"Accelerated postoperative rehabilitation protocol for Medial Open Wedge High Tibial Osteotomy enhances early return to routine activities"

Abstract

Objective

The primary objective of this research was to investigate the timeframe required for the resumption of daily activities following medial open wedge high tibial osteotomy (HTO) with accelerated rehabilitation protocol.

Method

ology: This study encompassed a cohort of 26 patients, consisting of 11 males and 15 females, all diagnosed with medial compartment osteoarthritis (grades 2 and 3). Each patient underwent medial open wedge HTO and was subsequently monitored for a minimum period of 8 weeks. Patients were advised to engage in early weight-bearing walking, with or without assistance, based on their comfort levels. The assessment of functionality involved the utilization of the Visual Analog Scale (VAS) score, Katz Index of Independence in Activities of Daily Living (ADL), and Lawton index, performed at intervals of postoperative day 1, 2 weeks, 4 weeks, 6 weeks, and 8 weeks.

Results

The average age of the patients at the time of surgery was 51.5 ± 7.2 years. The mean preoperative VAS score registered at 8.6, which exhibited a substantial reduction to 1.3 at the 8-week postoperative follow-up (p < 0.001). On average, patients were capable of walking with full weight-bearing without any external support at 6.9 weeks post-surgery. The initial preoperative Katz index was tabulated at 6, and within 6 weeks, all patients had successfully regained their pre-surgery functional levels, restoring the Katz index to its original value of 6. In addition, the mean Lawton index both before surgery and at the 8-week postoperative mark remained stable, with no significant variation (n.s.).

Conclusions

The immediate outcomes observed in knee preservation surgery are indeed promising. Within the 8-week timeframe, a majority of patients successfully reinstated their preoperative levels of independence, accompanied by a notable alleviation of pain.

1. Introduction

Knee osteoarthritis (OA) is a prevalent condition that impacts around 3.8 % of the worldwide population. Significantly, there is a rising prevalence of OA in the knee joint among individuals under 55 years of age.¹ For individuals in the advanced stages of OA knee, Total Knee Replacement (TKR) is a popular treatment option. However, despite the continuous advancements in arthroplasty procedures, patients under the age of 55 face a significant lifetime risk (ranging from 20 % to 35 %) of requiring revision arthroplasty.²

Isolated medial compartmental arthritis can be managed with two surgical approaches: HTO or UKR. UKR involves the replacement of only the medial compartment with a prosthesis and is typically more suitable for older individuals.³ In contrast, Medial Open-Wedge High Tibial Osteotomy (MOWHTO) is an accepted procedure, particularly for younger patients and those with high physical demands, aiming at "knee preservation".⁴ MOWHTO is primarily based on the notion of “knee preservation”.⁵ HTO is based on the concept of realigning the lower limb's mechanical axis, which helps redistribute weight, thereby reducing pain and improving function. This is especially beneficial for active young individuals, potentially postponing the need for prosthetic replacement.^6,7

While HTO is a knee-preserving surgery, it does come with a longer recovery period when compared to TKR or UKR. Nevertheless, HTO remains the preferred surgical choice for young OA knee patients due to its potential to delay the necessity for knee replacement. Concerns associated with MOWHTO include postoperative pain and an extended recovery period.⁸ However, it is important to note that there is a limited number of studies that thoroughly evaluate key factors such as the VAS, independence in ADL, and the resumption of work following HTO.^{9, 10, 11}

For active individuals living with osteoarthritis, a primary concern is the timing of their return to daily work activities after surgery. Therefore, the present observational study was designed to assess early postoperative pain, independence in ADL, and the prompt return to one's respective occupation with minimal discomfort, all achieved through an optimal early rehabilitation protocol.

2. Methods

A total of 27 knees in 26 patients (11 males and 15 females) with medial compartment osteoarthritis; Kellgren Lawrence (KL) Grade 2 and 3 with or without Anterior Cruciate Ligament (ACL) tear, aged between 30 and 60 years were included in this study.¹² Patients with any of the following conditions were excluded from the study: KL Grade 4 OA, bi/tri-compartmental OA knee, BMI >30 kg/m2, Varus >20°, Fixed flexion deformity >15°, or inflammatory arthritis. Written and informed consent was received from all the patients.

