Optimizing Recovery in Patients with Dual Impairments: Proprioception and Balance Enhancement through Combined Vestibular and Knee Rehabilitation

1.1. Joint Position Matching

It is observed that, at the time of the initial evaluation, the affected upper limb shows negative position average values, unlike the unaffected upper limb, where the position indicator shows/display/presents positive values. Although the joint position matching test was adapted so that all study participants (operated and non-operated) had equal chances in performing the test, we can see that for the affected upper limb, at the initial assessment, the 60⁰ flexion and abduction, respectively, were not achieved by most subjects (table 1). This fact was not due to the lack of joint mobility in the direction of abduction or flexion (with visual control the subjects performed the 60⁰ necessary for the evaluation), but to the proprioceptive sense. Although for the initial assessment at the level of the unaffected upper limb the values ​​of the position averages are positive, this still indicates an impairment of proprioception, but it shows that the subjects performed the movement over 60⁰ (Table 1).

Analyzing the data contained in Table 1, we can conclude the following:

proprioception is affected both in the affected upper limb and in the unaffected one, at the level of the scapulohumeral joint;

although movement up to an angle of 60⁰ is possible, in the subjects evaluated in this study, this may not be achieved without visual control. This fact is due to the impairment of proprioception, which compromises the ability to perceive and precisely control the movement of the joint;

at the level of the unaffected joint, although the values of the position averages are positive, they still indicate a deviation from the 60⁰ angle, proving an impairment of proprioception.

Following the initial assessment, the physiotherapy recovery program was outlined and applied to improve the symptoms caused by BPPV and to recover the scapulohumeral joint. While the recovery program of the shoulder joint went through several stages (recovery of joint mobility, regaining muscle strength identical to the contralateral upper limb, recovery of coordination and proprioception), the procedures applied for the recovery of the vestibular system continued throughout the recovery period until to the socio-professional reintegration of the individual.

It is observed that, at the time of the final assessment, both the affected upper limb and the unaffected upper limb show positive position average values - except for the minimum value (Table 2).

Comparing the minimum value of the postural averages between the initial assessment and the final assessment, for both the affected and the unaffected limb, a significant improvement in proprioceptive sense can be seen.

For the maximum value, comparing the results of the initial testing with those of the final testing, we observe that for the affected upper limb, the abduction movement, there is still a significant deviation (of 4⁰) between performing the movement with visual control and without visual control; however we consider that the maximum mean value for the affected upper limb at initial testing suggested a deviation of -7⁰ from the target value. Thus, we can say that there has been an improvement in proprioceptive perception, but expressed as a value of 3⁰ benefit, considering that there is still a deviation of 40 from the target angle.

1.1. DGI Index. Descriptive Statistics

Assessment of motor function and balance in patients with orthopedic and vestibular conditions is essential to understand the impact of these health dysfunctiones on quality of life and to develop effective rehabilitation programs. The Dynamic Gait Index is a commonly used assessment tool to measure an individual's ability to adapt their gait and balance in various dynamic situations. This is particularly relevant for people with BPPV and impairments of the scapulohumeral joint, as these conditions can significantly influence stability and motor function.

The data in Table 7 suggest a significant improvement in the subjects' balance and walking ability after the physiotherapy intervention. The increase in means (from 9.81 initial to 14.77 final), the median (from 10.00 to 15.00) and the decrease in variability (standard deviation from 1.797 initial to 0.774 final) indicate an even and efficient recovery. In addition, the increase in minimum (from initial 6 to final 10) and maximum (from 12 to 15) values ​​underlines the success of the interventions in achieving optimal performance by the subjects. The fact that the values ​​corresponding to the 25th, 50th, and 75th quartiles are all at 15.00 at the final assessment shows that most subjects achieved maximum or near maximum scores, reflecting the high uniformity and effectiveness of the treatment.

We used the Mann-Whitney U-test to determing whether there were statistically significant differences between baseline and final assessment for DGI scores in our study subjects. The results indicate significant improvements in the subjects' DGI scores, which underlines the success of the physiotherapy interventions. The p value < 0.001 indicates that these improvements are not due to chance and are statistically significant (Table 8).

To obtain a more detailed picture of the distribution of DGI scores and their variation before and after the application of the recovery program, we applied the Mann-Whitney U test for independent samples (Table 9). The statistics provide satisfactory results, showing that the therapeutic interventions had a significant impact on the walking ability and balance of the subjects, reflected by significant improvements in the DGI scores. The p value < 0.001 indicates that these improvements are highly unlikely to be subject to chance, underscoring the effectiveness of the rehabilitation program.

Total N=192 represents the total number of assessments analyzed in the Mann-Whitney U test for independent samples, including DGI assessments for 48 subjects, each assessed for joint position matching in the affected and unaffected upper limb at two assessment times (initial and final).

