Evaluation of Biodegradable Temporizing Matrix for Functional and Aesthetic Outcomes in Hand Soft-tissue Defect: A 3-year Retrospective Study

Abstract

Background:

Hand soft-tissue defects compromise both function and aesthetics, significantly impacting quality of life. Traditional reconstructive techniques frequently lead to complications, such as donor-site morbidity and suboptimal aesthetic outcomes. The NovoSorb biodegradable temporizing matrix (BTM) may address these challenges by promoting tissue ingrowth. This study evaluates BTM’s effectiveness in managing hand soft-tissue defects.

Methods:

A retrospective cohort study was conducted on 67 patients who underwent BTM placement for hand soft-tissue defects from July 2020 to May 2024. Data were collected on patients’ demographics, wound size, cause of injury, time to tissue integration, postoperative complications, and clinical outcomes. Functional outcomes were assessed using range of motion and grip strength, whereas aesthetic outcomes were evaluated using the Patient and Observer Scar Assessment Scale (POSAS). Descriptive and correlational analyses explored the relationship between wound size, return to work, and outcomes.

Results:

Among the 67 patients (58 men, 9 women; mean age 43.3 y), 97% achieved successful BTM integration, with only 2 cases of failure due to poor vascularity. The mean range of motion for metacarpophalangeal joints was 76.17 degrees, and grip strength averaged 21.3 kg. Functional outcomes, based on the Finger Injury Outcome Score, were good to excellent in 58.2% of cases. Aesthetic outcomes were generally favorable, with a mean POSAS observer score of 3.58. The correlation between wound size and return to work was weak (r = 0.132).

Conclusions:

NovoSorb BTM appears to be a promising alternative for managing complex hand injuries, providing both functional and aesthetic benefits with minimal complications.

Takeaways

Question: Can biodegradable temporizing matrix (BTM) serve as an alternative to traditional reconstructive methods in hand injuries, for clinical efficacy and patient satisfaction?

Findings: A retrospective cohort study of 67 patients who underwent BTM for hand soft-tissue defects was conducted. The average grip strength was 21.3 kg. Finger Injury Outcome Score was good to excellent in 58.2% of cases. Favorable aesthetic outcomes were achieved, with an average POSAS observer score of 3.58.

Meaning: NovoSorb BTM is an effective alternative for managing hand injuries, providing functional and aesthetic benefits.

INTRODUCTION

Hand soft-tissue defects pose significant challenges due to the hand’s complex role in both mechanical function and aesthetic appearance. These injuries significantly impact the quality of life and may also lead to psychological distress due to altered appearance.¹ Managing such defects is fundamental to reconstructive surgery, with techniques ranging from simple skin grafts to microsurgical free tissue transfers. However, these approaches often come at a cost—donor site morbidity, prolonged surgical and recovery times, and aesthetic limitations.²

NovoSorb biodegradable temporizing matrix (BTM) has emerged as a different solution for soft-tissue defect management. BTM is a synthetic dermal template designed to facilitate tissue regeneration while gradually biodegrading, potentially reducing the need for more invasive surgery.³ It is composed of biodegradable, 2-mm-thick polyurethane foam and nonbiodegradable polyurethane seal. The biodegradable component facilitates vascularized neodermis formation, supports split-thickness skin grafting, and mitigates wound contraction during remodeling. The nonbiodegradable part prevents water loss and minimizes infection risk, distinguishing it from collagen-based scaffolds. Following vascular integration, the sealing membrane is removed, exposing the foam for subsequent graft application.⁴ Early evidence suggests that BTM can provide satisfactory functional recovery with favorable aesthetic outcomes, but comprehensive data, in the context of hand reconstruction, remain limited.