Functional assessment was done using VAS, Katz Index of Independence in ADL, and Lawton Instrumental ADL scale pre-operatively and post-operatively at day 1, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks.^{13, 14, 15}

3. Radiological assessment

Radiographic evaluation played a crucial role in our pre-operative planning procedures, involving the utilization of weight-bearing full limb-length X-rays. These X-rays were instrumental in assessing the degree of osteoarthritis based on the Kellgren-Lawrence classification.¹²

Our radiological assessment included various essential imaging parameters such as the Weight-Bearing Line (WBL), mechanical Lateral Distal Femoral Angle (mLDFA), Medial Proximal Tibial Angle (MPTA), and Joint Line Convergence Angle (JLCA). To determine the correction angle, we employed the Miniaci method.¹⁶ This method entails drawing the initial correction line, extending from the center of the hip through 62.5 % of the tibial plateau width (referred to as the Fujisawa point) and continuing beyond the ankle.¹⁷

In open-wedge osteotomy procedures, a hinge point is typically identified on the lateral proximal tibial metaphysis, positioned approximately 15 mm below the subchondral sclerosis zone of the lateral plateau and at the level of the proximal border of the tibio-fibular joint. The second line is drawn from this hinge point to the center of the ankle, while the third line connects the osteotomy hinge point to the arc intersection of the first line. The angle formed by the second and third lines represents the planned correction angle, denoted as alpha. This correction angle (alpha) is then projected onto the tibia, using the hinge point as a reference.

4. Surgical technique

Diagnostic and therapeutic arthroscopy was performed in every patient before MOWHTO to address the concomitant intra-articular lesions, which included meniscal tears, cartilage lesions on weight-bearing regions of the condyles, ACL tear, synovitis, and intra-articular loose bodies. These lesions were managed by meniscectomy/meniscus repair, micro-fracture, ACL reconstruction, debridement, and loose body removal, respectively. After performing therapeutic arthroscopy, a vertical incision of approximately 6–8 cm was made over the proximal aspect of the anteromedial tibia, centered over the pes anserinus. Following soft tissue dissection, the sartorius fascia was exposed and cut. The superficial part of the Medial Collateral Ligament (MCL) and hamstring tendons were carefully retracted away from the osteotomy site. Two parallel guide wires were then inserted, starting 3–4 cm distal to the medial joint line and directed toward the hinge point, guided by an image intensifier. The osteotomy was executed along these guide wires using an oscillating saw, with completion done using an osteotome under the guidance of an image intensifier. The osteotomy was intentionally limited to 1 cm medial to the lateral tibial cortex to create a lateral hinge.

Subsequently, the other limb of the biplanar osteotomy was performed behind the tibial tuberosity. This particular osteotomy, carried out in the coronal plane using a narrow saw blade and a thin osteotome, was designed to prevent any potential injury to the patellar tendon. The osteotomy was then systematically distracted with the assistance of a bone spreader, aligning it to the pre-operative correction angle under the guidance of an image intensifier. Verification of alignment was conducted using a metallic alignment rod placed on the weight-bearing line (WBL) from the center of the femoral head to the center of the ankle joint.

For stabilization, the osteotomy was fixed using a Tomofix plate and locking screws. Final confirmation of alignment was performed using a metallic alignment rod under the image intensifier.

5. Postoperative rehabilitation

Post-operative rehabilitation involves a multi-phase approach. Initially, patients participated in active knee Range of Motion (ROM) exercises and static quadriceps exercises right after the surgery. In contrast to the conventional rehabilitation protocol, which typically involves keeping patients non-weight or partially weight-bearing for 6–12 weeks,^18,19 We initiated partial weight-bearing with the support of a walker on the first postoperative day. Following two weeks, patients were encouraged to transition from partial to full weight-bearing, with the pace of progression determined by their pain tolerance. Over the subsequent weeks, weight-bearing was gradually augmented to enhance the patient's self-sufficiency in their everyday activities In contrast to the previous rehabilitation protocol, which advocated for assisted walking for a minimum of 3 months, contingent upon the union of osteotomy,¹⁹ our approach involves encouraging patients to walk unassisted as soon as they feel comfortable. No casts or braces were applied post-operatively, distinguishing our approach from previous studies where a knee brace or cast was typically provided for 6 weeks.^19,20

6. Statistical analysis

Statistical analysis was conducted utilizing IBM SPSS version 24.0 software (IBM Corp., Armonk, NY, USA). Continuous variables were assessed through mean, standard deviation, and range, while the two-sample t-test was employed for group comparisons. Categorical variables were described and analyzed using the chi-square test.