We plotted the distribution of DGI scores for subjects assessed at baseline and final, using the Mann-Whitney U test for independent samples (Figure 6). One can see the mean rank of 49.54 at the initial assessment, suggesting a low level of gait and balance function. At the final assessment the scores increase significantly, the average rank being 143.46, reflecting a significant improvement.

Box plot Figure 7 compares DGI scores at baseline to final assessment. At initial assessment, a median of approximately 10 is highlighted, with a greater variation in scores indicated by a wider interquartile range (IQR) and the presence of extreme values ​​(outliers). This suggests considerable variability in subjects' gait and balance prior to recovery procedures. At the final assessment, the median score is 15, with a very small IQR, reflecting a highly concentrated distribution around the maximum value. This indicates an even and significant improvement in DGI scores after the intervention, demonstrating the effectiveness of the rehabilitation program in improving walking ability and balance.

1.1. Correlations

Table 10 shows the Pearson correlations between the DGI index and joint position matching (PPC) for flexion and abduction of the affected upper limb at both baseline and final assessments. At baseline assessment there are no statistically significant correlations between DGI and PPC for flexion (r = .022, p = .884) or abduction (r = .186, p = .205), suggesting that before physiotherapy intervention, DGI scores are not significantly associated with upper limb joint position matching. At final assessment, there are also no statistically significant correlations between DGI and PPC for flexion (r = -.094, p = .524) or abduction (r = .047, p = .752), indicating that after the intervention, the scores DGIs remain insignificantly associated with upper limb joint position matching.

Table 11 shows Pearson correlations between DGI and PPC for flexion and abduction in the unaffected upper limb at both baseline and final assessments. At the initial assessment there are no statistically significant correlations between DGI and PPC for flexion (r = .073, p = .622) or abduction (r = .247, p = .090). At final assessment, there are also no statistically significant correlations between DGI and PPC for flexion (r = -.142, p = .335) or abduction (r = .048, p = .745). These results suggest that, regardless of time of assessment, DGI scores are not significantly associated with joint position matching of the unaffected upper limb.

The results of Table 10 and Table 11 show the Pearson correlations between the Dynamic Gait Index (DGI) and joint position matching (PPC) for flexion and abduction, in both the affected and the unaffected upper limb, before and after the application of the physiotherapy procedures. This suggests that improvements in walking ability and balance, reflected by DGI scores, are not directly associated with changes in upper limb joint position matching, hence highlighting the complexity of the interactions between the vestibular and proprioceptive systems in the rehabilitation process.

4. Discussion

The recovery of shoulder function following an orthopedic condition is inherently complex and demands a multifaceted approach. A critical, yet often underestimated, component of this process is the vestibular system. This system plays a pivotal role in maintaining balance, coordination, and proprioception—key factors in achieving a full and effective recovery [1]. The integration of vestibular assessments and targeted interventions into rehabilitation programs could potentially lead to the development of more holistic and effective physiotherapy strategies that address both the primary symptoms and the underlying contributing factors of dysfunction [2]. Such an integrated approach can ensure sustainable recovery and significantly enhance the quality of life for affected individuals [3].

The findings of this study suggest that, as symptoms related to Benign Paroxysmal Positional Vertigo (BPPV) improve—assessed using the Dynamic Gait Index (DGI)—there is also an improvement in scapulohumeral proprioception, as indicated by joint position matching in flexion and abduction. Although the study did not find statistically significant correlations between DGI scores and joint position matching in either the affected or unaffected limbs, the overall trend underscores the importance of incorporating vestibular assessments and interventions into shoulder rehabilitation programs. The vestibular system's role in coordination, a fundamental aspect of scapulohumeral joint function, is particularly noteworthy in this context.

This study's results demonstrate that bilateral therapeutic interventions were effective in restoring functional symmetry and proprioceptive accuracy among the study's participants. By the final assessment, the initial significant differences between the affected and contralateral, unaffected upper limbs had become non-significant, indicating a balanced and effective recovery process. These outcomes highlight the critical importance of applying integrated therapeutic interventions to maximize rehabilitation outcomes.

The effectiveness of vestibular rehabilitation in enhancing postural stability and reducing fall risk has been well-documented in the literature. Whitney et al. (2000) demonstrated that vestibular rehabilitation can lead to significant improvements in balance and gait in patients with vestibular disorders [10]. Similarly, Marchetti and Whitney (2006) emphasized the necessity of specific vestibular rehabilitation interventions to reduce fall risk and enhance balance confidence in patients with vestibular imbalances [11]. Furthermore, Herman et al. (2013) validated the use of the Dynamic Gait Index as a reliable tool for evaluating and monitoring patient progress in rehabilitation, thereby contributing to reduced fall risk and improved motor function [12].