Synthetic skin substitutes, such as Suprathel and BTM, are increasingly used in hand and upper extremity reconstruction for their ability to reduce donor site morbidity and infection rates. Galati et al⁵ suggested that Suprathel reduces donor-site complications and dressing-change pain but has limitations such as prolonged healing time and increased hypertrophic scarring risk. BTM demonstrated in small-scale studies offers advantages such as faster healing, reduced need for grafting, and excellent functional outcomes, particularly in tendon injuries. However, current research on both substitutes is limited by small sample sizes, short follow-up periods, and a lack of randomized controlled trials.^6,7 Although BTM shows promise as a superior option in complex wounds, particularly for tendon mobility, further multicenter and hand-specific studies are required to validate these findings and address gaps in the literature. Future studies should focus on larger patient cohorts and longer follow-up periods.

This study seeks to address the gaps in the literature by evaluating the use of BTM for hand soft-tissue defects, focusing on both functional recovery and aesthetic outcomes. Through this analysis, we aimed to determine whether BTM can serve as a viable alternative to traditional reconstructive methods in hand surgery.

METHODS

This retrospective cohort study was conducted after obtaining institutional research board approval (National Healthcare Group Domain Specific Review Board Reference number 2023/00968). The retrospective design was chosen to leverage existing patient data and evaluate BTM outcomes in a real-world clinical setting.

Patient Selection

A total of 67 patients underwent BTM placement for hand soft-tissue defects between July 2020 and May 2024. Patients were included if they had soft tissue defects measuring more than 100 mm², no contraindications to surgery, and were able to attend follow-up visits for at least three months postsurgery. Patients with severe systemic comorbidities or preexisting hand conditions that could interfere with wound healing were excluded.

BTM Application and Surgical Technique

The BTM was applied to the defect site after surgical debridement. It was secured using Monocryl 5/0, with a tie-over dressing of Flavin-soaked cotton balls, secured with Ethilon 5/0. The tie-over was removed on postoperative day 5. Weekly wound care with nonadhesive dressings was provided until complete tissue integration. In 6 cases, a split-thickness skin graft (STSG) was applied over the BTM after delamination of the sealing membrane. The remaining patients healed by secondary intention.

Data Collection

Data on patients’ demographics, defect size and cause of injury, and postoperative outcomes were collected. Functional outcomes were assessed through range of motion (ROM) measurements of the metacarpophalangeal (MCPJ), proximal interphalangeal (PIPJ), and distal interphalangeal joints (DIPJ), as well as grip strength of both hands. Complications, including BTM integration failure, were also documented.

Outcome measures: functional outcomes were primarily evaluated using the Finger Injury Outcome Score (FIOS),⁸ which grades function based on ROM, grip strength, and hand function during daily activities. Aesthetic outcomes were assessed with the overall score of the observer component of the Patient and Observer Scar Assessment Scale (POSAS) V2.0.⁹ Both functional and aesthetic assessments were conducted at the patient’s final follow-up visit, approximately 91.12 days postsurgery.

Statistical Analysis

Descriptive statistics were used to summarize patient demographics, defect characteristics, and clinical outcomes. Paired t tests were used to compare pre- and postoperative ROM and grip strength. Pearson correlation coefficients were calculated to assess the relationship between wound size and clinical outcomes, including return-to-work time, functional scores, and scar assessments. Statistical significance was set at a P value less than 0.05. The statistical analysis of this research was performed using IBM SPSS Statistics version 29.

RESULTS

Demographics

The study cohort included 67 patients, with a male-to-female ratio of 6.4:1 (58 men, 9 women) and an average age of 43.3 years (SD = 15.7). The average wound size was 864.73 mm² (SD = 2543.50 mm²), with a range of 100–20,800 mm².

