Rehabilitation following rotator cuff repair

Tears of the rotator cuff tendons (RC) are a frequent cause of shoulder complaints [44]. Improvement in terms of strength, movement and pain reduction can be expected after rotator cuff repair surgery [27]. Unfortunately, there is no consensus on the rehabilitation protocols and contents following the surgical procedure [24]. Conventional rehabilitation protocols after reconstruction of the rotator cuff (RCR) often vary considerably, even in terms of basic content such as the length of immobilization, movement limitations and whether or not an orthosis should be used. There still is a lack of evidence for many common forms of rehabilitation contents, although in many health care systems evidence-based medicine has gained ground. In Germany, among others, the guideline program of the German Pension Insurance Association focused on this conflict [23, 25].

The rehabilitation commission of the German Society for Shoulder and Elbow Surgery (DVSE) has studied this issue intensively. The aim of this paper was, firstly, to conduct an evidence-based evaluation of the most important forms of treatment after RCR, based on an extensive literature review and, with the help of a survey among DVSE shoulder experts, to determine if there is an existing best-clinical practice consensus for or against specific forms of treatment.

The guideline search resulted in one hit for the American Academy of Orthopedic Surgeons. Two systematic reviews and 13 clinical studies in the databases were examined. A manual search revealed two additional systematic reviews and four individual studies. An overview of all the papers is listed in Tables 2, 3 and 4.

In order to do justice to the amount of information contained in each publication, the individual sub-topics of the overall rehabilitation process are thematically assessed and discussed in individual sub-sections below. Furthermore, the results of the expert survey are presented according to topic.

Directly after the operation, the question arises as to whether and to what extent the shoulder should be immobilized. The risk of a re-rupture or disrupted tendon healing as a result of too much strain have to be weighed against a stiff shoulder caused by too little mobilization. Cadaver studies reveal that the so-called “time zero strength” of the sutured supraspinatus tendon resists 70–100% of the forces affecting it [40]. However, biomechanical studies have shown there is a “gapping effect” for cyclical, clinically relevant strain, even in the case of double row suture techniques [40]. As tendon healing progresses, the biomechanical properties of the tendon-suture-construct change. Therefore, the time it takes for tendons to heal should be taken into account. Animal studies are frequently referred to, since the tendon healing process has already been intensively studied in animals. In animal models a fragile scar appears 0–14 days after the operation during the inflammatory phase [7]. In the subsequent proliferative phase, 3–4 weeks after the operation, fibroblasts, myofibroblasts and endothelial cells appear, neoangiogenesis begins, and a stronger tendon-bone connection develops. In the maturation and remodeling phase, starting in weeks 4 to 6, collagen III is increasingly replaced by mature collagen I and the tendon integrates more strongly and stably into the bone.

Animal studies have shown that the time it takes to achieve full strength varies between 12 and 26 months [7]. When the issue of early exercise therapy is translated to animal models, difficulties arise in comparing and interpreting the different animal models. It is also difficult to standardize any exercises for animals. Transferring the findings to humans also poses a challenge.

Li et al. [30] found that early passive exercise benefited tendon healing in rabbits. Peltz et al. [36] demonstrated in a rat model that movement was poorer when there was passive exercise directly after the operation as a result of increased scar formation. There were no differences with respect to tendon healing. By contrast, Gimbel et al. [16] found in rat models that the healing tendon had better mechanical properties when immobilization was extended. However, it is interesting to note that complete strain reduction using a botulinum toxin appears to have negative effects on tendon recovery in animal models [13]. In a comparison study of rabbits that compared immediately allowing movement, short-term immobilization with subsequent passive exercise and complete immobilization [47] Zhang et al. found that direct, post-operative passive exercise with intermittent immobilization did not negatively affect tendon healing histologically and in magnetic resonance imaging (MRI). However, tendon healing was found to diminish when function was completely allowed.