The improvements observed in DGI scores post-intervention underscore the positive impact of integrated rehabilitation programs that simultaneously address vestibular and proprioceptive components. Such comprehensive interventions contribute to a more uniform and effective recovery, as evidenced by the reduced variability in scores and increased consistency in improvements, as reflected in the analysis of standard deviations and percentiles.

These results underline the necessity for a holistic approach in shoulder rehabilitation, one that includes vestibular evaluations and interventions to optimize recovery and enhance the patient's quality of life. Integrating vestibular rehabilitation into orthopedic treatments offers significant benefits, leading to improved recovery outcomes and better long-term functionality.

The primary objective of this research was to initiate and conduct a fundamental multidisciplinary study with direct clinical applicability, focusing on the mechanisms involved in shoulder joint function following various conditions, whether traumatic or degenerative. A particular emphasis was placed on understanding the vestibular system's role in the recovery process. By integrating expertise from fields such as ENT, orthopedics, neuroscience, and physical therapy, the study aimed to provide a deeper understanding of how vestibular dysfunction can impact recovery, even in a non-weight-bearing joint like the shoulder.

The study's findings confirm this objective by demonstrating that vestibular rehabilitation, when integrated into shoulder rehabilitation protocols, significantly enhances scapulohumeral joint function. Despite the lack of statistically significant correlations between DGI scores and joint position matching, the overall improvements in proprioception and joint function support the hypothesis that the vestibular system is crucial to the recovery process. These results advocate for a multidisciplinary approach that incorporates vestibular elements to optimize shoulder joint recovery and improve patient outcomes.

However, the study's limitations include a relatively small sample size, which may affect the validity and generalizability of the results. To strengthen these aspects, future studies should expand the sample size and include a control group to allow for more rigorous assessments of the effects of physiotherapy interventions. Additionally, controlling for potentially confounding variables, such as baseline severity of conditions and adherence to treatment protocols, is essential to ensuring more accurate interpretations of the results. Implementing a larger experimental design would facilitate direct comparisons of outcomes and provide a stronger foundation for drawing conclusions.

5. Conclusions

The results of our research demonstrate that integrating vestibular rehabilitation into shoulder recovery protocols significantly improves joint function. Bilateral physiotherapy interventions proved effective in restoring functional symmetry and proprioceptive perception. At the conclusion of the study, the initial significant differences between the affected and unaffected upper limbs became non-significant, suggesting a balanced and efficient recovery.

The study findings highlight the importance of a multidisciplinary approach that includes vestibular assessments and therapeutic interventions in scapulohumeral rehabilitation. The integration of vestibular and proprioceptive elements into orthopedic treatments contributes to improved motor function and reduced fall risk, positively impacting the quality of life of the subjects. This study provides new insights into the role of the vestibular system in scapulohumeral joint rehabilitation, offering a more comprehensive understanding of the interactions between different body systems.

These results are particularly relevant in the context of orthopedic rehabilitation, demonstrating the specific benefits of integrating vestibular rehabilitation into shoulder recovery treatments. The findings contribute to the existing literature, emphasizing the need for more comprehensive and personalized therapeutic strategies that address both the primary symptoms and underlying factors of orthopedic conditions.

Our research has several important limitations that should be considered. The relatively small sample size may influence the validity and applicability of the results. Additionally, baseline variability in the degree of orthopedic impairment and adherence to the treatment protocol are factors that could affect the interpretation of the results. Tighter control of these variables could provide a more accurate assessment of the effects of therapeutic interventions.

Validation and generalization of the results obtained in this study could be achieved by including an extended sample of subjects, distributed into control and experimental groups. It is necessary to explore the specific mechanisms through which the vestibular system influences scapulohumeral recovery and to develop personalized physiotherapy strategies accordingly. Additionally, investigating the long-term effects of integrating vestibular rehabilitation could provide valuable insights into the durability of the benefits obtained.

Benign Paroxysmal Positional Vertigo affects the vestibular system, which can lead to imbalances, sensory confusion, and compensatory strategies that compromise proprioception and movement control, even in a shoulder unaffected by an orthopedic condition. This phenomenon underscores the importance of including vestibular rehabilitation in treatment plans to ensure complete and effective shoulder function recovery, highlighting the systemic impact of BPPV on general motor control.

In conclusion, the results of the present research confirm the importance of integrating vestibular rehabilitation into shoulder rehabilitation treatments. The proposed multidisciplinary approach not only improves scapulohumeral joint function but also contributes to a more balanced and efficient recovery, reducing variability in results and increasing uniformity in rehabilitation improvements. These findings underscore the need for comprehensive physiotherapy strategies that include vestibular assessments and interventions.