Cause of Injury

Traumatic injuries accounted for 91%. Surgical resections of finger lumps accounted for 3%, and soft-tissue infection accounted for 6%. Forty-three cases involved fingertip injuries with composite tissue loss, including 26 cases with exposed bone. Fourteen patients had injuries of the palmar or dorsal aspect of the finger with exposed tendons or the neurovascular bundle. Five of those 14 patients were associated with tendon injury and neurovascular bundle injury. Three cases of the defect were after multiple debridement of infection, 2 cases were finger abscesses, and 1 was a hand abscess. Two cases of the defect were after the excision of finger lump over the palmar aspect with exposed flexor tendon. Two cases were soft-tissue defects over first webspace. One case had a soft-tissue defect over the volar and dorsum of the wrist caused by chemical burn. One case had a soft-tissue defect over the volar aspect of the forearm following forearm abscess debridement and fasciotomy. (See table, Supplemental Digital Content 1, which shows the patients’ demographics, site and size of defect, and mechanism of injury, https://links.lww.com/PRSGO/E141.)

All defects were covered with BTM. In 6 cases, STSGs were used for coverage on top of integrated BTM after delamination of the sealing membrane. In the rest of the cases, healing was by secondary intention after delamination. The mean healing time was 68.65 days (SD = 25.98) from the time of injury.

According to the FIOS, 34.3% of patients achieved “good” outcomes, 23.9% had “excellent” outcomes, and 6.0% had “fair” outcomes. A “good” or “excellent” FIOS score indicates near-complete functional recovery, with only minor limitations in daily activities.

Aesthetic Outcome

Aesthetic outcome was evaluated using the overall score of the observer component of POSAS, where lower scores indicate better outcomes. The average observer score for scar quality was 3.58 (SD = 1.07) on a scale of 1–10, suggesting that most patients had acceptable to good cosmetic results.

There is a significant difference in the FIOS, indicating that men had better outcomes compared with women (P = 0.045). For the other variables, including age, follow-up period, return to work, POSAS, wound area, grip strength, MCPJ range, PIPJ range, and DIPJ range, the P values are greater than 0.05, indicating no statistically significant differences between men and women. These results suggest that although there are some differences in finger injury outcomes between sexes, most other clinical and demographic variables are comparable between men and women in the dataset, as shown in Table 1. The Mann-Whitney U tests were used to identify any statistically significant differences between the two groups. High variability, as indicated by a large SD, may suggest potential deviations from normality, making it important to conduct a normality test to determine the appropriate statistical method. Hence, a normality test is required to confirm whether the data meet the assumption of normality as presented in Table 2. Nonparametric methods were used in this analysis because the data did not follow a normal distribution. To determine whether the data is normally distributed, normality tests using Kolmogorov–Smirnov and Shapiro–Wilk tests were conducted. When data are nonnormally distributed, traditional parametric tests (eg, t tests, Pearson correlation) may produce misleading results due to their reliance on assumptions such as normality of the data and homogeneity of variances. Nonparametric tests do not require these assumptions, making them more appropriate for analyzing nonnormal data, and allowing for more reliable and valid conclusions, especially in small or skewed samples. The test results showed that the majority of variables, including age, follow-up period, return to work, FIOS, POSAS, wound area, MCPJ range, and PIPJ range, are not normally distributed (P < 0.05 for both Kolmogorov–Smirnov and Shapiro–Wilk tests). Grip strength and DIPJ range are approximately normally distributed (P > 0.05 for both tests).

Table 1.

Demographic Characteristics and Descriptive Statistics of Study Participants

	Total				Male			Female			Male vs Female
Variable	N	Median	IQR	SEM	N	Median	IQR	N	Median	IQR	Mann-Whitney U P
Age, y	67	39.00	31.00–53.00	1.919	58	38.00	31.00–53.00	9	49.00	32.00–61.50	0.320
Follow-up period, d	67	72.00	55.00–111.00	7.473	58	80.50	54.25–111.25	9	62.00	53.00–130.00	0.804
Return to work, d	67	68.65	55.00–75.00	3.174	58	68.65	55.00–85.00	9	68.66	52.50–69.33	0.592
FIOS	43	14.00	12.00–17.00	0.470	41	15.00	12.00–17.00	2	10.50	10.25–10.75	0.045*
POSAS	19	4.00	3.00–4.00	0.246	12	3.50	2.25–4.00	7	4.00	3.00–5.00	0.379
Wound area, mm2	67	400.00	230.00–600.00	310.738	58	387.50	245.00–600.00	9	400.00	187.50–979.50	0.956
Grip strength	37	19.40	13.10–30.15	0.985	33	21.30	14.26–31.70	4	12.00	8.35–17.15	0.074
MCPJ Range	64	80.00	70.00–85.00	1.842	57	80.00	72.50–85.00	7	70.00	40.00–85.00	0.175
PIPJ range	64	85.00	60.00–91.50	2.701	57	85.00	62.50–91.00	7	90.00	40.00–95.00	0.896
DIPJ range	53	40.00	26.50–60.00	2.924	46	42.00	27.25–60.00	7	30.00	10.00–35.00	0.123