7. Results

A total of 27 knees in 26 patients, comprising 11 males (42.3 %) and 15 females (57.7 %), underwent MOWHTO along with therapeutic arthroscopy. The average age at the time of surgery was 51.5 ± 7.2 years, ranging from 35 to 61 years. Among the patients, 23 (85 %) had meniscal tears, with 20 of them (74 %) undergoing partial meniscectomy and three (11 %) receiving meniscus repair. In 20 patients (74 %), microfracture procedures were performed on the medial femoral and tibial condyles. Additionally, ACL reconstruction, chondroplasty, and the removal of loose bodies were conducted in six (22.23 %), one (3.7 %), and two (7.4 %) patients, respectively (see Table 1).

Table 1.

Demographic details of patients with procedures done.

1	Mean age	51.5
2	Male:Female	11:15
3	MOWHTO	27 (100 %)
4	Arthroscopic debridement	27 (100 %)
5	Partial Meniscectomy	20 (74 %)
6	ACL reconstruction	6 (22.2 %)
7	Microfracture	20 (74 %)
8	Loose Body Removal	2 (7.4 %)
9	Meniscus Repair	3 (11.1 %)
10	Chondroplasty	1 (3.7 %)

The average pre-operative VAS score was 8.56, which decreased to 1.34 at the 8-week (p-value = 0.001) follow-up (see Table 2). Patients no longer required oral NSAIDs as early as 4 days after the surgery, and they reported a VAS score of 3 (indicating mild pain) at an average of 9 ± 5.9 days without oral NSAIDs.

Table 2.

Short terms functional outcomes after medial open wedge high tibial osteotomy.

	Pre-op	Day 1	Week 1	Week 2	Week 4	Week 6	Week 8
VAS	8.56 ± 0.5	4.81 ± 0.86	3.29 ± 1.03	2.92 ± 1.07	2.22 ± 0.8	1.59 ± 0.69	1.34 ± 0.73
Katz index	6	3.4 ± 0.57	4.78 ± 1.01	5.92 ± 0.38	6	6	6
Lawton index	7.74 ± 0.65	2	2.96 ± 0.51	3.7 ± 0.67	5 ± 0.67	6.18 ± 0.73	7.92 ± 0.38

The mean pre-operative Katz index of ADL score was 6, signifying full function, and by the end of 4 weeks, all patients had attained a Katz index score of 6 (see Table 2). This achievement occurred at an average of 2.1 ± 1.1 weeks. The mean Lawton Instrumental ADL scale scores before and 8 weeks after the surgery were 7.7 and 7.9, respectively (n.s.). Patients reached a Lawton score of 8 (indicating high function) at an average of 7.9 ± 0.4 weeks.

On the first day after the operation, all patients were capable of partial weight-bearing with the aid of a walker. Fourteen patients (51.85 %) progressed to full weight-bearing with the walker, mainly for psychological reassurance, by the fourth week. By the eighth week, all patients had ceased using the walker. Among them, nine patients (33.33 %) regained the ability to walk independently without any support by the sixth week. Achieving full weight-bearing without the need for external support took place at an average of 7.0 ± 1.5 weeks. Patients returned to their respective workplaces, on average, at 7.4 ± 0.9 weeks.