Compared to these heterogeneous animal studies, prospective studies of humans provide a good level of data. Early passive exercise does not appear to be disadvantageous [19]. Both Chan et al. [6] and Shen et al. [41] were able to show in meta analyses of randomized clinical comparative studies that no significant differences can be expected in the clinical outcome and in terms of the re-rupture rate. When there is early passive exercise, the full range of motion (ROM) is also achieved more quickly, particularly in terms of flexion. In a detailed evaluation of the meta analyses and our own additional review of the literature, a total of four Level I studies were identified that support the recommendation of early passive mobilization [2, 8, 20, 22].

By contrast, early aggressive active exercise should be avoided since this negatively impacts the healing process [20]. In order to protect patients from excessive strain outside the therapy setting, an aid can be used to immobilize the arm. Based on the timeframe of tendon healing mentioned above, the length of immobilization varies widely between 4 and 8 weeks [2, 4, 14, 21, 22, 29]. There are no prospective studies that deal only with the length of immobilization.

While the duration of immobilization is the subject of debate, immobilization in slight abduction is predominantly preferred by the experts surveyed as this increases blood circulation in the tendon and reduces the strain on the reconstruction [38]. Gerber et al. [15] and Thomopoulos et al. [45] were also able to show in animal models that a position that lowers the strain on the tendon reconstruction has a positive effect on the orientation of the collagen fibers and the elasticity of the tendon. Orthoses are, in principle, suitable for lowering the activity of the RC muscles. This was proven by Alenabi et al. [1] in an electromyographic study. When the elbow and hand were moved in a splint, the activity of the RC muscle was measured at no more than 10% of normal activity. There are no clinical investigations that specifically look at the type of orthoses used. The German catalog of medical aids allows both the use of arm slings and abduction pillows with a varying abduction of 15–45° for post-treatment after an RCR.

Cryotherapy, electrotherapy and exercise in an exercise pool are frequent methods of physical therapy that are used following an RCR. In a randomized clinical trial (RCT) with 50 patients conducted in 1996, Speer et al. [43] investigated the effects of using cryotherapy systems after a variety of shoulder operations, including RCR. Continuous cryotherapy leads to a reduction in pain, a reduced need for pain killers and better sleep quality in the night after the operation. When cryotherapy was used (4 to 6 times per day depending on patient requirements) there was less pain when the arm was at rest and in motion in the 10 days following the operation. In another RCT, the same working group also observed clinically relevant effects on pain in the cryotherapy group when at rest and when physical strain was placed on the shoulder following open and arthroscopic shoulder operations (n = 70; water temperature 7–13 °C; length it was worn: continuously 48 h postoperatively; at night on days 3–7; daily 2–4 h on days 8–21 followed by exercise therapy; [42]). Speer’s group also demonstrated that continuous cryotherapy directly following reconstruction of the RC reduced the temperature in the glenohumeral joint and subacromial space by around 0.5–1.0 °C [35].

Blum et al. [4] compared two types of electrotherapy in an RCT with 22 patients who received RC reconstruction. The control group received 2 × 1 h of electrotherapy per day in connection with physiotherapy that started 6–8 weeks post-op. The intervention group received the same length of sham electrotherapy and physiotherapy that began 8 weeks after the operation.

In contrast to the control group, movement improved in the intervention group by around 10° 45 and 90 days after the operation, however strength did not. The methodological quality of the study should be regarded critically as the authors had a relevant conflict of interest.

A non-randomized study indicates that additional group sessions of aquatic theraphy (starting 10 days after reconstruction) have a positive effect on passive movement (anteversion and external rotation), pain and activities of daily living (Western Ontario Rotator Cuff Score) 3 and 6 weeks, though not 12 weeks, post operation [5]. However, the effects were slight and could also be the result of an overall higher amount of active intervention in the aquatic therapy group.

Continuous passive motion therapy with a motorized CPM machine is one of the most frequently used elements of treatment following an operation on a shoulder joint, and particularly after RCR. The passive motion machine typically serves to mobilize the joint shortly after the operation without the patient having to actively support the extension of motion.