^*P < 0.05.

IQR, interquartile range from 25% to 75%.

Table 2.

Test Statistic Computed by the Kolmogorov–Smirnov and Shapiro–Wilk Tests for Normality test

	Kolmogorov–Smirnov			Shapiro–Wilk
Variable	N	S	P	N	S	P
Age, y	67	0.131	0.006	67	0.930	<0.001
Follow-up period, d	67	0.182	<0.001	67	0.786	<0.001
Return to work, d	67	0.165	<0.001	67	0.931	0.001
FIOS	43	0.149	0.018	43	0.946	0.043
POSAS	19	0.232	0.008	19	0.873	0.016
Wound area, mm2	67	0.382	<0.001	67	0.229	<0.001
Grip strength	37	0.079	0.200	37	0.964	0.273
MCPJ range	64	0.187	<0.001	64	0.859	<0.001
PIPJ range	64	0.208	<0.001	64	0.865	<0.001
DIPJ range	53	0.109	0.165	53	0.976	0.370

S, test statistic.

Complications

Postoperative complications were minimal, with only 2 (3%) cases of failed BTM integration. One failure was attributed to poor vascularity following a traumatic amputation, whereas the other occurred in a burn injury case. Both patients required additional surgical interventions, including terminalization and the use of a thenar flap. Three patients were lost to follow-up. No cases required revision of the procedure after coverage apart from the 2 failed cases.

Correlation Analysis (Nonparametric)

The correlation between wound area, return to work, FIOS, and POSAS was explored using the Spearman rank correlation. The sample size varied between analyses, ranging from 67 for wound area and return to work, to 43 for FIOS, and 19 for POSAS as in Table 3. The following is a summary of the key findings from the analysis.

Table 3.

Spearman Correlation Coefficient Between Wound Area, Return to Work, FIOS, and POSAS

Test Type	Variables	Correlation Coefficient	P	Interpretation
Spearman correlation	Wound area vs time to return to work	0.224	0.069	Not statistically significant. Weak positive relationship
	Wound area vs POSAS	0.206	0.397	Not statistically significant. Weak positive relationship
	Wound area vs FIOS	0.248	0.108	Not statistically significant. Weak positive relationship

Based on Dancey and Reidy,¹⁰ a correlation coefficient of the range of 0.20–0.29 represents a weak relationship, which can apply to both positive and negative correlations.

Correlation between Wound Area and POSAS

The Spearman correlation coefficient between wound area and POSAS was 0.206, indicating a weak positive correlation.

The P value was 0.397, which is not statistically significant at the 0.05 level. This suggests that the correlation between wound area and POSAS could be due to chance.

The small sample size (N = 19) limits the power of this analysis and may contribute to the lack of significance.

Correlation Between Wound Area and FIOS

The Spearman correlation coefficient between wound area and FIOS was 0.248, also indicating a weak positive relationship.

The P value was 0.108, which again is not statistically significant. This means that the weak positive trend observed may not represent a meaningful association.

The sample size for this analysis was 43, which is moderate but may still be insufficient for detecting significant correlations in the presence of high variability.

Correlation Between Wound Area and Return to Work

The Spearman correlation coefficient between wound area and return to work was 0.224, indicating a weak positive correlation.

