Gait, Function, and Strength Following Lower Limb Salvage Surgery for a Primary Malignant Bone Tumor: A Systematic Review
Authors: Nashed Joy , Sundaresh Akshita , Laurie Colin , Page Carolyn , Hines Claire , Ong Su Ming , Black Susie , Heywood Sophie 
Published: June 2022

Background:
Primary malignant bone tumors are a rare form of cancer, treated with limb salvage surgery (LSS), which includes sacrifices of muscle and bone.

Purpose:
To systematically appraise outcomes of gait, physical function (including dynamic balance, transfers, sit-to-stand, and stair climbing) and muscle performance related to the trunk and lower limb in current literature for individuals who have undergone LSS due to a primary bone tumor.

Data Sources:
Medline, Cochrane, and PEDro databases were searched from inception to June 2020.

Study Selection:
Following PRISMA guidelines, articles were screened by 2 reviewers independently (J.N. and C.H.) to determine eligibility based on population of interest (adults who have had LSS) and outcomes (gait, trunk, and lower limb physical function or muscle performance). Discrepancies were resolved with a third reviewer until a mutual consensus was reached (S.H.).

Data Extraction:
Data on gait, function, and muscle strength were extracted and grouped based on the surgical location (ankle, proximal tibia, distal femur, proximal femur/hip, or pelvic region).

Data Synthesis:
Data were extracted into tables and grouped first based on participants' surgical site and then based on a domain of outcomes (individual or mean group results for gait measures, strength, balance, use of walking aids, or ability to complete a task such as balance or stairs).

Results:
One thousand four hundred and forty-five abstracts were screened with 32 studies (354 participants) included in the review. Gait speed was reported in 16 studies and use of walking aids reported in 14 studies; these were the most reported outcomes in the review. Knee extensor strength was reported in 6 studies. Following internal hemipelvectomy surgery, 42% of participants ambulated without a walking aid and gait speed was reported as 0.61 to 1.6 m/s. For those who underwent surgery at the hip, 71% ambulated independently with an average gait speed of 0.94 to 1.20 m/s. Of participants who underwent surgery at the knee, 89% ambulated independently with an average gait speed of 0.36 to 1.32 m/s. Following knee LSS, knee extensor strength of the operated limb varied from 2% to 84% compared with the nonoperated side. Physical function outcome measures that were reported in the studies included the Timed Up and Go (TUG), single-leg balance and stair climbing. Two studies reported the TUG for participants who underwent LSS at the knee and 1 study for participants who underwent LSS at mixed locations on the lower limb. Single-leg balance and stair climbing were both reported in the same study on participants who had undergone LSS at the ankle.

Discussion:
Approximately 50% of people following hemipelvectomy surgery required a walking aid, with majority of the participants (58%) displaying a gait speed less than 1.1 m/s. Conversely, few people who underwent LSS at the knee and ankle required the use of walking aids. Knee and ankle-related LSS may more likely lead to independent ambulation when compared with surgical procedures at more proximal locations on the lower limb or pelvis. Gait speed is a relevant outcome and was most commonly reported in these participants. Muscle strength in participants varied widely, and physical function was not often measured, limiting insights into these domains.

Limitations:
Large variability in age, time since surgery, and surgical techniques across patients as well understanding of participants' comorbidities were limitations.

Conclusions:
Following internal hemipelvectomy surgery, individuals generally have greater functional limitations in gait independence and speed when compared with more distal surgical locations. Further investigation of other functional activities such as sit-to-stand and stair climbing in subacute timeframes is required.