8. Discussion

Knee osteoarthritis (OA) is a chronic joint condition with substantial implications for healthcare. It is characterized by the degradation of articular cartilage, the misalignment of the knee joint, synovial hyperplasia, and the formation of osteophytes. These factors contribute to pain, stiffness, deformity, and limited mobility.²¹ In recent years, MOWHTO has gained popularity for addressing medial compartment disease in young patients due to its various advantages, including the preservation of bone stock, avoidance of common peroneal nerve dissection, no requirement for fibular osteotomy, and the ability to facilitate multiplanar correction compared to closing wedge osteotomies.²² Importantly, MOWHTO can be more easily converted to TKR than closing wedge HTO.²³

When compared to UKR, MOWHTO offers superior pain relief, increased range of motion, better quality of life, restoration of Weight Bearing Line (WBL) resulting in the deceleration of disease progression, and improved conditions for cartilage repair following microfracture procedures.²⁴

Various studies have reported different postoperative weight-bearing protocols following MOWHTO, including the use of long leg casts and variable timelines for allowing full weight-bearing.^{25, 26, 27, 28} However, the present study advocates an early weight-bearing rehabilitation protocol following MOWHTO, which contradicts the common practice of extended immobilization. In a prior study, Ryohei et al. successfully implemented an early weight-bearing rehabilitation protocol, and notably, there were no reported cases of implant failure, loss of correction, or non-union.⁸

Patients in this study who had pre-operatively taken oral NSAIDs for medial compartmental OA, with a mean VAS score of 8.6 ± 0.5, experienced a significant reduction in the need for post-operative NSAIDs. This reduction was due to MOWHTO off-loading the medial compartment, resulting in even weight distribution across the articular surfaces, which led to a VAS score of 3 (indicating mild pain) at a mean of 8.96 ± 5.94 days post-surgery without the use of oral NSAIDs.

The study evaluated patients' independence in performing daily activities using the Katz Index of Independence in Activities of Daily Living and the Lawton Instrumental Activities of Daily Living scale. The Katz Index measures six functions related to daily living, and a score of 6 indicates full function. In this study, patients achieved a Katz score of 6 at 2.1 ± 1.1 weeks. The Lawton scale evaluates more complex daily activities and a score of 8 indicates high function. In this study, patients reached a Lawton scale of 8 at 7.9 ± 0.4 weeks. Studies that adhered to the standard rehabilitation protocol of six weeks of non-weight/partial weight bearing reported varying mean times to return to their respective work, ranging from 12.7 to 16.7 weeks..^29,30 Cezary et al. employed an accelerated rehabilitation (early weight-bearing) and found that the mean time to return to work was 2.6 months.³¹

The accelerated rehabilitation protocol employed in this study allowed patients to achieve full weight bearing as early as 2 weeks (mean 4.7 ± 1.3 weeks) with support and 4 weeks (mean 7.0 ± 1.5 weeks) without support. Furthermore, it empowered patients to regain mobility and return to their respective professions swiftly. Kim et al. documented that patients undergoing high tibial osteotomy (HTO) took 6.2 months to achieve unassisted walking with a standard rehabilitation protocol.³² In contrast, Moris et al. reported a mean time for unassisted weight-bearing walking was 55 days with an early weight-bearing protocol.¹¹ In their comparative study, Schroter et al. advocated for the early weight-bearing rehabilitation protocol, noting that the functional scores at 6 months were significantly superior in the early weight-bearing group compared to the partial weight-bearing group.¹⁰

While there are concerns associated with early weight bearing like tibial plateau fractures, implant failure, loss of correction, lateral hinge fractures, compartment syndrome, and infections, this study did not encounter such complications despite the early weight-bearing rehabilitation protocol.

The findings of this study strongly support the adoption of an early weight-bearing rehabilitation protocol. However, it is important to acknowledge certain limitations, including the observational nature of the study rather than a comparative design, a relatively small sample size, and a lack of medium and long-term follow-up.

9. Conclusions

The short-term results of knee preservation surgery are encouraging; by the end of 8 weeks, most patients achieved pre-operative independence levels with significant improvement in pain.

Ethical approval

It was an observational study, and ethical approval was not necessary.

Consent

Written Informed Consent was obtained from all patients.

Consent of publication

Consent of publication is given by all authors.

Authors contributions

Ravi Gupta- Primary surgeon and structured the manuscript.

Vishal Dudeja- Data collection.

Himanshu Bansal-manuscript writing.

Anil Kapoor-manuscript writing, study design planning and data analysis.

Sources of funding

This case has no funding resources.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.