The P value was 0.069, which is not statistically significant at the conventional 0.05 threshold. However, it suggests a trend toward significance that may warrant further exploration, especially with a larger sample size.

The sample size was 67, and although this is larger than the other analyses, the high SD observed in the dataset could still be a factor in the lack of statistical significance.

Overall Interpretation

Across all three analyses, weak positive correlations were observed between wound area and the outcome measures, namely the POSAS, FIOS, and time to return to work. However, none of these correlations reached statistical significance. Several factors may explain this lack of significance. First, the small sample sizes, particularly for the POSAS and FIOS subgroups, limited the statistical power and reduced the likelihood of detecting meaningful associations. Second, high variability in the clinical measures, as reflected by large standard deviations, may have further masked potential relationships. Lastly, unmeasured confounding factors, such as variations in treatment modalities or individual patient characteristics, could have influenced the outcomes and introduced additional bias.

Cost Analysis

Under the same table code charge for comparing the cost of the application of BTM for hand injuries under local anesthesia and STSG for the same injuries under general anesthesia, both procedures had nearly the same cost. Given the fact that BTM procedures include the cost for the implant as compared with STSG, which does not have implant cost, the difference between the latter, done under general anesthesia, and the former, done under local anesthesia, brings both procedures to nearly the same cost. We mainly use size 50 × 50 mm. As regards the cost of the product itself, in our hospital, we have compared the cost of BTM with other available dermal substitutes. The cost is 2.67% cheaper than one of the biological dermal substitutes of the same size and 25.14% more expensive than the other biological one. The latter is only available in 30 × 70 mm size, so maybe this could make the difference in price. The synthetic dermal substitute is available in 100 × 125 mm, so BTM is not the same size; therefore, it is cheaper by 298.18%.

Examples of Use Case

Case 1

The male patient is 61 years of age and right-handed and works in construction. The left middle finger was crushed by a concrete slab while moving it. The patient underwent wound debridement and coverage with BTM. After 1 month from the first surgery, the patient underwent coverage with an STSG on top of BTM after delamination of the sealing membrane. Clinical photographs of the wound and outcome are shown in Figure 1.

Fig. 1.

Clinical photographs of case 1. A, Defect size 20 × 30 mm, (B) after application of BTM, (C) after removal of the sealing membrane, and (D) after STSG on top of BTM.

Case 2

Case 2 is a 60-year-old female patient, a right-handed music teacher who plays piano and violin. A fall while hiking overseas resulted in a laceration of the left index finger. Initial wound debridement and primary closure were done overseas. The patient presented with a left index finger flexion deformity, as shown in Figure 2. The patient underwent wound debridement and coverage of the defect by BTM. Figure 3 shows the patient’s injury and the aesthetic and functional outcome after coverage with BTM and healing by secondary intention.

Fig. 2.

Case 2: patient's left index finger injury preoperatively.

Fig. 3.

Case 2: injury and outcome after coverage with BTM and healing by secondary intention. A, 10 × 20 mm skin and soft-tissue defect. B, After application of BTM, (C) after delamination of sealing membrane, and (D) 24 weeks postoperative.

Case 3

Case 3 is a male patient, 48 years of age, right-handed, with a medical history of uncontrolled diabetes mellitus and gout. The patient was admitted for right forearm swelling. Magnetic resonance imaging was done, and it revealed a collection in the right forearm and hand. The patient underwent fasciotomy and multiple debridements. Figure 4 shows the post forearm compartment syndrome fasciotomy soft tissue defect, coverage with BTM (patient opted for noncomplex reconstruction), and healing by secondary intention.

Fig. 4.

Post forearm compartment syndrome fasciotomy soft tissue defect: (A) defect size 260 × 80 mm, (B) After application of BTM, (C) after removal of the sealing membrane, (D) 10 weeks postoperative, defect size 150 × 30 cm, and (E) 19 weeks postoperative.