Currently scientific literature only contains two reviews [3, 10] and one prospective randomized study [14]. The review by Baumgarten et al. [3] is based on two studies in which a CPM machine was used on 26 patients [37] and 31 patients respectively [28]. Both investigations compared physical therapy treatment (manual passive exercise) to the use of a CPM machine. Baumgarten et al. [3] concluded that the validity of the data is limited due to its poor methodological quality and provides insufficient evidence for the development of an evidence-based rehabilitation protocol. CPM treatment was not found to be superior. Du Plessis et al. [10] compared the effects of standard physical therapy to CPM therapy combined with physical therapy. The group of patients receiving CPM combined with physical therapy treatment, were given passive, isometric and actively supported exercises, shoulder mobilization and strength training. Manual passive mobilization, active exercise, and therapist coordinated self-exercise were used in the group that received standard physical training. Data on the range of movement, muscle strength, and pain reduction was collected, and studies previously conducted by Raab et al. [37] and Lastayo et al. [28], as well as a paper by Michael et al. [33] were also included. The authors of the review concluded that the use of a CPM machine in combination with physical therapy as part of follow-up treatment after an RCR can be regarded as safe [10]. A paper by Garofalo et al. [14] looked at 100 patients, comparing a standard program of passive exercise (therapist coordinated self-exercise: three series with 10 repetitions, pendulum movement, passive abduction, flexion and external rotation) to the same program with the addition of a CPM chair. This was applied for two hours a day for 4 × 30 min. In this comparison, the additional use of a CPM chair led to an improvement in results. It remains unclear, however, whether the device itself or the additional movement produced this effect [14].

In addition to CPM, self-exercise is another important component of post-operative follow-up treatment which is used to varying degrees [8, 11, 18, 29]. There are major differences in point in time, intensity, type of exercise and supporting measures. Patients can be instructed through written directions, videos and/or receive instruction from the physiotherapist (PT). Roddey et al. [39] found there was no significant difference in the post-operative outcome when the instructions were given by the PT or by video.

Pendulum exercises were often described in the first post-operative phase. Biomechanical studies have shown that it is important to carry them out correctly so that there is low electromyographic activity (EMG) in the reconstructed RC (see below, [32]). The lowest activity was recorded in small pendulum circles (d = 20 cm) with an initiation of the arm movement by moving the torso and not by using the shoulder muscles themselves [32]. Additional use of a 1.5 kg weight on the hanging arm increases the EMG activity of M. supraspinatus and M. infraspinatus, though not to a statistically significant degree [12]. Furthermore, mobilization exercises (with the help of the contra-lateral arm) and, in later phases, muscle activation/strengthening exercises using simple devices (e. g. theraband, dumbbells) are other primary forms of self-exercise [8, 11, 46]. There is no homogeneous data on the extent of the passive mobilization and when to start it [2, 8, 21, 29]. The question of whether self-exercise, in addition to physiotherapy, has a positive effect cannot be sufficiently answered. Both are combined in many published studies, however a direct comparative study currently does not exist [1, 11, 31, 33, 46]. Scientific literature contains only two randomized controlled trials that look at self-exercise versus physiotherapy exercise [3]. In their Level II study, Hayes et al. [17] were able to randomize 58 patients into two control groups. After both groups received instructions on the self-exercise program in the first week, one group subsequently received physiotherapy treatment while the other group continued to do the self-exercise program. No significant differences in ROM, strength measurement and shoulder scores were found at any of the follow-up treatments (6, 12 and 24 weeks). Critical aspects of the study include the low number of cases, the high conversion rate from the self-exercise group to the physiotherapy group (n = 9) and the high drop-out rate (27%).

The second study by Lee et al. conducted a clinical and neurophysiological examination of 11 patients per group at days 20 and 40 post operation [29]. The results showed significantly better active mobility at both follow-ups in the group receiving physiotherapy. This group also achieved a significant improvement in the activation of motor units in the EMG; this was not detected in the self-exercise group. In this study the low number of cases, the short follow-up period and an absence of clinical scores should be viewed critically.