successful RC repair. Bundles of suture limbs originating from the same anchor should be kept together with external clamps etc. to maintain overview over their respective relations and for prevention of bacterial adherence (see the later section low-grade infections). In order to avoid eyelet-pullout during suture passages, the anchor bottom should be visualized during suture strand pull in order to confirm handling the appropriate end of it. A lost suture usually cannot be reinserted to the anchor. Hence, the anchor must be used with the remnant suture as “single-loaded” and/or be replaced with a new one.

Tendon-suture interface cut-out can occur with current strong synthetic suture materials placed through rather weak and degenerative RC tendon tissue. To prevent such, it is safer to resign tying down sliding knots with long suture limb travelling distances through the tendon, and to rather tie direct knots using a knot pusher/sixth finger^®.

8.3 Immediate Postoperative Complications

Among summarized shoulder arthroscopy complications in general (5–10% of cases), infection, stiffness, deep venous thrombosis are typically postoperative ones [28].

As summarized before, factors such as higher age, female gender and particularly chronic RC-tears predispose for osteopenic tuberosities with higher rates of suture anchor loosening. In this setting, not just acute, but also subacute or postoperative anchor loosening may occur. Very early metal anchor loosening (as assessed by X-ray in >5700 patients) revealed a rate of 0.1%, however, follow up was done at the day of surgery [35]. Depending on the duration of follow-up, others found rates between 0.01% and 3% of anchor loosening [36]. Ongoing patient-reported discomfort and/or scratching noise should lead to further diagnostics. Depending on the anchor body material, ultrasound, X-ray or MRI will help to identify a displaced anchor (Fig. 8.4). While in the majority of cases simple anchor removal is sufficient (Figs. 8.5 and 8.6), re-repair of the non-healed RC-tendon can become necessary.