DISCUSSION

The results of this study suggest that BTM is a promising alternative for managing hand soft tissue defects. The study demonstrated a high success rate, with 97% of patients achieving successful BTM integration, and minimal complications. Functional outcomes were particularly encouraging, with 58.2% of patients achieving good to excellent recovery, based on the FIOS. Aesthetic outcomes, as measured by the POSAS, were also favorable, with an average overall observer score of 3.58, indicating acceptable scar quality in most patients.

We opted not to perform a second skin graft procedure in most cases, reducing the number of surgical procedures required. This approach did not negatively affect functional or aesthetic outcomes, as evidenced by the favorable results in both domains. We postulate that the rich vascularity of the hand may contribute to the successful healing of soft-tissue defects without the need for additional grafting. This may allow for faster recovery and fewer complications, particularly in hand reconstruction, where vascular support plays a crucial role in tissue integration.

Comparison With Existing Literature

These findings are consistent with prior studies evaluating BTM for upper extremity wounds. Cheng et al⁶ and Wu-Fienberg et al⁷ reported good functional recovery and minimal complications in their case series of patients treated with BTM. However, although these studies focused on upper extremity wounds in general, this study provides more specific data on hand soft-tissue defects, offering new insights into the utility of BTM in hand reconstruction. Notably, the low complication rate observed in this study is consistent with findings from Jou et al,¹¹ who also reported minimal complications with BTM in patients with complex hand injuries.

In contrast to synthetic substitutes like Suprathel, which have been associated with longer healing times and higher risks of hypertrophic scarring,⁵ BTM appears to provide faster healing with fewer complications. This makes BTM a particularly attractive option for hand defects, where aesthetic outcomes are critical and functional recovery is essential.

Clinical Implications

These findings have important implications for clinical practice. The ability of BTM to facilitate tissue integration with minimal complications suggests that it could be a valuable tool in the management of hand soft-tissue defects, particularly in patients where donor-site morbidity is a concern. Given its favorable functional and aesthetic outcomes, BTM may be especially suitable for use in patients with large or complex wounds, or those with comorbidities that limit the use of traditional reconstructive techniques. Additionally, the low incidence of complications makes BTM a safer option in high-risk patients.

Limitations and Future Research

Despite these promising findings, this study has several limitations that should be addressed in future research. The retrospective design introduces potential biases, including selection bias and incomplete data collection, and the relatively small sample size limits the generalizability of the results. Furthermore, the short follow-up period (91.12 d on average) may not capture long-term outcomes, including late complications or the durability of functional recovery. Last but not least is the lack of a control group.

Future studies should adopt a prospective design with extended follow-up periods to assess the long-term efficacy of BTM in hand reconstruction. Additionally, a comprehensive cost analysis is warranted to evaluate its economic impact. The inclusion of a control group and comparative study with other types of dermal substitutes would make further research more robust. Larger, multicenter trials are also necessary to validate these findings across diverse patient populations. Additionally, randomized controlled trials comparing BTM with other synthetic skin substitutes could provide more definitive evidence of its comparative effectiveness.

CONCLUSIONS

This study provides strong evidence that BTM is highly effective in hand reconstruction. With a 97% success rate and minimal complications, BTM offers reliable tissue coverage and facilitates favorable functional and aesthetic outcomes. The majority of patients achieved good-to-excellent functional recovery, and scar quality was rated as acceptable to good, highlighting the matrix’s ability to balance both functional and cosmetic results.

The findings suggest that BTM has the potential to serve as a valuable alternative to traditional reconstructive methods, especially in complex cases. Its ability to support tissue integration and healing with minimal risk of complications presents a promising option for reconstructive surgery.

DISCLOSURES

The authors declare that the publication fees for this article are being sponsored by Polynovo, the company that manufactures Novosorb BTM. Although Polynovo has provided financial support for the publication, the company had no role in the study design, data collection, analysis, interpretation, or in the decision to publish the results. The authors maintain full responsibility for the content and findings presented in this article, and all conclusions are based solely on the scientific evidence derived from the study. None of the authors receive any payments from Polynovo.