Post operative knee stiffness after surgical fixation of knee osseous injuries

INTRODUCTION

It is observed that following surgical fixation of knee osseous injuries, patients may develop varying degrees of post-operative knee stiffness (POKS). The influence of POKS on an individual’s function is worse in the knee joint when compared to the ankle, elbow, and wrist joints.^[1] For instance, good function is observed in the stiffness of the ankle and wrist, yet in the knee joint, post-operative stiffness affects the occupational, daily, and leisure activities more negatively. This influence depends on the degree of POKS.^[1,2]

Furthermore, controversies in the literature exist on the association between several factors with the severity of POKS.^[1,3,4] For example, Bishop et al. showed an association between time from injury to surgery with the severity of POKS,^[1] a finding that was disputed by Wang et al.^[4]

The lack of knowledge on POKS and its associated factors hinders its identification, complicates its treatment and rehabilitation, and, at the same time, impairs the patient’s ability to perform activities of daily living, thus affecting their quality of life.

Therefore, against this background, this study aimed at assessing the severity of POKS after surgical fixation of knee osseous injuries and evaluating its associated factors; our findings may be useful in the identification, prevention, and rehabilitation of POKS.

MATERIAL AND METHODS

This hospital-based cross-sectional study was conducted for 6 months among 115 patients.

RESULTS

Of the 115 patients, 90 had varying degrees of POKS, with severe and extreme cases being the most common [Table 1]. Severe POKS was the median severity category. Flexion limitation was present in 39 (43.3%) patients, extension limitation was present in 15 (16.7%), and combined limitations were present in 36 (40%) patients. For distal femur fractures, 34 patients had flexion limitations, four had extension limitations, and three had combined limitations.

For proximal tibia fractures, 19 patients had extension limitations and 17 patients had flexion limitations. Twelve patients with patella fractures presented with extension limitation as opposed to flexion and combined limitations. For combined lower limb injuries, two patients had limitations in extension and flexion, and seven had combined limitations.

At bivariate ordinal logistic analysis, the factors that were significant included: Age (years), using external fixators and K-wires/cerclage as the type of implant, cigarette use, time from injury to surgery, and adherence to physiotherapy [Table 2]. At multiple ordinal logistic regression, adherence to physiotherapy, cigarette use, and time from injury to surgery >2 weeks were statistically significant [Table 3].

DISCUSSION

POKS is a well-recognized complication following surgical fixation of knee osseous injuries.^[2,5,6] In this study, 78.3% of the patients assessed between 6 months and 2 years after surgery exhibited varying degrees of POKS. The functional impact of POKS is directly related to its severity, and as highlighted by Robertson et al.,^[7] the functional consequences of POKS also depend on patient activity levels.^[8] The similarities in the distribution and severity of POKS found in this study align with findings from other research, such as that by Wang et al.,^[4] and Mangone.^[6] This may be attributed to multiple factors, including variations in surgical techniques and the surgeon’s experience.

The type of movement limitation observed varied by fracture location. Flexion limitations were more common in distal femur fractures, while extension limitations were frequent in proximal tibia and patella fractures. These findings align with previous studies by Lara et al.^[9] and Vaish et al.^[10] and may be influenced by surgical techniques and implant types.

For example, retrograde nails are associated with posterior angulation and flexion deficits, while plating systems such as distal femur locked plates allow for better control of joint alignment.^[11,12] Conflicting findings in a study by Xing et al.^[13] reported different outcomes in patella fractures, may be due to smaller sample sizes or different fixation methods.

This study found that adherence to physiotherapy significantly reduced the severity of POKS, with adherent patients being 72% less likely to fall into higher severity categories. These results are consistent with previous studies by Kumar et al.,^[2] Sharma et al.,^[14] and Ono et al.^[15] which highlighted that physiotherapy supports joint mobility by promoting collagen remodeling, regulating inflammation, reducing pain sensitization, and preventing disuse.

Cigarette use was significantly associated with increased severity of POKS, with smokers being 3 times more likely to develop higher severity categories. This aligns with findings by Lara et al.^[9] Cigarette smoking contributes to POKS severity through multiple mechanisms, including reduced tissue oxygenation due to vasoconstriction^[16] heightened systemic inflammation promoting fibrosis,^[17] and impaired cellular healing responses. In addition, smokers often exhibit lower adherence to physiotherapy, compounding the risk of joint stiffness.^[18] The study also found that patients who underwent surgical fixation more than 2 weeks after injury were significantly more likely to develop severe POKS. The delay increases the risk of fibrosis, inflammation, and joint contractures, limiting mobility. While literature on the timing of surgery is mixed, differences in study definitions and surgical techniques likely explain inconsistencies.^[10,11,17]

To ensure accuracy and consistency, a standard digital goniometer was used for measuring knee joint range of motion, with all measurements conducted by the Principal Investigator to reduce variability. Research assistants underwent pre-study training covering recruitment procedures, data collection, and consent processes to standardize assessments. This study had limitations, as a cross-sectional design, it could not establish causality and was prone to recall bias due to reliance on self-reported data, and it did not account for the severity of the initial injury, which likely influenced POKS outcomes.

CONCLUSION

This study revealed a substantial variation in the severity of POKS among adults following surgical fixation of knee osseous injuries, and a notable proportion of patients experienced severe or extreme grades of POKS. Three factors were identified as independent predictors for the development of severe or extreme POKS, namely, non-adherence to prescribed physiotherapy protocols, delayed surgical fixation, defined as surgery performed more than 2 weeks post-injury, and cigarette smoking.

Targeted interventions addressing these risk factors may play a role in improving post-operative recovery and long-term joint function.